Grade 8 Operating System

 Operating System

Modules of Operating System

i)                    Process Manager

ii)                  Memory Manager

iii)                File Manager

iv)                Device Manager

Booting – The process of loading the system files of MS-DOS from the secondary storage sucha as the hard disk into the computers primary memory i.e. RAM is called booting

Types of booting

a)      Cold Boot

b)      Warm Boot

Cold Boot- The initial loading of system files is called cold boot.

Warm Boot – The re-loading of system files is called warm boot. E.g. re-starting the computer.

System files of MS-DOS

i)                    COMMAND.COM

ii)           IO.SYS

iii)                MSDOS.SYS

COMMAND.COM- Acts as a command interpreter and creates an interface between the user and the hardware.

IO.SYS- Handles the input/output operations.

MSDOS.SYS- Program for use by application programs.

File – a file is a collection of related information . Hence a collection of information saved in a computer is called file.

General types of file:  i) Data file                  ii) Program file

Filename- To differentiate one set of information from another, files are given a unique identification or name known as filename.

Extension/ secondary name

Example of filename:                         BOOKS.TXT

Directory- A directory is an index of files stored on a disk which contains information about all files stored on a disk like their name, size, date and time etc.

Sub-directory- A directory within a directory is called a sub directory.

Root directory- A root directory is the parent directory of all the directories and sub directories that can be created in a disk. A root directory is symbolized by “\”. ( C: \)

Advantages of directory

a)      Orderly layout and good management of files

b)       Quicker access to files

Disk drives- The medium in which mass data is stored are called disks. To store data on such disk, we need some device. Hence those devices through which we store data on disks are called disk drives.

Default drive- the condition given or assumed by a system is called its default. Similarly, the drive which is used to load the system is known as default drive.

Volume Label- The name given to a hard disk is referred to as a volume label. It can have a maximum of 11 characters.

Error message- An error message is a notice on a display screen (monitor) informing the user of an incorrect data entry or command or machine malfunction.

Example of error message- Bad Command or file name

Wild card characters- Wild cards are commonly used for the quick function or the execution of DOS commands. Instead of typing complete filenames, we can specify the parts of the name by using few characters like * or ? , known as wild card characters.

For example - * = any file or extension

                        ? = any character       

The PATH command- By using this command one can display or set the directory path that DOS is to follow when looking for an external DOS command, user command or application command. PATH only works for external commands.

Syntax = PATH [ DRIVE : ] PATH [; ….. ]

Types of MS-DOS commands:

i)                    Internal Commands

ii)                  External Commands

Internal Commands- Internal commands are the commands that are a part of the MS-DOS command interpreter. They are small routines and are stored within the COMMAND.COM file. Internal commands can be used as soon as you boot the computer i.e. you get DOS prompt (e.g. C:\> )

Some examples of internal commands- DATE, TIME, CLS, COPY, DEL etc.

External Commands- External commands are commands that are stored in a disk as program files. They are not part of COMMAND.COM file. They must be read from the disk before they are executed. External commands need their own file having the extension .COM, .EXE or .BAT

Some examples of external commands are - FORMAT, CHKDSK, EDIT, etc.

MS-DOS COMMANDS

1.   

           DATE

FUNCTION - Displays system date and allows the user to change the date.

SYNTAX – DATE

2.         

      TIME

FUNCTION - Displays system time and allows the user to change the time.

SYNTAX – TIME

3.      CLS

FUNCTION – Clears the screen.

SYNTAX – CLS

4.      VER

FUNCTION - Displays the version of the operating system.

SYNTAX – VER

5.      VOL

FUNCTION - Displays the volume label.

SYNTAX – VOL

6.      LABLE

FUNCTION - Displays volume label and allows the user to change the volume name.

SYNTAX – LABEL (11 characters)

7.      COPY CON

FUNCTION – To create a new file.

SYNTAX – COPY CON <FILENAME>

8.      COPY

FUNCTION – To make a backup or copy of an existing file.

 SYNTAX – COPY <SOURCE FILENAME><NEW FILENAME>

9.      TYPE

FUNCTION - Displays the contents of a file.

SYNTAX – TYPE <FILENAME>

10.  REN

FUNCTION –Renames or changes the name of a file.

SYNTAX – REN <OLD FILENAME><NEW FILENAME>

11.  DEL

FUNCTION –Deletes a file or group of files (when used with wildcard characters)

SYNTAX – DEL <FILENAME>

12.  DIR

FUNCTION - Displays the list of files and directories of a specified drive.

SYNTAX – DIR

13.  EDIT

FUNCTION –The EDIT command is used to compile, edit, save, copy and print the text. EDIT is a full screen text editor with menu, mouse support. It is useful for creating AUTOEXEC.BAT and CONFIG.SYS file.

SYNTAX – EDIT <FILENAME>

14.  MD

FUNCTION – For making a directory.

SYNTAX – MD <DIRECTORY NAME>

15.  CD

FUNCTION –Changes a directory.

SYNTAX – CD <DIRECTORY NAME>

16.  RD

FUNCTION – Removes an empty directory.

SYNTAX – RD <DIRECTORY NAME>

17.  FORMAT

FUNCTION –The FORMAT command prepares a diskette or hard disk for the storage of  information.

SYNTAX – FORMAT <DRIVE NAME>