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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.
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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