BIOS & CMOS

So I'm picking back up on the A+ thing. Some notes about CMOS and BIOS.

BIOS = Basic Input Output System.
It is firmware that is stored on a ROM chip. This information is the basic information that the computer needs to start up. For example the first thing that runs in when the BIOS kicks off is the POST or Power On Self Test. This makes sure that important pieces of hardware are available for use, for example the keyboard. BIOS is automatic and when the CPU receives power the BIOS automatically loads and executes.

CMOS Memory = special memory chip powered by its own dedicated battery. Ususally a little 3 volt jobby. CMOS holds the settings that the BIOS uses. It has all of the basic configuration data that your computer needs to start up. Examples of data in CMOS are: Current Date and Time, Hard Drive Type, IDE Primary and Secondary Masters, Boot Order, Floppy Drive Type, Serial and Parallel ports, shadow BIOS (this means the BIOS can load itself into RAM where it can execute faster) finally, whether or not the OS is Plug-and-Play.

Getting into the CMOS editor is different for different Hardware Mfgrs. I often call this getting into the BIOS, actually what I'm doing is accessing the CMOS editor.
AMI BIOS = Delete Key
Award BIOS = Delete, Ctrl+Alt+Insert
Phoenix BIOS = F1, Ctrl+Alt+Escape, Ctrl+Alt+S
IBM = Ctrl+Alt+Insert
Dell = F2