Transcript 4.5 the startup process

DIT314 ~ Client Operating System
& Administration
CHAPTER 4
CONFIGURING HARDWARE
DEVICES AND STARTUP PROCESS
Prepared By : Suraya Alias
4.5 THE STARTUP PROCESS
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4.5.1 Startup Phases (sequences)
 Power-on self test (POST) phase
 Initial startup phase
 Boot loader phase
 Detect and configure hardware phase
 Kernel loading phase
 Logon phase
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This sequences applies only to the system that was shut
down ad restarted normally, not applicable for
hibernation and standby mode
4.5 THE STARTUP PROCESS
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For Win XP to start, the systems and boot partitions must contain
below files
Filename
Description
Ntldr
The operating system loader
Boot.ini
Contains the OS choices that display on startup menu
Bootsect.dos
Hidden system file loads by Ntldr, used for multiple-boot systems
Ntdetects.com
File that passes info about the hardware configuration to Ntldr
Ntbootdd.sys
The device driver used to access devices attached to a SCSI or
ATA h/disk whose adapter is not using BIOS
Ntoskrnl.exe
The kernel of Win XP operating system
Hal.dll
Hardware Abstraction layer (extract h/w details from OS and
provide interface to devices)
System registry file
Contains the data used to create registry key
HKEY_LOCAL_MACHINE\SYSTEM.
Device drivers
Driver files for h/w devices, such as keyboard, mouse and videos
4.5 THE STARTUP PROCESS
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4.5.2 Preboot sequences
1. Computer runs POST routines to determine the
amount of physical memory, whether the hardware
component are presents. Check plug and play
compatible BIOS and hardware configuration
2. The comp BIOS locates the boot device, loads and
runs the Master Boot Record (MBR)
3. The MBR scans the partition table to locate the active
partition, loads the boot sector on the active partition
in memory the executes it
4. The computer loads and initializes the NTLDR file
4.5 THE STARTUP PROCESS
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Problem that can occur during Preboot sequences
1. Improper hardware configuration or malfunctioning
hardware
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Usually message hard drive cannot be located
Corrupt MBR
2.
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If MBR becomes corrupted (virus), can be repaired back
using Recovery console or using Anti virus s/w
Floppy or USB inserted
3.
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Message non system disk or disk error, or No OS is found,
maybe USB is inserted during startup
4.5 THE STARTUP PROCESS
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4.5.3 Boot sequences
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After NTLDR has been loaded into memory, the boot sequence
gathers information about the hardware and drivers in the
preparation for Win XP load phases.
The boot sequences uses these files; NTLDR, BOOT.INI,
BOOTSECT.DOS (optional), NTDETECT.COM &
NTOSKRNL.EXE
The 4 phases of boot sequences
1.
2.
3.
4.
Initial boot loader phase
Operating System Selection
Hardware Detection
Configuration Selection
4.5 THE STARTUP PROCESS
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4.5.4 BOOT.INI file
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Boot.ini is saved in active partition when we install Win XP.
NTLDR uses information in boot.ini to display the boot loader
screen, from which you select the OS to start.
Boot.ini includes two section [boot loader] and [operating system]
which contains information that NTLDR uses to create the Boot
Loader Operating System Selection menu
Example
[boot loader]
timeout=30 default=multi(0)disk(0)rdisk(0)partition(2)\WINDOWS
[operating systems]
multi(0)disk(0)rdisk(0)partition(2)\WINDOWS="Microsoft Windows XP Professional"
/fastdetect
multi(0)disk(0)rdisk(0)partition(2)\WINNT="Windows 2000 Professional" /fastdetect
4.5 THE STARTUP PROCESS
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4.5.5 Troubleshooting the Boot Sequence (Problem)
Missing or corrupt boot files
1.
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If the NTLDR, BOOT.INI, NTDETECT.COM & NTOSKRNL.EXE files
become corrupt or missing, the error message indicating the situation
and windows startup fails
Improperly configured BOOT.INI
2.
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If manually edited, or change the configuration. If BOOT.ini corrupt, use
the Recover console
Improperly configured hardware
3.
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NTDETECT.COM cab fail during its detection of hardware if the h/w is
wrongly configured, bad driver or malfunctions
Use step by step of removal, uninstalling the devices and adding it one
by one at a time
4.6 EDITING THE REGISTRY
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Win XP stores hardware and software settings in a hierarchical database called
the Registry (replaces the .ini, .sys and .com configuration in previous windows)
Registry controls the Win XP OS by providing information in starting
applications, load components and devices also network protocols
4.6.1 Registry
 Hierarchical database that contains data includes;
 The hardware installed in computer (cpu, bus type..)
 Installed device drivers
 Installed applications
 Installed network protocols
 Network adapter card settings
4.6 EDITING THE REGISTRY
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Components that access and store data in
registry
1.
2.
3.
4.
5.
6.
Windows XP Pro kernel
Device drivers
User profiles
Setup programs
Hardware Profiles
NTDETECT.COM