Disk Operating System (DOS) in Detail Explain

There are two types of command: - 

Internal commands: 

Internal commands are the commands stored in the file command.com which is loaded into main memory at the time booting thus internal commands are also loaded in the main memory and remains in the main memory as long as computer is on. These commands can be executed at the any time as no extra file is required to run them. 

Ex. Dir, cd, md, cls, copy, delete, rd, etc.

External commands: 

External commands are stored in different files. Each external command as its own File. Thus they cannot be executed if there files is not loaded in the memory. Generally these files are stored on the secondary storage and loaded into the main memory whenever requested. Ex. Format, Attrib, tree, disk copy. 

File name should be only 11 characters, in which 8 character for main name and 3 characters for extinction name. We can use A to Z characters and 0 to 9 numbers and some special symbols like that $, @, ~, {,}, &. 

Ex. Akhil.doc Akhil is File Name, doc in Extinction name.

MD: - For make directory. 

CD: - For change directory. 

Del: - For Delete. 

Copy con: - For make file. 

Type: - for open file. 

Cls: - For clear screen. 

Cd.. : - For come out from any dir. 

/b : for space.

C:\>_ 
C:\>D: 
D:\>md bws 
D:\>cd bws 
D:\>ws>copycon file1 
D:\>ws>md sita 
D:\>ws>md ram 
D:\>ws>cd ram 
D:\>ws\ram>md net 
D:\>ws\ram>md game 
D:\>ws\ram>cd net 
D:\>ws\ram\net>md dos 
D:\>ws\ram\net>copycon file2 
D:\>ws>ram>net>cd\ 
D:\>

Copy command

C:\> copy <source file name> <new file name>
Ex. C:\> copy ram shyam 
If want to copy from C :\> to D:\> then 
C:\> copy ram D:shyam

Wild card:- It have two special symbol “? and *”. When we misspell our file name or forgot file name then use “?” symbol.

Ex. - ???n.com 
    (arun.com) 
    * Symbol shows all file.

Ex. – C :\> dir *.com 
This will show all file which extinction is .com. 
C:\>dir b *.* 
This will show all file with any extinction. 

C:\> Account> b copy b a:*.* 

Thus will come from a: to account folder of c:. 

C:\> copy b a:*.* 

All document or copy of a: will be copy in c: 

C:\>account>copy a: ram.* 

Copy will be in account from a: ram file with any extinction.

Rename:- 

C:\>ren b<source file name>b <new file name>

Ex. – ren b rakesh b Narendra 

Shorting: - for alphabetical arrangement. 

Ex. – C:\>dir| sort> prg 

If we delete any file by mistake then for finding them used undelete command. 

C:\>undelete 

External commands: 

Tree:- We know that DOS stores the files and directories in a tree structure. Tree commands in used to display full tree structure of the files and sub dir within a directory. 

Syntax:- C:\>tree b <dir/drive name> 

Ex. – C:\>tree b ws b d:

Deltree commands:- The deltree commands is used to delete an unwanted directory. If we want to delete directory with its all subdirectory and file we used deltree command. 

Syntax:- C:\>deltree b <directory name>

CHKDSK (check disk):- this command is used to determine the status of a hard disk and known as the status of the disk. 

C:\>CHKDSK b <path name> b switch 

Disk compare:- This command is used to compare to floppies. 

Syntax:- C:\>disk comp b <drive1> b <drive2> b switch 

C:\>disk comp b A: b B: 

C:\>disk comp b A: b B:/1 

This switch (/1) is used to compare only one side disk. 

C:\>disk comp b A: b B:/8 

This switch (/8) is used to compare to disk track by track. 

Disk copy:- this command is used to make an abject copy of floppy disk it also copies the system files and other hidden files one disk to other disk. 

Syntax: - disk copy b <source drive> b <target drive>

Booting: - The term booting is used to describe the process of loading and operation system from the secondary memory into the computer main memory.

Initially the diagnostic routine test the main memory and other components of the system to insure that they are working properly. Then ROM- BIOS (Basic Input Output System) is copies to main memory and check the input output devices. 

File Attributes: - Thus to insure the security of file, four attributes are there to indicate the type of file with to access authorization. 

These four attributes are as follows:- 

(1) Read only file: - If a file attributes of a file set as read only then it can be deleted or modified. 

(2) Hidden file:- This attributes is also used avoid the unauthorized access the file. If this attributes is set “on” then that file is not shown in the common listing of all file. 

(3) System file:- If this attributes is set “on” then is work as a combination of read only and hidden attributes. It means such a file is set as read only and is not display in file listing. 

(4) Archive file:- If an archive bit is set it means that the file is modified since last time it was accessed