Transcript for:
Core Computing Concepts

today we are going to be looking at what affects the performance of the CPU So first of all we need to understand what is the CPU So CPU stands for central processing unit and that's a common mistake that people make that because people often think that the C stands for computer but we know that it doesn't stands for central and they they can ask that on your exam they might sometimes get you to fill in the gaps in the blanks things like that And you don't want to fill in one of those wrong because it's a very easy mark that you don't want to lose Okay So in terms of what the CPU actually does well it it actually does billions of what we call the fetch decode execute cycle And we're going to go into more detail about that in just a moment Now in terms of where these instructions come from they can come from input devices like your mouse or your keyboard for example or it could be program instructions So the the the open programs that you've currently got running How do the CPU and RAM work together now I've put in brackets their main memory because RAM is main memory and you can use those terms interchangeably in your exam It doesn't matter you could you wouldn't lose the mark for using RAM rather than main memory and vice versa So the CPU will fetch the instructions from RAM That's the proper word for it because that's the F in the FTE cycle It will then bring that instruction back to the CPU The CPU will then decode it which is the obviously the D in FDA Once it knows what the instruction is it will then execute that instruction And that doesn't mean to execute it Not that kind of execution to carry out that instruction Okay And that is the FTE cycle which it will just keep on repeating billions of times in one second Now when it comes to the performance of the CPU and how well it carries out those FTE cycles every second the easy way to remember it are the three C's And the first one is the clock speed which we're going to talk about in a moment Next one is cause and finally it's the cache So your clock speed is measured in what we call hertz But common up to-date CPUs you won't often see just hertz You of you're going to be looking at something like gigahertz So a typical clock speed would be something like this 3.5 gigahertz Okay so the G being the giga but we still got hertz in there Now what that actually means is 3.5 billion instructions per second Per second is actually really important Okay so the higher that clock speed if that was a higher number you'll be able to carry out more FTE cycles per second Okay the next thing that affects the performance are the cores So a CPU can have multiple cores and if you were explaining uh why that might affect the performance you could say that each core works independently So let's have a look at some examples combining what we know about clock speed now and the cores So here here is an example of a CPU 3.2 gigahertz dual core Okay So when we see the word jewel it means it's got two cores Okay So we've got 3.2 gigahertz which we know is 3.2 billion But then because it's dual core it can do up to two times that amount So 3.2 times by two or multiplied by two will give you 6.4 billion instructions per second Let's have a look at one more example So here's 3.5 gigahertz quad core So we're going to do 3.5 multiplied by four this time And you can think of quads being like a quad bike with four wheels It's an easy way to remember it So 3.5 times by four will give you 14 billion instructions per second And the final thing that will affect the performance of the CPU is the cache So cache holds frequently used instructions and it's located on the CPU It has much faster access to cache than main memory Too much cache could be detrimental to the overall performance So some cache memory is good because it does you do have faster access to cache than main memory and that will speed up the performance of the CPU So just to finish this session I wanted to just put some example questions that you can have a little practice of So it's probably a good idea if you want to pause the video now The best way to revise with these kind of questions is try and not rewind the video Um try and not look back at any notes inside your book that you may have been making as you were going I want you to try these questions and then check your answers And if you've made any mistakes don't worry about it You can just try it again And that's the whole point when you you keep on trying and answering those questions that's how you will embed that knowledge So today we are going to be having a look at what is an embedded system Before we have a look at what is an embedded system we do need to understand what is a computer first So a computer is any programmable machine or electronic device which takes in data processes it and then outputs the result So this is that model the input process output model that we've probably heard of before Importantly as well computers are general purpose Now when we say general purpose it means that you can have multiple programs installed onto the computer and you can access them You can use the computers for different reasons So that is what is meant by general purpose An embedded system is similar to a computer However it's kind of the opposite So if you were going to answer a question about what is an embedded system you could quite simply say it is a system that is built into a larger machine That's accepted on the mark scheme and not as a separate answer but something you can add onto your answer You can say that they are built for one purpose And good thing about an embedded system is once it's been made it doesn't need updating for whichever machine that it's built into So all of the components of the embedded system are usually built into a single circuit board and we're going to look at a few examples now So the first example is a washing machine and this is top of the list on the mark scheme as well So if you think of a washing machine and if you were going to open it up which I wouldn't recommend you've got buttons on the front of your washing machine and inside you've got a single circuit board that these buttons will interact with And these buttons can do different things such as um starting your wash it could be to to change the temperature it could be to cancel the wash and so on And all of these will interact with that single circuit board that is being built into this larger machine Other examples include a microwave or a Mikawave if you're Nigella Lawson Got a toaster Notice that all of these are kitchen appliances by the way Apart from this unless you use that in the kitchen you've got a calculator but there are loads more So if you're trying to think of some examples in your exam think kitchen It's probably your easiest way to remember Here are some example questions that you can practice I would recommend pausing the video now and giving them a go Don't forget try and not look back at any notes that you've got in your book or try and not rewind the video Give them a go first and then you can go back and see if you got them right In this session we're going to be looking at what are the main parts of the CPU And a little bit later in the session we're going to be looking at what's known as volume and architecture which is less confusing than it sounds So we need to understand that the CPU has three main parts and these are the control units the arithmetic and logic units and finally the cache So we're going to start by talking about the control units Now the control unit manages the actual FTE cycle which we've talked about before So it manages the the fetching of the instruction itself Once it's fetched it and brought it back it will then decode that instruction and it will execute the instruction which as we know are the three main steps that are repeated billions of times in 1 second in the FTE cycle So if data needs to be moved around the CPU or maybe moved back into main memory then the control unit is the part of the CPU which will actually do that The next part of the CPU is the arithmetic and logic unit If you remember what that one stands for then you'll be able to remember what it does really because you've got the wording in the title itself the arithmetic part of it So it does all of the calculations and it performs logic operations such as and or and not Now we'll do a completely separate video on boolean operators and what logic gates and circuits look like Uh but all you need to know for now is that the the the arithmetic logic unit does all the calculations and it does perform the logic operations There has been questions in the past where you had to fill in the blanks You had to fill in what these letters stood for So it is worth understanding that the ALU does stand for arithmetic logic units in case you are asked to fill in the blanks So once the ALU has performed a calculation it then has another part in it which you can see there called the accumulator And the accumulator will actually store the results of the calculations themselves And this is one of the registers of the CPU And finally we've got cache Now we have mentioned cache in a previous video Uh and the main the main definition that we understood last time was that it stores frequently used instructions So when the FTE cycle is being carried out the CPU will actually check cache to see if the data is there first Now if it's not in cache then it'll go to RAM to fetch it basically Now one thing that we didn't mention last time is that there are different levels of cash So level one is the fastest and because it's so fast it does have the lowest amount of storage as well And it kind of follows that pattern So level two is not as fast but then it can hold more data And finally we've got level three Again even slower but it can hold the most data out of the three levels of cache But your main thing that you need to know from cache is that it stores frequently used instructions So they're the three main parts of the CPU But now we're going to look at what vonuman architecture Okay So I've put together this diagram which hopefully makes it nice and simple to understand So in terms of what vonuman architecture actually is it's a system where the CPU runs programs that are stored in memory So as we know the FTE cycle gets carried out billions of times in 1 second and that's where the CPU will fetch instructions that are in memory Now the other parts that you can see in this diagram are the registers which will actually help this process take place So the program counter keeps track of what instruction that it's up to and will just increase every FTE cycle that's carried out and it will pass that number to the memory address register So let's say it was at instruction number one It will pass that number one to the memory address register Now the CPU at that point knows that it needs to look in memory address register one which is in RAM or main memory So at that point it will do the fetch part of this cycle where it travels down to RAM and it will fetch whatever is in memory address one and it will bring it back and it will store it in the memory data register Now at that point going back to what the control unit does it will actually decode that instruction and find out what it is that needs to happen So it might be that it needs to perform a calculation or it might be that it needs to move somewhere else in memory and the control unit will make that happen That's the execution part of it If it was a calculation the ALU or the arithmetic logic unit will carry out that calculation and then temporarily store it in the accumulator The process just carried out again So the program counter is increased to two and it will then start that cycle again where it will then fetch whatever's in memory address register 2 and then it will bring it back to the MDR and the control unit will take care of it it will decode that instruction and it will execute whatever needs to happen next So it's a relatively difficult but short topic that people get a little bit confused on but it's actually fairly simple when you think about what what you need to know And we've got some example questions for you to try out So most of these are based on ones that we've had in the past And try and not look back in your notes when you're answering these and pause the video and then you can go back and check and see if you've got them right The repetition of this is what will make this topic much easier especially when it comes to thinking of the different registers and what their purpose are with the CPU Hey today's session we are looking at what is memory So a lot of people make the mistake of thinking that memory is how much storage you've got in your computer and that is not what memory is Do not make the mistake of saying that memory is the same thing as your secondary storage device like your hard drive That is not what memory is Main memory is your RAM So it's where programs and data are stored while they're being used So as we know we've got our CPU works very closely with the RAM and it will fetch instructions from the open programs that are currently stored in RAM Now if I've got software on my computer like PowerPoint it's actually stored long-term in my secondary storage device such as a hard drive or a solid state drive But because your secondary storage device is relatively slow when it's in use it does get copied into RAM Now the reason for that is because RAM is so much faster than your secondary storage device Now because it was only copied there temporarily if the computer was to be turned off your main memory would forget what was currently stored in it The word for that when it's forgotten is volatile Now let's have a look at another type of memory So the next one is read only memory or ROM Now you probably heard the terminology read only before and it's usually on when you open like a word document on Teams or something like that And sometimes it's on there as read only And it quite literally means that you can only read from it You can't write to it at all Now the reason for that is because it contains some very important information in there which are the instructions that your computer needs to boot up which is your BIOS If you were to accidentally overwrite that information then your computer might not be able to boot up again Now if I turn off my computer unlike RAM which forgets everything when you turn it off your ROM will remember it all because it is nonvolatile So everything's still there even after the computer is switched off So let's look at our final type of memory We've got something called virtual memory Now virtual memory is not necessarily a good thing It's when your secondary storage gets used as extra RAM What that means is your RAM or your main memory is full It means you've filled it to capacity And when it's full that's when your secondary storage device steps in and says "Right I will act as RAM so that you can free up a little bit of space." So whichever piece of software that you've currently got open that you've not used for a while will be the one which gets moved into your secondary storage device as virtual memory Well as you know the CPU fetches the instructions from RAM So what has to happen is the the software which is currently in virtual memory has to be moved back to RAM before it can be read by the CPU Now this process is really slow which is why virtual memory is not necessarily a good thing Okay So to finish with we've got some exam questions on our memory topic So what is the purpose of main memory in a computer got explain why Mr Moore might need more RAM in his computer What is meant by virtual memory and finally is ROM volatile or nonvolatile explain your answer So as always I would recommend not checking back in your notes if you can Try and answer these from your recall and then checking to see if you got them right afterwards And if you didn't don't worry about it You can just keep attempting those questions until they are firmly lodged into your long-term memory This session we are doing what is a secondary storage device I want to just talk about one of the most common mistakes that people make when it comes to that word secondary When people see the word secondary they assume that it means that it's a backup from the original storage So it's not the first storage device it's the second storage device Now that is a load of rubbish That is not true Do not make that mistake So your secondary storage is your long-term storage If you're going to describe it if you were asked define or explain what is meant by the term secondary storage it'll be a two mark answer And these are the two things that you need to say that it's long-term storage And you could say even after the device is switched off But then there's that other word in there nonvolatile which is what that means So the the files are going to be there even after the device is switched off Okay So here's the kind of things that you can store with your secondary storage device So general files like your your word documents your PowerPoints and things like that Uh audio files most common you'd probably store MP3 files video files like an MP4 images like a PNG or a JPEG that kind of thing And your programs which is something that people often forget will also also be stored in here All right So when we talk about storage they like to ask about the different types of storage Sometimes which one's the most suitable for a situation so these are the three main types of storage We've got optical we've got magnetic and solid state So let's have a little look at optical storage first So if we've got some examples so you can picture it a little bit easier So a CD is an optical storage device a DVD When you're asked questions about why you would choose optical storage you need to be able to justify why you think optical storage is better than another type of storage or maybe worse than another type of storage depending on whether you need to argue for or against So to do that we need to know about the characteristics So let's have a look at the good characteristics of optical storage first So it's really cheap So if you were going to buy a a CD for example it's really cheap So if you needed something uh very uh quick to put something on and you it's probably disposable You're not going to use it again It's good that it's not going to cost you a lot of money for that reason Also it's portable There was an exam question a long time ago now and it was talking about which storage device would be the most suitable to go on the front of a magazine and the answer was it was optical storage and that was because it's portable it's flat and uh it's cheap as well So those are some of the reasons why you would choose optical storage But let's have a look at some of the bad characteristics of optical storage So it's got a slow write speed And what that means is if you were going to put files on there it does take quite a while It's not durable so they scratch really easy which can be an issue It can't be read anymore by the laser and then it's not going to work anymore And they have relatively low storage Even the Blu-ray disc which out of those three has got the most storage it's still pretty low storage compared to other storage mediums Next we're going to look at magnetic storage So let's do some examples first So most common one is the hard drive which is probably the one that most people have heard of Most computers do come with a hard drive and we'll talk about characteristics why in a moment Um not as common we've got the tape drive and definitely not as common we've got the floppy disc So let's have a look at the characteristics of magnetic storage So first of all what's good about them buy a hard drive really cheap nowadays It wouldn't cost you much money to have a really high amount of storage for not that much money They're pretty durable as well Usually people use internal hard drives which means that they don't get moved around much which means that they're very unlikely to break from being banged or something like that And as previously mentioned they've got really high storage capacities as well So let's have a look at some of the bad characteristics of magnetic storage So it's got a really slow write speed Still slow It's marginally faster than optical storage right speeds but it's still not quick enough to use it as a as an advantage And it's not portable majority of the time I mentioned earlier an internal hard drive You can buy external hard