Topic Transcript
Introducing BIOS
Learning Objective
After completing this topic, you should be able to distinguish between the functions of the BIOS chip and the CMOS chip
1. BIOS and CMOS chips
All hardware requires software to run. This software communicates the characteristics of the hardware, such as its unique features, memory location, and input/output settings, to enable communication between the motherboard and CPU, hard disk drives, optical drives, keyboards, and other peripherals.
Usually this communication is performed by device drivers, which are responsible for translating information between software and hardware. During the startup process, however, information about hardware is provided by a microchip on the motherboard called the basic input/output system, or BIOS.
A BIOS is known as firmware – software that's hardcoded into hardware but that can be modified. In most cases, you can upgrade the BIOS on a motherboard with new BIOS software, which you can download from the motherboard vendor.
When you start a computer, the BIOS initializes the main hardware components and tests the system before selecting a hard disk to boot from and loading the operating system. This process is known as the poweron self test, or POST.
Several steps occur during a POST:
Graphic
The POST screen contains the following text:
Phoenix AwardBOIS v6.00PC, An Energy Srat Ally
Copyright(C) 19842005, Phoenix Technologies, LTD
ASUS ABNSLI Premium BIOS Revision 1011001
Main Processor: AMD Athlon(tm) 64 Processor 4000
Memory Testing: 2097152K OK(Installed Memory: 2097152K
Memory Information: DDR 400 Dual Channel, 128bit
Award Plug and Play BIOS Extension v1.0
Copyright(C) 1994, Award Software, Inc.
Detecting IDE Primary Master ... WDC20
Detecting IDE Primary Slaver ... None
Detecting IDE Secondary Master ... Generic CDROM
1. the BIOS is initialized and checked
2. the CPU registers are verified