By an external battery that is not connected to the PSU and only used for the CMOS RAM, this could be in the form of a Coin cell Battery (a silver coin shaped battery) or a barrel soldered battery.
This is why the date and time settings are not lost when the computer is unplugged.
The RAM ( Random Access Memory) is NOT powered when the system is powered down Unless the system is in Stand-by.
The coin-cell battery powers CMOS RAM when the system is turned off.Pg.162: A+ Guide to Managing and Maintaining Your PC. Jean Andrews 8th Edition.
The purpose of CMOS RAM is to hold the BIOS program as it is executed by the processor. BIOS is the first program to be loaded when a computer is powered on.
CMOS RAM is Powered by a trickle of electricity from a small battery located on the motherboard or computer case, usually close to the firmware chip, so that when the computer is off, CMOS RAM still retains it's data.
Cmos ram refers the random access memory used by the cmos which is the primary bios setup on the computer. Most computers use a regular loaded ram to load the basic input output system. The cmos ram can also sometimes refer to the cache that the motherboard has. In general when you mention cmos three things should come into mind. The CMOS battery, the CMOS ram ( stores settings) and the BIOS (basic input output system) Hope this Helps!
Cmos ram.
CMOS RAM
The ________ is the essential component of the operating system that remains in RAM when your computer is powered on.
The CMOS RAM, or computer motherboard operation system with rapid access memory can be accessed through the bios during startup. Typically repeatedly pushing the key F10 with give access.
Data saved in cmos ram cant recovered if ram crashes suddenly but in case bettery or power failler 1) dont eject the ram runddnly wait for halting .2) use alternative system for power .3)detach the ram and place it in another ram reading system and fatch the data.
CMOS Setup
ram is a computer data storage