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Chapter 3
Understanding the
Boot Process and
Command Line
You Will Learn…
 To understand the process of booting to a
command prompt
 To create and use Windows 9x rescue disks to
troubleshoot and solve problems when booting
Windows
 To use many commands at the command
prompt
Understanding the Boot Process
 When OS is functioning:
• Interface: command driven, menu driven or icon
•
driven
GUI (graphical user interface)
•
•
Desktop: menu & icon driven
Launch application using Windows Explorer to copy
files or create folders & troubleshoot
Understanding the Boot Process
 When OS is NOT functioning:
• No desktop
• Must use command driven interface
 MS-DOS: real mode to boot computer
 Command line: tried & true tool for worst OS
problems
• Essential to PC trouble shooting
Booting Up Your Computer
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
Refers to the computer bringing itself up to an
operable state without user intervention
Soft (warm) boot : CTRL + ALT + DEL
• Faster
or Restart
• Uses OS to reboot
Hard (cold) boot
• Uses on/off switch
• More stressful on the machine because of power surge
Booting Up Your Computer
 Plug and Play (PnP) standard
 File system
 What happens when PC is first turned on and
startup BIOS takes control and then loads OS
 What happens when essential components of
OS are loaded from hard drive or floppy disk
Plug and Play
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Standard designed to make installation of hardware
devices easier
Applies to OS, system BIOS, and hardware devices
Supported by Windows 9x and Windows 2000/XP but
not by Windows NT
ESCD (extended system configuration data) Plug and
Play BIOS: creates a list of all things you have done
manually to the configuration the PnP doesn’t do
Last paragraph on page 78 and
1st paragraph on 79
What Is a File System?
 Organizational method used by an OS to store
files and folders on a secondary storage device
 FAT (file allocation table) file system
 Files and directories
 File naming conventions
 File organization
 Partitions and logical drives on a hard drive
FAT File System
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Most common file system for floppy disks and hard
drives
Contains list of clusters and which clusters are used
for each file stored on the disk
Tracks: concentric circles on the disk surface
Sector: each track is divided into these segments
Cluster: smallest unit of space on a disk for storing
data
Tracks and Sectors
Files and Directories
Directory table:
Root Directory:
File Naming Conventions

Under DOS
• Can contain up to eight characters, a separating period, and
•

a file extension of up to three characters
a through z, 0 through 9, _ , ^, $, ~, !, #, %, &, -, {, },
comma, @,’,` --- do NOT use space, period, *, ? or \
Acceptable file extensions: .com, .sys, .bat., and .exe
Example: filename.ext
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•
Under Windows 95 and later Windows OSs
• Can be as long as 255 characters and can contain spaces
File Organization
 Create different directories on a hard drive or
other secondary storage media
Partitions and Logical Drives on a Hard
Drive
1 logical drive
2+ logical drives
Startup BIOS Controls the Beginning of
the Boot
 Boot steps
1. BIOS checking hardware
2. Loading the OS
3. OS initializing itself
4. Loading and executing an application
 Startup BIOS is in control for first step of the
boot, then it turns over control to the OS
Boot errors: communicated as
beeps or messages (Appendix A)
Overview of Boot Steps
 Step 1: POST (Power-on self test)
 Step 2: ROM BIOS startup program searches
for and loads an OS
 Step 3: OS configures the system and
completes its own loading
 Step 4: User executes application software
Boot Step 1: POST
Page 84
How the BIOS Finds
and Loads the OS
Partition table:
Active partition:
Boot Step 2: Loading the OS
Loading the MS-DOS Core
of Windows 9x
 When only MS-DOS core of Windows 9x is
loaded during booting
• Brings OS to real-mode command prompt similar
to DOS command prompt
 Real-mode DOS core is often used as a
