Introduction to DOS

What is DOS?

• Stands for "Disk Operating System"
• First operating system used by IBM-compatible computers
• Originally available in two versions: PC-DOS and MS-DOS

DOS Interface

• Uses a command line, or text-based interface
• Allows users to type commands
• Requires knowledge of basic commands to use effectively

The Command Prompt

• Displayed as a blinking underscore character
• Default prompt shows the drive letter and path of the current location
• Followed by a greater than sign (>)

Internal and External Commands

• Internal Commands:
  • Built into the OS under COMMAND.COM
  • Already in memory when the OS is loaded
  • Available anytime the computer is displaying a command prompt
  • Examples: DIR, COPY, CLS, CD, MD, DEL, TIME, DATE
• External Commands:
  • Not part of COMMAND.COM
  • Located in another directory as external files
  • Must be loaded into memory as needed by the OS
  • Examples: FORMAT, DEFRAG, DISKCOPY, DEBUG, EDIT

Command Syntax

• Rules for writing commands
• Order of elements in the command
• Example: DIR B:/P

Command Elements

• Action: what action to perform
• Object: what is acted upon
• Parameters: additional directions for the command
• Switches: special type of parameter that enables or disables optional functions

Backslash vs Forward Slash

• Backslashes () are used as separators when specifying directory or file information
• Forward slashes (/) are used to notify DOS that the next character is a command line switch

Getting Help

• Type HELP followed by the command you want to know about
• Type the command and then follow it with the switch /?

Frequently Used DOS Commands

• CHKDSK: checks a disk and displays a status report
• CLS: clears the screen
• COMP: compares two groups of files to find information that does not match
• COPY: copies and appends files
• DATE: displays and sets the system date
• TIME: displays and sets the system time
• DEFRAG: optimizes disk performance by reorganizing the files on the disk
• LABEL/VOL: creates or changes or displays a volume label for a disk
• MEM: displays amount of installed and available memory
• DEL: deletes files from disk
• DELTREE: deletes a directory including all files and subdirectories
• DIR: displays directory of files and directories stored on disk
• DISKCOMP: compares the contents of two disks
• ECHO: displays messages or turns on or off the display of commands in a batch file
• EDIT: starts the MS-DOS editor, a text editor used to create and edit ASCII text files
• EXIT: exits a secondary command processor
• COPY CON: creates a file

Batch File

• A script file in DOS, OS/2, and Microsoft Windows
• Consists of a series of commands to be executed by the command-line interpreter
• Stored in a plain text file with a .bat or .cmd extension

SET Command

• Accepts input from a user as the value for a variable
• Syntax: SET /P variable = []
• Example: SET /P uname=Please enter your name:

What is DOS?

• Stands for "Disk Operating System"
• First operating system used by IBM-compatible computers
• Originally available in two versions: PC-DOS and MS-DOS

DOS Interface

• Uses a command line, or text-based interface
• Allows users to type commands
• Requires knowledge of basic commands to use effectively

The Command Prompt

• Displayed as a blinking underscore character
• Default prompt shows the drive letter and path of the current location
• Followed by a greater than sign (>)

Internal and External Commands

• Internal Commands:
  • Built into the OS under COMMAND.COM
  • Already in memory when the OS is loaded
  • Available anytime the computer is displaying a command prompt
  • Examples: DIR, COPY, CLS, CD, MD, DEL, TIME, DATE
• External Commands:
  • Not part of COMMAND.COM
  • Located in another directory as external files
  • Must be loaded into memory as needed by the OS
  • Examples: FORMAT, DEFRAG, DISKCOPY, DEBUG, EDIT

Command Syntax

• Rules for writing commands
• Order of elements in the command
• Example: DIR B:/P

Command Elements

• Action: what action to perform
• Object: what is acted upon
• Parameters: additional directions for the command
• Switches: special type of parameter that enables or disables optional functions

Backslash vs Forward Slash

• Backslashes () are used as separators when specifying directory or file information
• Forward slashes (/) are used to notify DOS that the next character is a command line switch

Getting Help

• Type HELP followed by the command you want to know about
• Type the command and then follow it with the switch /?

Frequently Used DOS Commands

• CHKDSK: checks a disk and displays a status report
• CLS: clears the screen
• COMP: compares two groups of files to find information that does not match
• COPY: copies and appends files
• DATE: displays and sets the system date
• TIME: displays and sets the system time
• DEFRAG: optimizes disk performance by reorganizing the files on the disk
• LABEL/VOL: creates or changes or displays a volume label for a disk
• MEM: displays amount of installed and available memory
• DEL: deletes files from disk
• DELTREE: deletes a directory including all files and subdirectories
• DIR: displays directory of files and directories stored on disk
• DISKCOMP: compares the contents of two disks
• ECHO: displays messages or turns on or off the display of commands in a batch file
• EDIT: starts the MS-DOS editor, a text editor used to create and edit ASCII text files
• EXIT: exits a secondary command processor
• COPY CON: creates a file

Batch File

• A script file in DOS, OS/2, and Microsoft Windows
• Consists of a series of commands to be executed by the command-line interpreter
• Stored in a plain text file with a .bat or .cmd extension

SET Command

• Accepts input from a user as the value for a variable
• Syntax: SET /P variable = []
• Example: SET /P uname=Please enter your name:

Learn about the basics of Disk Operating System (DOS), the first operating system used by IBM-compatible computers, and its two versions, PC-DOS and MS-DOS.