drives which are plugged in via USB but majority of hard drives are internal I know I've talked mainly about the the hard drive here uh because that's the most common magnetic storage device So when you're thinking of magnetic try and think hard drive It's unlikely you're going to be asked for more than one example of magnetic storage device But just in case you are we've got these other ones the tape drive and the floppy disc And finally we've got solidstate storage So let's have a look at some examples first So we've got USB drives Don't fall into the trap of just saying USB That will not get you the mark on its own It's got to be USB drive SD cards like they go in in a camera micro SD cards if you're maybe upgrading the memory in your phone or your Nintendo Switch And nice and easy to remember because it's almost exactly the same as the title the solid state drive So let's have a look at some of the characteristics of solidstate storage So this is the going to be the the best overall storage device that you can choose So it's got some really good characteristics It's portable It's durable so if you dropped it it's unlikely to break It's got very high storage capacity and it's got a really fast right speed and that's due to having no moving parts inside So really fast right speed So that's probably it biggest advantage But it does have only one bad characteristic which is it is very expensive It's very expensive because it's so good Okay so here are some questions for you to practice I'd recommend giving them a go Try and answer them without looking back on the video or looking back into your notes There's plenty of questions here that you can have a little go at I just wanted to point out that at the bottom we've got a six mark answer which was a previous question on an exam where you had to describe the characteristics between magnetic and solid state storage devices And for a six marker you had to come up with the different characteristics and why one would be better in a certain situation So it was quite an ask really but it would be a really good practice for your extended writing if you can give that one a go as well In this session we are going to be looking at how to convert between file sizes So to understand this a little bit better we do need to find out what is binary Now this is a term that a lot of us have probably heard about binary before but we do need to recap it just so that we've got a good understanding of what our most basic file size actually starts at and then we can build from there so that we've got a good understanding of why and how we're going to be converting between these file sizes So in terms of a definition about what binary actually is which has been a question on previous papers computers use ones and zeros to represent the flow of electricity which is probably not the definition which you were expecting for what binary is A lot of people will put something like the language the computer understands and things like that which isn't necessarily wrong but in terms of an accurate definition this is what binary actually is All data is converted to binary so that it can be processed Like we've just kind of mentioned the computer does only understand binary So that's why it has to be converted into binary or machine code as sometimes referred to so that the computer can then process that information and figure out what the instructions actually are Here's the key bit that we needed to know The smallest unit of measurement is what we call a bit or a single one or a zero Now when it comes to file sizes the bit is the smallest file size possible that we need to know about in our exam When we hear the word file size what does that actually mean so it's the amount of actual storage that a file will take up on a secondary storage device So if I was going to store a picture onto my hard drive for example it's how much space that it's going to take up in the hard drive or how much storage it's actually going to use Now these are the different file sizes that we need to know about for the exam So a bit is our very beginning It's the smallest file size that we need And if we've got four bits we can refer to that as a nibble Eight bits is one bite Now this is where we come to what I usually refer to as the magic number 1,024 Now you are allowed to use a rounded version of that where you rounded down to a th00and and that's much easier to deal with and we're going to talk about that in a little bit So a th00and bytes or,024 bytes to be precise is 1 kilobyte 1,024 kilobytes is 1 megabytes 1,024 megabytes is 1 gigabyte 1,024 gigabytes is 1 terabyte And finally 1,024 terabytes is one pabyte So that you can see what is why I call it the magic number because look how many times that number comes up As long as you can remember a thousand or a,024 that makes our job so much easier when it comes to doing the actual conversions themselves Now there are known file sizes that are bigger than this and smaller However this these are the ones that we need to be able to convert between for our exam In the exam unfortunately it's non-calc and they do phrase some of the questions in some ways which makes it a little bit tricky to figure out what it is that it's asking of us So we're going to have a little look at a few ways that we can approach these kinds of questions So here's an example one How many megabytes are there in one terabyte now I've purposely done this because a lot of people would think oh well it just be something easy like how many gigabytes are in one terabyte and we just say a thousand But notice that I've not gone for that I've gone for megabyte where so gigabyte is in between the megabyte and the terabyte here So to do that we know that there's a th00and megabytes in one gigabyte So all we had to do there was multiply it by a th00and So 1 * 1,000 that gives us 1 gigabyte Notice that I didn't use the 1,024 here I've just gone for a,000 because it's much easier to deal with and it's accepted on the mark scheme to use the rounded number But because we're now at gigabytes we then need to multiply that again by a thousand because that's how we're going to get to one terabyte So in other words there are 1 million megabytes in one terabyte Now as you can see by looking at that the easiest way of doing that would just be to add the zeros onto the end of the one because we've got six zeros there which gives us 1 million megabytes But you can do it one times a thousand times a thousand That will also give us our correct answer which is 1 million megabytes in one terabyte Let's have a look at another one So Mr Moore has a 2 terbte hard drive An image is 1 megabyte How many images can Mr Moore store on his hard drive so this is almost the exact same question that we've just had However look how differently it's been worded And you would just need to not overthink it and just think well I need to know how many megabytes are in one terabyte And once we have our answer we can just multiply by two because it's 2 terab So again 1 megabyte th00and that gets us to 1 gigabyte We then multiply that by a,000 which gives us 1 terabte And finally we know that there's a million images in one terabyte So we can just times that by two So the answer would be two million images in 2 terab if they were all exactly 1 megabytes That's a lot of images Okay So to finish I've got some more exam questions for you to practice Very similar to the ones that we've just done but ones that we've definitely seen in the past on previous papers So how many bits are in a bite how many kilobytes are in one gigabyte and finally similar to one on our previous slide Mr Moore has an image that is 2 megabytes How many copies of the image could Mr Moore fit in a 2 GB hard drive so in this session we are going to be learning how to convert between dinery and binary And the first thing we need to know is what number system we use Now it can be referred to a few different things You've got deny or diner as some people say you've got decimal or base 10 Now the reason it gets called base 10 is probably the most accurate name for it And that's because we use 10 different values in our number system So we've got from 0 1 2 3 4 5 6 7 8 and 9 Now the binary number system can be referred to as base two And that's because it's only got two different values that it can possibly be which is a one or a zero Now for the sake of your exam you only need to be able to do up to one bite of information which our maximum binary number that we are going to be able to make with that uh will be the dinery 255 Now you're going to want to always draw this table out in your exam because it will help you with your conversions So if you ever see a binary conversion there's lots of space on your paper Just draw this table out You've got note pages at the back You just want to use the time You've got plenty of time Don't try and just do it in your head Just make sure you do the conversion to double check your answer And this is what it looks like Now if you're no good with powers of two which all of these are you can just start at the right hand side with the number one and you can keep on doubling it until you get to 128 So we're going to start with one We double it to get two We double it to get four 8 16 32 64 1 28 So here's how we would write the number one in binary And as you can see I've written it as a bite I've got seven zeros And then my final one I've put a one there because I needed that top value from the headings in that table to represent what a one looks like in binary Now let's try it with the value two So I've got zero for the first six this time but then I've got a one where the two is because that's what number I'm trying to make now I didn't need the one value at the end So I've got a zero there now So we're going up one at a time So here's how we would write three out in binary because I've got a one in both the one column and the two column That means that I've written out the binary for the diner three Let's look at a couple more examples So if this was an exam question convert the diner 88 into binary So again we're going to start by writing out our conversion table So what we need to look at is which of these numbers do we need to add up to make 88 Now we know that 128 is too big Okay that one's we it's it's over the value 88 So we don't need that one However we do want 64 That's the highest number that can fit into 88 So we need to try and make another 24 out of what we've got left So 32 is too high But if I add 16 that's going to bring me to 80 So we're really close now Okay So we're currently at 80 Now if I add another eight we have made it Okay that's all we would need to make the number 88 However we've not given our answer in a bite yet So we would need to finish this off and we would put a zero in the remaining columns there We're going to look at another one which is a little bit trickier but it's only tricky because it's quite a relatively high number And you're not allowed to use a calculator in your exam unfortunately So you do need to be able to do this addition yourself Now don't forget you can use your note pages to do any addition in any way you want It's usually a two mark answer when you do a conversion like this and each mark makes a massive difference in computer science So don't make any mistakes with your adding up Now the first trick that we're going to go for is that these two 128 add 64 These two add up to 192 So if you can remember that you are going to save yourself quite a lot of your battle straight away because you're dealing with quite big numbers here And the tricky bit is where people are going to try and add numbers to go over the 200 mark But that just comes with practice that the more of these that you do in your head you will get much faster at doing these So at that point we know we need to use both of these because we are trying to make 209 and we're currently at 192 If I added 32 to that we'd be way over So we're not going to need that one However if I add a 16 to that one that's going to bring us to 28 which puts me really close to our answer So all I need to do now is find another one So we can put a zero for all of these here And finally we need a one and we've made 209 Now what happens if we get it the other way round and they give you the binary number and they say convert this into a dinary number Now if anything this is actually easier because all you got to do is write out that binary number into your conversion table So we're going to do it just underneath So 1 0 1 1 0 1 0 0 like this Okay and again this comes into your practice of adding everything up where there's a one So 128 add 32 is going to give us 160 We're going to add 16 to that which gives us 176 We're going to add four to that which gives us 180 So this is the binary for the dinary 180 Okay So to finish with we've got some questions just to practice your conversions which are relatively straightforward So our first one convert the dinary 45 into binary Second question is convert the dinary 112 into binary Question three convert the diner 231 into binary And then I've got three binary conversions as well there for you Carry on our last session where we converted into binary We are now going to learn how to add binary values together So just as a little warm up let's first of all do a couple of conversions and then we're going to use our method to add them together So we're going to start by doing the conversion for 98 Now we don't need 128 because that is too high but we do need 64 and 32 because that's going to bring us to 96 So we're actually really close at this point All we're going to need is our two and that gives us 98 So that was a relatively straightforward one So now we need 142 So we know that we can squeeze in 128 but 64 32 and 16 are going to put us over 142 So we don't need those So the first thing that we're going to add onto that is eight which brings us to 136 If I add another four to that that's going to bring us to 140 We're really close now We're just going to add another two which gets us our answer We don't need this final value So we're just going to put that as a zero So at this point we've got two binary values and we are going to learn how to add these two together So I'm just going to put a little line underneath that So the method here is if we have a zero and a zero we add those together it's going to give us zero 0 add one is going to give us one One add zero is going to give us one One add one is going to give us a zero carry one One add one add one is going to give us a one carry one Now the problem comes in when we've got an answer of two And that's because you can't write the number two in binary So if I was to look at this point here we've got a one and a one Now that's not going to work for us So because if I was going to write a two in binary we would need to write it as one zero like this This is why I've written down there that it's zero carry one because we've got the zero here and we're going to carry this one And in a similar way again if we've got one add one and we're going to carry one That's because we again we can't write the number three in binary but we can put a one here and here to make the number three So that's why we're going to put the one as our answer And then we're going to carry this one Okay So let's carry out the addition and we'll use those rules on the sides and hopefully it'll become a little bit more obvious as to what's going on here So we're going to add 0 and zero This is going to give us a zero one add one We know that we can't represent that by writing two So we're going to put zero and we're going to carry one One add one is going to give us zero carry one One add one is going to be a zero carry one Zero add one is going to give us one One add zero is going to give us one One add zero is going to give us one And then finally zero add one is going to give us one So this is how we add two binary values together There's no requirement to then convert that into dy by adding up all these values uh across the top We don't need to do that It will usually tell you how to express your answer and it will usually just say to add them together which is fine to leave it as a bite in binary Similar to our last session you will get one mark for each nibble that you get correct So if I just draw a line down the middle of that you would get one mark for getting this side of it right You would get another mark for getting this side of it right Okay So I'm going to add these together now And let's see what happens So one add zero is going to give us one 0 add one is going to give us one 0 add 0 is going to give us zero One add zero is going to give us one 0 and one is going to give us one One add one is going to give us zero carry one Zero add one is going to give us one But one add one is going to give us a zero But then it should be a carry one I'm just going to park this carried one over here for now But I just want to read this question again It says give your answer as a bite Now we know that eight bits are in a bite So this is all you would need to write down on your exam If you wrote down this extra digit here you could lose a mark for that because it specifically says give your answer as a bite So don't fall into that trap It's not incorrect by having an extra value carried at the end We're going to talk about that in a minute But if it specifically says give your answer as a bite just keep in mind that a bite is eight bits So you need to keep your answer at eight bits So at that point there you would make sure that you didn't have this written on your paper You just kept it like that as your answer But it does bring us to an important point that we did have an extra value carried over at the end Now this gets a special name which is an overflow error and we're going to talk about it now So exactly as we've just done then when you're adding binary results together you could get more bits than the CPU was expecting and that's what's known as an overflow error You might get a question in your exam asking what is meant by an overflow error This was this is the kind of answer that you could give that it's more bits than the CPU is expecting but as a little bit more detail that you can give there you can say that it could cause software to crash if it can't deal with that extra bit So often software is written pretty well and it can handle those extra bits and it knows that it's going to store them somewhere else and that'll prevent the software from crashing Okay so to finish with today I've got some exam questions to practice So I've got three sets of bytes here that you can add together separately I would recommend doing it on a scrap piece of paper You can get your conversion chart out if that helps as well Now I've not specified here if you need to give your answer as a bite or not So if it's going to give you an overflow error then go with it That's fine You write that o overflow error down as a ninth bit We are going to be looking at how to perform a binary shift As this is a typical question that you might get in your exam Perform a two place binary shift to the left And as you can see what we've got there We've got an 8bit number there Now hopefully you know your left from your right That will obviously make a difference We are being asked to shift to the left by two places Okay we know our left from our right and we can count to two So what I'm going to do I'm just going to draw uh an arrow from each of them just so that you can really make sure you've got this correct So I'm going to draw that one is going to go two places to the left like that Okay So that one is going to be a one at this position because we've gone from this position here We've gone two to the left which has brought us here So that one has moved over here All right And this one is also going to move to everything is going to move two to the left So if we just draw this out So we've got one one 0 0 and then we've got one zero Now unfortunately these two have fell off the end Okay They have gone too far But we want to keep this as an 8bit binary number So those two have gone disappeared But that only leaves us with six bits filled in And we've not done anything with the side on the right So what we're going to do is just fill it with zeros And that's it It is as simple as that So you move exactly the number that it says two places is we went in the left direction and we filled it with zeros Now let's look at the exact same question but this time instead of shifting to the left we are