troubleshooting tool when hard drive fails
Buffer:
Batch file:
Boot Step 3: OS Initializes Itself
Loading the MS-DOS Core of Windows
9x
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When OS loads from hard drive, BIOS first executes
the MBR, which executes OS boot record, which, for
Windows 9x, attempts to find Io.sys on hard drive
Io.sys, which uses Msdos.sys, and Command.com,
form the core of real-mode Windows 9x
• All three are necessary to boot to a command prompt
Autoexec.bat and Config.sys contain commands used
to customize 16-bit portion of Windows 9x load
process
RAM drive
Emergency Startup Disks (ESDs)
 Bootable Disk: floppy with enough software
to load OS
 Bootable disks with some utility programs to
troubleshoot a failed hard drive
 Also called rescue disk or startup disk
 Created automatically by the OS beginning
with Windows 95
Windows 9x Startup Disks
Files Contained in the
Cabinet File, Ebd.cab
Cabinet file:
Windows 9x Startup Disks
 Creating your own bootable rescue disk for
Windows 9x
 Using a Windows startup disk with another OS
Creating Your Own Bootable Rescue
Disk for Windows 9x
Creating Your Own Bootable Rescue
Disk for Windows 9x
Using the Command Prompt
 Accessing a command prompt
 Launching programs from the command
prompt
 Using commands to manage files and folders
 Using utility tasks to troubleshoot a failed
system
Ways to Access
a Command Prompt
 Click Start, Programs, MS-DOS Prompt
 Click Start, Run, enter Command.com in the
Run dialog box
 When booting from a bootable disk or rescue
disk, you get a command prompt instead of
Windows desktop
Command Prompt Window
To Get a True Real-Mode Environment
in Windows 9x
 Click Start, click Shutdown, and select Restart
in MS-DOS mode from Shutdown dialog box
 Boot to a command prompt by holding down
Ctrl or F8 while booting; select “Command
prompt only” from the menu
Read paragraph on
page 97
Launching a Program Using the
Command Prompt
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OS receives command to execute the application
OS locates the program file for the application
OS loads the program file into memory
OS gives control to the program
Program requests memory addresses from OS for its
data
Program initializes itself; possibly requests that data
from secondary storage be loaded into memory
Program turns to user for first instruction
Finding a Program File
Using the Path Command
Using Commands to Manage a Floppy
Disk or Hard Drive
 Dir
 Type
 Del or Erase
 Undelete
 Recover
 Diskcopy
Wildcards:
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Using Commands to Manage a Floppy
Disk or Hard Drive
 Copy
 Xcopy /C /S /Y /D:
 Deltree
 Mkdir [drive:]path or MD [drive:]path
 Chdir [drive:]path or CD [drive:]path or CD..
 Rmdir [drive:]path or RD [drive:]path
Page 104 Tip
continued…
Mkdir Command
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Using Commands to Manage a Floppy
Disk or Hard Drive
 Attrib
 Unformat
 Path
 Sys Drive:
 Chkdsk [drive:] /F /V
 Scandisk Drive: /A /N /P
continued…
Using Commands to Manage a Floppy
Disk or Hard Drive
 Scanreg /Restore /Fix /Backup
 Defrag Drive: /S
 Ver
 Extract filename.cab file1.ext /D
 Debug
 Edit [path][filename]
continued…
Using Commands to Manage a Floppy
Disk or Hard Drive
 Editing Autoexec.bat and Config.sys:
• always make a rescue disk before editing
• Don’t use a word processor to edit unless saved ad
.txt file
 Fdisk /Status /MBR
• Fdisk: prepares HD for 1st use
 Format Drive: /S /V:Volumename /Q /U
/Autotest
Page 110 Tip
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Edit Autoexec.bat
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Options for the Fdisk Command
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Options for the Format Command
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Options for the Format Command
Using Batch Files
 To execute a group of commands using only a
single command to execute the batch file
Chapter Summary
 How a PC first boots up and loads the
operating system
 How to create floppy disks that can be used to
boot to a command prompt
 Essential commands for troubleshooting a
failing system