BIOS is an acronym for Basic Input / Output System. It is the first part of the computer to boot, and usually decides from where to boot the operating system. The BIOS is also responsible for some of the most basic computer interfaces such as keyboard and video, hence its name. Many modern BIOSes, such as those shipped by Award and Phoenix, are also able to communicate with NIC cards and USB devices, and even provide facilities for booting from these interfaces. While there is usually no need for an end-user to update or change which BIOS he uses, often times the individual settings of a particular BIOS may be changed. Thus, savvy computer users, and not just those with an advanced information technology MBA, can add password-protection to their machines, can change which devices get loaded or checked at startup, and can even overclock their processors. These settings are stored in a flash memory device adjacent to the BIOS, which allows for both read and write access.
When a computer is first started, it reads the BIOS chip for instruction on what to do. The BIOS usually performs the Power-On Self Test to ensure that all the necessary hardware components are attached to the computer. After the POST test, the major components (keyboard, system memory, IDE drives) are initialized and made functional. Only then can an operating system be found and made functional. The BIOS looks in predetermined (usually by the computer manufacturer) locations for a bootable operating system. Common places are the legacy floppy drive, then the CD-ROM drive, and finally one of the hard drives. This is important info to figure out whether you are studying in your GIS programs or other technology driven field. Once a suitable operating system is found, the system is bootstrapped- the BIOS starts the OS and either provides it with an interface to the hardware (as in the case of DOS) or lets the OS handle the hardware itself (as in Linux and Windows). At this point, the BIOS has completed its duties and is not accessed again until the computer is restarted.
To configure or view one's BIOS settings, a special keystroke sequence must be performed at startup. There will be a message that indicates which keys to press, but as it is presented for no more than three seconds (and often less than one second!), these common keys should be tried: F1, F2, DEL, ESC. In secure systems, the user will be prompted for the master password, but on most home systems this is disabled. Once the BIOS configuration screen is visible, the user can usually alter the boot sequence, set passwords (to the OS or BIOS itself), alter the processor speed, and enable / disable Num Lock on the keyboard. Other common tasks include adjusting the system's time and date, and configuring low-level power management, such as hard disk and video shutdown. So long as the "Exit And Save" option is not enacted, there is no danger of changing settings. However, if one does make the wrong changes and saves them, then there is a chance that the computer will not boot, or that damage may occur to the processor and / or memory.
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