What is BIOS? Ins and Outs of BIOS Firmware

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Every casual or professional computer user is familiar with the term BIOS (Basic Input Output Device). Since the days of the older Disk Operating System, BIOS is there in our computers for more than 30 years.

It is a back screen crucial component, which doesn’t take any credit by appearing in front of our eyes. But proper functioning of the operating system depends on proper BIOS in place. If you want to learn in-depth about what is it, you have arrived at the right place. Let’s go ahead.

What is BIOS

Definition of BIOS

BIOS is the short form of the Basic Input /Output System. It is a tiny piece of code or set of instructions to load the OS mounted on the ROM, EPROM, or flash memory chip of the system board generally on a Windows-based computer system. It can also be flashed into USB.

As it links the software to the hardware, it is known as the motherboard firmware or low-level software. It has a size of approximately 16 MB. When the computer is turned on, this is the first software that comes into operation and simply wakes up the rest of the computer parts, just like an ignition system of the car that starts up the engine.


BIOS was introduced first in 1975 by Gary Arlen Kildall, a computer scientist. It was first featured in the CP/M operating system. It provided users the flexibility to install any desired operating system or repair in case of error.

Popular BIOS Manufacturers

  • American Megatrends Inc. (AMI)
  • Phoenix Technologies
  • Winbond
  • IBM
  • Dell
  • Gateway

How to Enter the Bios Setup?

First, switch on the power button and then tap and hold the delete or F2 button.  Then the setup page will appear.

Entering the BIOS setup utility permits you to change a variety of hardware settings and order of Booting. But simplified BIOS in laptops and tablets merely set the time and a couple of other things. Advanced BIOS of gaming computers includes configuring CPU clocks and voltage, RAM latency, and many other facilities.

An inexperienced user is not recommended to change the settings. After making necessary changes, tap F10 to save the changes made and exit the page.

How to Enter the Bios Setup

What Can You Control in the BIOS System?

  • Alter Boot order
  • Load default set up
  • Update BIOS
  • Change or remove password
  • Change floppy and hard drive settings
  • Change the time and date of the computer
  • Change CD/DVD/BD drive and CPU settings
  • Check the amount of installed memory
  • Enable or disable Computer Logo, RAID, onboard USB
  • Enable or disable POST, CPU cache
  • Enable or Disable system resources control
  • Enable or disable onboard IEEE1394, audio, floppy controller, serial/parallel ports, ACPI
  • Change multi-display setup display initialization
  • Alter the ACPI suspend type, power button function, power-on settings
  • Reset ESCD
  • Change settings of Fan speed
  • Check temperatures, fan speeds, and system voltages.
What Can You Control in the Bios System

What is the Function of BIOS in a Computer?

The function of a BIOS is from when you press the power button to the displaying of the OS logo on the screen. Old-school ones provide a connection between all the peripherals along with the OS. But newer versions of windows have direct control over hardware and here BIOS only activates when you need it to start things up. Let’s have a look at the main functions it has to perform.

What Is the Function of Bios in a Computer

Checking CMOS Chip

The BIOS first checks settings stored in the 64-byte RAM located on the CMOS chip to know how the user intends the system to operate. This corresponds to the tapping delete or F2 in older computers when first booting up. According to this, then it initializes CPU, RAM, Graphics Card Peripherals, and so on and sets up the date and time. After this, the interrupt handlers and device drivers are loaded and power management and registers are initialized.

Performing POST

BIOS starts Power-on self-test or POST to ensure everything in the case is operating properly. It first checks the RAM and processor and then checks the attached devices. If the result is positive, then a single beep is produced from the speaker installed with the motherboard. If there is an error, multiple beeps will be heard. If everything is good then it will display system settings and go to the booting process.

Performing the Booting Process

BIOS identifies, configures, tests, and connects computer hardware to the OS for further instruction. The whole process is known as the Boot process. It will check for a bootable device or some kind of drive along with the Operating system and hand over control to the operating system by loading essential parts of OS on RAM. Boot options are checked in a configured sequence; Boot from CD-ROM, Hard Drive, and then LAN, etc.

Storing Configuration Settings

When the computer is powered off, this stores the configuration settings. A tiny volatile CMOS memory is used to store this.

How to Update BIOS

To cope with the latest devices, the BIOS of your computer has to be updated if required. If it’s not upgraded, the result is, your operating system will not recognize a new device.

For this first, check what version of BIOS your computer has. To do so, open up the BIOS setting page as described before. Now that you know the version, visit the computer manufacturer website for the latest version available of BIOS.

If you find something simply download and run it. but, remember all your previous information on the BIOS chip will be gone. Assure that while this whole updating process you have an uninterrupted power supply. Computer Technicians are recommended for this.

How to Update BIOS

Limitations of BIOS

The BIOS has merely 1,024 KB executable space which results in trouble initializing multiple peripherals. Also, it will take up to 30 seconds to start booting. So, it cannot handle large storage devices.  As it still works in 16-bit mode, it has a limitation in reading and executing the amount of code. These limitations led to the creation of Unified Extensible Firmware Interface UEFI.

Wrap Up

Without a BIOS, your computer operating system is nothing but an inactivated medium-level software. The most important role here is to load the computer Operating System. When the computer is turned on, the CPU activates it to locate hardware and ensure the proper functioning of all hardware. Then BIOS loads the Operating System in memory and completes booting.

In this article, we discussed in detail and what you can do with it. Professionals can squeeze the maximum performance of the computer using this. But still, for the memory and speed limitations, UEFI is replacing BIOS eventually.

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