Understanding the Boot Process and Command Line 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

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

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 Finds and Loads the OS Partition table: Active partition:

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 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 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

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 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 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…

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