Nonvolatile BIOS memory

CMOS batteryCMOSCMOS memoryCMOS RAMCMOS setupNVRAMbattery backed RAMBIOS configuration dataBIOS settingsCMOS BIOS
Nonvolatile BIOS memory refers to a small memory on PC motherboards that is used to store BIOS settings.wikipedia
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CMOS

RF CMOScomplementary metal–oxide–semiconductorcomplementary MOS
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.
CMOS technology is used for constructing integrated circuit (IC) chips, including microprocessors, microcontrollers, memory chips (including CMOS BIOS), and other digital logic circuits.

BIOS

ROM BIOSSystem BIOSBasic Input/Output System
Nonvolatile BIOS memory refers to a small memory on PC motherboards that is used to store BIOS settings.
If Ctrl+Alt+Delete was pressed ("warm boot"), a special flag value stored in nonvolatile BIOS memory ("CMOS") tested by the BIOS allows bypass of the lengthy POST and memory detection.

Non-volatile random-access memory

NVRAMnon-volatile random access memorynon-volatile
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.
For example, IBM PC's and successors beginning with the IBM PC AT used nonvolatile BIOS memory, often called CMOS RAM or parameter RAM, and this was a common solution in other early microcomputer systems like the original Apple Macintosh, which used a small amount of memory powered by a battery for storing basic setup information like the selected boot volume.

Real-time clock

RTCreal time clockReal-Time Clocks
The memory battery (aka motherboard, CMOS, real-time clock (RTC), clock battery) is generally a CR2032 lithium coin cell.
The alternate power source can also supply power to battery backed RAM.

Motherboard

motherboardsmainboardlogic board
Nonvolatile BIOS memory refers to a small memory on PC motherboards that is used to store BIOS settings.

List of battery sizes

AA batteries217002CR5
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 NiCd CMOS battery that looks like a "barrel" (common in Amiga and older IBM PC compatibles), which serves the same purpose.

Southbridge (computing)

southbridgesouth bridgeSouthbridges
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.

Button cell

CR2032LR44coin cell
The memory battery (aka motherboard, CMOS, real-time clock (RTC), clock battery) is generally a CR2032 lithium coin cell.

ATX

EATXATX motherboardATX12V
On ATX motherboards, turning on power switch on PSU, will supply 5V standby power to the motherboard to keep CMOS memory energized during computer turned off period.
The 5 V SB supply is used to produce trickle power to provide the soft-power feature of ATX when a PC is turned off, as well as powering the real-time clock to conserve the charge of the CMOS battery.

Extended System Configuration Data

ESCD
It consists of a method for storing configuration information in nonvolatile BIOS memory and three BIOS functions for working with that data.

Computer memory

memorymemoriesmain memory
Nonvolatile BIOS memory refers to a small memory on PC motherboards that is used to store BIOS settings.

Personal computer

PCPCspersonal computers
Nonvolatile BIOS memory refers to a small memory on PC motherboards that is used to store BIOS settings.

Volatile memory

volatilememoryvolatile program memory
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.

Static random-access memory

SRAMstatic RAMstatic random access memory
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.

Motorola

Motorola, Inc.Motorola Inc.Motorola Semiconductor
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.

Lithium battery

lithium batterieslithiumlithium cell
The memory battery (aka motherboard, CMOS, real-time clock (RTC), clock battery) is generally a CR2032 lithium coin cell.

Power supply unit (computer)

power suppliespower supplypower supply unit
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.

AC power plugs and sockets

electrical outletoutletwall socket
Unwanted BIOS reset may be avoided by replacing battery cell with PSU power switch turned on and plugged into electric socket on the wall.

Power Mac G4

G4Power Mac G4 GraphiteAGP Power Mac G4
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 NiCd CMOS battery that looks like a "barrel" (common in Amiga and older IBM PC compatibles), which serves the same purpose.

IBM PC compatible

PCPC compatibleIBM PC compatibles
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 NiCd CMOS battery that looks like a "barrel" (common in Amiga and older IBM PC compatibles), which serves the same purpose.

Barrel

caskbarrelscasks
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 NiCd CMOS battery that looks like a "barrel" (common in Amiga and older IBM PC compatibles), which serves the same purpose.

Amiga

Commodore AmigaAmiga ComputerAmiga 500/600 (OCS/ECS)
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 NiCd CMOS battery that looks like a "barrel" (common in Amiga and older IBM PC compatibles), which serves the same purpose.

Ralf Brown's Interrupt List

Ralf D. BrownInterrupt List for MS-DOSsoftware interrupts
Ralf Brown's Interrupt List (aka RBIL, x86 Interrupt List, MS-DOS Interrupt List or INTER) is a comprehensive list of interrupts, calls, hooks, interfaces, data structures, CMOS settings, memory and port addresses, as well as processor opcodes and special function registers for x86 machines (including many clones) from the very start of the PC era in 1981 up to 2000, most of it still applying to PCs today.