Transcript PowerPoint 簡報

Chapter 5
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5.1
5.2
5.3
Basic Input/Output
System (BIOS)
Introduction to BIOS
The BIOS Boot Process
Configuring the BIOS
5.1 Introduction to BIOS
Basic Input / Output System (BIOS)
boot the computer by providing a basic set of
instructions
load the operating system after turning on the
computer
perform POST (Power-On Self Test)
provide set-up program for changing BIOS
parameters
provide low-level routines for the
communications between OS and hardware
devices
5.1 Introduction to BIOS
BIOS combination
BIOS program
CMOS stores BIOS program
BIOS parameter
5.1 Introduction to BIOS
Advantages of storing BIOS in ROM
code and data are readily available during booting
BIOS content are not corrupted by errant
applications
BIOS hardware components
BIOS ROM
PC startup program (POST)
BIOS CMOS memory
house the configuration information of individual PC
5.1 Introduction to BIOS
The BIOS ROM
All BIOS are contained in ROM in old days
BIOS is now located in EEPROM chip
erased and rewritten by special programs
called flash BIOS
BIOS CMOS memory
provide a non-volatile storage for PC’s control
information
need very little power to operate
powered by lithium battery
5.1 Introduction to BIOS
BIOS chip
5.2 The BIOS Boot Process
1. The power supply sends a signal to the
components in the system unit.
2. The CPU finds the ROM chips that contains
BIOS.
3. The BIOS performs the POST which checks
components (e.g. mouse, keyboard
connectors and expansion card)
4. The results of the POST are compared with
data in the CMOS chip.
5.2 The BIOS Boot Process
5. The BIOS looks for the system files in floppy
disk drive and hard disk.
6. The system files and the kernel of the OS load
into RAM from hard disk.
5.2 The BIOS Boot Process
Beep codes
A series of beep: BIOS program encounter
problems
One short beep: everything is normal
Errors can be indicated when video screen does
not function
Interpret the beep codes by consulting main
board menu
5.2 The BIOS Boot Process
POST Error messages
Error messages are shown on display system
Interpret error messages by consulting owner’s
manual
5.3 Configuring the BIOS
Setup program interfaces
1. Hit a particular key or key combination at a right
time to enter the BIOS setup utility
5.3 Configuring the BIOS
Setup program interfaces
2. A BIOS setup screen is displayed.
5.3 Configuring the BIOS
Typical key control
Incorrect settings of BIOS may lead to system halt
Quit the setup without saving changes if we are
not sure about the changed settings
Boot sequence
control the order in which BIOS looks for an OS on
start-up
usual sequence: floppy disk  hard disk  CD-ROM
5.3 Configuring the BIOS
Typical key control
Performance tuning through BIOS settings
BIOS settings are responsible for how the chipset is
controlled.
Chipset is the key to the overall system performance
BIOS parameters:
– Choose the optimal bus speed settings
– Enable the CPU’s internal cache
– External cache memory
– Enable system BIOS shadowing
– Quick power-on self test
– Update the BIOS
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