BIOS: What Is It? And What Are Its Functions?

Shivendra Nath



First of all let’s know what does BIOS stands for? simply it stands for Basic Input/Output System. If anyone thinks that computer system can function properly without the BIOS then I should say that the person is completely wrong. One cannot ignore BIOS as it is crucial component of computer system.

Pronounced as Bye-Oss is nothing but a ROM chip found on the motherboards of system. Whenever you press the power button of the CPU, the first thing that runs on your computer is BIOS. Moreover, other names of BIOS are ROM BIOS, System BIOS as well as PC BIOS.

It was Gary Kildall who was computer scientist of United States first coined the term BIOS in the year 1975. Also, Basic Input/Output System is available on every modern motherboards. Another thing you should note that it is Operating System independent. This means that whether you install Windows based OS or Linux Based OS, BIOS will function as usual without being affected.

In case if you are interested to access the BIOS setup of your computer then you have to perform few things. Like When you turn on the PC continuously press DELETE or F2 Key. Then BIOS setup of your computer will launch.

Also, you should note that the key may vary from manufacturer to manufacturer of computer. So, it is always recommended that you should check your PC manufacturer website to know which key can open BIOS setup. In simple terms, you can consider BIOS as that component which creates link between computer hardware with computer software. Furthermore, many tasks can be done through BIOS setup which we will look in this article. So now let’s know the functions of BIOS which will justify about its importance in PC.

Functions Of Basic Input/Output System:

  1. POST: POST in terms of BIOS stands for Power On Self-Test. When system is turned on this is the first test that is run by BIOS. Basic Input/Output System POST test ensures that every hardware devices that is connected to the system is in functioning state. For example, during POST it checks RAM, keyboard, mouse,etc so on and so forth. Moreover, if POST fails due to any reason then the computer system will generate beep codes in a specific pattern to indicate the cause of problem. And if POST passes successfully then the system continues to boot. In this article I have also mentioned the beep codes of different BIOS manufacturers. In case you want to go through, it is placed at the end of this article.
  2. Bootstrap Loader: The primary task of Bootstrap loader is to locate the Operating System. And if the OS is successfully located then the control will pass from the BIOS to the OS of the system.
  3. BIOS drivers: BIOS drivers are nothing but are low-level drivers. When you ask about the function of BIOS drivers, they simply provide information of computer hardware at the basic level.
  4. BIOS Setup: BIOS setup is also known as CMOS setup. It is a configuration program that enables users to configure hardware settings for their PC.

List of tasks that can be performed from BIOS setup:

  1. Change the boot order.
  2. Load the setup defaults of BIOS.
  3. Update or flash BIOS.
  4. Change date/time of the system.
  5. Create or delete a BIOS password.
  6. Alter hard disk drive settings.
  7. View size of Installed memory.
  8. Enable or disable quick POST.
  9. Enable or disable CPU internal cache.
  10. enable or disable BIOS caching.
  11. change different CPU settings.
  12. change memory settings.
  13. change the voltages of system.
  14. Enable or disable RAID.
  15. Enable or disable USB port(s).
  16. Enable or disable audio.
  17. Enable or disable onboard parallel or serial ports.
  18. Enable or disable ACPI.
  19. Change the suspend type of ACPI.
  20. Change the function of power button.
  21. Change the power-on settings.
  22. Reset ESCD.
  23. enable or disable BIOS controls over the system resources.
  24. change the fan speed.
  25. View CPU and system voltages as well as temperatures.
  26. view fan speed.

Types of Basic Input/Output System:

There are mainly two types of BIOS are present and they are:

Legacy BIOS: It is usually found on older motherboards. The limitation that legacy BIOS has is that it is not capable to recognize disks drive which are larger than 2.1 TeraBytes (TB). Moreover,it controls the way by which CPU and components communicates with each other. Also, One more point to note about the legacy BIOS is that, installations systems of this kind of BIOS have menus in text-only form.

UEFI: UEFI stands for Unified Extensible Firmware Interface. It has big advantage over legacy BIOS, that it can recognize drives of size 2.2 TB or larger. It usually handles drives using MBR or Master Boot Record technology instead of GPT or GUID Partition Table technology. Also, Apple Mac PCs have never used BIOS.