going to shift to the right This time going to start at the other side and these ones are going to go two places to the right like this Okay All of them are going to just go two places to the right So I will do this one is moving over here So I'm going to put my one just there Let's carry on writing it out So we've got another one zero one zero and zero Okay so everything's been moved to the right However this one and this one fell off the end They don't exist anymore They've gone So at that point we've got a gap over on the left hand side because this time we shift it to the right So we are going to fill it with zeros Now it is only going to be a one mark question on your exam this if you get a binary shift However they can ask you to describe the effect that it has and that's what we're going to have a look at now So for the first example that we looked at we shifted everything to the left Now it has a different effect on the actual binary number by shifting to the left And that effect is it multiplies the number So if you were to shift it one place to the left that actually multiplies the number by two And if you were going to shift it two places to the left that is going to multiply it by four And finally if you were going to shift it three places to the left that will multiply the number by eight Now you won't be asked for any more than that in your exam They may ask you that how what effect does it have making a binary shift to the left by three places and that's a two mark answer if you have if you're being asked to describe that But I it's very very unlikely it's going to go in hiding that but it does carry on with that pattern So if it did shift four places to the left it would multiply by 16 You can also divide in binary by using the binary shift And it just quite simply is going the opposite way So it's multiply if it's going to the left and it's division if it's going to the right So if you wanted to divide by two you would do a one place shift to the right If you wanted to divide by four it's two places to the right And finally if you want to divide by eight it is three places to the right So we've got some exam questions to practice on the binary shift As always it's probably best if you pause the video and give it a go and then if you need to go watch back just to double check your answer then that's fine But try and answer them all without looking at your notes in your book and then obviously check afterwards to see if you got them correct In today's session we are going to be looking at what is a character set Now you might be asked in your exam explain what is meant by a character set Now if it says the word explain you should know by now that that is a command word and that is going to be a two mark answer If you asked to explain something so if you asked explain what it is meant by a character set your answer is the characters that can be represented by a computer system What does that actually mean now when I say a computer system obviously we don't actually need to be using a computer or a laptop We could be talking about just general devices like a smartphone If you were going to be messaging someone on your smartphone you are going to be using things like uppercase characters lowerase characters uh numbers symbols and emoji and so on And all of those need to be stored inside your device But as you know the computer can only process binary information machine code So if you were to enter a letter on your keyboard it has to be converted into binary so that it knows what it is that you've done so that it can then be displayed on the screen correctly The computer does that using something known as the character set Characters that can be represented by your computer system Now a really common character set is ASI Now ASI is a seven bit character set However it does have a zero at the beginning of all ASKI characters which is going to make it into an 8bit character set and each character is given a code and that code is stored in binary which takes up one bite which as we know one bite is eight bits So as we said earlier if you were to press a key on your keyboard that will send that signal to the computer telling it which key was pressed and then the computer uses that character set to translate that binary code into that particular character So at that point it would be outputed on the screen and you get exactly what it is that you've asked for So another character set that we need to be aware of is Uniode and Unicode uses multiple bytes So we were looking at ASKI earlier that only used one bite of information whereas Unicode uses multiple bytes and because it's got multiple bytes of information it can store millions of possible characters which is obviously enough to cover all major languages which is great if you want to change a keyboard on your device to a different language And as we mentioned earlier ASI is actually a subset of Unicode So the first 128 codes of Unicode are exactly the same as AS asy In the latest exam there was an unusual question which asked you to write down the binary for an ASKY character So we need to be able to write out the ASI character alphabet And it is really straightforward to remember as long as we follow these steps So let's do an example Write the binary for the asky character J Now notice that this is a capital J and that makes a difference to how we're going to start our bite of information If it's a capital letter like this one is we're going to start our bite with 0 1 0 But if it was a lowercase J you would start with 011 instead Now we do need to know our alphabet to do these questions So it might be an idea just so we don't make any mistakes use your note pages at the back of your book I would write out your alphabet if you were asked to do one of these in your exam and then that way there can be no mistakes So J is the 10th letter of the alphabet So we're going to write the binary for 10 So we're going to use our good old conversion table At the beginning of it you can see we've got our 0 1 0 So 0 in 128 one in 64 and 0 in 32 But then the rest of this binary number you just needed to make the the number 10 in binary where we've got an eight and we've got a two So this is J in ASI So let's do one more example So if we were going to convert the character the lowerase character P for example we would first need to count out how many letters in the letter P is So A B C D E F G H I J K L M N O P So it's the 16th letter in the alphabet And we said we're going to do a lowercase letter So the lowerase P is going to look like we're going to have a zero at the beginning It's lowerase So we want a one one And we need to make 16 for the letter P So we're going to put a one there which is 16 and the rest can be zero and that is a lowercase P So to finish here's some exam questions that you can have a little practice of So I want to know what is meant by a character set How many bits is ASI written in got a couple of conversions which is a capital letter Q and then a lowerase T into ASI binary And then finally a bit of practice based on the last video as well Once you've converted into binary I want you to then convert it into hexadimal So as always pause the video at this point give the questions a go without rewinding back or checking in your notes and then obviously check your answers afterwards Just repetition is key to making sure that you are confident in these areas In today's session we are going to be looking at what is an image So images are made up of tiny dots called pixels There's thousands of dots in every single image Every pixel is a different color and to know what color to light up that pixel to to actually create the image It has to get a specific code which is a binary code so that it knows what color to become The amount of colors actually depends on how many bits are available for each of the different pixels So what I mean by that if we think about our binary conversion chart where where we often use eight bits if we were to use just one of those bits there'd be two colors available if it was a one or a zero in that one position And if we were to use four bits so like a nibble there are 16 different possible combinations So like you've got 0000 0 1 0 0 1 0 and so on And there's there's 16 different combinations that you can make there which means there'd be 16 different colors available with four bits 24 bits would be over 16 million colors available And to calculate that there is actually a way of calculating it So you can just do uh two to the^ of n where n is the number of bits per pixel So for example if we were just using our 8 bit conversion chart like we've done loads of times with our binary conversions We can do 2 to the^ of 8 which gives us 256 which is a really quick way of working it out The other way of working out is if you had a one in every single position of our conversion chart and added it all up together it would give you 255 But then there's the null value as well if they were all zeros Which means in total we've got 256 colors available with eight bits So that means that each bit could be one of those 256 colors But if we then use 24 bits because there's so many colors available that means that the overall file size of the image is going to be much larger What is image resolution so image resolution is quite simply the number of pixels that are in an image and you can you can calculate it a bit like you would in maths uh if you were calculating the area of a square So you just do the width times the height So if an image has more pixels it would be much higher quality because there's more dots available in that picture So there's more quality there However because there's more pixels that means you're going to have to have more binary information stored about that image which means that the the overall file size is going to be much bigger So there's two things so far that's affected the file size The number of pixels that are available which is the resolution and the number of bits per pixel which is the color depth So all of those pixels can be a number of possible colors So the higher those are the higher the file size overall Now when it comes to storage on the computer you can actually calculate how many bits the image is going to take up And there's a little formula we can do for it So first of all we can do the width times the height like we did to calculate the resolution and how many pixels are in the image But then we can also multiply by the color depth by how many bits are in each pixel Let's say that one image uses three different colors Now we know we need at least two bits to be able to create three different colors So this image next to me has got 25 different pixels So to calculate this resolution I did five times by five And then because the number of bits needed was two I'm then going to times that by two So in total that's going to give us 50 bits to store the image Now you may be asked to calculate how many bits are in an image But they may ask you to give your answer in something like bytes or kilobytes depending on the size of the image But in the question itself it will give you all the information that you need to know to be able to do this Just remember to multiply them all together Okay Finally we need to talk about something called metadata It's been a question on past exams a couple of times actually Explain what is meant by metadata And it is one that throws people off It's a two mark answer So in terms of a definition metadata stores additional image information So if you wrote that and then gave some examples of metadata then you would get your two marks Another thing that you can write about metadata when explaining is it helps the computer recreate the image on screen from the binary data in each pixel So these are the examples So with things like your file format uh the width height color depth resolution there's sometimes more than that as well That's just a few of the examples like GPS information will be on there as well Okay so that's it for your image representation topic We've got some questions that we can practice So question number one state what is meant by the term resolution Because it's a state question it's often only a one mark answer that one Describe how images are represented in binary State what is meant by metadata Give one example of metadata that could be stored alongside an image Explain how reducing the number of colors in an image can reduce its file size And finally calculate how many bits an image uses with a resolution of 15 by9 which uses 16 colors So as always give these questions a go before you check back in your notes or anything like that And then obviously if you're not sure then go back watch the video again and check your notes again In this session we are going to be looking at how is sound stored So if we were going to be recording a sound we would use a microphone a bit like this one Now this is an analog signal However if it was going to be stored onto a computer it has to be converted into digital data It's called an analog to digital converter But how is sound converted so we take what's known as samples of the amplitude of the wave at regular intervals You can only take amplitude based on values in a certain bit depth If you think back to our last lesson on image representation So if we think about each of the pixels could only be a certain number of colors based on how many bits were in each pixel Well this is the same kind of thing but for sound So the more bits that are available the more possible sounds that it can be And that's what's known as bit depth Okay So in terms of what we need to know and think about in our answer we need to think about what affects the size and the quality overall So sample frequency is how many samples are taken in 1 second We mentioned earlier sometimes it be called sampling but sample frequency is probably the more common name for it Now a really common sample frequency is 44,100 samples every second but it is measured in hertz which is the same as saying 44.1 kohertz And as we said before the bit depth is the number of bits available for each of those samples So if you think every second there's 44,100 samples and if there's more possible sounds available then it's going to increase the file size significantly But because you've got more possible sounds it will be closer to the original sound which means it's going to be higher quality overall Now we can calculate the size of a sound just by the information that we know about it So we've got our sample frequency which is how many samples it is per second which is measured in hertz That's going to be multiplied by the bit depth And then finally you will multiply that by how many seconds the sound is So if you had 20 seconds of audio with a bit depth of eight bits and a sample rate of a th00and then all you need to do is multiply it all together So 20 * 8 * a,000 which will give you 160,000 bits or 160 bytes So if you're trying to think about what you need to include in your answer it can be quite difficult to remember it So I've got a stupid but easy way to remember it So these are the two things that we know already that we need to include in our answer We've got bit depth and the sample frequency because they're the two things that will affect the overall quality and the file size itself So your way of remembering is blue ducks sound funny So you've got BD blue ducks which is bit depth and then sound funny sample frequency which is the SF part of it So if we can remember blue ducks sound funny we need to think that we need to include bit depth and sample frequency in our answer because they are the two things that affect the file size and the quality If you were asked a question such as explain what affects the overall file size of a sound file you could give an answer something like the more samples per second will give a more accurate sound to the original and that's the sample frequency And to expand on that you can put the bit depth will affect how many possible sounds can be stored digitally And overall increasing the sample frequency or bit depth will improve the quality but will also increase the file size The bottom point that I've made there increasing the sample frequency or bit depth will improve the quality but increase the file size That's enough to get you a two mark answer However for a more detailed answer if it was like a three or four marker you would have to include the other points as well So to finish with we've got some example questions that you can practice We've got describe how sampling is used when storing sound Explain the effect of the sampling frequency on the size and the quality of the sound file recorded State what is meant by the sound bit depth And finally calculate how many bits would be in a sound that has 30 seconds of audio with a bit depth of 8 bits and a sample rate of 500 hertz Show your working session We are going to be looking at what is compression So I always think it's quite easy to remember what compression is because we can think of it like crushing a can So if you've had a can of Coke or something like that finish with your can You will often with shoes crush that can and then you will recycle it But when you crush it down you've still got the whole can there but you've made it smaller so it takes up less space And that is what compression is But there's different forms of compression So we need to talk about that So in terms of a definition you're reducing the file size but you're trying to keep the file as true to the original as possible Now there's different reasons why you would compress a file The main one is just so it takes up less space on your secondary storage device So let's say you've got a hard drive in your computer and you want to store as many files as possible on there So the files are going to be compressed so that you can store the maximum amount possible In addition to that if you're going to download something from the internet it's going to be much faster If it takes up less storage then the file itself will download faster So I'm not sure how many of you have tried to attach files to an email There's actually a maximum of 25 megabytes that you can attach to an email If you have got smaller files you'll be able to fit more files onto the email as an attachment And finally if you're on the internet using a browser the web pages themselves will actually load quicker if they've got smaller file sizes and less information to pull down So I mentioned earlier we've got two different types of compression Now your two different types are lossy and lossless compression Let's have a look at lossy compression first Now if you've got a file such as a JPEG which is an image file lossy compression will actually reduce the number of colors available in that image So reduce the amount of bits needed per pixel That's the color depth that we were talking about in our image representation video So less bits available per pixel means that there will be less colors available per pixel But because there's now less colors available it means that the image itself won't look as clear because the colors aren't going to be as accurate to the original actual color But because there's less binary information per pixel it is going to reduce the overall file size The other thing that happens during lossy compression is the actual overall number of pixels could be reduced Now when using certain software you can actually choose how much compression you want to apply to an image when you are saving it or a different file So if you're going to heavily compress it it's going to really reduce the file size by a lot However the more you compress an image it's going to look less and less like the original but it will have a smaller file size because overall you've got less pixels and colors available So obviously it comes with some advantages having a smaller file size and using lossy compression you can store more files and the often the images which are compressed like this like a JPEG are compatible with most software so you can open it on pretty much piece of any piece of software you've got on your computer and with the small file size it means that it can also be downloaded really quickly As mentioned though it does come with some disadvantages as well So once the data has been removed it is actually gone permanently So if you reduce the amount of pixels you can't get those back and it will have lower quality overall And lossy compression can't actually be applied to a text file Now that seems