What is Complementary metal-oxide-semiconductor
Complementary metal-oxide-semiconductor is a small amount of memory on a computer motherboard that stores the Basic Input/Output System settings. The BIOS is the software stored on the memory chip on the motherboard. It instructs the computer on how to perform a number of basic functions such as booting and keyboard control. The BIOS is also used to identify and configure hardware in the computer.
For no boot or no display issues, clearing CMOS may help recover the boards because that restores the BIOS default settings.
What Is a CMOS Battery?
The CMOS is usually powered by a CR2032 cell battery, referred to as the CMOS battery.
Most CMOS batteries will last the lifetime of a motherboard, up to 10 years in most cases, but will sometimes need to be replaced.
Incorrect or slow system date and time and loss of BIOS settings are major signs of a dead or dying CMOS battery. Replacing them is as easy as swapping out the dead one for a new one.
When the computer is starting up, there’s an option to boot into BIOS or CMOS. Opening the CMOS setup is how you can change the settings it’s storing, like the date and time and how the different computer components are first started up. You can also use CMOS setup to disable/enable some hardware devices. That is the BIOS pulls information from the CMOS chip to understand the hardware settings, time, and anything else that’s stored in it.
CMOS chips are desirable for battery-powered devices like laptops because they use less power than other types of chips. Although they use both negative polarity circuits and positive polarity circuits (NMOS and PMOS), only one circuit type is powered on at a time.