Understanding the Boot Process and Command Line

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Chapter 3

• Understanding the Boot Process and Command Line

2
You Will Learn

• About the boot process and some tools for
  troubleshooting a failed boot
• To use many commands at the command prompt

3
Booting Up Your Computer

• Hard (cold) boot versus soft (warm) boot
• Startup BIOS is in control when boot process
  begins
• Turns control over to the OS

4
Steps in the Boot Process

• Startup BIOS runs power-on self test (POST) and
  assigns resources
• ROM BIOS startup program searches for and loads
  an OS
• OS configures the system and completes its own
  loading
• Application software is loaded and executed

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Boot Step 1 POST
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How the BIOS Finds and Loads the OS
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How the BIOS Finds and Loads the OS (continued)

• BIOS executes MBR program
• Turns to partition table to find OS boot record
• Program in OS boot record attempts to find a boot
  loader program for OS
• Ntldr (Windows NT/2000/XP)
• Io.sys (Windows 9x)

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Boot Step 2 Loading the OS
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Loading the MS-DOS Core of Windows 9x

• Brings OS to real-mode command prompt
• Relevance Real-mode DOS core often used as a
  troubleshooting tool

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Loading the MS-DOS Core of Windows 9x (continued)

• Files necessary to boot to command prompt
• Io.sys
• Msdos.sys
• Command.com
• To customize 16-bit portion of load process
• Autoexec.bat
• Config.sys

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Boot Step 3 OS Initializes Itself
12
Emergency Startup Disks

• Bootable disks with some utility programs to
  troubleshoot a failed hard drive
• Each OS provides automated method to create a
  rescue disk (Windows 9x) or set of disks (Windows
  2000)

13
Emergency Startup Disks (continued)

• Creating a Windows 9x startup disk
• Add/Remove Programs icon in Control Panel
• Using a Windows 9x startup disk with another OS

14
Windows 9x Startup Disks
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Using the Command Prompt

• Multiple ways of accessing a command prompt
• Launching a program using the command prompt
• Using commands to manage files and folders and
  perform utility tasks when troubleshooting a
  failed system

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How to Access a Command Prompt in Windows
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How to Access a Command Prompt in Windows
(continued)
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Launching a Program Using the Command Prompt
(continued)

• Type filename of program file at command prompt
• OS
• Attempts to find program file by name,
• Copies file into RAM, and
• Executes program

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Launching a Program Using the Command Prompt
(continued)
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DOS File and Directory Naming Conventions

• 8.3 format
• Up to 8 characters, separating period, and file
  extension of up to 3 characters (eg,
  filename.ext)
• Acceptable characters
• Letters a through z
• Numbers 0 through 9
• _ ! - ( ) _at_
• Do not use space, period, , ? or \
• Acceptable extensions .com, .sys, .bat, .exe

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Windows File and Directory Naming Conventions

• Up to 255 characters
• Can contain spaces
• When DOS part of system is operating, it
• Truncates long filenames
• Assigns new 8-character names (eg, Mydocu1.doc)

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Wildcards

• Question mark (?)
• Wildcard for one character
• Asterisk ()
• Wildcard for more than one character

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Commands to Manage Disks, Drives, Files, and
Directories
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Result of Dir Command
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Commands to Manage Disks, Drives, Files, and
Directories
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Commands to Manage Disks, Drives, Files, and
Directories
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Commands to Manage Disks, Drives, Files, and
Directories
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Commands to Manage Disks, Drives, Files, and
Directories
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Commands to Manage Disks, Drives, Files, and
Directories
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Commands to Manage Disks, Drives, Files, and
Directories
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Editing Autoexec.bat and Config.sys
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Options for Fdisk Command
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Options for Format Command (continued)
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Options for Format Command (continued)
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Using Batch Files

• To execute group of commands using single command

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Summary

• How a PC first boots up
• Parts of the boot process
• POST
• Loading the OS
• OS initializing itself
• Loading and executing an application
• Troubleshooting tools to use when the boot fails
• Essential commands used from a command prompt
  when troubleshooting a failed system