like a a weird point to make but in the past it's asked in an exam which would be the most appropriate type of compression to use on a text file And you wouldn't have been able to choose lossy compression as your answer Because if lossy compression was applied to a text file it would actually be missing information from that text file So if you are asked a question like that in your exam you cannot apply lossy compression to text files So the other type of compression we've got is lossless compression Now this is kind of similar to my analogy before about the can of Coke So lossless compression temporarily removes data from a file and then restores it when it's opened So it's a bit like if you can think of it crushing down and then if you need it you then open it again That's like lossless compression Now the way it does this is by remembering the information from the file in a bit of a different way So it will follow an algorithm So it knows what information is stored about that file So if we were talking about an image file such as a PNG that's an example of lossless compression Now if the next 50 pixels were all red rather than saying red pixel red pixel red pixel red pixel it would just say 50 red pixels which is going to reduce the number of binary information that's needed to store that image file But then when it comes to actually recreating that image if it was suddenly in use it would know exactly what information to include in that image because all of the information is right there It's just stored in a bit of a different way because of the algorithm And the proper name for that method is called run length encoding but you don't really need to know that for your exam All you need to know is that it temporarily removes the data and then it will restore it when the file is in use and it's been opened Again it comes with some advantages and disadvantages So the biggest advantage is that there's no reduction in quality It will look or sound as true to the original as possible You can use it on text files and obviously it can be decompressed back to its original form Disadvantage is it will reduce the file size but nowhere near as much as lossy compression will reduce the file size and they will take longer to download because they've got that larger file size Okay so some exam questions to practice on this topic So Mr Moore wants to compress a text file Which type of compression is the most appropriate justify your answer Explain why Mr Moore might want to compress his audio files And finally explain why lossy compression is suitable for a video clip but it is not suitable for a text document This session we're going to be looking at what is a network So a nice definition of what is a network is two or more devices that are connected Now I purposely used the word devices there because a lot of people think that it has to be a computer like a desktop computer to be a network But that's not true That's why we use the word devices because it's more of a generic term for different kinds of devices like laptops phones and that kind of thing And in terms of what a network actually is used for and what it does they are used to share information and resources So we've got some advantages and disadvantages of using a network So the advantages you can share your files with each other easily working in a school it's much easier to share my files with all the students because I can just put them into one place on the network and all of the students can find that file nice and easily So I find a massive advantage of using a network by sharing files As I mentioned earlier sharing hardware So any printers that you might have you might just have one printer in the room or in the building and everyone shares that one printer because no matter where you are if you send your work to print you can get it from that one printer rather than every single computer having its own printer which would be a massive cost So depending on the type of network that you got you can have user accounts So if you come in and you sit at one machine then you can log in which is ideal if you come in and the computer's not working or if maybe you've been moved in a new seating plan and that kind of thing you can still access all of your work And from a technician point of view a technician will find it much easier to install software on all of the devices on the network because they can just do it centrally and to all of the computers that are part of the network or selected computers and that includes any updates as well So disadvantages of a network It's expensive to set up a network because you've got to buy network hardware which is it's a really big cost initially and also an expert is often required and when I say expert I'm talking about a network technician who will actually set up the network and maintain it And also another disadvantage is viruses can affect multiple devices Okay So we're just going to talk about two different types of network now And the first one is uh a LAN So what is a LAN so LAN stands for local area network So as a nice definition of what a LAN is So if you were asked on your exam explain what is meant by a LAN that would be a two mark question You would answer something like devices that are connected in a small geographical location within one mile on a single site That single site bit at the end is quite important That that on its own can get you an extra mark So a local area network can be wired or wireless And you will often find them in places like schools and small businesses Now one important feature of a LAN as well is that the companies or schools or businesses themselves will own the cables or and hardware for the LAN So they will have actually paid for all of their network cables all of the the switches and the servers and so on The other type of network we're looking at today is a WAN So what is a WAN it stands for wise area network or sometimes wider area network What we mean by that as a definition is devices that are connected over a large geographical location And as you can guess it's kind of the opposite of a land because it's over one mile and it's across multiple sites So so it could be that there you have like a huge business and the business has got sites in different parts of the country or it may maybe over different countries across worldwide but they're all linked together by it could be through satellite links or radio links telephone lines and so on Now because the company themselves won't own something like telephone lines they will have to hire these lines to be able to connect their network together And that's a huge cost if you're setting up a one Okay so some exam questions to practice So we've got explain two advantages of using a network Mr Moore wants to set up a network for his small business What type of network would this be justify your answer Explain what is meant by a one and state two disadvantages Mr Moore may face when setting up a home network So I'm going to give you the chance to pause this now and then we will go through the answers Okay let's go through the answers then So explain two advantages of using a network So your first one you could have had was sharing files Uh users can easily share files to work collaboratively So you got one mark for writing sharing files and then the the little bit afterwards is the explanation which we'll get the second mark for Uh sharing hardware for example printers This will reduce cost as an explanation And finally user accounts login from any device in the network So that would be enough for the second mark But if you wanted to go into more detail you could put if a computer stops working the user can move to another computer and still access their work Mr Mo wants to set up a network for a small business What type of network would this be justify your answer So it would be a local area network which is within one building small geographical location not across multiple sites And as a final reason to justify it it will allow file sharing between colleagues So explain what is meant by a WAN It's a wide area network across multiple sites over a large distance And finally state two disadvantages Mr Moore may face when setting up a home network So the cost to set up the network initially and may possibly need an expert to set up the network In this session we are going to be looking at what affects the performance of a network things that can affect the performance of a network But the main ones are going to be bandwidth depending on whether it's wired or wireless the network interference on wireless networks and your choice of hardware So what hardware you've bought when you set up the network So what is bandwidth so bandwidth is the amount of data that can be transferred in a given time So this is where my little weird picture comes from with these cars and the lanes So if you think about my drive in the morning to work where I go on the motorway if it's at say 3:00 in the morning there's not going to be much traffic which is another word that you can actually use when describing a network And if it's busy lots of people using it you can say there's lots of traffic But if too much data is transferred at one time the performance will slow down So it's a bit like if I leave at rush hour in the morning there's going to be tons and tons of cars there and I will definitely slow down with my journey to work It's going to take me a lot longer to get there And it's exactly the same when using a network If there's lots of users logged in lots of people using the services of the network logging in at the same time or trying to access a file at the same time Because all of those users are going to be sending traffic then it's going to really slow down the network So when you set up a network you can choose whether you're going to set up as a wide network or a wireless network Now wide networks are faster and more reliable than wireless A regular Ethernet cable usually has around 10 times faster transfer rate than it does a wireless network But then lots of networks will use fiber optic as well which is even faster than that And we will do a lesson on network hardware which goes into a bit more detail about each one and which one performs the best But also wireless is affected by things like interference which is just quite literally physical obstructions like the walls and doors So if you're sat upstairs in your bedroom and you're using a wireless network to connect to your router downstairs or something like that and you've got your door closed you don't want to wake anybody up while you're talking to your friends or something like that then that is an that is a physical obstruction and it will affect the performance of your device But also your devices have only got limited range So if you live in quite a large house for example and your f your bedroom is further away then it will also affect the performance of your device if it's operating wirelessly Depending on your budget and how much money you've got to set up your network your choice of hardware will affect the performance of the network as well Because there's multiple pieces of hardware that do a similar job but some of them do it in a much more efficient way So if you can afford the more expensive one it will affect the performance of your network in a positive way One piece of hardware that would affect the performance of your network is if you had to choose a hub over a switch or vice versa So you would normally always go for a switch rather than a hub because with a hub you have more data collisions whereas a switch because it uses a MAC address it goes all data goes directly to where it needs to be which means there's less collisions which means it will perform much faster and also when you're actually buying the cabling for your network if you can choose fiber optic cables then that will have much better performance than a copper cable but again fiber optic cable is much more expensive so it depends on how much budget you've got when you're setting up your network Okay just some questions to practice on What affects the performance of a network So state two ways Mr Moore could improve the wireless network performance in the upstairs bedroom Mr Moore switched from using a wireless network to a wired network Explain how introducing a wired network could speed up the performance Mr Moore has a family of five How can bandwidth affect the performance of a network so I'm just going to give you the chance to pause the video and give these questions a go And we're going to go through the answers very shortly Okay let's go through the answers So state two ways Mr Moore could improve the wireless network performance in the upstairs bedroom So you could reduce the interference between the bedroom and the router and you could move your network hardware closer to the bedroom Mr more Switch from using a wireless network to a wide network Explain how introducing a wide network could speed up the performance So wide networks are not affected by interference This will provide a consistent strong connection And finally Mr Moore has a family of five How can bandwidth affect the performance of a network so each device connected to the network will use bandwidth If more devices are connected performance will slow down This video is about network hardware what hardware is and what software is But this specifically is asking what is network hardware So as we know hardware is something physical that you can touch Network hardware are devices that are needed to allow communication between devices So using the network hardware you can build a network Now for your exam you need to know the different common pieces of network hardware and what the differences are between them So the first one I'm going to talk about is the nick or network interface controller or network interface card Sometimes so quite often these are found just as a separate card inside older devices but most of the time now they are built into the motherboards themselves These just allow you to plug in your Ethernet cable so that you can connect to the internet It's probably the one of the most common cables that you'll have seen So the next device which is probably the most common one that you'll hear about on your exam is what we call a network switch Now a switch is a very clever device because it will remember where other devices are on the network using the MAC address And because of that it makes it really secure and it doesn't broadcast any information to any other device It will send the data directly to the device it's intended to go to So this device is the router I'm guessing most people have probably heard of that one Uh most people have got a router in their home And if you get asked what does a router do i bet nine people out of 10 will probably say it connects you to the internet Now yes when we're at home we will connect to our router However the actual job of the router if you're describing it is very different So roots are used to connect multiple devices together In terms of sending data you could describe it as forwarding packets to the correct destination or you could say receiving packets So the next one is our WAP our wireless access point So if you think of a network say in a school you might not be able to visibly see these because quite often they're found underneath you know those those tiles in the ceiling which you can move and it will allow other devices such as laptops and phones tablets to join the network Okay Next is cabling in the network So the most common cable that you will come across is the Ethernet cable And you won't really need to know this for your exam but the most common forms of Ethernet cable are Cat 5e and Cat 6 The actual structure of these cables they are made using copper wire H sometimes referred to as twisted purr And the reason that that happens is to reduce interference which allows the data to travel quicker Another really common cable is coaxial cables Now they are very cheap They're surrounded by plastic and it is a single copper wire and they have a metallic mesh around them Not on the outside of the case but inside of them which will also shield against that interference that we've just been talking about And finally your last cable is fiber optic Now you've probably heard of this when you sign up for say your internet like you know fiber broadband that kind of thing Data is transmitted extremely fast because it's transmitted as light So it's really expensive to install this but it's actually really effective and data can travel very fast Those are our most common types of network hardware We've got some questions to practice as well So this was one from a past exam So this is quite a difficult one So if you want to scroll back on the video and have a little look at it uh some of the differences between a router and a switch Now as always it's a four mark question which means you need to come up with at least two differences but then you need to explain the difference between those in a little bit greater detail Next one what is the role of a router remember to include that some of our key terminology things like packets forwarding and receiving from destination Uh and finally explain why Mr and more should use a switch that is not a Nintendo Switch a network switch when creating a LAN Okay so let's go through the answers to those then So what are the differences between a router and a switch so a router connects you to the internet A switch connects devices on a local area network A router uses IP addresses for communication between devices A switch uses MAC addresses What is the role of a router so a router forwards packets to the correct destination A router connects multiple networks together And finally explain why Mr Moore should use a switch when creating a LAN H It allows communication between devices meaning data and files can be shared easily And finally it allows secure connections between devices due to using devices MAC address This video is about client server networks or peer-to-peer networks So when you set up a network you need to make a decision about whether or not you want it to be a client server network or a peer-to-peer network Both of them have advantages and both of them have disadvantages So it's purely about your situation and the reasons why you would want to choose one over the other one So first we're going to look at what is a client server network As you can guess from the name a client server network is managed by a server And just to recap a server is a powerful computer which has lots of functionality often used for different reasons Uh but in this case you can think that all of the clients which are the people that would log in and access the network They will type in their username and password and then they will pull all of that information from the server so that they can see everything they need to and have access to certain things In a school situation the technician is usually the person who will decide what things people can access from the server whether they can access certain areas whether they can access certain software and so on So as I said all of the devices that are connected to the server are known as clients and the client is the person that asks for the data by logging in and then the server responds to that request So the service stores the user profiles and all of those files are stored centrally Now the good things about a client server network is that all of the files are stored centrally which means that you don't have to take up the storage on one particular computer and you can let's say you come in one day and your computer has stopped working then you can move to another computer and still log in and still access all of your files because they are pulled from the server as you log into that account on that other device From a technician's point of view they're really good because you can install software on all of the devices that are connected to it and you can perform updates rather than going to each individual computer to install the software and perform these updates And as I mentioned briefly you can set user access levels So if you think of it from a school a teacher might be able to see some parts of a system that other users maybe students might not be able to see Something like confidential information for example So there are some disadvantages of a client server network It is expensive to set up and that's because that you know the the actual server itself is going to cost