CMOS is a short form of the
complementary metal-oxide-semiconductor which is a small amount of memory generally used in computer motherboard, mainboard in order to store BIOS settings. CMOS can also be named as Real-Time Clock(RTC), CMOS RAM, Non-Volatile RAM(NVRAM), Non-Volatile BIOS Memory, and COS-MOS.
The first CMOS chip was used in early IBM computers. This CMOS chip was two main components of RTC and CMOS RAM. This CMOS also has 64-byte memory where 14 bytes were used system clock RAM and 50 bytes of storage were used for system settings.
Hardware Using CMOS
There is a lot of different type of computer hardware which is using the CMOS. Here are some of them.
- Digital Circuits
- SRAM (Static RAM)
Main Functions of CMOS
As stated previously CMOS is used to store BIOS and Clock/Date settings.
- From the beginning of the computers, BIOS data is used to stored in CMOS where there are a lot of BIOS data like boot priority, PC configuration, virtualization and GPU settings, BIOS administrative password.
- The clock is another important component because even a computer is disconnected from the electricity and internet it should store and track the correct date/time configuration. CMOS is used to store this date/time configuration.
Reset BIOS Configuration with CMOS
CMOS stores the BIOS and Clock information where the power source is a little CMOS battery. If we need to reset the BIOS and Clock information we can remove the battery for 3-5 minutes. This will cut the power of CMOS and data stored in the CMOS ram will be lost.