computers use firmware to initialize Hardware firmware is a small program stored inside a chip on the motherboard when we start a computer it is the first program that the computer runs it performs three tasks initialize all Hardware devices find the bootloader program and execute it in the first step it checks whether all Hardware devices are functional if yes it moves to the Second Step if not it halts the startup process this process is known as power on cell test or post in the second step it finds the bootloader program we can store a bootloader program on any external storage device such as a hard disk USB drive CD or a DVD all OS installation discs come with a bootloader program the installation program transfers it to the hard disk when we install the operating system firmware allows us to specify the boot device priority the boot device priority defines the boot order firmware checks the specified devices in a sequence until it finds a bootloader program once it finds a bootloader program it does not check the next device in the sequence let us take an example suppose three devices hard disk DVD ROM and USB drive are configured in the boot device Priority First firmware will find the bootloader program on the hard disk if it finds a bootloader program on the hard disk it executes it and does not check the CD ROM and USB drive if it does not find a bootloader program on the hard disk it checks the DVD ROM if the DVD ROM has a disc it finds the boot loader program on it if the DVD ROM does not have a DVD or has a non- bootable DVD the firmware checks all USB ports for a connected USB drive if a USB drive is attached the firmware finds the bootloader program on it if firmware does not find a bootloader program on any specified device it halts the boot process if it finds a bootloader program on any specified device it executes the bootloader program the boot boot loader program controls the remaining boot process there are two types of firmware bios and UA both find the boot loader program on different regions of the specified devices in the boot device list bios finds it on the first sector of the specified devices it reads the first 512 bytes of the device it calls them MBR if the MBR contains a bootloader program it executes the program if it does not contain a bootloader program it finds a bootloader program on the MBR of the next speci specified device in the boot device list UA finds a bootloader after the first sector it reads 4 kilobytes after skipping the first 512 bytes it calls them GPT if the GPT contains a bootloader program it executes the program if it does not contain the bootloader program it checks the GPT of the next specified device in the boot device list bios is a classical method to save firmware it was released in 1975 5 it operates in 16bit mode and provides only basic UI navigation using the keyboard it supports up to 14 partitions and a maximum partition size of 2 tbytes it takes a bit longer time to boot the system it supports only password protection UAV is a modern way to save firmware it was released in 2002 it operates in 32-bit and 64-bit modes it provides graphical UI navigation it supports up to 128 partitions and a maximum partition size of 18x xtes it takes only a few seconds to boot the system and supports secure boot features MBR is a classical way to store a bootloader program and partition information it reserves the first 512 bytes of the storage device to save this information only bios-based systems use it UAV based systems do not use it they use GPT to store partition information and a bootloader program MBR is non-redundant it does not replicate the records it contains if if it is corrupt the system will not boot it supports a maximum of 14 partitions GPT is a modern way to store a bootloader program and partition information to save this information it uses 4 kilobits dis space after the first 512 bytes of the hard disk since it does not modify or use the reserved dis space for MBR both bios and UF based systems can use it GPT is redundant it saves a copy of the partition information at the end of the dis it supports a maximum of 28 partitions you can use the entire dis as a single partition or create multiple partitions on it usually administrators create partitions to make Disk Management easier let us take an example suppose you have a 2 terabytes hard disk you want to use it to store text files media files and script files without any partition you have to save all three types of content on the same partition you can do that but it would make accessing and managing them difficult the correct way would be to create and use three partitions one for each type you can create a small-sized partition for text files a meat sized for script files and a large siiz partition for media files it makes finding and managing files much easier there are two types of partitions standard and advanced you can use any type based on disk size and your requirements standard partitions are easy all operating systems by default include tools and utilities to create an manage them they are mainly used on personal computers they do not need any additional discs you can create and use them on a single dis GPT and MBR are used to store standard partitions information GPT supports a maximum of 128 partitions it uses a flat partitioning scheme all partitions are equal you can create them in a sequence starting from one MBR supports a maximum of 14 partitions it uses a bit complex partitioning scheme it divides partition into three types primary extended and logical you can create a maximum of four primary partitions if you need more partitions you need to convert the last primary partition into an extended partition an extended partition works like a container for logical partitions you can create a maximum of 11 logical partitions inside the extended partition an extended partition is not used to store data it is used to store only logical partitions Advanced partitions are complex they are mainly used used on server systems and usually need more than one dis by default operating systems may or may not include tools and utilities to create and manage them if tools and utilities are not installed by default you need to install them before you can create and use Advanced partitions lvm and ridar advanced partitions lvm creates a logical pool from standard partitions and uses it to create logical partitions the main difference between standard partitions and lvm logical partitions is that standard partitions are fixed while LV VM logical partitions are flexible you cannot extend or shrink the size of a standard partition however you can increase or decrease the size of a lvm logical partition raid creates an array of diss it can store the same data on multiple diss it is mainly used to create the real-time backup of data a hard disk contains tracks and sectors it uses tracks to organize sectors and sectors to save data when we save a file on it the operating system saves the file on any of these sectors it uses an index known as a file system to know which file is stored in which sector a file system is a database of all files and directories stored on the hard disk it also specifies conventions for file names such as the maximum number and types of characters we can use in a file name along with the names and locations of the files it also stores information about their sizes attributes and metadata different operating systems use different file systems ntf s ext4 and xfs are widely used file systems that's all for this video if you have any suggestions comments or feedback about this video please share them in the comment section given below