Understanding the Boot Process and Command Line

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Chapter 3

• Understanding the Boot Process and Command Line

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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

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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

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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

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Booting Up Your Computer

• 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

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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

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Plug and Play

• 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
  doesnt do

Last paragraph on page 78 and 1st paragraph on 79
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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

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FAT File System

• 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

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Tracks and Sectors
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Files and Directories
Directory table Root Directory
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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, _at_,, --- do NOT use space,
  period, , ? or \
• Acceptable file extensions .com, .sys, .bat.,
  and .exe
• Example filename.ext
• Under Windows 95 and later Windows OSs
• Can be as long as 255 characters and can contain
  spaces

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File Organization

• Create different directories on a hard drive or
  other secondary storage media

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Partitions and Logical Drives on a Hard Drive
2 logical drives
1 logical drive
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Startup BIOS Controls the Beginning of the Boot

• Boot steps
• BIOS checking hardware
• Loading the OS
• OS initializing itself
• 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)
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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

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Boot Step 1 POST
Page 84
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How the BIOS Findsand Loads the OS
Partition table Active partition
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Boot Step 2 Loading the OS
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Loading the MS-DOS Coreof 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
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Boot Step 3 OS Initializes Itself
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Loading the MS-DOS Core of Windows 9x

• 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
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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

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Windows 9x Startup Disks
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(No Transcript)
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Files Contained in theCabinet File, Ebd.cab
Cabinet file
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Windows 9x Startup Disks

• Creating your own bootable rescue disk for
  Windows 9x
• Using a Windows startup disk with another OS

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Creating Your Own Bootable Rescue Disk for
Windows 9x
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Creating Your Own Bootable Rescue Disk for
Windows 9x
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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

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Ways to Accessa 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

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Command Prompt Window
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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
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Launching a Program Using the Command Prompt

• 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

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Finding a Program File
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Using the Path Command
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Using Commands to Manage a Floppy Disk or Hard
Drive

• Dir
• Type
• Del or Erase
• Undelete
• Recover
• Diskcopy

continued
Wildcards
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Using Commands to Manage a Floppy Disk or Hard
Drive

• Copy
• Xcopy /C /S /Y /D
• Deltree
• Mkdir drivepath or MD drivepath
• Chdir drivepath or CD drivepath or CD..
• Rmdir drivepath or RD drivepath

continued
Page 104 Tip
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Mkdir Command
continued
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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
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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 pathfilename

continued
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Using Commands to Manage a Floppy Disk or Hard
Drive

• Editing Autoexec.bat and Config.sys
• always make a rescue disk before editing
• Dont use a word processor to edit unless saved
  ad .txt file
• Fdisk /Status /MBR
• Fdisk prepares HD for 1st use
• Format Drive /S /VVolumename /Q /U /Autotest

continued
Page 110 Tip
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Edit Autoexec.bat
continued
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Options for the Fdisk Command
continued
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Options for the Format Command
continued
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Options for the Format Command
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Using Batch Files

• To execute a group of commands using only a
  single command to execute the batch file

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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