a lot of money There's going to be a lot of cabling involved and so on So it is a high cost initially to set up H you do need an expert Now when I say expert I'm referring to a technician like an IT technician You will have to employ a network technician to be able to manage that server And the final disadvantage is that because you're solely relying on that server if you came in one day and the server wasn't working then nobody would be able to access those files at all So the other option is a peer-to-peer network And you don't need a server for this one All the devices are equal in a peer-to-peer network And because each device is individual each person's computer is their own and they can store their own files on their own device So quite often these are used for smaller networks like in a home or a small office and you can still share files between these devices So for the advantages of a peer-to-peer network they are easy to set up So you won't need to employ uh a technician to be able to do this for you Most people can do it without much training You don't depend on that server which is often ideal if you just want to come in and get on with your work You know where to find everything on your own computer You don't need a login As long as you're sat at the same place you can access all of your things and know exactly where everything is And you can still share files between these devices which is if that's all you wanted to do then that's all you need Now there are some disadvantages of it If you came in one day and your computer was broken for whatever reason then you can't move to another computer as your files are not central So that might be you out of action for the entire day And because you don't need to log into these devices they're not as secure Okay So we've got some exam questions to practice on this topic So we've got describe what is meant by a client server network Describe what is meant by a peer-to-peer network Mr Moore wants to set up a network at his house Recommend what type of network he should choose And then justify your answer So that justifies what makes it a three mark question So you would get a mark for choosing the right type of network and then an extra two marks for a correct justification of whichever network you've chosen And then finally identify two benefits of using a client server network Okay let's go through the answers then So first one describe what is meant by a client server network So you would get some marks if you'd said all the devices connected to the server are known as clients You'd also get a mark if you say a client requests data The server processes the request and then responds Then we've got describe what is meant by a peer-to-peer network So no server is needed All devices are equal when sending information Files are stored on individual devices rather than centrally So Mr Moore wanted to set up a network at his house recommend what type of network he should choose then justify your answer So Mr Moore should use a peer-to-peer network because it is easy to set up No experts required And then this will still allow file sharing for easy sharing of files between family members And finally we've got identify two benefits of using a client server network Files are stored centrally so that clients can move to another computer and still access their work And finally we can set user access levels which makes it more secure So this so users don't accidentally delete or move important work and files on the network and also you could have said won't have access to anything confidential that other people might need to have access to In this video we're going to be looking at what is a network topology A lot of people get confused over the word topology It's just a fancy way of saying the way the network is laid out So when someone sets up a network they've got to make a decision on what they think will be best for the network in terms of how the traffic and the data is getting sent and what's the fastest most efficient way but also managing that network And that's when they decide on what network topology that they're going to use Now for your exam the only two that we need to know about now is the star topology and the mesh topology So we're going to look at those but there are a few other topologies that if you're interested you can also do some further research on So the first one we're going to look at is what is a star network topology This is a common mistake that a lot of people make and the central device is what we call a switch or a hub And a lot of people think it's the server but that's not the case You've got this central device which is called the switch Now the switch is a piece of network hardware and all of your different devices like all of your PCs that are attached like your printer and things like that they're all going to be attached to your central device your switch and it's what allows the communication between all of the different devices Now most commonly on your exam you're going to be asked for the advantages and disadvantages of a star network topology but you may be asked to draw one as well But just if if you are asked to draw one then you need to remember that you've got this central device is going to be your switch Don't put your server in the middle And you don't need to do any fancy drawings uh of like a PC You can just do like a little box and then just write and label it So PC switch just keep it simple So for your advantages of the star network topology uh your network will continue to operate if a device fails So think of it from a school's point of view Let's say you go into a classroom and one of the computers has for whatever reason stopped working Now the user can just move to a different PC They can log in and then they can still access all of their information Whereas on older network topologies if that computer had failed then the whole network would stop working So it's a really big advantage of a star network is that you can just move to a different PC and still access all of your information So it's got really good performance because the switch is quite a clever piece of network hardware There's very few if not zero data collisions And what that means is when you're sending data at the same time as somebody else the data is not going to have any collisions which slows down the network usually quite significantly because of your central device which is the switch Data goes directly to where it needs to then you're going to have very few collisions Okay It's a lot easier to add extra devices as well So there's a proper word for this which is scalability and that is where you are increasing the number of devices that you've got on that network So it's easily scalable So you don't get asked this as often but you may be asked for the disadvantages of a star network topology So we need to know these as well First one is that it's actually really expensive Now you've got a lot of cabling you've got network hardware involved and you're also going to need to pay a technician to maintain this network So you've got the extra cost of employing someone to look after this network So it's quite expensive So that I'm actually going to put as a separate disadvantage that an expert is required So if you had a very small business you may not want to employ somebody else to come and operate this network for you You might want to just do everything yourself Whereas actually you need a bit of expertise maybe a bit of extra training to be able to maintain one of these networks The final disadvantage I've got for you is if that central device breaks so the switch or the hub then the whole network will stop working So the other topology we're going to look at is the mesh network topology Now as you can see from the little diagram you don't need a central device on this one So you're already going to save a little bit of cost because you don't need to buy as much network hardware All of the devices are fully connected Sometimes it's referred to as a fully connected network and the data will choose the fastest route between those devices So because it's fully connected there's no single point that the network can break which is a big advantage Now as a disadvantage because you've got so much cabling between all of these different devices it is very expensive to to set up but you can have a wireless mesh which obviously would save some cost on all of that cabling That's all you need to know for network topology So let's have some exam questions to practice So question one explain two advantages of a star network topology Now just keep in mind we've got that word explain in there and it's actually worth four marks So you need to tell me what the advantage is and then why it's an advantage Question two Mr Moore has set up a mesh topology instead of a star network topology Explain one advantage and one disadvantage of a mesh topology compared to a star topology And then finally what is the central device of a star network topology all right let's run through the answers then So explain two advantages of a star network topology So network continues to operate if a device fails That will get you your first mark to ensure users can work for the maximum amount of time That will get your second mark because you're explaining why that is an advantage Few data collisions So better performance That's your next mark This means that when sharing files the network will run faster So Mr Moore set up a mesh topology instead of a star network topology Explain one advantage and one disadvantage of a mesh topology compared to a star topology So the advantage no central device like a switch needed to connect all devices together which will save cost And for your disadvantage initially expensive to set up due to having all of that cabling And your final question so what is the central device of a star network topology the answer is a switch or if you put h it will be accepted as well So today we're going to be looking at the topic of DNS and how DNS is used to convert a URL into an IP address Now before we get into what DNS actually is we need to understand a little bit more about the worldwide web So let's say you're about to make a website and you're going to buy something called a domain So the domain is the actual name that people will remember So like bbc.co.uk or eBay.co.uk So the this is the actual domain that we remember the eBay part of it for example or Mr Moore CS Now when somebody buys a domain it has to be hosted on something known as a web server Now when I say hosted it means that that's where people will actually connect to to be able to access the website itself So people will pay for their website to be hosted on a web server somewhere in the world So the URL is usually nice and memorable It's why they're so expensive for ones which are really short and easy to remember Now because that website is being stored on a web server to be able to access that web server we would need something known as an IP address Now an IP address just a long string of numbers which is the location of where that is So because we are able to remember the name of a domain but it's unlikely that we can remember the IP address of where that website will be stored That's where DNS is used so that you don't have to remember the IP address the DNS part of it will translate the name of the website into the IP address so that you don't need to remember the IP address and then your website will still appear in front of you on your browser So you can think of it a bit like a phone book So you might not remember your friend's mobile number but you remember their name hopefully So let's say you've got a friend called Bob You can click on Bob and it will call Bob However you probably don't remember Bob's number off the top of your head So all you need to remember is the name Bob you click on it it dials it And it works in the exact same way with DNS because you can remember the name of the website but not the number that's associated with it So these are the steps that are involved with DNS So the website gets hosted on a web server We've already talked about that The web server has an IP address Your browser something like Google Chrome or Edge sends the URL to DNS which don't forget is like a system which is being used So DNS will then find that IP address that's linked to the URL Now let's say you've made a spelling mistake and you've gone to type in Mr Moore CS but then you've actually put like Mr Moore CD and it doesn't exist Now at first DNS will try and pass that request to a higher DNS which means it's going to look elsewhere to see if that website actually exists But if it doesn't exist and it can't find it it will just return an error But if it does find it that's when it will send all of that data to you and the website will load up correctly So here's an example question about DNS where it doesn't actually use the word DNS in the question itself So the IP address 192.130.129.226 see it's hard to remember is linked to the website with the URL of Mr morcs.co.uk When mmorcs.co.uk is entered into a browser the website homepage is loaded Describe the relationship between the website URL Mr CS.co.uk the IP address and the web server So as you can see it is talking about the process of DNS without talking about the process of DNS So you need to realize that that's what it's talking about and then relay those different steps that I've given you on the previous slide Now you could actually bullet point your answer on this one but sometimes it's nice to just maybe use parts of the scenario as well So if a user was going to visit mrmorcs.co.uk they would type in the URL But your answer could look like this So the website host is on a web server The website server has an IP address The browser sends the URL to DNS The URL has a linked IP So DNS finds the IP If DNS can't find the IP it passes it to a higher DNS but if not found an error is returned And finally the web server sends the web page and all that data to the user Today we're going to be looking at how devices communicate Devices communicate using something called standards And they also use something called protocols We're going to be looking at protocols next time So don't worry too much about that one So the reason devices communicate is so they can transmit data over a network But let's have a look how they actually do that A network standard is an agreement about the hardware and software which is going to be communicating and sending the data to each other So a really common one that people have heard of an Ethernet cable but then there's also an Ethernet protocol as well for communication And by having these standards it just helps manufacturers to create products uh and software so they're compatible with other manufacturers So they can develop their own product but then this is the standard that they will all use so they can still communicate with each other Some really common ones include like on your web browsers where they agree that they'll use HTTP to communicate or HTML Now if devices are on the same network as each other there's a way that they can communicate with each other and this is by using a unique address If they're on the same network they'll use something called a MAC address Now it's important we understand what a MAC address is what it looks like and the properties of a MAC address So here it is So a MAC address has 12 characters The MAC address is unique to every device and it can't be changed A MAC address in hexadeimal So if we look back at our data representation unit we can see what hex decimal looks like And if we think about our network hardware we discussed what a network switch was And that is what will use the MAC address to be able to send the data to the right place If the device is on a different network it won't use a MAC address It will use a different type of address one that you probably heard of called an IP address Now IP stands for internet protocol So if you remember what IP stands for you'll probably remember that you would use that one to communicate over the internet Now there are two versions of IP address There's IP version 4 and then there's IP version 6 So IP addresses can be reused They can be changed and can be automatically allocated when you are using the internet They've started to use IP version 6 uh which is almost limitless in the amount of combinations of types of address that are available so they can start assigning to all the devices that are using the internet An IP address will need to be allocated before that device can actually use the network So we've got some practice questions to finish on just on that short topic Uh question number one is what is a MAC address used for uh question number two is explain what is meant by a network standard Question number two how many bits is in IP version six and finally explain how devices on a star network make use of a MAC address Okay let's run through the answer then So question number one what is a MAC address used for it is used for communications between devices on a same network Question number two explain what is meant by network standards Standards allow manufacturers to create products and software that are compatible from other manufacturers Question number three how many bits are in IP version 6 128 bits And finally explain how devices on a star network make use of a MAC address An answer you could have given is something like when a device sends information to another device within the same network A network switch will use the unique MAC address of the device to ensure that data reaches the correct device Today we're going to look at what are network protocols A network protocol as definition because you can sometimes get asked this on your exam is uh what is meant by a network protocol and as a definition it's a set of rules for how devices communicate and transmit data across a network So the protocol specifies how communication begins and then how it ends between those two devices and it could be within the same network or it could be over the internet but it's what will say how the data gets organized and then if the data goes missing what's going to happen next Now this isn't an exhaustive list We're going to look at the protocols you need to know for your exam So your first one which is the one they like to ask the most questions about is called TCPIP and it stands for transmission control protocol internet protocol Now TCP is probably like the main protocol which allows packets of data to reach where they're going and make sure that everything is spot on So it will say how the devices are going to communicate how that data is going to get split uh how they get rearranged when once they've arrived and it will check that they've all been sent and delivered correctly The IP part of that as we've mentioned in a previous video it stands for internet protocol So you can think that if the data is going to be set getting sent over the internet then they need IP to make sure that it will reach their destination over the internet Now HTTP is probably one that you've definitely seen before uh at the top of your browser maybe if you are on a website using Google Chrome something like that and it stands for hypertext transfer protocol As we said it's what browsers will use to access the websites and then communicate with the web service wherever the website is being stored in the world If we go on further than that there's HTTPS where the S then stands for secure So any information that's being transmitted to that website it could be like your username password email address or anything like that All of that information gets encrypted if it's using HTTPS to make sure that it's all secure when it's being sent You'll find that the majority of websites use this nowadays especially things like social medias Basically anywhere that you would be submitting any information will be using HTTPS and if it's not you shouldn't really be using that website Another common protocol that we need to know about is one called FTP which stands for file transfer protocol And this is just a protocol which is used to access and then move files between devices over a network So it could be that the files are stored somewhere in FTP server and then you will use FTP to sort of communicate with that device and then pull all those files across So the first one we're going to look at is one called POP 3 which stands for post office protocol version 3 Now if we think once you're trying to access your emails they