BIOS

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BIOS

(computer science)

BIOS

BIOS

(Basic Input Output System) A set of routines residing in firmware that boots the operating system and sets up the hardware in an x86-based PC. Prior to loading the operating system, the BIOS provides software drivers for the basic peripheral support that is part of the motherboard, including the keyboard, mouse, monitor and hard disk. The drivers enable the user to edit configuration settings and allow the hardware to boot from the hard disk or other storage device.

After the operating system is loaded, more elaborate drivers are typically loaded, which replace the BIOS routines. The BIOS also supports internal services such as the real-time clock (time and date).

The BIOS Sets Up the Computer
On startup, the BIOS tests the system and prepares the computer for operation based on the installed hardware and the configuration settings from the manufacturer and user. For example, it initializes memory and caches and assigns resources to all devices connected to the PCI bus. The BIOS searches for BIOS extensions (option ROMs) on plug-in cards and sets up pointers (interrupt vectors) in main memory to access those routines. It then loads the operating system and passes control to it.

From ROM BIOS to Flash Memory
The BIOS, which dates back to the first IBM PC in 1981, used to be permanently stored on a read-only memory (ROM) chip. In the early days, adding a larger disk or new type of peripheral sometimes required a BIOS change, and in order to update the BIOS, it had to be replaced. Later, the BIOS was stored in rewritable flash memory. See BIOS setup, BIOS upgrades, beep codes and UEFI.


BIOS Interaction
On startup, the BIOS provides the routines necessary to test and configure the hardware and use the peripheral devices included on the motherboard.







BIOS Identification
TouchStone Software's BIOS Wizard is a nifty utility that identifies and tests your PC's BIOS to see if it needs to be updated. The program is available at www.esupport.com/bioswiz/index2.html. (Screen image courtesy of TouchStone Software Corporation, www.esupport.com)
References in periodicals archive ?
The SC6H SCSI-based subsystem may be configured for operation either through the cPCI bus using the onboard SCSI controller with boot BIOS ROM, or through the system SCSI host via J5 as an ultra-wide LVD or SE SCSI peripheral.
The SC6F SCSI subsystem may be configured for operation either through the CPCI bus using the onboard SCSI controller and boot BIOS ROM, or through the host system SCSI adapter via J5 as an ultra-wide LVD or SE SCSI peripheral.
The SC6 SCSI based subsystem may be configured for operation either through the CPCI bus using the onboard SCSI controller with boot BIOS ROM, or through the system SCSI host via J5 as an ultra-wide LVD or SE SCSI peripheral.
The ATTO ExpressPCI UL2D represents the next logical step in the evolution of ATTO's complete family of SCSI host adapters, and offers outstanding performance features including: Compatibility with both Macintosh and PC systems; Support for Tagged Command Queuing; Multiple Initiator Support; Flash BIOS ROM for easy field updates; PCI 2.
By building directly into the system ROM, the overall BIOS footprint is reduced and BIOS updates are simplified, since only the BIOS ROM needs to be flashed.
It also contains either 4 or 8MB of memory, PC AT BIOS ROM, plus an I/O controller with two serial ports, a parallel port and speaker port.