Popular Basic Input/Output System Creating Companies:

There are several companies that manufactures BIOS for the computer system and they are Dell, Foxconn, AMI, Hewlett Packard(HP), Ricoh, ASUS, BYOSOFT, Gateway to name a few.

What BIOS does my Computer has?

To find out what BIOS does your system has , simply open your BIOS setup and you will find out the BIOS name. For example, it can AMI, Award, or Insyde etc.

Beep Codes List:

If POST test is failed, then your system will generate beep code to give you idea about the origin of the problem. In this article I will list the beep codes of different BIOS manufacturer such as Award BIOS, AMI BIOS, IBM BIOS, Dell, Insyde BIOS, and Macintosh startup tones.

[su_note note_color=”#ffd701″ text_color=”#000000″]Note: The beep codes mentioned in this article may vary slightly.[/su_note]

Award BIOS beep Codes:

Beep CodeDescription
1 Long , 2 short BeepsVideo error occurred and BIOS is unable to initialize video screen for further display of any additional information.
1 Long , 3 short beepsVideo card is not detected
Beeps repeating endlesslyRAM problem has occurred.
Continuous High frequency beeps during running pc.Overheating of microprocessor or CPU.
Repeated beeps with alternating high and low frequency.Problem with processor or damaged processor

AMI BIOS beep codes:

 Beep CodeDescriptions
1 short beepDRAM refresh failed
2 short beepParity circuit failed.
3 short beepBase 64 K RAM failed.
4 short beepSystem timer failed.
5 short beepProcess failed.
6 short beepKeyboard controller Gate A20 error has occurred.
7 short beepVirtual mode exception error has occured.
8 short beepDisplay memory Read/write test failed.
9 short beepROM BIOS checksum failed.
10 short beepReplace the CMOS battery.
11 short beepCache memory error has occurred.
1 long, 2 short beepsVideo card memory problems.
1 long , 3 short beepsConventional/Extended memory failed.
1 long, 8 short beepsDisplay/retrace test failed.
Two-tone sirenLow CPU fan speed.

IBM BIOS Beep Codes:

Beep CodeDescription
1 short beep Normal POST, computer is OK.
2 short beepPOST error occurred, check screen for error code.
Continuous beepNo power, loose card or short.
Repeating short beepNo power, loose card or short.
1 long, 1 short beepMotherboard problem.
1 long, 2 short beepsVideo issue(Mono/CGA display circuitry)
1 long, 3 short beepsVideo (EGA) display circuitry.
3 long beepsKeyboard error or Keyboard card error.
1 beep, blank or incorrect displayVideo display circuitry.

Dell Beep Codes:

Beep CodeDescription
1 beepBIOS ROM corrupted or failed.
2 beepsRAM not detected.
3 beepsMotherboard failed.
4 beepsRAM failed.
5 beepsCMOS battery failed.
6 beepsVideo card failed.
7 beepsBad processor or CPU.

Insyde Beep Codes:

Beep Code Description
 5 short and 1 long beep.Issues with the DMA page registers.
4 short,1 long, 1 short beep.Circuit for refreshing RAM is not working.
4 short and 2 short beeps.BIOS ROM checksum failed.
3 short, 1 long, 2 short beeps.CMOS RAM test failed.
3 short, 1 long, 1 short, 1 long beep.DMA controller failed.
3 short , 2 long , 1 short beep.Interrup controller failed.
3 short and 3 long beeps.Keyboard self-test problem.
2 short, 1 long, 3 short beeps.Video card not found.
2 short, 1 long, 2 short, 1 long beep.No RAM present or RAM not recognized.

Macintosh Startup tones:

Tones Error
Error Tone.( two sets of different tones)Issues with logic board or scsi bus.
Startup tone, drive is spinning but no videoIssues with video controller.
Powers on, no tone.Logic board issue.
High tone, four higher tones.Problem with SIMM.

I hope you found this article helpful and please don’t forget to share this article with your family and friends. Thanks for Reading and Keep visiting Novadroid360.


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