introduction
DESCRIPTION
The BIOS (an acronym for Basic Input Output System) software has a number of different roles, but its most important role is to load the operating system. BIOS is sometimes called firmware because it is an integral part of the system hardware. INTRODUCTION. About BIOS. - PowerPoint PPT PresentationTRANSCRIPT
INTRODUCTIONINTRODUCTION
The BIOS (an acronym for Basic Input Output System) software has a number of different roles, but its most important role is to load the operating system.
BIOS is sometimes called firmware because it is an integral part of the system hardware.
The BIOS is the default control for the
most important functions of PC.
It defines the compatibility of our PC with
expansion hardware.
Without it our PC couldn’t even boot.
About BIOSAbout BIOS
HISTORYHISTORY Before 1990 or so BIOSes were held on ROM chips.
BIOS firmware stored on EEPROM or flash memory devices.
To avoid BIOS corruption, some new motherboards have a backup BIOS ("Dual BIOS" boards).
Hardware manufacturers frequently issue BIOS updates to upgrade their products and remove bugs.
WHAT BIOSBIOS DOES?
A power-on self-test (POST) for all of the different hardware components in the system to make sure everything is working properly.Activating other BIOS chips on different cards installed in the computer - For example, SCSI and graphics cards often have their own BIOS chips. Providing a set of low-level routines that the operating system uses to interface to different hardware devices - It is these routines that give the BIOS its name. They manage things like the Keyboard, the Screen, and the Serial and Parallel ports, especially when the computer is booting. Managing a collection of settings for the hard disks, clock, etc.
POST POST
1. The first step of POST is the testing of the Power Supply to ensure that it is turned on and that it releases its reset signal.
2. CPU must exit the reset status mode and thereafter be able to execute instructions.
3. BIOS checksum must be valid, meaning that it must be readable.
4. CMOS checksum must be valid, meaning that it must be readable.
POST(CONT…)POST(CONT…)
5. CPU must be able to read all forms of memory such as the memory controller, memory bus, and memory module.
6. The first 64KB of memory must be operational and have the capability to be read and written to and from, and capable of containing the POST code.
7. I/O bus / controller must be accessible
ACCESSINGACCESSING BIOSBIOS
Keys used to access the BIOS are "Esc," "Del," "F1," "F2," "Ctrl-Esc" or "Ctrl-Alt-Esc" key.
Power on the computer system and press the key to enter the BIOS after the beep for a clean POST is signaled.
If the procedure has been done correctly, the BIOS screen should be displayed rather than the typical boot screen.
Common Options Includes :-Common Options Includes :-
System Time/Date Boot Sequence Plug and Play Mouse/Keyboard
Drive Configuration Memory Security Power Management
Exit
What Happens when System Boots??What Happens when System Boots??
The BIOS reads sector 0 (known as the MBR - the Master Boot Record) from the first disk (or from floppy or CDROM), and jumps to the code found there - usually some bootstrap loader.
A bootstrap loader or bootstrapping or boot loader, is a program that resides in the computers EPROM,PROM, or other Non- Volatile Memory that automatically executed by the processor when the computer is turned on.
EPROMEPROM
PROMPROM
Check the CMOS Setup for custom settings Load the interrupt handlers and device drivers Initialize registers and power management Perform the power-on self-test (POST) Display system settings Determine which devices are bootable Initiate the bootstrap sequence
BOOT SEQUENCEBOOT SEQUENCE
CMOSCMOS
CMOS an acronym of Complementary Metal-Oxide Semiconductor is an on-board semiconductor chip powered by a CMOS battery inside computers that stores information such as the system time and system settings.
Types of CMOS batteriesTypes of CMOS batteries
Batteries used are –• External Lithium• Coin Cell• Barrel Style Solder• PS2 6v
Life Time of a CMOS battery - Standard lifetime of a CMOS battery is around 10 Years.
Flash memoryFlash memory
A form of non-volatile memory that can be electrically erased
Reprogrammable Flash memory is used for easy and fast
information storage It is erased and programmed in blocks
consisting of multiple locations .Less costlier.
TYPES OFTYPES OF BOOTINGBOOTING
COLD BOOT
WARM BOOT
BIOS Boot DevicesBIOS Boot Devices
A Boot Device is any device that must be initialized prior to loading the operating system.
This includes :primary input devices (keyboard). primary output device (display). Initial program load device (floppy drive, hard
drive, CD-ROM,USB flash drive, etc).
OVERCLOKINGOVERCLOKING
Process of forcing a computer component to run at a higher clock rate than designed or designated by the manufacturer.
Boost a computer system's performance by increasing clock frequencies
Advanced Configuration and Power Advanced Configuration and Power InterfaceInterface
The Advanced Configuration and Power Interface (ACPI) specification is an open industry standard first released in December 1996 developed by HP, Intel, Microsoft, Phoenix and Toshiba that defines common interfaces for hardware recognition, motherboard and device configuration and power management. According to its specification[1], "ACPI is the key element in Operating System-directed configuration and Power Management (OSPM)".
