What is BIOS?

BIOS is an acronym for Basic Input/Output System. It is the boot firmware program on a PC, and controls the computer from the time you start it up until the operating system takes over. When you turn on a PC, the BIOS first conducts a basic hardware check, called a Power-On Self Test (POST), to determine whether all of the attachments are present and working. Then it loads the operating system into your computer's random access memory, or RAM.

The BIOS also manages data flow between the computer's operating system and attached devices such as the hard disk, video card, keyboard, mouse, and printer.

The BIOS stores the date, the time, and your system configuration information in a battery-powered, non-volatile memory chip, called a CMOS (Complementary Metal Oxide Semiconductor) after its manufacturing process.

Although the BIOS is standardized and should rarely require updating, some older BIOS chips may not accommodate new hardware devices. Before the early 1990s, you couldn't update the BIOS without removing and replacing its ROM chip. Contemporary BIOS resides on memory chips such as flash chips or EEPROM (Electrically Erasable Programmable Read-Only Memory), so that you can update the BIOS yourself if necessary.


220 manufacturers are listed on Wim's BIOS Page!computer for BIOS and driver updates

2 the Maxx
Aaeon
Ability
Abit
Acer
Achitec
Achme
Acma
Acorp
Adcom
ADI
ADLink Technology Inc.

Advanced Logic Research (ALR)
Advantech
Aeton Technology
AIR
Alaris
Albatron
ALD Technology
Alton
Amaquest
Amax
AMI
Amptron
AMS
Anigo
AOpen
Aotexin
Aprocom
Arima
Aristo
Arvida
ASK Technology
Asrock
AST
Asus
AT&T
Atrend
Austin Direct
AVT
Azza
BCM
BCom / ASI
BEK-Tronic Technology

Biostar
Boser
California Graphics
Chaintech
Chaplet
Chicony
Clevo
CMC
Commate
Compaq
Computrend
Daewoo
Darter
Dataexpert
Datavan International
Dell
Delta Electronics
DFI
Digicom
Digital
Domex (DTC)
DTK
Dual Tech
ECS (Elitegroup)
EFA
Elonex
ENMIC
ENPC
EPoX
ESPCo
Evalue Technology Inc
Expen Tech
Fastfame Technology Co., Ltd.

FIC (FICA)
Flagpoint
Flytech Group International
Ford Lian
Formosa Industrial Computing
Foxconn / Hoxtek (with FK)
Foxconn / Hoxtek (with FL)
Free Tech
Fugutech
Fujitsu
Full Yes
Gainward
Gateway
Gemlight
Giantec
Gigabyte
Global Circuit Technology (GCT)
Globe Legate
GVC
HighTech Information System
Holco Enterprise
Hope Vision
HP
IBM
ICP
Industrial Technology Research Institute
Informtech International
Inlog Microsystem
Intel
Inventa
Inventec
Iwill
J&J Technology
J-Bond
J-Mark
Jamicon
Jetta
Jetway
Joss Technology
Kaimei
Kapok
KINPO Electronic
Lanner Electronics
Leadtek
LeadTek/Foxconn
Lian Guan
LiPPERT Automationstechnik
LiPPERT Automationstechnik GmbH
Lucky Star
Lucky Tiger
Luckytech Technology
Macrotek
Matra
Matsonic
Maxtium Computer
Micro Leader Enterprises
Micron
Microstar
Mitac
Mustek
MyComp
Nature Worldwide Technology Corp
Nec
New Tech
Nexar
Nexcom
NMC
Ocean Office Automation
Packard Bell
Palmax
PC Chips (Hsin Tech)
PcPartner
PCWare
Pine Technology
Pionix
Polaris
Powercolor
Powertech
President (Formerly Wang Labs)
Procomp Informatics
Protech
Puretek
QDI
Quanta
Rectron
Redfox
Research Machines PLC
RioWorks Solutions
Rise Computer
RSAP Technology
S&D
San Li
Seanix
Seavo
Seritech
ShenZhen Zeling
Shuttle (Holco)
Smart D&M Technology
Soltek
Sono Computer
Sony
Sowah
Soyo
Spring Circle
Sukjung
Super Grace Electronics
Supermicro
SuperPower
T&W Electronics
Taeli (Techmedia)
Taken
Tatung
Tekram
Top Star
Toshiba
Totem Technology
Trangg Bow
Transcend
Trigem
Tsann Kuen (EUPA)
Twinhead
Tyan
U-Board
UHC Advanced Integration Research
Umax
Unicorn
Unitron
Universal Scientific Industrial
Uniwill
Vision Top
Vobis
VTech
Warp Speed
Weal Union Development
Well Join Industry
Win Lan
Winco
WinTechnologies (Edom)
Yamashita
YKM (Dayton Micron)
Zenith
Zida
Zillion

What is the difference between memory and disk storage?

Memory and disk storage both refer to internal storage space in a computer.

