CMOS (Complementary metal-oxide-semiconductor)
CMOS stands for complementary metal-oxide-semiconductor. Its the type of technology used in making batteries and BIOS. It is also used in making ICs, rams, microprocessors, etc. It is used in making transistors which are used in manufacturing the microchips today we see.
They are also often referred to as complementary-symmetry metal-oxide-semiconductor (COSMOS), Real-Time Clock (RTC), Non-Volatile RAM (NVRAM).
CMOS was first used in Motorola 146818 chip as RTC and CMOS RAM chip which was in used in IBM computers capable of storing 64kb of data.
The battery is usually referred to as CR2032 battery. Its lifetime is mostly 10 years but it needs to be replaced sometimes. When the date and time are running slow in the PC it means that the battery is dying and needs to be replaced.