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In this chapter, you'll learn about the essential boot process of a computer and how to leverage the command line for troubleshooting in Windows 9x. Understand the different interfaces and methods of booting, including soft and hard boots, the critical role of BIOS, and the process of loading the operating system. You'll also explore creating and using rescue disks for problem-solving when booting issues arise. Familiarize yourself with command-line commands and file organization on various storage media for better PC management.
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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 • 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
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 2+ logical drives 1 logical 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 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:
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:
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
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
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
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
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 • 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 continued… Page 110 Tip
Edit Autoexec.bat continued…
Options for the Fdisk Command continued…
Options for the Format Command continued…
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