What is BIOS

Bios

The BIOS is a dark and dangerous world, where a wrong setting can toast your OS, cook a hardware component, melt your motherboard and leave you with a lump of electronics looking at you in silent baleful accusation: “You killed me!” That said, it is not so easy to damage your system through the BIOS—but only if you’re careful. Messing around with the BIOS requires patience first and patience last! You also definitely need to understand what you are doing when you’re changing any setting. Scared already? OK, pay attention now…

The BIOS

Bios Setup

            The BIOS (Basic Input/ Output System) is the software code that first runs when the PC powers on. It contains all the information necessary to initialise nearly all the hardware components of the PC. Normally, when you switch on the PC, the BIOS performs a Power on Self-Test, or POST as it is called. This is a series of diagnostic tests on the RAM and other hardware. It also initialises all the hardware devices such as the hard disk, memory, video and other hardware, identifies and reserves memory addresses for all the IRQs and ports available on the motherboard, and calls a small operating system program known as the boot loader. The boot loader, using the BIOS information amongst other things, starts calling the programs that will load the OS. And finally, the OS uses the BIOS information to take control over the hardware devices.

          Motherboard manufacturers use the BIOS to define settings for the various hardware components including the hard disk, RAM, CD-ROMs, I/O ports etc. These are generally set at the factory and are what is called the Factory Settings or the BIOS Setup Default Settings.

       The BIOS software code and all the settings for the PC are stored on a memory chip that’s continuously supplied with power by a battery. The battery also powers a real-time clock that keeps accurate time. Hence, these settings (and time values) are retained even when the power is switched off.

        Motherboard manufacturers and BIOS vendors frequently release updates, which can be “flashed” to the BIOS. In some troubleshooting cases, your only option is to update the BIOS. Look later in this section to learn how.

        

         To enter the BIOS setup, you’ll need to press [Delete], or something similar, when your computer is booting up. Depending on the PC, the key may be different—[Esc], [F1], [F10], etc.

BIOS Beep Codes

           When your system has a problem that won’t let it start up properly, the first thing you will hear is warning beeps. These could be because of hardware or even because of the BIOS itself.

            Unfortunately, beep codes are not standardized across BIOS vendors and motherboard manufacturers. Below are mentioned the beep codes, along with the possible problem that could be causing the beep, and some suggestions towards resolution. These are for two popular BIOS vendors—AMI and Award. If your BIOS is from any other vendor, you will need to refer to the motherboard manufacturer’s or the BIOS vendor’s manual for details.

             Also, motherboard manufacturers may modify the beep codes to their convenience and not maintain consistency. Keep an open mind when you decipher the beep, and don’t get into a tizzy if the codes don’t match what is in here or in the BIOS vendor’s manual! You should always try and contact the manufacturer to get the correct beep codes.

AMIBIOS (American Megatrends Inc.)

Amibios

One beep: RAM failure

 Problem: Motherboard problem or failed RAM.

Solution: Troubleshoot the motherboard and/or the RAM.

Two beeps: Parity Circuit Failure

 Problem: Motherboard problem or failed RAM.

Solution: Troubleshoot the motherboard and/or the RAM.

Three beeps: Base 64K RAM failure

 Problem: There is a failure within the first 64K of memory.

 Solution: Troubleshoot the motherboard and/or the RAM.

Four beeps: System Timer Failure

 Problem: One or more of the system timers on the motherboard has failed; usually indicates motherboard failure.

 Solution: Troubleshoot the motherboard. You may need to replace it.

Five beeps: Processor Failure

 Problem: The processor is generating an error condition. This does not mean that the processor is not working—with a dead processor, the computer won’t boot at all.

Solution: Check if the processor is overheating, and whether it is set correctly on the motherboard. Troubleshoot the motherboard.

Six beeps: Keyboard controller or gate A20 failure

 Problem: Keyboard, keyboard controller or motherboard error.

 Solution: Check if the keyboard is connected properly. Use another keyboard to see if the problem persists. If it does, look for the keyboard controller chip on the motherboard and see if it is seated properly and that it is not damaged. If the problem continues, troubleshoot the motherboard.

Seven beeps: Virtual mode exception error

 Problem: This error is reported when testing the processor’s virtual mode. Solution: Troubleshoot the motherboard/processor. Verify that’ll jumpers are properly configured.

Eight beeps: Display memory read/write failure

Problem: The BIOS is not able to read/write the display card’s memory.

Solution: Troubleshoot the motherboard and/or display card.

Nine beeps: BIOS’ ROM checksum failure

 Problem: The BIOS CMOS chip is most likely defective. May also be a problem with the motherboard.

 Solution: The CMOS chip can be replaced, but replacing the motherboard is simpler and more cost-effective.

Ten beeps: CMOS shutdown register read/write error

 Problem: A motherboard component is creating an error when interacting with the CMOS.

Solution: Troubleshoot the motherboard and verify that all components are properly set up and configured.

Eleven beeps: Cache memory error

Problem: There is an problem with the processor’s L2 cache.

Solution: Verify that the L2 cache chip is inserted correctly. Verify that all connections inside the PC are correct. Replace the cache module if the problem persists.

Continuous beeps: Video / Memory problem

Problem: A problem with the RAM, display card or motherboard.

 Solution: Troubleshoot the RAM first, followed by the display card and then the motherboard.

Other beeps: Check motherboard manual

Problem: Check the motherboard manual or the vendor’s Web site for more information. Treat it as a motherboard problem.

Solution: Troubleshoot the motherboard.

Award BIOS

Award Bios

             Award has the least number of documented beep codes. They prefer to display an error message on the screen. Beep codes are used only if the BIOS can’t access the display subsystem.

One long beep: Memory problem

 Problem: A problem with the memory or motherboard

 Solution: Troubleshoot the memory and the motherboard

One long and two short beeps: Video error

 Problem: The BIOS is not able to access the video sub-system                  
Solution: Troubleshoot the video card, and if the problem persists, go on to the motherboard.

One long and three short beeps: Video error

 Problem: The BIOS is not able to access the video sub-system                  
 Solution: Troubleshoot the video card, and the if problem persists, go on to the motherboard.

Continuous beeps: Video / memory problem

Problem: There is a problem with the RAM, display card or motherboard. 
Solution: Troubleshoot the RAM first, followed by the display card and then the motherboard.

Other beeps: Check the motherboard manual

 Problem: Check the motherboard manual or the vendor’s Web site for more information. Treat it as a motherboard problem.

Solution: Check the motherboard manual. Troubleshoot the motherboard.