PC Hardware Servicing
Chapter 27: The Boot Process
Chapter 27 Objectives
Understand bootable disks Identify key boot files in each OS version List the boot sequence for each OS Use alternative boot modes Create and use a boot floppy Use the Recovery Console Create and use an ERD Troubleshoot startup and shutdown problems
What Constitutes a Bootable Disk?
A disk that can bring the PC to a functional level, with the OS ready to accept user commands
Startup Configuration Files for DOS
[Link]
Used primarily under MS-DOS Plain text file Lists environment variables and device drivers Runs only at startup
Used primarily under MS-DOS Plain text file Lists applications to run at startup Simple batch file, can be rerun at any time
[Link]
Sample [Link]
Sample [Link]
Startup Configuration Files for Windows 3.x
[Link]
Loads device drivers Defines environment variables
[Link]
Loads applications Sets display settings and I/O device settings Defines application settings
Sample [Link]
Sample [Link]
The Registry
32-bit versions of Windows system settings files In Windows 9x: [Link] and [Link] In Windows NT/2000/XP: SAM, SECURITY, SYSTEM, SOFTWARE, DEFAULT Accessed through the Registry Editor as a single database
MS-DOS Boot Sequence
1. BIOS performs POST 2. BIOS searches for master boot record (MBR), which defines the active partition 3. MBR takes control and locates [Link] 4. [Link] takes control, identifies hardware 5. [Link] runs [Link] 6. [Link] takes control, loads OS kernel into RAM 7. [Link] runs [Link] 8. [Link] displays a command prompt
Windows 9x Boot Sequence
1. BIOS performs POST 2. BIOS searches for MBR 3. MBR takes control and locates [Link] 4. [Link] takes control, runs [Link] instructions 5. [Link] loads [Link] (graphic file) and displays it as Windows splash screen 6. [Link] looks for [Link] and [Link] and checks them
Windows 9x Boot Sequence
7. [Link] loads [Link] 8. [Link] executes [Link] and [Link] if present 9. [Link] loads [Link] 10. [Link] loads [Link] 11. [Link] loads [Link] (virtual memory manager) 12. [Link] loads 32-bit device drivers
Windows 9x Boot Sequence
13. [Link] processes [Link] if present 14. [Link] loads [Link], [Link], and [Link] 15. [Link] executes [Link] if present 16. [Link] runs any programs from Startup folder on Start menu
Alternative Boot Modes for Windows 9x
Press F8 as PC is starting up to see Startup Menu
Alternative Boot Modes for Windows 9x
Safe Mode
Minimal set of drivers Standard VGA driver No support for CD, sound, modems
Step by Step Confirmation
Accept or reject each line of the startup
Windows NT, 2000, and XP Boot Sequence
1. 2. 3. 4. BIOS performs POST BIOS searches for MBR MBR takes control and locates NTLDR NTLDR switches CPU into 32-bit protected mode 5. NTLDR reads [Link]. If multiple OSes, it displays a menu for user choice, and passes control to the chosen OS 6. NTLDR runs [Link], which detects the hardware for Registry
Windows NT, 2000, and XP Boot Sequence
7. NTLDR reads NTOSKRNL (OS kernel) into memory 8. NTLDR locates drivers for Registryreported hardware 9. NTLDR hands over control to [Link] 10. [Link] loads the device drivers and the GUI
Alternative Boot Modes for NT 4
VGA mode
Alternative Boot Modes for Windows 2000 and XP
Troubleshooting 9x Startup
No operating system found
No bootable disk is available PC does not see hard drive Hard drive not formatting No OS installed Loose connection to hard disk Physical malfunction Virus infection [Link] or [Link] missing or corrupted
Troubleshooting 9x Startup
Error in [Link] Line xx
Driver called for in [Link] missing or corrupted
Bad or Missing [Link] Stuck at Windows splash screen
Press Esc to see what is going on behind it Disable virtual memory Rebuild paging file
Troubleshooting 9x Startup
Missing, Corrupt, or Unloaded [Link] Windows protection error
Virtual device driver problem Start in Safe Mode and check for a real-mode driver on [Link] Remove and reinstall the device
Device referenced in [Link] or [Link] not found
Troubleshooting 9x Startup
General protection fault (GPF)
Two programs try to use the same memory space Make a note of the file causing the error, and restart If repeats, try reinstalling the associated program or using EXTRACT to re-copy file from Windows disc
Troubleshooting 2000/XP Startup
Try Safe Mode Try restoring last known good configuration If Windows XP, use System Restore Repair Windows installation by booting from Setup CD and choosing Repair
Controlling What Loads at Startup
Disable items in [Link], [Link], [Link], and [Link] through the System Configuration Editor (SYSEDIT)
Controlling What Loads at Startup
Delete items from Startup folder on Start menu
Controlling What Loads at Startup
Use System Configuration Utility (MSCONFIG) to disable startup items
Creating a 9x Startup Floppy
1. Open Control Panel 2. Add/Remove Programs, Startup Disk tab 3. Click Create Disk and follow the prompts
How a Boot Floppy Works
[Link] from floppy creates RAM disk [Link] files are decompressed onto RAM disk Therefore some utilities are directly on the floppy, and others are on the RAM disk
Files on a Boot Floppy
[Link]: Support for hard disks compressed with DriveSpace [Link]: The compressed file containing extra utilities to be placed on RAM disk [Link] and [Link]
[Link]: Locates the RAM disk
[Link]: Extracts compressed files to RAM disk FDISK: Partitions disks
[Link]: Information
CD-ROM drivers
Files on the RAM Disk
What is an ERD?
Emergency Repair Disk For Windows 2000/XP only Not bootable Stores settings that can help repair Windows, along with Windows Setups Repair mode Specific to that PC
Creating an ERD
1. Start the Backup application 2. Click the Emergency Repair Disk button
3. Follow the prompts
What Is the Recovery Console?
Command-line interface Limited set of commands Accessible even when Windows will not start normally Can repair the MBR, disable services, etc.
Booting to the Recovery Console
[Link] from the Windows CD [Link] R for Repair [Link] C for Recovery Console [Link] 1 to choose the Windows installation [Link] administrator password when prompted
Recovery Console Commands
Some
are same as with Win9x startup disk:
DIR EXIT EXPAND FORMAT MD RD REN
ATTRIB CD MD COPY DEL CHKDSK
Recovery Console Commands
Some are different from normal command prompt commands:
BATCH DISABLE DISKPART ENABLE FIXBOOT FIXMBR LISTSYS
Troubleshooting Shutdown Problems
Does not shut off with Shut Down command
Is ACPI enabled in BIOS Setup? Is it an ATX motherboard? Is ACPI enabled in Windows? Are case wires connected to motherboard? Is a BIOS update available for motherboard?
Troubleshooting Shutdown Problems
Application Not Responding
Click End Task if dialog box appears Press Ctrl+Alt+Delete and shut down application
No Shutdown with Power Button
Hold power button down for 5 seconds
Troubleshooting Shutdown Problems
Windows 98 locks up when shutting down
Download patch for Windows 98 Disable Fast Shutdown (in MSCONFIG)