are stored somewhere on a server then if you receive those emails but don't want them to stay on the server then you would use POP 3 because then it will remove from the server but then you would then retrieve your email and still get it But if you wanted to stay on the server in case you want to access it again later you could use one called IMAP which stands for Internet Message Access Protocol And this is where you will receive a copy of the email from the server instead and it will still also exist on on the server The final email protocol is SMTP which stands for simple mail transfer protocol Even though the S stands for simple a good way to remember this one is to pretend that the S stands for send instead And then we can remember what this one's used for which is for sending emails There's a concept that we need to know for the exam which is something called layers and layers get considered and thought about because it's it helps us break down the complex problem about transferring data across a network And in our last video we talked about standards and how it can make uh products from other manufacturers make some sort of agreement and protocols that they're going to use to be able to communicate we can focus on one area of the layers so that we can design software that's for one particular layer and it will just simplify that whole process of how these devices are actually going to communicate Now in the four layer model the layers that we need to know about are the application layer the transport layer the network layer and the link layer You can assume that these layers are what will decide whereabouts that protocol will sit in that process of communication between the devices If a manufacturer wanted to develop a protocol which was around transferring files then that would sit in the application layer and they could develop then something which is similar to FTP for example or HTTP because it's the transfer of data If the manufacturer was looking at something around communication about how packets are going to be sent between devices then that will be somewhere around the transport layer which is things like TCP So by understanding the layer model it will just allow us to think about what protocols there are and whereabouts they would sit in development of new protocols for different manufacturers and their products And as long as the data that is received in the correct format then the layers don't need to worry about each other They only need to worry about the one thing that they are doing Okay So few extra questions today but a little bit shorter on our answers So hope you don't mind So question number one h is what is meant by a network protocol question number two is what is meant by a layer question number three is what is an advantage of using layers and then I want you to identify protocols for the following scenarios So first one is transferring files between devices over a network Next one is encrypting information that is sent and received and finally for sending emails Okay let's have a little look at the answers then So question number one is what is meant by network protocol nice simple answer They are the rules for communication between devices on a network Question number two is what is meant by a layer and a layer is a group of protocols and you could have written that layers are self-contained Question number three what is an advantage of using layers so layers can be changed without other layers being affected Each layer has its own purpose that can be programmed individually And a file advantage you could have written for that is manufacturers can focus on developing software for just one layer Last little bit where we wanted to identify protocols for these scenarios The first one transferring files between devices over a network You could use FTP Next one is uh for encrypting information sent and received we would use HTTPS because don't forget that S stands for secure And finally we're sending emails we would use SMTP Today we're going to be looking at what is meant by the cloud Now quite commonly when people think about the cloud the first thing they think of is storage and things like iCloud and things like that And they're not wrong but there is way more to the cloud than you probably realize Not only is it file storage there's also different services that are available over the internet Uh most businesses will have sort of servers which has and offers storage of files which is what probably most people think of when they think of the cloud And like I said that is right But what's really handy about it is because clients can use and access their files and the services over the internet So sometimes this can be referred to as a cloud application So there are tons and tons of different applications that you can access quite often for free as well And so some examples of it might be like a Google slides for example or it could be Google Docs And you've got other ones which are really common like teams And as we know that was a massive thing that was used during lockdown because then people could access all of their files and still communicate and speak to each other with online lessons and things like that Now what's handy about it is that some of these applications are actually really powerful So because of that they get stored on a powerful server somewhere else and then even with less expensive hardware that somebody might have at home they can still access and use these powerful applications because they're actually being hosted somewhere else in the world on somebody else's server The most common thing that's asked about the clouds in your exam are the advantages and disadvantages And they can actually hold a lot of marks They can often be worth two to four marks for then just the advantages and then four marks possibly on the disadvantage as well So if we nail this little bit then we'll do really well And if you think every seven marks is potentially another grade on your exam then it holds a lot of weight in this bit So we need to get this right So we'll start with the advantages So the first one is it's easy to increase how much storage you have available Now if you were a business if you need to then back your answer up with why that's an advantage uh you might start with the free version where you've got a certain amount of storage but then let's say you start running out of storage then you can pay and immediately get that extra storage and it's it's available to use straight away Now if you've got hardware or storage that you've got maybe within a school or a small business you would have to pay someone like a technician to be able to manage all of that stuff for you Whereas other IT staff that are working say for Google will manage those for you which is a massive advantage because it's going to save a business a lot of money as an as the explanation for the advantage Now whoever that host is again let's say it's Google they're the ones that will manage the security and all the backups for you So if there was a problem then they are the ones in charge of that They always keep it up to date for you which is great So you're always using the latest version of the software whatever it is that you're using And finally as probably the biggest advantage of it as long as you've got an internet connection you can access your stuff So you don't need to carry around like a pen drive with you or anything like that You just need to be able to log in and then access that service Let's have a look at the disadvantages of the cloud Now on the flip side to what we were just saying if you've got no internet access then you cannot access your things which is a pretty big disadvantage Now we said before that the security is managed by the the other company which is good However it could be vulnerable to hackers Now if you've got a business which is storing loads of let's say large files videos then the actual subscription fee for that amount of storage can be quite expensive Let's have a little practice with it then and we're going to start with explain two advantages of using cloud-based storage So we're being specific here about the storage elements of it two advantages of it And then for our second question I want you to explain one disadvantage of using cloud-based service Right let's run through the answers then So to start with explain two advantages of using cloud-based storage Uh users can access files and applications anywhere with an internet connection So you could work remotely if you were unwell Uh and you could have written as well It's easy to increase how much storage is available So if more storage is needed then you could get it instantly and potentially here's an answer for explain one disadvantage of using cloud-based services So subscription fees for the cloud storage and applications can be expensive which might be necessary depending on the service Okay that's it for this one See you next time Today we're going to be looking at malware and some other threats Let's start by looking at what's meant by malware So the word malware is broken down into malicious software And don't forget software are things like applications that are installed on the device itself Now you can't see malware Often it's installed in the background so that you don't actually know that it's there but it's harmful and it can be really damaging to your computer or device Often they get installed so they can edit delete or steal information A way this could happen could be something like a Trojan virus which is where you go to download something and you think it's one thing but actually it installs malware on your computer and you don't even know that it's there Another potential threat is unauthorized access So unauthorized access is when someone's not been given permission to access data but they access it anyway There's multiple ways that this can happen It's not just because somebody's left their laptop or device unattended So one method could be by intercepting messages as data is being transmitted If it's not being encrypted the data once it's intercepted can be read or it could be copied which means that they can gain access to your confidential information Another method of unauthorized access is just by finding out someone's password which we're going to be talking more about in a moment As a result of unauthorized access it could cause loss and cause damage Now sometimes people do this on purpose Sometimes people accidentally cause damage once they've gained access to something by maybe moving an important file or deleting it Now there's different ways that people can find out someone's password It could be through something called a brute force attack A brute force attack is when a piece of software will try multiple combinations of passwords to try and find the correct password A common prevention method of this is by having a strong password which consists of a password having over 12 characters and has uppercase lowercase characters special characters and numbers Another method is by using social engineering techniques Social engineering is where you trick someone into giving away their confidential information A common example is something called fishing Someone might open a malicious email which contains a link and when they click on that link because they've been tricked into clicking on it it will take them to a very believable website where they might enter their details and it will go back to the attacker Other methods might include pretext phone calls which is sometimes referred to as bragging and this is over the phone where you trick someone into divulging some confidential information by making up a scenario that they might believe like they've been in an accident or they're owed PPI A final method we could talk about is shoulder surfing Shoulder surfing is quite literally looking over somebody's shoulder to try and find out their passwords This doesn't only have to be on a computer It could also be at say a cash machine at a checkout when people are entering their PIN or to gain access to a locked room like maybe a staff room at someone's workplace The best prevention method of this is staff training and awareness The more people talk about it the more people know about it and what to look for the dangers and signs then they might not be victim to these attacks Another thing I want to talk about today is something called user access levels So when you join a network you will have a different level of user access depending on who you are So a network manager will have total access to everything so they can manage the network properly But somebody else using the network might not have access to everything For example a student might have access to program files in case they accidentally move or delete one So there's three different levels of access that I want to talk about The first one is called read write access This would be someone very high up someone like the network manager and they can view any files and they can make changes to them Read only access is where you can view the files and read them but you can't make any changes to them And finally just having no access You're not allowed to see them You're not allowed to do anything to them Okay let's look at the questions for this topic So describe three user access levels Give two examples of social engineering What is meant by malware and explain the process of a brute force attack Okay let's go through the answers So describe three user access levels So we've got read write access where you can view the files and make changes to them We've got readonly access where you can view the files but you can't make changes to them And there's no access where you can't view the files Next one's give two examples of social engineering So the ones that we've said were fishing farming pretext phone calls or blogging or shoulder surfing Next one is what is meant by malware So if we break it down it's malicious software designed to edit delete or steal data And finally explain the process of a brute force attack trying every combination of words and numbers until the password is guessed Today we're going to be looking at online threats So last time we were looking at general threats whereas these threats are specifically looking at network threats So a common one that a lot of people have heard of and often just refer to as a DDoS is a denial of service attack or DOSs or DDoS When you use a network you're sending packets of information And a DOSS attack is when a large amount of packets are sent to a destination Now the sheer volume of this amount of information being sent is what's going to overload the server or bandwidth This in itself can just stop a computer network from working Now the difference between a DOSs and a DD DOS is the extra D in DOS stands for distributed So a distributed denial of service is much harder to track as it comes from multiple places One that I want to mention today but we're going to go into in more detail in the next video is something called an SQL injection Now SQL is a type of programming which is used to edit search and manage a database If people use malicious SQL they might be able to gain access to the database and steal the information or change it This is often done through a website input and the website not being very well tested for any vulnerabilities Now we've got different ways of protecting that data Let's have a little look at the prevention methods So the first one which is a really common one is a firewall A firewall will check all the different signals that are going in and out of a network This will prevent any malware from entering the network So if a packet looks suspicious the firewall will prevent it from entering the network Another common method is something called encryption We've talked about encryption when we did protocols when we were talking about HTTPS with the S standing for secure This is where all the data will get scrambled if it's getting sent so that anybody who does intercept that data it will be useless to them Only people with an encryption key are the ones who can see that information Different apps will use encryption called endtoend encryption without you even realizing A really common one might be on something like WhatsApp So that when you're sending messages to other people you can see it as plain text As you send it the message gets encrypted and as it's received on the other end that's when it becomes decrypted so that they can see it in plain text again But anyone in between who tries to intercept that information it'll be useless to them Final method is penetration testing This is where authorized people are allowed to try and break into the network and find vulnerabilities in it And if they do find any weak points they will report it back and they will work on fixing that area to make it more secure As well as these we've got physical security methods These can be as simple as keeping computers in a locked room Or we might use something like biometrics These are really common on smartphones where you've got things like Face ID retinal scanners fingerprint scanners and so on You might employ a security guard which will just stop any access unless they are authorized And you could use a swipe card like I have for work which is a little badge which will just get me in and out of the buildings Okay let's have a look at some questions on this topic then So explain how penetration testing is used to make a system more secure Identify three physical security methods What is the purpose of encryption what is SQL injection okay let's run through the answers then So explain how penetration testing is used to make system more secure You could have put something like people try and break into a computer system to find weaknesses that can then be fixed Next one identify three physical security methods So I went for security guard locked rooms swipe card entry Next question is what is the purpose of encryption data is unreadable by anyone who intercepts it And finally what is SQL injection it's malicious SQL commands that are entered to steal or delete files from a database Today we're going to look in more detail at what is meant by an SQL injection So to start off with let's just get a bit of an understanding of what SQL means SQL stands for structured query language This is something that is used to edit manage add to delete search a database Databases contain loads of really important information This could be the information on a website but it could also be user details Often that's really valuable information to a hacker So an SQL injection is a type of cyber attack where they will try and gain access to this information by using malicious SQL code Now this will take place on websites that haven't been tested very thoroughly and it could be somewhere where the user has to type in information This could include somewhere like a login form or a search box on a website Now as the user is using the website like this this is called user input And if the website's got good web design it will check what the user is putting in and it will clean that information before it's being inputed So let's have a look at some methods of prevention of an SQL injection The most common one is something called input validation And if we think about that word validation and the word valid when something's valid it's it's correct So only if the user has put in correct information will it be allowed This could be down to the type of information that somebody puts in So if they were asked to enter their age it might be that they're only allowed to put in an integer Or even better it might come down with one of those little drop-own calendars where you will choose the date that you were born and then that way there's no way the user can type in information in that box On some websites you could use something called a prepared statement So rather than the user typing in something potentially into say like a search bar you could use something called a placeholder So for example if you're on a shopping website and you're trying to find t-shirts rather than them typing in t-shirts in a search bar you would have a little drop-own menu so that you can just click on the section that says t-shirt and it will run that SQL query for you so that the search is done without the user having to type any information that that could potentially be malicious Linking back to the last video you might just not want to give them any access to anywhere that they shouldn't