Definition of computer bios


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Definition of computer bios

The Basic Input/Output System (BIOS) is a Firmware interface in your Computer. It is also known as PC BIOS or ROM BIOS or System BIOS. Basic Input/Output System (BIOS) plays an important role to Run your Computer. The Basic Input/Output System (BIOS) Software is built into the Computer and is the first Software run by a Computer when “Powered On”. After “Powered On” of your Computer, you choose what to do with your Computer by enter to the Basic Input/Output System (BIOS). You can change the “System Booting Device” or “First/ Second/ Third Boot Device” options by enter to the Basic Input/Output System (BIOS) in your Computer.


Characteristics of computer bios


Definition of computer bios

1) Test system hardware components

The Basic Input/Output System (BIOS) are to initialize and test the “System Hardware Components” and to load a bootloader or an Operating System from a Mass Memory Device in your Computer.

2) Access hardware components

Differences in the System Hardware are hidden by the Basic Input/Output System (BIOS) from programs which use Basic Input/Output System (BIOS) services instead of directly accessing the Hardware. Modern Operating Systems ignore the make layer provided by the Basic Input/Output System (BIOS) and access the Hardware components directly.

3) Transitional process

BIOS technology is in transitional process toward the Unified Extensible Firmware Interface (UEFI).

4) Interact with hardware devices

Definition of computer bios

The Basic Input/Output System (BIOS) provides construct layer for the hardware which is the dependable way for application programs and operating systems to interact with the Keyboard, Monitor Display and other Input/Output Devices.

5) Generate signal errors

Error messages were displayed on the Monitor screen or coded series of sounds were generated to signal errors.

6) Configure hardware

The “Options” on the Computer set by switches and jumpers on the “Motherboard” and on peripheral cards. It access at system power up by a specific “Keyboard Key Sequence” in new Computer. The user can configure hardware options using the keyboard and video display.

7) store of bios

Basic Input/Output System (BIOS) Software is stored on a non volatile “ROM Chip” on the “Motherboard”. Basic Input/Output System (BIOS) works with each specific model of computer, interfacing with different devices that make up the complementary chipset of the system. Basic Input/Output System (BIOS) contents are stored on a flash memory chip. The contents can be rewritten without removing the “Chip” from the “Motherboard” in new computer systems.

8) Add new feature and fix bugs

Basic Input/Output System (BIOS) Software can be easily upgraded to add new features and fix any types of bugs.

9) The bios boot process

The address of the Basic Input/Output System (BIOS) memory is situated such that it will be executed when the computer is “First Started Up”. A jump instruction then directs the processor to start executing code in the Basic Input/Output System (BIOS). If the system has just been “Powered Up” or “Reset Button” was pressed from your “CPU Casing Box”, the full “Power On Self Test (POST)” is run. The “Power On Self Test (POST)” tests and identifies “System Devices” such as the CPU, RAM, interrupt and DMA controllers and other parts of the Chipset, Video Display Card, Keyboard, Hard Disk Drive, Optical Disc Drive and other basic Hardware. The Basic Input/Output System (BIOS) then locates “Boot Loader Software” held on a storage device designated as a “Boot Device”, such as a hard disk, a floppy disk, CD, or DVD and loads and executes that software, giving it control of the PC. This process is called as “Booting” or “Booting Up”.

10) Bios components

The Basic Input/Output System (BIOS) may contain components such as the “Memory Reference Code (MRC)”. It is responsible for handling memory timings and related hardware settings.

11) Boot devices

Definition of computer bios

The Basic Input/Output System (BIOS) selects candidate boot devices using information composed by POST and configuration information from EEPROM, CMOS RAM in the earliest Computers, DIP switches. Option ROMs may also influence or supplant the boot process defined by the “Motherboard BIOS ROM”. The Basic Input/Output System (BIOS) checks each device in order to see if it is bootable. For a disk drive or a device that logically emulates a disk drive, such as an “USB Flash Drive” or perhaps a “Tape Drive”, to perform this check the Basic Input/Output System (BIOS) attempts to load the “First Sector (Boot Sector)” from the disk to memory address and checks for the boot sector signature in the last two bytes of the sector. If the sector cannot be read (due to a missing or blank disk or due to a hardware failure or if the sector does not end with the boot signature, that time, the Basic Input/Output System (BIOS) considers the disk unbootable and proceeds to check the next device. Another device such as a network adapter attempts booting by a procedure that is defined by its option ROM (or the equivalent integrated into the “Motherboard BIOS ROM”. The Basic Input/Output System (BIOS) proceeds to test each device sequentially until a bootable device is found, at which time the Basic Input/Output System (BIOS) transfers control to the loaded sector with a jump instruction to its first byte at address.

