BIOS(Basic Input Output System)

BIOS is "Basic Input Output System" abbreviations, literal translation after Chinese name is "basic input output system." Fact, it is a group curing to computer motherboard inside a ROM chip program that preserved computer most important basic input output procedure system settings information boot self procedures and system self startup programs. Its main function is computers bottom, most direct hardware settings and control.BIOS settings procedure is stored in BIOS chip, only boot when can set. CMOS primarily for storage BIOS Setup program set parameters and data rather BIOS setup mainly computer basic input output system manage and settings so system run in best state, use BIOS setup also exclude system failure or diagnose system problems. Suggested that since BIOS "procedural" that it should belongs software, feels like own common Word or Excel. But many people not think so because it general software there some differences and it and hardware contact also quite closely. Figuratively said, BIOS should connection software program with hardware devices a "bridge" responsible solve hardware instant requirements. Motherboard BIOS chip perhaps motherboard unique labeled chip, generally it an 32 pin DIP IC, emblazoned "BIOS" words. 586 Previous BIOS mostly rewritable EPROM chip, above label plays protection BIOS content role (ultraviolet radiation make EPROM content lost) not casually tear. 586 later ROM BIOS use more EEPROM (Electrically erasable read only ROM), through jumper switches and systems equipped belt driver disk, can EEPROM be rewritten easily achieve BIOS upgrade. Computer users in the use of computers in the process, will be exposed to BIOS, it is in the computer system plays a very important role. An motherboard superior performance depends largely on motherboard BIOS management function whether advanced. BIOS chip is motherboard a rectangular or square type chip, in microcomputer development early, BIOS are stored in ROM (Read Only Memory, Read Only Memory). ROM internal information is in ROM manufacturing processes, in factory use special method is burn into the where content only read not change, once burn go, user only verify written information whether correct not further any changes. If found information any error, only abandon not, EPROM (Erasable Programmable ROM, erasable programmable ROM) chip repeatable erase and write solve PROM chip only writable once disadvantages. EPROM chip an obvious characteristics its positive ceramic package, opened a glass window through the window can see its internal IC, ultraviolet through the hole irradiation internal chip can erase its data within complete chip erased operations to use EPROM Eraser. EPROM inside information to use a dedicated programmer to write and to write the contents of the chip must be added a certain programming voltage (VPP = 12-24V, with a different chip model). EPROM model is based on 27 at the beginning, such as the 27C020 (8 * 256K) is a 2M Bits capacity of the EPROM chip. EPROM chips write information, also to opaque stickers or tape put window sealed avoid contamination surrounding ultraviolet radiation Ershi information damaged.By the EPROM operation inconvenience later out motherboard BIOS ROM chip most have adopted EEPROM (Electrically Erasable Programmable ROM, electrically erasable programmable ROM
 BIOS main stored:
 ● self Diagnostics: by reading in CMOS RAM content identification hardware configuration, and its self and initialization;
 ● CMOS setup program: the boot process, start with a special hot key, the settings, stored in CMOS RAM;● system bootstrap loader: in self successful will disk relatively 0 0 sector on bootstrap loader memory, let run to load
 DOS system;● major I / O devices drivers and interrupt service: Due BIOS direct and system hardware resources dealing therefore always against certain type hardware system while various hardware system also different, so exist different kinds of BIOS, With hardware technology, same BIOS also successively appeared different versions, new version BIOS than old version speaking, function stronger.