List of BIOS suppliers:List of BIOS suppliers:
American Megatrends (AMI) Phoenix Technologies Award Software International (merged with
Phoenix in 1998) MicroID Research (MR BIOS) Insyde Software (Insyde) General Software (General Software)
The Fall and Rise of the BIOSThe Fall and Rise of the BIOS Older operating systems such as DOS called on the
BIOS to carry out most input-output tasks within the PC; with the introduction of newer operating systems such as Microsoft Windows and Linux, the BIOS was related to principally providing initial hardware setup, and bootstrapping. Once it was up and running, the operating system didn't have to rely on the BIOS for much.
In recent years, however, by way of systems such as ACPI, the BIOS has taken on more complex functions such as aspects of power management, hot plug, thermal management etc. This has led to renewed reliance on the BIOS by operating system producers, and an increase in complexity in the BIOS code
AMI BIOS BEEPCODES DESTRUCTION
1 short DRAM refresh failure
2 short Parity circuit failure
3 short Base 64K RAM failure
4 short System timer failure
5 short Process failure
6 short Keyboard controller Gate A20 error
7 short Virtual mode exception error
8 short Display memory Read/Write test failure
9 short ROM BIOS checksum failure
10 short CMOS shutdown Read/Write error
11 short Cache Memory error
1 long, 3 short Conventional/Extended memory failure
1 long, 8 short Display/Retrace test failed
AWARD BIOS BEEP CODES Description
1 long, 2 shortIndicates a video error has occurred and the BIOS cannot initialize the video screen to display any additional information
Any other beep(s) RAM problem.
IBM Beep Code Description
No Beeps No Power, Loose Card, or Short.
1 Short Beep Normal POST, computer is ok.
2 Short Beep POST error, review screen for error code.
Continuous Beep No Power, Loose Card, or Short.
Repeating Short Beep No Power, Loose Card, or Short.
One Long and one Short Beep Motherboard issue.
One Long and Two Short Beeps Video (Mono/CGA Display Circuitry) issue.
One Long and Three Short Beeps. Video (EGA) Display Circuitry.
Three Long Beeps Keyboard / Keyboard card error.
One Beep, Blank or Incorrect Display Video Display Circuitry.
MACINTOSH TONES ERROR
Error Tone. (two sets of different tones)
Problem with logic board or SCSI bus.
Startup tone, drive spins, no video Problem with video controller.
Powers on, no tone. Logic board problem.
High Tone, four higher tones. Problem with SIMM.
PHOENIX Beep Code Description / What to Check1-1-1-3 Verify Real Mode.
1-1-2-1 Get CPU type.
1-1-2-3 Initialize system hardware.
1-1-3-1 Initialize chipset registers with initial POST values.
1-1-3-2 Set in POST flag.
1-1-3-3 Initialize CPU registers.
1-1-4-1 Initialize cache to initial POST values.
1-1-4-3 Initialize I/O.
1-2-1-1 Initialize Power Management.
1-2-1-2 Load alternate registers with initial POST values.
1-2-1-3 Jump to UserPatch0.
1-2-2-1 Initialize keyboard controller.
1-2-2-3 BIOS ROM checksum.
1-2-3-1 8254 timer initialization.
1-2-3-3 8237 DMA controller initialization.
1-2-4-1 Reset Programmable Interrupt Controller.
1-3-1-1 Test DRAM refresh.
1-3-1-3 Test 8742 Keyboard Controller.
1-3-2-1 Set ES segment to register to 4 GB.
Top 6 Reasons To Upgrade BIOSTop 6 Reasons To Upgrade BIOS
AGP Video
CPU Upgrading
Large Hard Drive support
Faster I/O Speeds
Windows XP ACPI 2.0 Compliance
Windows 2000 ACPI 2.0 Compliance
LINKING TO HARDWARELINKING TO HARDWARE
BIOS routines uses memory or I/O Ports to pass the commands and data to Hardware Devices.
In Memory Mapping a block of memory is used.
In I/O mapping I/O Ports are used .
BIOS SETUP ENTRY POINTSBIOS SETUP ENTRY POINTS
BIOS MAKER ENTRY KEYS WHEN
AMI del During POST
AWARD Ctrl + Alt +Esc Anytime
IBM Ctrl + Alt +Ins After Ctrl + Alt + Del
PHOENIX Ctrl + Alt +Esc Anytime
FLASH BIOSFLASH BIOS
Better than EPROM
Can Encode the BIOS Program more quickly into Flash ROM than EPROM.
BIOS SHORTCOMINGSBIOS SHORTCOMINGS
Device DriversFlash LazinessBIOS ShadowingDirect ControlBIOS Bugs
BIOS TROUBLESHOOTINGBIOS TROUBLESHOOTING
During POST BIOS generates two types of error messages –
• Beep Codes.
• POST Codes.
GENERAL SYMPTOMSGENERAL SYMPTOMS
BIOS Checksum Error – default loadedCMOS Memory Size MismatchData ErrorCMOS Battery FailedHard Disk FailureBIOS ROM Checksum Error –System Halted
BIOS BIOS UPGRADE UPGRADE TROUBLESHOOTINGTROUBLESHOOTING
Flash Loader Utility Refuses to RunErase Chip FailureFlash Chip Not SupportedSystem Refuses To Recognize DrivesCannot Print Under DOS Or Windows