ByE.ThirumeniDepartment of ElectronicsSt. Joseph’s College (Autonomous)Trichy
What is a BIOS?basic input/output system (BIOS), also known as theSystem BIOSTheBIOS software is built into thePC on a non-volatile ROM andis the first code run by a PC when poweredon.BIOSsoftware is stored on a non-volatile ROM chip on the motherboard. It is specifically designed to work with each particular model ofcomputerABIOS has a user interface (UI), typically a menu system accessed by pressing a certain key on the keyboard when the PC starts. In the BIOS UI, a user can:configure hardwareset the system clockenable or disable system componentsselect which devices are eligible to be a potential boot deviceset various password prompts, such as a password for securing access to the BIOS UI functions itself and preventing malicious users from booting the system from unauthorized peripheral devices.
Whatis a POST?Itmeans:Power On Self TestPOSTincludesinstructionstoperform internaltests, asdesigned bythe device manufacturer.The Instructions are stored in ROM memory, and performed every time the computer system is started.When the PC starts up, the first job for the BIOS is thePower-onself-test, whichinitializes and testsystemcomponentssuch asthe CPU,video display card,Memory,hard diskdrive andother hardware. The BIOS then locates boot loader software(OS) froma hard disk or a CD/DVD, and loads and executes that software, giving it control of the PC.
Beep Code:Descriptionof Problem:NoBeeps=Short,Nopower, Bad CPU/MB, LoosePeripheralsOneBeep= Everythingis normal and ComputerPOSTedfineTwoBeeps= POST/CMOSErrorOneLong Beep,OneShort Beep= MotherboardProblem
Beep Code:Descriptionof Problem:One Long Beep,Two Short BeepsOROne Long Beep,Three Short Beeps= VideoProblemThreeLong Beeps= KeyboardErrorRepeatedLong Beeps= MemoryErrorContinuousHi-LoBeeps = CPUOverheating
There are many types of BIOS the most common ones are:IBM POSTAMI BIOS (American Megatrends)AWARD BIOSPhoenix BIOS
Standard Original IBM POST Error Codes
1 BeepAsingle beep from an AMI based BIOS means there has been a memory refresh timer error. The solution is often to replace the RAM in the computer.2 BeepsTwo beeps means there has been a parity error in base memory. This is an issue with the first 64KB block of memory in your RAM. The solution is usually to replace the memory.3 BeepsThreebeeps means there has been a base memory read/write test error. Replacing the RAM usually solves this AMI beep code.4BeepsFourbeeps means that the motherboard timer is not working properly. A hardware failure with an expansion card or the motherboard itself could be the cause of this beep code.
AMI BIOSPOST Error Codes
5 BeepsFive beeps means there has been a processor error. A damaged expansion card, theCPU, or the motherboard could be prompting this AMI beep code.6BeepsSixbeeps means that there has been an 8042 Gate A20 test error. This beep code is usually caused by an expansion card that has failed or the motherboard that is no longer working.7 BeepsSeven beeps indicates a general exception error. This AMI beep code could be caused by an expansion card problem, a motherboard hardware issue, or a damaged CPU. Replacing the faulty hardware usually fixes the cause of this beep code.8 BeepsEight beeps means that there has been an error with the display memory. This beep code is usually caused by a faultyvideo card. Replacing the video card usually clears this up.
AMI BIOSPOST Error Codes
1 Short BeepA single, short beep from an Award based BIOS is actually an "all systems clear" notification.Notroubleshooting necessary!1 Long Beep, 2 Short BeepsOne long beep followed by two short beeps indicates that there has been some kind of error with thevideo card. Replacing the video card is usually the most you'll have to do to fix this one.1 Long Beep, 3 Short BeepsOne long beep followed by three short beeps means that either the video card isn't installed or the memory on the video card is bad. Reseating or replacing the video card will typically fix the cause of this Award beep code.
AWARD BIOSPOST Error Codes
1 High Pitched Beep, 1 Low Pitched Beep (Repeating)A repeating high pitched / low pitched beep pattern is an indication of some kind ofCPUproblem. The CPU could be overheating or malfunctioning in some other way.1 High Pitched Beep (Repeating)A single, repeating, high pitched beeping sound means that the CPU is overheating. You'll need to figure out why the CPU is getting too hot before this Award beep code will go away.Important: Turn your computer off immediately if you hear this beep code. The longer your CPU is running hot, the higher the chance that you'll permanently damage this expensive part of your system.All Other Beep CodesAny other beep code pattern you hear means that there has been some kind ofmemoryproblem. Replacing your RAM is the most you'll need to do to fix this problem.
1 BeepA single beep from a Phoenix based BIOS is actually an "all systems clear" notification. Technically, it's an indication that thePOST iscomplete. No troubleshooting necessary!1Continuous BeepCPUnot inserted properly or not present.1 Long Beep, 2 Short BeepsOne long beep followed by two short beeps indicates that there has been a checksum error. This means that there is some kind of motherboard issue. Replacing the motherboard should fix this problem.1-1-1-1 Beep Code PatternMostoften, it's a problem with the system memory. This Phoenix BIOS issue is usually corrected by replacing the RAM.1-2-2-3 Beep Code PatternA 1-2-2-3 beep code pattern means that there has been a BIOS ROM checksum error.Need to replacethe entire motherboard.1-3-1-1 Beep Code PatternA 1-3-1-1 beep code pattern on aPhoenixBIOSsystem means that there has been an issue while testing the DRAM refresh. This could be a problem with the system memory, an expansion card, or the motherboard.
Phoenix BIOSPOST Error Codes
1-3-1-3 Beep Code PatternThisusually means that there is a problem with the currently connectedkeyboardbut it could also indicate a motherboard issue.1-3-4-1 Beep Code PatternA 1-3-1-1 beep code pattern on aPhoenixBIOSsystem means that there is some kind of issue with the RAM. Replacing the system memory usually fixes this problem.1-3-4-3 Beep Code PatternA 1-3-1-1 beep code pattern indicates some kind of issue with the memory. Replacing the RAM is the usual recommendation for solving this problem.
Phoenix BIOSPOST Error Codes
1-4-1-1 Beep Code PatternA 1-4-1-1 beep code pattern on aPhoenixBIOSsystem means that there is an issue with the system memory. Replacing the RAM usually fixes this problem.2-1-2-3 Beep Code PatternA 2-1-2-3 beep code pattern means that there has been a BIOS ROM error, meaning an issue with the BIOS chip on the motherboard. This Phoenix BIOS issue is usually corrected by replacing the motherboard.2-2-3-1 Beep Code PatternA 2-2-3-1 beep code pattern on aPhoenixBIOSsystem means that there has been an issue while testing hardware related to IRQs. This could be a hardware ormisconfigurationproblem with an expansion card or some kind of motherboard failure.
GROUP DISCUSSION:Why does the computer beepeverytimeduring start up?Why is it important to know different beeps when dealing with computers?How do you know what BIOS you are using on your computer?What is the BIOS used for and its purpose?