be able to access to So we don't want to cause unauthorized access So you will limit their access to different areas And finally a great method of prevention is again penetration testing in this case So you will do regular checks on your system to see if there's any weaknesses any vulnerabilities and if there are then you can go back and fix them So just a couple of questions on this topic So what is SQL injection and explain a method of prevention for an SQL injection Okay let's run through the answers then So what is SQL injection it's malicious SQL commands are entered to steal or delete files from a database And the other question is explain a method to prevent SQL injection So I've gone for input validation It's where we ensure all user input is checked and it only allows the expected type of data And I've given a little example there as well Numbers for age no special characters for usernames That would have been enough for the two marks but you also could have gone for regular security testing So you could use penetration testing to identify any vulnerabilities before the hackers do And that's it for this one I'll see you next time Today we're going to be looking at different types of operating systems When we've thought about software in the past we're thinking about the different programs the different apps that are installed on the computer And an operating system is very similar It's just software that runs on the computer But the operating system is the thing that is in charge of the different hardware that's on your computer and any other software that is running So the operating system itself is a platform that allows us to interact with it but it also allows all of your other applications programs to run Now for us as people it's not as easy to interact with a computer or device So we have something called a user interface which is what we're looking at when we're using the operating system on the device Now there's different types of user interface All have got their advantages and disadvantages and we're going to look at some of them now So the first one we're going to look at is this a graphical user interface or GUI or guey for short And what you can see is just uh all the different icons that help people who may not have much experience using a device It might make it easier for them to use Now an easy way to think about this and remember it is something called WIMP So for the W in WIMP that stands for windows And you've got things like this as a window which it allows us to interact with it and see different things that we might store or keep in different places You can move the window around you can resize it whatever you want to do with it The I stands for icons So like in real life they try and use pictures and icons that are relatable and can help us remember what we're going to actually use it for So for example I know that if I don't want something anymore I can put it in the bin And we've got an icon here of a recycle bin because it's relatable We know what it would be used for So if I don't want something I can just move it and put it straight into the recycle bin So it just allows us to remember what it should be used for and interact with the device in that way So the M stands for menus We've got tons of menus in the graphical user interface For example when I click on start and go to all my programs we've got a list here This is our menu We've also got different menus when we right click in places of different things that we can do as well And then finally we've got the P which is for pointers And you can see I've got my nice bright pink pointer So I can see exactly what it is that I want and I can just click wherever the pointer is and I'll be able to access it Another type of menu is something called a command line interface An example of a command line interface is command prompt where we can type in commands and still control the device in this way Other examples would include on a Linux operating system you could use the terminal So to use this you just type in different commands so that you can control it So for example if I wanted to change which folder I'm currently looking in which directory I can do cd which is for change directory I can change to this one which is what I want to look at and send in that command And now that's the directory that I'm looking in If I wanted to make a directory I can type in another command MKDIR and then give it a name like example one I'll press enter Send that command in Let's open that folder now and look And here is the folder that I've just created using that command Other examples of user interface would include a menudriven interface which is a bit like when you get to a cash machine and your options come up on the screen in front of you and then you've got different buttons that you would press on to interact with what it is that it says you can do The final interface I want to talk about is a voice activated interface This could be something like Siri where you would say Siri and then your command and then it will listen to you and then it should hopefully do what it is that you've asked it to do It then might follow up with further questions and get you to interact with it in that way For your operating system to manage all of this different software it has to allocate memory to each of these different open applications Now you can actually see how much memory is being allocated to different applications by doing this control altdelete on your keyboard selecting task manager and you can see what's currently open in this way You can see at the moment I'm using about 39% of my memory for the current open applications You've also got the different background process which run in the background anyway which are also using memory but not as much Sometimes this is referred to as multitasking So as you've seen I've got different applications at the moment that are open And to do that the operating system has to multitask and run those different programs at the same time Now as we know all the way back from our hardware unit we've got the CPU which is fetching decoding those instructions that are coming from all the open applications Multitasking allows that to happen smoothly and the operating system will interact with the CPU to ensure that that is happening Okay let's have a look at a few questions on this topic So question one explain the role of an operating system Question two identify three types of user interface And question three explain what is meant by memory management Okay let's go through some answers then So question one was explain the role of an operating system You could have written something like an operating system is software that manages computer hardware and software resources You could extend your explanation by saying the operating system provides a platform for applications to run Question two was identify three types of user interface So some of the ones we've looked at are graphical user interface command line interface and menu interface Question three was explain what is meant by memory management So you could have written something like the operating system allocates memory to different applications transfers data between RAM and storage when needed In this video we're looking at system software In the last video we looked at operating systems and how it is software that manages both hardware and software resources System software in this video is referring to the different software and processes that are available as part of your operating system The first one that I want to have a look at is peripheral management and drivers So first of all let's look at what's meant by peripherals Now if you think peripheral vision something that's on the outside that should hopefully remind you about what is meant by peripheral which is external devices It could be things like a keyboard a printer a mouse and so on As part of system software you can manage these different devices that are connected And sometimes you need to install an update to make that device work properly This is also known as a device driver So a driver is actually software that allows the operating system to correctly communicate with the peripheral If you connect a device that your operating system has never seen before it might be that they can't communicate with each other By installing the correct drivers it will fix any bugs and allow that communication between the device and the operating system itself This usually improves performance and enhances its capabilities but will also fix any bugs that it might have been experiencing as well Another feature of system software is user management The operating system allows different users to have separate accounts Now it might be that different users like having things set up in a different way So you can personalize your own profile so it's set up in the way that you like Now if different people are using the computer it might be that you want to have different access rights We've talked quite a lot about access rights in the past when we looked at our networks topic but as a quick reminder an admin might have access to more things than a guest might have The admin might be able to make changes to the computer itself install extra programs whereas a guest might just be able to use the things that are already on there but not make any actual changes to the computer itself As part of a user management feature you've also got security features as well This can be setting up things like passwords authentication finger ID and so on Another feature of system software is file management So when you've got your files stored in a hard drive or a solid state drive it can be quite confusing for us to understand But how we see it and interact with it is actually really easy And that's because we store our files in a structured way in folders that we can recognize So what we're looking at here is a folder that I've got on my computer This is actually stored in a place on my hard drive So for us to interact with it we can click on the file that's inside it and we can perform different actions with it Most of these actions are across the top here So we can copy them we can rename them we can share them with other people we can delete them and we can move them For example I can drag and drop this one inside here Whereas actually that's changing the location of that on the hard drive So as a final overview of system software file management we've got naming renaming files so they're given easy identification for us We've got folder allocation so that files are stored in the different directories or folders as we call them And we can move and save different files Files can be copied moved or deleted And all of this comes under what we call file management Okay let's practice some questions on this topic Question number one explain what is meant by a device driver Question number two identify two features of user management And question number three give two advantages to a user of file management Okay let's run through the answers then So question one was explain what is meant by a device driver You could have put something like software that allows the operating system to communicate with peripherals They can add extra functionality to the devices Question number two was identify two features of user management So we could have gone for security and access rights And for question number three give two advantages to a user of file management I've gone for a user can rename files that would get me one mark so that they can be found and identified easily So that's your second mark on that first advantage You also could have gone for files can be stored in folders That's one mark So that they can be kept organized and found easily by the user That's your second mark for that one And that's this video We're going to be looking at utility software Now as a definition utility software is system software that helps maintain and optimize a computer So the first one we're going to look at is encryption software Now encryption is a feature that we've come across quite a few times especially in the networks topic when we're sending information to other people and it's very similar in this case but it's just a feature of an operating system to also protect data So encryption data protects data by converting it into an unreadable code And like before if anybody was to intercept it or try and get it it will prevent unauthorized access to see that sensitive data that they might be after Common examples will include Bit Locker and VeraCrypt If you've not seen Bit Locker before this comes as a feature on Windows computers And if you plug in something like a pen drive it might give you the option to encrypt the file using Bit Locker And what that will do it will make it so that anybody else who tries to access that pen drive it will require a password for them And if they did manage to access the files without the password all of it will be scrambled and it will be useless to them The next one I want to talk about is disc defragmentation Now this is something that only happens to hard drives it will optimize the hard drive so that the read and write speed is much faster Over time hard drives can become what we call fragmented Now what that means is that blocks of data of related files are usually stored next to each other on a hard drive But if a file gets deleted it might free up gaps on the hard drive And as a new file is added if it doesn't quite fit in that gap it will go across multiple parts of the hard drive So that now when it's going to read that information from the hard drive it's got to look in more than one place to actually access the larger file that's taking up those blocks that became freed up in the first place Disk defragmentation is the thing that moves the related files back together so it's only looking in one place to see those related files and that will speed up overall access A final one that I want to look at is data compression Now we've looked at data compression before when we were doing our memory units Data compression reduces the file size This is good because it will reduce the amount of storage that your files are taking up on the hard drive but it also means if you're transferring data it will speed up that process as well because it's got the smaller file size Another advantage is it makes it faster to send files over the internet We've got the two types of compression that we've already mentioned which is lossy compression and lossless compression One that we didn't talk about were zip folders for lossless compression So if you were going to create a zip folder you would select all of your files You can rightclick and put them into a zip folder This will compress all the files without removing any of the data This makes it much easier to send to somebody else because the file size is much smaller and you can attach it to an email and send it to somebody over the internet Okay let's look at some questions for this topic So question one what is the purpose of encryption software question two explain how files may have become fragmented on a hard disk drive And question three what are two benefits of data compression okay let's go through the answers then So question one what is the purpose of encryption software so encryption protects data by converting it into unreadable code Question number two explain how files may have become fragmented on a hard disk drive So it was a three marker so we've gone into a little bit of extra detail on this one So when files are saved in non-ontinuous blocks of free space this will cause parts of the file to be scattered across different locations on the disk As files are modified or deleted gaps will form leading to more fragmentation and making the read write head take longer to access the data And question three what are two benefits of data compression it saves disc space and it makes it faster to send files over the internet And that's it for this one I'll see you next time Today we are looking at legislation When we think about legislation we're talking about law and how it can affect our use of digital devices and other technology So there's four pieces of legislation that we need to know about not in and out because they're absolutely huge documents but we need to have an understanding about what they are why they're in place and how they can affect technology The first one we're going to have a look at is called the data protection act So the data protection act is in place to make sure that organizations a bit like a school or a business are handling data properly So if we think of it from a school point of view schools collect data about their students and staff and then they have to store it Now they have to have this data They need to know like medical history They need to know where you live They need to be able to do things in certain situations like if there was an emergency who to contact if there was a problem again who to contact and so on For schools to be able to store data they have to do it responsibly There's a phrase that's used for the data protection act and it's the key principles This is what should be followed by organizations to make sure that they are handling data properly So when collecting the data in the first place it should be collected fairly Once the organizations have got that data it needs to be kept secure You couldn't just leave it in like a tray That would be breaking the data protection act Part of this as well is that a school would only store it for the amount of time necessary Final one to keep in mind is that individuals have the right to be able to access their data Okay so the next one we're going to have a look at is called the Computer Misuse Act of 1990 As a general what it's about this prevents anybody from hacking and any cyber crime that goes on what that means It's illegal to be doing any hacking creating any viruses or spreading them or carrying out any cyber attacks So there's three main offenses that we're going to have a look at but these are kind of overarching and lots and lots of different things will come under these They're just general terms for the majority of things that can go on in the Computer Misuse Act There's going to be more specific cases but they would probably categorize it under one of these three main things The first one's unauthorized access which is accessing anyone's data without permission The next one is unauthorized modification of data which means to change it unnecessarily and that's usually done by spreading malware And then finally using computers for any type of fraud which is cyber crime The next one most people are quite familiar with which is the copyright design and patent act of 1988 So this is what protects people's content their digital contents and it means that people aren't allowed to copy things like books uh images videos or anything without permission It also protects intellectual property and make sure that creators are getting paid for what they've made This is also the act that allows legal action against piracy This is stealing digital things without paying for it Okay so we've got some questions to practice about this topic So what's the general purpose of the data protection acts give to offenses covered by the computer misuse act 1990 Why was the computer misuse act introduced okay let's go through the answers then So question one what is the purpose of the data protection act so you could have written something like it makes sure that personal data is collected stored and then used securely and fairly So that would get you one mark Then you could extend it by saying it gives individuals the rights over their data such as access and correction Second question give two offenses covered by the computer misuse act 1990 So you get one mark for saying unauthorized access to data And then you could get another mark by suggesting something like spreading malware or modifying data without permission And finally why was the computer misuse act introduced to prevent unauthorized access hacking and cyber crime would get you one mark and then protecting individuals and organizations from the misuse of computer systems Today's video is about licensing So software or applications have got licenses and these are kind of the rules that you need to follow to make sure that they are being used properly or modified and shared properly So whoever created the software application in the first place they're the people who make the decision about