Main notions and operation BIOS

DPMS

Display Power Management Signaling - a signals of control of энергопотреблением monitor - a standard, created assotiation VESA for многостадийного of the reduction of энергопотребления monitor. For realization of the standard his(its) must support the monitor. Four levels are stipulated In standard:

0 - "DPMS Mode On" - a Monitor is used as usually;

1 - "DPMS Mode Standby" - a Scenes no, consumption is reduced;

2 - "DPMS Mode Suspend" - a Scenes no, consumption else more reducing;

3 - "DPMS Mode Off" - a Scenes no, consumption is reduced before minimum.

DRAM

Dinamic Random Access Memory - a dynamic memory of the direct access - a memory, схемотехнически executed in the manner of two-dimensional matrix (the line h column) capacitor. Very cheap, but requires constant "refreshments" or regenerations (Refresh) of the charge on capacitor. The Regeneration is executed as "started" reading to memories. This process deprives significant time, since in this period no device can not gain access to memories, except controller of the regenerations.

ECP

Enhanced Capability Port - a port with extended possibility - differs from standard printer port with interface Centronics, that that transferred information divides on commands and given with support of the mode DMA and coding on method RLE (Run-Length Encoding - a coding the reiterative sequences given).

EDO

Extended Data Output DRAM - when functioning(working) on record does not give no advantage in contrast with FPM DRAM, but requires greatly time less when reading to account that that given remain on leaving the microcircuit EDO DRAM long, than in FPM DRAM. EDO (either as FPM) does not give no advantage at random access given from memory, but such situation appears extremely seldom. Time of the access is indicated On microcircuit EDO DRAM in nanosecond to given in casual order.

EPP

Enhanced Parallel Port - an extended parallel port - a bidirectional variant of the printer port with maximum velocity of the acceptance/data communication before 2 MB/c. Became possible addressing several devices, entering 8-mi bit data. Memory is used For buffering given with FIFO organization by volume in 16 bytes.

FPM

Fast Page Mode DRAM - an most old type to memories, which became be used as far back as 80-h year. Differs from standard that that allows to shorten reading/record data, located one for others in memories, but herewith on each word is required not less three tacts of the system bus. Time of the access is indicated On microcircuit Fast Page Mode DRAM in nanosecond to given in casual order.

I/O

The Port of the entering-output - a channel data communication between device and microprocessor. The Port introduces in microprocessor as one or several addresses to memories, from which possible read or in which possible write the data.

IrDA

The Abbreviation from "Infrared Data (sometimes as Device) Association". In the same way is identified the interface with use the infrared port, providing беспроводное connection of the peripherals of the low speed, which are located in close proximity PC.

Plug and Play

In 1993 "Compaq", "Intel", "Phoenix" and "Microsoft", стремясь do PC else more knowledge-based, have developed the concept "Plug and Play". The Main her(its) idea is concluded in following: when boot PC BIOS interviews all cards on subject their need for resource and distributes their so that when functioning(working) PC did not appear the conflict to situations.

The Contact between card of the extension and BIOS possible to provide else эффективнее when use PCI-buses. So, majority PnP-cards is designed for bus PCI only. All are PCI-cards differ, besides, additional ability. Unlike their own ISA-relative they can work with variable resource and by means of exactly determined identification record distinctly to declare about their own ресурсных need.

Accordingly this BIOS, maintaining "Plug and Play", first checks hard adjusted ISA-cards, but will then distribute the remained facility PCI-device. Is it As a result formed list of the distribution resource ESCD (Extended System Configuration Data), placed BIOS'ом in non-sensitive to absence of the power supply the area to memories to under each start to have a possibility of the comparison and reconstruction last functioned to combinations.

RAS

Raw Address Strobe - a strobe of the address of the line - a signal, used when work with dynamic memory (DRAM), is intended for запоминания in microcircuit DRAM address of the line.

Refresh

Possible three different methods to regenerations data:

The Regeneration one RAS (RAS Only Refresh - ROR). This method was used as far back as first microcircuit DRAM. The Address of the regenerated line is transferred on bus of the address and is issued signal RAS (just as when reading or record). Is it Herewith chosen line cell, and given of them enter on internal circuit of the microcircuit whereupon they are written back. Since hereinafter signal CAS does not follow, cycle of the reading/record does not begin. Is it Then transferred address of the following line and so on until will is passed whole matrix to memories whereupon cycle to regenerations is repeated. To defect of this method possible to refer that concerns with the bus of the address, and at moment of the regenerations is blocked access to the other computer subsystem.