The term memory usually means RAM (Random Access Memory). To refer to hard drive storage, the terms disk space or storage are usually used. Typically, computers have much less memory than disk space, because RAM is much more expensive per megabyte than a hard disk.

Virtual memory is disk space that has been designated to act like RAM.

Computers also contain a small amount of ROM, or read-only memory, containing permanent or semi-permanent (firmware) instructions for checking hardware and starting up the computer. On a PC, this is called the BIOS.


What is RAM?
Overview

Random Access Memory (RAM) provides space for your computer to read and write data to be accessed by the CPU (central processing unit). When people refer to a computer's memory, they usually mean its RAM.

If you add more RAM to your computer, you reduce the number of times your CPU must read data from your hard disk. This usually allows your computer to work considerably faster, as RAM is many times faster than a hard disk.

RAM is volatile, so data stored in RAM stays there only as long as your computer is running. As soon as you turn the computer off, the data stored in RAM disappears.

When you turn your computer on again, your computer's boot firmware (called BIOS on a PC) uses instructions stored semi-permanently in ROM chips to read your operating system and related files from the disk and load them back into RAM.
SDR, DDR, DDR2, and DDR3 RAM

There are several types of RAM used in modern computers. Prior to 2002, most computers used single data rate (SDR) RAM. Most computers made since use either double data rate (DDR), DDR2, or DDR3 RAM. DDR2 is able to achieve faster transfer rates to prevent limitation of your CPU's performance, and DDR3 technology takes these advancements even further.

Note that these RAM technologies are not interchangeable. One type of RAM will not function if installed with another type, and physical differences in the RAM modules prevent them from even being inserted in the same computer.

What is ROM?

ROM is an acronym for Read-Only Memory. It refers to computer memory chips containing permanent or semi-permanent data. Unlike RAM, ROM is non-volatile; even after you turn off your computer, the contents of ROM will remain.

Almost every computer comes with a small amount of ROM containing the boot firmware. This consists of a few kilobytes of code that tell the computer what to do when it starts up, e.g., running hardware diagnostics and loading the operating system into RAM. On a PC, the boot firmware is called the BIOS.

Originally, ROM was actually read-only. To update the programs in ROM, you had to remove and physically replace your ROM chips. Contemporary versions of ROM allow some limited rewriting, so you can usually upgrade firmware such as the BIOS by using installation software. Rewritable ROM chips include PROMs (programmable read-only memory), EPROMs (erasable read-only memory), EEPROMs (electrically erasable programmable read-only memory), and a common variation of EEPROMs called flash memory.


What is CMOS?

CMOS, short for Complementary Metal Oxide Semiconductor, is a low-power, low-heat semiconductor technology used in contemporary microchips, especially useful for battery-powered devices. The specific technology is explained in detail on this CMOS definition page.

Most commonly, though, the term CMOS is used to refer to small battery-powered configuration chips on system boards of personal computers, where the BIOS stores the date, the time, and system configuration details.

On a PC, how do I reset or remove the CMOS password?

A CMOS password, if present, is one that you must enter when the computer is booting up. It comes before a network or operating system password. You will not be able to run any programs, view files, or even start the operating system if you do not enter this password.

If you'd like to change the password, you can do so by restarting your computer and entering the CMOS setup. You usually enter CMOS setup by typing a certain key or combination of keys as your computer is booting up; F2, Del, and Ctrl-Enter are common possibilities. However, your BIOS should display a line during startup explaining which key(s) to type to enter setup, BIOS setup, or CMOS setup. There should be a password option in the setup program. If you are not able to find this option, you will need to consult the manual that came with the computer or motherboard.

If you have forgotten your password, you will need to clear it by physically changing jumpers on your motherboard to short out certain pins, thereby erasing the password. The location of these pins varies from motherboard to motherboard, so you will need to refer to your computer or motherboard's manual.

Some motherboards have a default password. For example, the AMI BIOS default password is AMI. Check your computer or motherboard manual for the default password. It's worth trying this password if you don't know or have forgotten the CMOS password.

For some older computers, you must have a reference disk to make changes to the CMOS settings, including the password.

What's the difference between BIOS and CMOS?

Many people use the terms BIOS (basic input/output system) and CMOS (complementary metal oxide semiconductor) to refer to the same thing. Though they are related, they are distinct and separate components of a computer. The BIOS is the program that starts a computer up, and the CMOS is where the BIOS stores the date, time, and system configuration details it needs to start the computer.

The BIOS is a small program that controls the computer from the time it powers on until the time the operating system takes over. The BIOS is firmware, which means it cannot store variable data.

CMOS is a type of memory technology, but most people use the term to refer to the chip that stores variable data for startup. A computer's BIOS will initialize and control components like the floppy and hard drive controllers and the computer's hardware clock, but the specific parameters for startup and initializing components are stored in the CMOS.