Thanks. I didn't know that RTC chips use CMOS RAM. > And the term "CMOS Battery" makes no sense other than shorthand for "battery that backs up CMOS memory".

Thanks. I didn't know that RTC chips use CMOS RAM. > And the term "CMOS Battery" makes no sense other than shorthand for "battery that backs up CMOS memory". Nowadays BIOS is replaced by UEFI but we sometimes still call it "BIOS", so I thought that possibly "CMOS" battery is same story.