in this video we discussed the need for operating systems and their function and purpose we know that all computer systems input data they process that data and they output a result and quite often this process is going to involve a user that's going to provide that data and the output is going to be produced by some hardware whether that's a display or printer of some form so the user needs a way of interacting with that hardware and that's the purpose of an operating system it provides the interface between the user and the hardware now the user doesn't tend to interact directly with the hardware but instead they use application software such as word processors spreadsheets or graphics programs in order to accomplish a given task and it's the role of the operating system to provide a platform on which that application software can run application software today usually involves a common user interface so the user is interacting with the application software in a familiar and friendly way the application software will have a user and the operating system is providing a platform for those applications to run and it's also providing its own user interface experience in addition to the application software there are also a number of utility programs some of which are built into the operating system that help to maintain the computer some typical examples might be encryption software compression software and defragmentation software loading the various programs into memory so they can be executed and managing the data that those programs acquire is not a trivial task so a very important part of your operating system is memory management the user will also want to save what's in the memory from time to time so they don't lose their work when the power switched off so the operating system also has to manage the file store it has to make decisions about where files are going to be stored and where they're going to be loaded from again the large array of additional peripheral hardware connected to computers are also going to operate in a very specific way and therefore they need some device drivers in order to translate operating system instructions into something that the hardware is actually going to understand the operating system is also responsible for handling and dealing with what are known as interrupts this is when any device requires the attention of the processor this could be quite dramatic as in a power failure or something that seems quite trivial like a user pressing a key on a keyboard we look at interrupts in more detail in a later video the user interface which is a catch-all umbrella term for the way in which you interact with a computer as a human being there are a number of ways of providing that interaction by an operating system and one of the most common and familiar to you is what's known as the graphical user interface or gui so here we've got windows we've got icons we've got menus and we've got the pointer and this is often known as a wimp interface windows icons menus and pointers it's a very visual interface and it's very interactive it's quite intuitive to use so it's ideal for beginners and it's optimized for the mouse and touch gesture input the opposite of a graphical user interface is a command line interface it's very text heavy but it's less resource heavy compared to a gui it's very slim lined and efficient it tends to have more commands than a graphical user interface it's best suited for advanced users that want to accomplish tasks quickly it's useful for automating process with scripts and it's often the interface that's used if you want to do something quite technical with your computer another type is the menu driven interface this is the sort you're going to find at cache points and on chip and pin devices so here in this example we see a chip and pin device asking the user whether they want to give a gratuity a tip and the user is going to choose yes or no depending on the buttons they press so we have successive menus presented to the user with a single option chosen at each stage and you often interact with them via buttons on a keypad a user interface that's gaining popularity today is the natural language interface the idea that you can actually speak in your natural language into a computer system so it responds to question for example said in spoken english the historical problem with these interfaces is though often not very reliable but the technology is certainly gaining in pace and accuracy siri cortana hey google and alexa are all examples of this and it is pretty cool to be able to say to advise hey siri what's the weather today or alexa how many emails haven't i read that's everything for this video here's a summary of what you've learned so pause and take some notes [Music] [Applause] [Music] you