BIOS Set Up
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Wikipedia
BIOS, computing, stands for Basic Input/Output System. The BIOS is a computer program embedded on a chip on a computer’s motherboard that recognizes and controls various devices that make up the computer. The purpose of the BIOS is to make sure all the things plugged into the computer can work properly. It brings life to the computer, and the term is a pun on the Greek word βίος, bios meaning “life”.
“Booting”, sometimes called “Booting up” is the process that the computer completes to get it ready to use when it is first turned on. When the computer turns on, the BIOS starts up and performs a Power-On Self Test (POST). During the POST, the BIOS will check various devices in the computer like the computer processor, memory, the video card and others to make sure they are present and functioning. Once the POST has completed successfully, the BIOS looks for an operating system to load, which is usually located on the computer’s hard drive. When it finds one, it starts to load it. At this point, the operating system takes over control of the system.
Some people try to configure their computer to run faster than it was designed to do. This is called “overclocking”. Since the BIOS controls the computer processor, entering the BIOS setup screen while it is booting up gives people access to advanced computer settings. For most computers, pressing the delete or F12 button while the computer is booting up will bring up the BIOS setup screen. There are many ways a computer can be overclocked to run faster, but most involve simply turning up the speed of the computer processor. Doing this will usually make your computer run much hotter, though, and can sometimes break your computer, which is why overclocking will usually void your computer’s warranty. Only people who are computer hardware experts should attempt to overclock their computers.
Nonvolatile BIOS memory refers to a small memory on PC motherboards that is used to store BIOS settings. It is traditionally called CMOS RAM because it uses a volatile, low-power complementary metal-oxide-semiconductor (CMOS) SRAM (such as the Motorola MC146818 or similar) powered by a small “CMOS” battery when system and standby power is off. It is referred to as non-volatile memory or NVRAM because, after the system loses power, it does retain state by virtue of the CMOS battery. The typical NVRAM capacity is 256 bytes.
The CMOS RAM and the real-time clock have been integrated as a part of the southbridge chipset and it may not be a standalone chip on modern motherboards. In turn, the southbridge have been integrated into a single Platform Controller Hub.
Today’s UEFI motherboards use NVRAM to store configuration data (NVRAM is a part of the UEFI flash ROM), but by many OEMs’ design, the UEFI settings are still lost if the CMOS battery fails.
The memory battery (aka motherboard, CMOS, real-time clock (RTC), clock battery) is generally a CR2032 lithium coin cell. This cell battery has an estimated life of 3 years when power supply unit (PSU) is unplugged or when the PSU power switch is turned off. This battery type, unlike the Lithium-ion battery, is not rechargeable and trying to do so may result in an explosion. Motherboards have circuitry preventing batteries from being charged and discharged when a motherboard is powered on. Other common battery cell types can last significantly longer or shorter periods, such as the smaller CR2016 which will generally last about 40% less time than CR2032. Higher temperatures and longer power-off time will shorten battery cell life. When replacing the battery cell, the system time and CMOS BIOS settings may revert to default values. Unwanted BIOS reset may be avoided by replacing the battery cell with the PSU power switch turned on and plugged into an electric wall socket. On ATX motherboards, the PSU will supply 5V standby power to the motherboard to keep CMOS memory energized while the system is off.
Some computer designs have used non-button cell batteries, such as the cylindrical “1/2 AA” used in the Power Mac G4 as well as some older IBM PC compatibles, or a 3-cell nickel–cadmium (Ni–Cd) CMOS battery that looks like a “barrel” (common in Amiga and older IBM PC compatibles), which serves the same purpose. These motherboards often have a four pin straight header, with pin 2 missing, for connecting to an external 3.6v battery, such as the Tadiran TL-5242/W, when their soldered-on batteries run out. Ni–Cd batteries have a tendency to leak devastatingly after a period of disuse, damaging components and traces on the circuit board near the battery.