MS DOS

Introduction

DOS

The set of program that acts as a translator between man and computer is called DOS (Disk Operating System). It is associated with the disk operations. It is stored in ROM that is usually called bootstrap loader because when we switch on the compute the program reads the very first part of the system diskette where DOS startup program is written, which is called Boot Reader.

MS-DOS

MS-DOS stands for ‘Microsoft Disk Operating System’. MS-DOS is a set of programs that manages the flow of information to and from various part of computer system. It enables you to communicate with your computer and its peripheral devices.

Features of MS-DOS

·         

Directory: A directory is a table of contents for the disk. It contains the names of files, there sizes, last date of modification and the address of the file to locate where on the disk the file is resides.

Root Directory: Every disk has at least one directory even though many directories can be maintained it. This is called root directory.

Sub-Directory:A directory inside a directory is called sub-directory. A sub-directory sometimes called child-directory and sometimes called parent directory.

File: The file in the Computer is a collection of related information. Each file for its identification has unique file name. file names are divided into two parts first one is called filename and other one is extension.

Extension: Extension helps us to identify the file. MS-DOS uses the following extensions.

·        .EXE (EXECUTABLE) OR .COM (command) is used for files that contain programs. Example EDIT.EXE. COMMAND.COM etc.

·        .SYS (system) is used for files that contain information about the hardware. Example CONFIG.SYS, ANSI.SYS etc.

·        .BAT (batch) is used for files that contain list of commands that MSDOS carries out as a set Example AUTOEXEC.BAT

Difference between File and Directory:

Wildcard Character:

*	Indicates any file name.
.*	Indicates any extension.
*.*	Indicates any file names and extension.
?	Indicates any one character.
:	Indicate drive to be specified. E.g. A: B: C:
^	Indicate control sign
<	Indicate redirection e.g. A:\>TYPE

System Files: The operating system has three essential files and many command files for booting computer system.

IO.SYS	This file lets the DOS communicate with hardware through the BIOS. This file provides the basis capabilities of I/O for the system, allowing it the ability to communicate with other different peripherals. I/O.SYS direct the overall process of loading the OS.
MS-DOS.SYS	This is the program used by application programs. It contains special subprograms to make common operations easy for the programs.
Command.Com	This file accepts and understands the commands that enter using the above two files to give desired results. It is the command interpreter.
Config.sys	Config.sys is a kind of text file containing special Dos commands that tells the OS how the computer is initially setup. It commands to configure computer’s hardware component so that MS-DOS and application can use them.
Autoexec.BAT	All the programs that are supposed to run at startup are called here. It is a file used to run initialization programs and commands that we would normally type each time we start the computer.

Internal command

The command which source file is command.com and will be in the memory when the DOS is loaded in your computer is called internal commands. The various internal commands are as follows.

Break Cd Chdir Cls Copy Color

Date Del Dir Echo Erase

Exit Md Mkdir Move Path

Pause Prompt Rd Rem Rename

Rmdir Set Start Time Type

Ver Verify Vol

External commands

The command, which is not included in the command.com file and need the external (separate file) is called external command and used to facilitate more in disk operation. The command that is stored on system disk as program files are called external commands. They must be read from the disk before they are executed. External comman have the extension like .exe, .com and .bat. They can be listed by dir commands because they are not the part of command.com.

Attrib Backup Chkdsk Choice Debug Defrag Deltree

Deskcomp Diskcopy Doskey Edit Edlin Extract fc

Fdisk Find Format Help label Mem mode

More Msbackup Print restore Recover Scandisk

Scanreg Server Share Sort subst Sys

Tree Undelete Unerase Uniformat xcopy

Booting Process

The process of initiating an automated routine that clears the memory loads the operating system and prepares the computer for use.

Cold Boot

The process of starting computer by using on/off switch each time is called cold boot.

Warm Boot

The process of starting computer by using reset button or keyboard combination key ALT+CTRL+DEL.