CAS before RAS (CAS Before RAS - CBR) - a standard method to regenerations. Under normal cycle of the reading/record signal RAS always comes first, for he follow CAS. But if CAS comes earlier RAS, that begins the special cycle to regenerations - CBR. At address of the line is not transferred, but microcircuit uses its internal counter, which the contents increases on 1 under each CBR-cycle (t.n. инкрементирование address of the line). This mode allows to regenerate the memory, not occupying bus of the address that, certainly, more economical.

The Automatic regeneration to memories (Self Refresh - SR, or саморегенерация). This method is usually used in mode энергосбережения, when system moves over to condition "VWVappear in the dreams" ("suspend"), and pulsing generator ceases to work. In such condition renovation to memories on above-mentioned method impossible (simply are absent the sources a signal), and microcircuit to memories executes the regeneration by itself. In she is started own generator, which тактирует the internal circuit to regenerations. Such technology of the functioning to memories was introduced with appearance EDO DRAM. Necessary to note that in mode "VWVappear in the dreams" memory comsumes very small current.

SDRAM

SDRAM - comparatively new type to memories, which also shows their own advantage only under consequent sample given from memory. But under consequent sample (or flow, conveyor - burst) reading/record are executed in two times quicker, than for EDO DRAM On microcircuit SDRAM is indicated time of the access in nanosecond to given under consequent sample. Real numerals on body of the microcircuits to synchronous memory practically report the maximum clockrate of the system bus, on which given memory can work.

SDRAM is released presently only in 168-mi excretory 64-bit module DIMM. Unlike usual modules SIMM these can close at maternal board singly. In accordance with JEDEC standard on module DIMM must be installed special microcircuit SPD device. Some are a modern maternal board, for instance company Intel on set 440LX, are not started if it is installed plank to memories without SPD. The Microcircuits SDRAM in the same way are broadly used as local memory видеокарт.

SE

Single-Ended - technology device, data communication, connector, in which are used однополярные signals in level TTL-logic that for Ultra Wide SCSI characteristic of. The Internal restrictions SCSI-standard were to a considerable extent преодолены in interface Ultra2 Wide SCSI, provided send rate before 80 MB/with.

The Constant development SCSI-interface put the purpose increasing frequencies that provided in total to restriction of the maximum length of the interface cable. Technology LVD works, unlike SE, with two arctic low-level signals. Each signal of the bus Ultra2 Wide is transferred on two wires in antiphase (differential). This - so named низковольтная differential transmission signal, or Low Voltage Differential (LVD). Due to her to manage to enlarge possible length of the connecting cable before 12 m.

SIMM

Single In-line Memory Module - an unilateral module to memories - an конструктов of the module to memories, gradually leaving in 1997 with the market. Has 72 outputs with each parties, but pair(vapour)s output with one and the other parties are closed between itself so they are considered unilateral. Strictly memory, placed on module, can be as FPM, so and EDO. The Memory in SIMM has разрядность 32 (with parity - 36) of the bit and can be used in computer with processor Pentium only vapour(pair).

SPD

Serial Presence Detect - a device of the determination of the presence with consequent access - is made on special microcircuit (as a rule, this electrically reprogrammable memory), containing information on type device and his(its) main feature. The Volume to such memories - 512 bytes.

SPP

Standard Parallel Port - a standard parallel port - a classical printer interface, named, as a rule, Centronics, by name long ago liquidated company, developed this interface. The Interface allows to transfer given on byte at the speed of before 80 KB/c. When receiving given possible to use four lines of the signal from printer (the breakaway of the paper, buffer of the printer packed and etc.).

Boot the system

When enabling PC is automatically started residing in BIOS program of the boot BOOT-ROUTINE. This program causes the subroutine an самопроверки POST (Power-On Self Test), checking operative memory, processor, hard disk and etc.Hereinafter, the program of the boot searches other BIOS-chips, which can be built-in, to example, in plug-in card. SCSI- controllers will herewith start their own own test programs.

Hereon BIOS rs already concretely for plug-in card and placement and checking the distribution resource (IRQ, DMA, I/O).

Hereinafter with load sector of the hard disk in deal enters the initial loader, BOOTSTRAP LOADER, - a program, knowing file structure of the carrier data. The Initial loader causes boot the load programs of the operating system.

This is a standard algorithm vastly дополнился and was modernized with introduction PnP-technologies and new PCI-buses, but with appearance of the operating systems later, designed with provision for introduction the most latest technology.