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

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

Understanding the Boot Process

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

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

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

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

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 steps1. 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 Findsand Loads the OS

Partition table:

Active partition:

Boot Step 2: Loading the OS

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:

Boot Step 3: OS Initializes Itself

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

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 theCabinet 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 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

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

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

continued…Wildcards:

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

continued…Page 104 Tip

Mkdir Command

continued…

Using Commands to Manage a Floppy Disk or Hard Drive

AttribUnformat 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 /BackupDefrag Drive: /SVerExtract filename.cab file1.ext /DDebugEdit [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

continued…Page 110 Tip

Edit Autoexec.bat

continued…

Options for the Fdisk Command

continued…

Options for the Format Command

continued…

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