CMOS is the term commonly used to describe the small amount of memory on a computer motherboard that stores BIOS settings. Some of these BIOS settings include the system time and date, as well as hardware settings.
What is CMOS and what is it used for?
CMOS (pronounced see-moss) is rarely referred to by its full name: complementary metal-oxide semiconductor. However, it is also sometimes called Real-Time Clock (RTC), CMOS RAM, Non-Volatile RAM (NVRAM), Non-Volatile BIOS memory, or complementary-symmetry metal-oxide semiconductor (COS-MOS).
Most of the conversations about CMOS revolve around clearing CMOS, which means resetting the BIOS settings to their default levels. This is a very simple task that is a great step in solving many types of computer problems.
For example, your computer may freeze during POST. In that case, clearing the CMOS to reset the BIOS settings to factory defaults may be the easiest solution.