12) Firmware

In other types of computers, the terms boot monitor, boot loader and boot ROM are used instead. Some Computers use Open Firmware for this purpose. There are a few alternatives to the functionality of the “Legacy BIOS” in the x86 supported “Motherboard” which is Extensible Firmware Interface, Open Firmware used on the OLPC XO-1 and coreboot.

13) Overclocking

Some Basic Input/Output System (BIOS) chips allow overclocking, an action in which the CPU is adjusted to a higher clock rate than its factory preset.

14) Setup utility

Definition of computer bios

Enable or Disable system components
Select which devices are potential “Boot Devices”
Configure Hardware
Set various password prompts, such as a password for securing access to the BIOS user interface functions itself and preventing malicious users from booting the system from unauthorized peripheral devices
Set the system clock

15) Virus attacks

The Basic Input/Output System (BIOS) can be affected by the Computer Viruses. That time, you have to “Remove” the “BIOS Computer Viruses” from the Basic Input/Output System (BIOS).

16) Operating system services

The Basic Input/Output System (BIOS) provides a small library of basic input/output functions to operate peripherals such as the keyboard, elementary text and graphics display functions etc. When using MS-DOS, Basic Input/Output System (BIOS) services could be accessed by an application program by executing an “INT 13H Interrupt Instruction” to access disk sectors, or one of a number of other documented Basic Input/Output System (BIOS) interrupt calls to access video display, keyboard, cassette etc. Basic Input/Output System (BIOS) is used only during “Booting” and “Initial Loading of System Software”. Before the “Operating System’s First Graphical Screen” is displayed, input and output are typically handled through BIOS. A boot menu such as the textual menu of Windows that allows one to choose an “Operating System” to “Boot” or to boot into “Safe Mode” or to use the “Last Known Good Configuration” which is displayed and receives keyboard input through Basic Input/Output System (BIOS).

17) Re-programmable to memory devices

Motherboard ROMs could be replaced, but not altered, by users for your Computer Basic Input/Output System (BIOS). To allow for updates, many compatible computers used re-programmable memory devices such as EEPROM and later flash memory devices. Flash chips are programmed (and re-programmed) in-circuit, while EPROM chips need to be removed from the “Motherboard” for re-programming for your Computer Basic Input/Output System (BIOS). Basic Input/Output System (BIOS) versions are upgraded to take advantage of newer versions of hardware and to correct bugs in previous revisions of Basic Input/Output System (BIOS).

18) Flashing the BIOS

The Basic Input/Output System (BIOS) is stored in “Rewritable Memory”. The Basic Input/Output System (BIOS) allow the contents to be replaced or ‘Rewritten’ in your Computer which is called “Flashing”. This can be done by a special program, usually provided by the “System’s Manufacturer”. A Basic Input/Output System (BIOS) might be reflashed in order to upgrade to a newer version to “Fix Bugs” or provide “Improved Performance” or to “Support Newer Hardware” or a reflashing operation might be needed to “Fix a Damaged Basic Input/Output System (BIOS)”.

19) Enter to bios

After “Powered On” your Computer, you have to Press the following Keyboard Shortcuts instantly from your “Keyboard” to enter to your Computer Basic Input/Output System (BIOS).


Press Del (Award BIOS) Press F2 (Phoenix BIOS)
instantly from your “Keyboard” after “Powered On” your Computer.





1. Computer User

2. Computer

3. Computer “Motherboatd”

4. Motherboard ROM (Read Only Memory)

5. Motherboard Firmware

6. Need “Keyboard” to enter to your Computer Basic Input/Output System (BIOS).




a) You should use the Basic Input/Output System (BIOS) for Controlling your Computer.

b) You can change the “System Booting Device” or “First/ Second/ Third Boot Device” options by enter to the Basic Input/Output System (BIOS) in your Computer.

In this way, you can understand about Definition of Computer BIOS, Characteristics of Computer BIOS, Requirements and Tips for using the “Basic Input/Output System (BIOS)” in your Computer.

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