chapter 3 understanding the boot process and command line
TRANSCRIPT
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