What is BIOS in computer? What does it do?

What is BIOS (basic input/output system)?

Ever since the day Microsoft introduced the world to DOS, the BIOS has been an integral part of our computing systems. Yet, not many know much about it other than its full name. The BIOS is an integral part of our computers and had stayed that way for years. Though a lot of us have either installed or upgraded our Operating Systems multiple times over, the BIOS always remains the same from day one.

What is BIOS

BIOS (basic input/output system) is a software program made available to the microprocessor on an erasable programmable read-only memory (EPROM) chip. When you switch on your machine, the microprocessor passes control to the BIOS which is always located at the exact same place on the EPROM. When the BIOS boots up, it first runs a check to ensure all attachments are in place and operational. Only once that is done, it will load the OS into your computer’s RAM from your disk storage. Owing to the BIOS, your machine’s individual software are exempted from having knowledge of the attached input & output devices. Therefore, when device details change, only the BIOS needs to be changed instead of every individual piece of software.

Although theoretically, the BIOS is supposed to be the intermediary between the microprocessor and the I/O devices, in some cases the BIOS can even facilitate the direct transfer of data to memory from the devices for those that require a faster data flow, such as video cards. If the BIOS doesn’t work smoothly, your OS will most certainly fail. The four main functionalities of the BIOS can be listed as:

  • POST (Power on self test) – Test the computer hardware to ensure no errors exist before the OS is loaded.
  • Bootstrap Ladder – Locate the OS, if one is detected, pass on the control to it
  • BIOS drivers – These are low level drivers that give the computer basic operational control over the computer’s hardware
  • BIOS / CMOS setup – This is a configuration program that allows one to configure hardware settings.

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Delwyn Pinto
Delwyn Pinto
A person proud to have an alternate view


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