What is BIOS (basic input/output system)? - ComputerWork22

 What is BIOS (basic input/output system)?

A BIOS (Basic Input/Output System) Short for memory is a boot computer code program that a laptop uses to with success begin operative. The BIOS is found on a chip within the pc and is meant in a very method that protects it from disk failure.

When you activate a computer, the BIOS initially conducts a basic hardware check, referred to as a Power-On Self-check (POST), to work out whether or not all of the attachments are gift and dealing. Then it masses the package into your computer’s random access memory or RAM. The BIOS conjointly manages information flow between the computer’s package and connected devices like the fixed disk, video card, keyboard, mouse, and printer. The picture below is AN example of what a BIOS chip could seem like on a laptop motherboard. The BIOS pictured is of AN early AMI BIOS, a sort of BIOS factory-made by AMI

Image Source - Google | Image By -  SuperTechman

Functions of BIOS

(i) BIOS Power on Self Test (POST): It is an integral service program. This self takes a look at ensures that the pc has all of the mandatory elements and practicality required to with success begin, like the use of memory, a keyboard, and alternative elements. Then extra tests square measure done throughout booting. If errors square measure detected throughout the take a look at, the BIOS instructs the pc to grant a code that reveals the matter.

The BIOS conjointly works to administer the pc basic data concerning the way to act with some essential parts, like drives and memory that it'll get to load the package. Once the essential directions are loaded and therefore the self-test has been passed, the pc will proceed with loading the package from one in all the hooked up drives. laptop users will usually make sure changes to the BIOS through a configuration screen on the pc. 

We can conjointly use flash-memory cards to carry BIOS info. this enables users to update the BIOS version on computers when a marketer releases the associate updates. this method was designed to unravel issues with the initial BIOS or to feature new practicality. Users will sporadically check for updated BIOS versions, as some vendors unharness a dozen or a lot of updates over the course of a product’s period. circuit board (System) BIOS, Video adapter computer code (BIOS), Drive controller computer code (BIOS), electronic equipment Card computer code (BIOS), Network adapter board BIOS, small computer system interface adapter BIOS. The circuit board BIOS provides routines to support motherboard options.

Bootstrap Loader: To boot the package. The BIOS contains a program referred to as bootstrap loader whose responsibility is to look and begin the package boot program. Then the boot program of the package controls the pc system and boots the package.

(iii) BIOS Setup Utility Program: 

A non-volatile memory (NVRAM) is employed to store info concerning the pc system. throughout the installation of a system, the user runs the BIOS setup program and enters the proper parameters. The settings of memory, disk sorts, and different settings square measure keep in NVRAM and not in BIOS chip itself. To construct NVRAM, the fabric needed is CMOS (Complementary metal chemical compound semiconductor). These CMOS chips square measure terribly economical storage devices as they store and maintain knowledge on terribly low values of current. The system’s configurations so also are termed as CMOS settings, so we are able to set mistreatment BIOS originated program. 

CMOS settings will be maintained by battery backup either by mistreatment electrical condenser or by battery engineered into NVRAM chip. This chip conjointly has a system clock. If there's no battery, the setting remains for a brief amount of your time, and that we have to be compelled to reset the system. With it, there's a loss of BIOS positive identification that protects the BIOS-originated programs.

To clear the CMOS RAM contents, 2 strategies used square measure

(i) By mistreatment clear CMOS jumper.

(ii) By holding down enter key throughout booting of the system.

For Pentium III motherboards, completely different setups square measure there in AMI BIOS. These are:

• Commonplace CMOS Setup: It is employed to line time date, disc kind, kind of floppy drive, kind of monitor, and keyboard.

Advanced CMOS Setup: It is employed to line typematic rate and delay, on top of one MB memory take a look at, memory take a look at tick sound, Hil < Del> message show, system boot-up sequence, etc.

• Advanced Chipset Setup: It is employed to line options of the chipset.

• Power Management Setup: It is employed to manage power conservation choices.

• PCI/Plug and Play Setup: It is employed to line choices of PCI bus which of plug and play devices.

• Peripherals Setup: It is employed to manage choices associated with I/O controllers.

 • central processor Configuration Setup: This setup is employed to pick out the categories of central processors put in within the motherboard. In AMI BIOS, the settings square measure machine because it mechanically finds out the sort of central processor within the ADP system.

(iv) System Service Routines: The BIOS provides numerous package routines (subprograms) that may be known as by higher-level packages such, as DOS, Windows, or their applications, to perform totally different tasks. nearly every task that involves accessing the system hardware has historically been controlled exploitation of one or additional of the BIOS programs (although many more modern operative systems currently bypass the BIOS for improved performance). 

BIOS services square measure accessed exploitation package interrupts, that square measure like the hardware interrupts except that they're generated within the processor by programs rather than being generated outside the processor by hardware devices. One factor that this use of interrupts will is to permit access to the BIOS while not knowing wherever in memory every routine is found.

Normally, to decision a software system routine you wish to grasp its address. With interrupts, a table referred to as associate degree interrupt vector table is employed that bypasses this drawback. once the system is started up, the BIOS puts addresses into this table that represent wherever its routines are placed for every interrupt it responds to. Then, once DOS or associate degree application desires to use a BIOS routine, it generates a software system interrupt. 

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