In computer science, COMS often refers to chips saving basic boot information (such as date, time and startup configuration) of computer. Sometimes, people are confused by CMOS and BIOS. Actually, CMOS is a RAM chip that can be read and written on master board. It is a hardware configuration storing BIOS and some parameters set by users. CMOS charges from batteries on master board. Even the system powers off, the information will not be lost. CMOS RAM is only a storage device with data storage function. And various parameters of BIOS must be set through specific programs. BIOS setup utilities are integrated in chips. And by pressing specific button, users can enter BIOS setup program and set up the system conveniently. Therefore, BIOS setup utility is called CMOS setup utility sometimes.

How to set CMOS
If the computer is compatible desktop and its BIOS setting utility is from Award, AMI or Phoenix company, after the enablement, users press Delete or Del of keypad to enter CMOS setup interface.
If the computer is brand name computer (including desktop and laptop), and users can not enter CMOS by pressing Delete, the note shown on the screen should be noticed. Normally it will show[Press XXX to Enter SETUP]. Then users press "XXX" and enter CMOS.
If there is no note, the operating instruction manual should be referenced to. If relative information can not be found, the following buttons can be tried: "F2", "F10", "F12", "Ctrl+F10", "Ctrl+Alt+F8" and "Ctrl+Alt+Esc".

Setups
The following details can be set up:
Standard CMOS Setup: including date, time, and parameters of soft and hardware.
BIOS Features Setup: including some system options.
Chipset Features Setup;
Power Management Setup;
nP/PCI Configuration Setup;
Integrated Peripherals;
Other settings including hard disk auto detection, system password, loading default setup and log out.