What is the BIOS?
The BIOS, or basic input/output system, is a piece of software that runs on a computer when it is first turned on. The BIOS is responsible for performing a series of checks and initializations to make sure that the computer is ready to boot up and start running. This includes checking the computer’s hardware, such as the CPU, RAM, and hard drive, to make sure that they are functioning properly.
The BIOS is stored in a special type of memory called ROM, or read-only memory, which means that it cannot be changed or erased. This is important because the BIOS is the first program that runs on a computer, and it needs to be reliable in order to ensure that the computer starts up properly. The BIOS is also responsible for starting the computer’s operating system, which is the program that manages the computer’s hardware and software and allows you to use the computer to do things like run programs, browse the internet, and play games.
If a BIOS is stored in ROM, how am I able to change the settings?
The BIOS settings are saved in a type of memory called CMOS, or complementary metal-oxide semiconductor, memory. CMOS memory is a type of non-volatile memory, which means that it retains its data even when the power is turned off. This is important for the BIOS settings, because they need to be preserved even when the computer is not in use.
The BIOS settings are saved in the CMOS memory when you save them using the BIOS setup utility. The BIOS setup utility writes the settings to the CMOS memory, where they are stored until the next time you start your computer. When the computer is turned on, the BIOS program reads the settings from the CMOS memory and uses them to initialize the computer’s hardware and start the operating system. This allows the computer to start up with the same settings every time, which is important for maintaining a consistent and predictable computing experience.
What is POST?
When a computer is turned on, it goes through a process called the power on self test, or POST. During the POST, the computer’s BIOS performs a series of checks and initializations to make sure that the computer’s hardware is functioning properly and that the computer is ready to start up.
The POST begins when the computer is first turned on and continues until the computer’s operating system is loaded and ready to use. During the POST, the BIOS checks the computer’s hardware, such as the CPU, RAM, and hard drive, to make sure that they are functioning properly. If the BIOS detects a problem with any of the hardware, it will display an error message on the screen, which can help you diagnose and fix the problem.
The POST also includes a series of tests and checks to make sure that the computer’s hardware is working together properly. This includes checking the memory, the motherboard, and the keyboard and mouse, as well as any other peripherals that are connected to the computer. If the POST detects a problem with any of these components, it will display an error message and may stop the boot process until the problem is resolved.
Once the POST has finished and all the hardware has been checked and initialized, the BIOS will start the computer’s operating system and hand control over to it. At this point, the computer is ready to use and you can begin working or using your favourite programs.
Why is BIOS no longer used?
The BIOS is considered legacy because it has many limitations compared to newer types of firmware like UEFI. For example, the BIOS can only boot from hard drives that are formatted with the MBR (Master Boot Record) partitioning scheme, while the UEFI can boot from drives formatted with either MBR or the newer GPT (GUID Partition Table) scheme. The BIOS also has limited support for features like booting from USB drives or networking, while the UEFI has much better support for these and other modern features.
Because of these limitations, the BIOS is no longer the default system firmware on most computers. Instead, most computers now use the UEFI as their system firmware, and the BIOS is only used on older computers or on computers that need to support legacy hardware or software. Even on these computers, the BIOS is often replaced with a UEFI-based system firmware that provides many of the same benefits as the UEFI, but is compatible with legacy BIOS software and hardware.