What is CMOS?
CMOS (pronounced See-moss) stands for Complementary Metal-Oxide Semiconductor. The CMOS chip is a specialized electronic component mounted on the motherboard that is designed to hold a small amount of information when the computer is completely powered down. The information is kept in memory electrically and is powered by a small on board battery. Among other pieces of data, CMOS holds the current date and time as well as the information necessary regarding changeable types of hardware on the computer such as RAM, Hard Drives, Floppy Drives, and Video Cards. CMOS has a capacity of about 64K but uses much less; typically 128 bytes. The key thing to remember about CMOS is that it keeps track of changeable types of hardware on the computer. The other thing to remember although it is commonly forgotten is that the CMOS battery will not last forever. If you suspect a CMOS battery may be getting old and at the end of its lifetime, change it for a fresh battery. Once the charge is exhausted, the data stored on the CMOS chip will disappear.
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