Purpose of Coin Cell

What is the purpose of the coin cell on my motherboard ?

I know it enables my PC to remember what time it is (it keeps the RTC chip going when power is off)

I am confused about its role the boot process: I thought all that info was stored in an EEPROM which doesn't need power to remember its contents :confused

Dumb_Question
10.May.2012
Compaq Presario S5160UK DT261A (Celeron 2.7 GHz) - MSI MS6577 v2.1 - XP/SP3

 

Although a bit off-topic, if you ever need to replace a coin cell (CR2032) battery, do not go to a drug or electronics store - they charge up to $4 each.

I usually buy a pack of three for $1 at Dollar Tree or 99 Cents Only. In addition to the PC, my garage door opener control and keyless car entry remote use the same battery. The cheap ones last just as long as Energizer or Duracell.

 

So, the default BIOS settings are stored in EEPROM and are non-volatile, but the ones your system uses are in volatile memory (some kind of RAM ?), even if you have not changed from the default ? OK


-> gman863: Thanks for the tip - I had already noticed the variability of prices of coin cells. In fact I have one of the right type already. The problem I face is removing the old one, it doesn't come out as easily as from the coin cell holder I bought for another project. Is there a tip for getting the battery out of the holder in a PC ?

Dumb_Question
11.May.2012
Compaq Presario S5160UK DT261A (Celeron 2.7 GHz) - MSI MS6577 v2.1 - XP/SP3

 

It should have a sprung clasp, and I use a pair of long nosed pointed pliers (which are quite small) squeeze the clasp and battery should literally ''POP'' out. It must be held in there somehow otherwise it would fall out when rig is put in upright position.