what type of license it's going to have The license will protect the rights of the software creator but it also lets others use it legally and it states how they should be using that software Now if somebody's gained access to a piece of software it might be that they're using it at home which would be for personal use If a business or a school are using a piece of software then there might be other rules that that they need to follow to make sure that they are using it correctly Some type of licenses allow people to actually change the software and modify it while other licenses may have some restrictions on whether thing it could be copied or shared with other people But if you don't have a license for your software it could lead to legal action So there's two main types of licenses that we're going to be talking about and we need to know about for our exam which is open-source software and proprietary software So we're going to start with open-source software which is software that is usually free to download and the source code is freely available Now what we mean by that is that you can modify and change that software to your liking Part of the license being an open license means that you are allowed to do that Now what's really nice about open-source software is that it's very communitydriven So lots of people will download it because it's free to use saves them a bit of money But then anything they find out about the software or learn about it or any changes that they make part of the license is that they will share that information and discuss it Which means the community are the ones driving that that software further updating it and fixing it as it's going along to make improvements along the way So we also need to be able to talk about the advantages and disadvantages of the two types of licenses that we're going to discuss today So let's have a look at the advantages of open-source software So as I said earlier there's no cost usually which is a big advantage that you don't need to pay for the software and also you don't need to pay to be able to modify it So if you needed to use that as a basis and then modify it to your liking then you're allowed to do that It generally has lots of security benefits as well because the different developers that are using it will find fixes and develop it further and fix any vulnerabilities And as I mentioned you can adapt it for your specific needs So if you work for a company and you need to make an adjustment to fit the needs of the business then you're allowed to under that license Now there are some disadvantages to open-source software The first one is that it generally lacks technical support because it's not a paid for piece of software It's mainly relying on the community to be able to push it further support it So there's not going to be somebody that you can call to make fixes which sometimes if you're the first to come across an issue there might not be the answer to what it is that you're looking for And on a similar strand to that if it needs some sort of fix or a patch you're relying on the community to be able to create that patch and then download it And usually because it's open- source software it's not as userfriendly as paid for software So to begin with there can be quite a steep learning curve with open-source software Okay Okay the other type of license we're going to have a look at is proprietary software So this is one that's owned by a company and you've not got access to the source code Sometimes it's referred to as an offthe-shelf product because when you buy it that is what you end up with and get to keep Now if you're somebody who's quite happy to just accept software for what it is that application you don't want to make any changes or modify it then it's usually fine But as I said earlier you've got no access to the source code If you try to access the source code that would actually be illegal under this license So when you purchase the software you get a license to be able to use it That is your legal copy of the software And because it's proprietary software it gets supported There'll be regular updates for that piece of software So for the advantages of proprietary software because you get reliable support and updates regularly from the company that's a huge advantage Generally are more features on proprietary software and it's quite userfriendly as well because it's being developed with the majority in mind And often you get a warranty or guarantee with it So if it's not working or there's a problem with it then you could get your money back So for disadvantages of proprietary software it can actually be quite expensive to purchase in the first place Even though it's a good thing that it comes from the company sometimes you can be waiting for that company to come up with any fixes And as a big disadvantage compared to open source you've not got the ability to modify or customize the software So if it's not exactly what you're after then there's no changes that you're allowed to make to that Okay let's have a look at a couple of questions on this topic So question one give one benefit and one drawback of using open-source software And question two explain two advantages of using proprietary software for a business Okay let's go through the answers then So give one benefit and one drawback of using open-source software So as a benefit it's usually free to use which reduces costs And as a drawback it may have less support or documentation compared to commercial software And question two explain two advantages of using proprietary software for a business So advantage one it usually comes with professional support and regular updates So that would be one mark The software is working optimally at all times So that would get you two marks Then for your next two it has been thoroughly tested That's one mark So it's often more reliable and secure for business use That would be your other marks to get all four marks And today we're going to be looking at ethical issues So ethics means the rules of what's right and wrong This is a very opinionated topic but sometimes some of the bigger things that you can talk about come from cultural beliefs religious beliefs and generally people's own thought on a matter So this topic is always based around technology and the ethics of using technology and it's about how we believe it to be right or wrong in using technology in a certain way Now this is not an exhaustive list You could be asked anything about this topic Absolutely anything So you've got to be able to just come up with reasons around it and but generally with a bit of common sense it's quite easy to come up with different things to talk about in it And as you'll see in a moment on the next slide is that we that you are always given some things to sort of base your answer around You've just got to then be able to apply it Here are some topics that are quite common with technology and could often be asked about in your exam So cyber bullying and online messages is a big one Privacy issues is another one that keeps going back to and exposure to content So what people are able to access and see when they're using the internet for example Other things that are common on an exam but are not necessarily a bad thing is about technology being a tool for learning How it can be used in education and employment and it's very common that technology is used for meeting other people nowadays Now I'm able to share these with you because these are from quite old past papers now You may have even seen these yourselves already But these are two previous questions on this topic Each of these were worth eight marks And if you think a roughly every seven marks is another grade on your exam this is a huge one It's an extended writing task this So let's have a look at these two This first question says the use of digital technology in medicine is constantly evolving Discuss the impact of digital technology on medicine including diagnosing patients treating patients and storage of records So what you've noticed straight away there is they've given you the three bullet points that they want you to focus your answer on It doesn't mean that you wouldn't get marks if you wrote about something different that you thought was very relevant but it's just so easy to stick to these three bullet points And for the examiner they will be given a mark scheme that are based on those bullet points So it's always wise to stick to the bullet points that you're given in your exam Another example question and I've shared these with you so that you can have a little go with these questions if you wanted to Social networking websites use AI to monitor posts from users AI is a massive topic at the moment I think it's very likely it could be on this year's exam but it is a complete guess So discuss the positive and negative uses of AI by social networking websites including legal issues ethical issues privacy issues Three huge bullet points that we keep coming back to in this topic Looking at that first question with the impact of digital technology on medicine let's have a look at the mark scheme of that so we can see what we're looking for with these topics Now we're only going to look at the the top mark scheme because obviously we're aiming for top marks on these exams So the candidate demonstrates thorough knowledge and understanding of a wide range of considerations in relation to the question The material is generally accurate and detailed So as long as you're sticking to those bullet points you are talking about the right things So I wouldn't recommend deviating away from the bullet points unless you are 100% confident that it is a solid solid answer The candidate is able to apply their knowledge and understanding directly and consistently to the context provided So we were given a little scenario at the beginning of this question talking about how medicine is evolving So you need to be able to talk about that in your answer to shows that you've read the question Evidence and examples will be explicitly relevant to the explanation So if you're waffling on for ages about something that's not even relevant then you're wasting your time Now there was a command word at the beginning of this question It was discuss Now when you see the word discuss you need to be able to weigh up both sides of the argument If you're arguing totally for something and never against or vice versa you won't fit into this top category It is one of the most important things that will get you your top marks in these kind of answers Now this is how I think you should approach one of these questions At the back of your exam paper there is extra additional pages Now these don't have to be marked You can use these to just jot your ideas down and it's especially important when you're going to start a huge answer like one of these The best way to do it is get the main topic as a spider diagram in the middle The three bullet points that it provided to you you can then write around your spider diagram And then all you need to do is come up with a couple of points about each of those that they've given you So that's what you're going to base your answer on So for this question about the technology in medicine for diagnosing patients I went for you could search records faster It's more accurate but it could may miss symptoms or suggest incorrect results So I've got things there for both sides of the argument I could get some marks for saying that it's really fast to search records which would save people time But then I could also discuss the opposite of why it's not good by saying it may miss symptoms or suggest incorrect results So this is already a solid part of my answer However that's only talking about the diagnosing patients part of it So then I would move on to the next one which is the storage of records Overall you would then have a conclusion to talk about why you think technology is either good or bad for the evolution of medicine So if you nail all of these points and you've talked about the three bullet points you've given an argument for and against with a conclusion you've got the perfect answer and you've officially gone up an entire grades on that paper So I've come up with a question for you to give it a go I think you should pause the video and write down a an extended answer Like we discussed focus on the bullet points Jot down your ideas first as a little spider diagram It'll be really good practice for the real thing So the question is discuss the ethical and legal concerns of AI replacing human jobs including job displacement legal regulations and the economic impact If you think on your exam you should be aiming for one mark per minute Then to write your answer it should take roughly eight minutes to jot down your ideas for it Give yourself another three or four minutes So what I've tried to do for the answers for this then obviously you could have written about anything So this is not an exhaustive list but I want to go through some of the things that you could have written about if you couldn't really come up with any ideas on this one So for the first one for job displacement you could have written about how AI automates jobs reducing employment opportunities in certain industries There's some ethical concerns over mass unemployment and economic inequality It may affect low-skilled workers increasing social divisions and AI chatbots replacing customer service workers might reduce cashier jobs But you could argue any of them for or against those points So for example the AI chatbot might get somebody faster customer service if there's not enough people that they can employ It might get them an answer to what they need over the phone without even needing to speak to a human Okay so for the next one legal regulations So there's a debate over whether government should regulate AI in workplaces as a possible solution You could have AI taxation uh or there could be employment lords that are protecting different workers So the next bullet point was on economic impact So AI increases efficiency productivity and lowers business costs That's a definite argument for there's potential to create new jobs in AI development and robotics So lots of programming jobs that be going to become available to develop AI further So as final points that you could have included your answer So some ethical considerations So should AI be limited if it improves efficiency but harms employment some people could argue that AI should assist humans rather than replace them And finally businesses prioritizing profit over ethical concerns about worker displacement Now as I said earlier all of these are just ideas that you could have written about It's not an overall list but generally as long as you're talking about the topic and those bullet points you can almost guarantee that you've written enough for that point and you've got yourself some marks in that one Today we're going to be looking at environmental issues Now specifically for your exam we need to talk about how technology can have an impact on the environment Now this isn't an exhaustive list but these are the main topics that seem to keep coming up about environmental issues So we've got climate change pollution and habitats Now one of the most common mistakes that people make is always think that everything that affects the environment to do with technology is a bad thing There's actually loads of positives that you can talk about and we're going to have a look at a few of them so that you can talk about it in your exam So the first big positive of technology on the environment is being able to work remotely So this was huge during co especially when people were using things like Teams and Zoom to be able to communicate teach lessons and still have business meetings It also meant that people didn't have to drive places as much which means there's less cars on the road which means there are less CO2 emissions in the air affecting the atmosphere Another huge positive is paperless communication So we communicate via email which is a lot faster to actually get to where it's going but also means there's less cars on the road which is going to be delivering letters We also use things like ebooks and digital documents which is having a big positive impact on the environment because we're not chopping down as many trees to produce these documents A final positive of technology on the environment is smart technology So most people in their homes now have a smart meter which is making people more aware about the energy that they're using in their homes As a result people are using less energy which is having a better impact on the environment So we do need to understand that technology is also having a negative impact on the environment What's important for this topic as well though is that for each of these you need to try and come up with a possible solution to how you would counteract that negative impact on the environment So the first one we're going to talk about is climate change So to actually manufacture digital devices it uses a lot of energy Now to produce that energy it comes from fossil fuels which are releasing greenhouse gases like CO2 into the atmosphere There's also a huge increase on people using streaming services like Netflix and now TV This is adding to the carbon footprint of digital technology A potential solution to this might be where we get our energy from Using green energy solar powered energy and so on might have a better impact on the environment We are still going to be needing to manufacture digital devices We just need to do it in a cleaner way The next big topic that we need to have a look at is pollution So toxic chemicals are used in the production of digital devices and as it's being produced if it's not being disposed of properly lead and mercury can actually have a really harmful impact on the environment Most of it will end up in landfill and in developing countries especially this can have a massive impact on the soil and the water in the environment Something else having a huge impact on this is the fact that huge companies like Samsung and Apple have got a lot of pressure on them from the public to be producing new technology every single year or two As a result of this people are replacing their phones all the time which means that their old phones aren't being disposed of properly and they're not being recycled so it ends up in landfill So as a potential solution to this people should have maybe a donation scheme where they can pass phones on to other people who might not have one There's a better way to recycle phones and digital technology to help reduce how much impact it's having on the environment when it's ending up in landfill The final topic we're going to talk about is the destruction of habitats Digital devices contains materials such as lithium cobalt and other rare earth metals These get used in things like batteries and circuit boards To actually source these materials it means there's going to be deforestation and the destruction of natural habitats This often occurs in countries where there's not very good environmental protection and it has a massive impact on wildlife and the communities As a possible solution to this government and leaders need to do a better job of governing where these things take place how often they take place and by doing it in a cleaner way to protect the environment So I've got a question on this topic for you to practice A company plans to replace all employees desktop computers with brand new laptops every two years to ensure high performance and security Discuss the environmental impacts this decision could have Note that this one is worth four marks So you're going to need to come up with two things and a reason why it's having an impact Okay let's have a look at the answers then So the question was a company plans to replace all employees desktop computers with brand new laptops every two years to ensure high performance and security Discuss the environmental impacts this decision could have So you could have put something like increased e-waste That would get you one mark Frequently replacing devices creates more electronic waste which may not be recycled properly That would get you a second mark You could have also put pollution from disposal That would be three marks You could then explain devices contain harmful chemicals which can pollute the environment if dumped in landfill That'll get you all four marks And that's it for this video I'll see you next time