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

Booting Up Your Computer  Refers to the computer bringing itself up to an operable state without user intervention  Soft (warm) boot Uses OS to reboot  Hard (cold) boot Uses on/off switch More stressful on the machine

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

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 and Sectors

Files and Directories

File Naming Conventions  Under DOS Can contain up to eight characters, a separating period, and a file extension of up to three characters 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

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

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

How the BIOS Finds and Loads the OS

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

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

Emergency Startup Disks (ESDs)  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

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

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

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  Label  Del or Erase  Undelete  Recover  Diskcopy continued…

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…

Mkdir Command continued…

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  Fdisk /Status /MBR  Format Drive: /S /V:Volumename /Q /U /Autotest continued…

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