MS-DOS ( Microsoft Disk Operating System):

Microsoft DOS (Disk Operating System) is a command line user interface. MS-DOS 1.0 was released in 1981 for IBM computers and the latest version of MS-DOS is MS-DOS 6.22, which was released in 1994. While MS-DOS is not commonly used by itself today, it still can be accessed from every version of Microsoft Windows by clicking Start / Run and typing "command" or by typing "CMD" in Windows NT, Windows 2000 or Windows XP.
Some points before MS-DOS
Drive Prompt: The drive prompt defines the drive in which you are working.
A: First Floppy Disk Drive
B: Second Floppy Drive
C: First Partition of the hard disk drive.
D: Second Partition of the hard disk drive. The last drive (Generally E: or F: ) : CD ROM Drive
2. Directory: Directory defines the root or path where you are creating files or directories. You can store sub-directories and files in a directory. In windows operating system It appears as a folder.
3. Path: path also defines the root where you are creating directory or file. It begins with drive prompt and displays all root directories name to reach to the current directory.
4. Wild Cards: In MS-DOS you can use some characters for special purpose, which are known as wild cards.
* (Astrik sign) : Which defines group of character. ? (Question mark) : Which defines individual character. # You can use these wild cards if you need to copy, cut or delete files or directories having same filename or extension.
5. Filename : It defines the name of the file. You could not create more than two files having same name with in a same directory. It supports only 8 characters as filename.
6. Extension: It defines the nature of the file. As people has different cast same as computer files has different extensions for different applications, files. .sys : System files .bat : Batch files .exe : Executable file .dll : Dynamic link library files. .doc : Document file (Microsoft Word) .xls : Worksheet file (Microsoft Excel) .ppt : Presentation file (Microsoft Powerpoint) .gif : Graphics Interchange Format (Image file) .jpg : Joint photographic expert group (Image file) .png : Portable Network Graphics (Image file) .htm/.html: Hyper text markup Language (Webpage format file) 7. System file : Those file having extension .sys, which are required to boot the computer are known as system files. In MS-DOS Three files are required to boot the computer IO.SYS MSDOS.SYS COMMANDCOM.SYS
Limitations of MS-DOS
1. It is a command line user interface (CUI) operating system. You must type commands from the keyboard for each and every action. 2. It is a single user Interface operating system and It doesn't support multitasking. You must close first file to open next file in MS-DOS. 3. It accepts only 8 characters as filename and 3 characters as extension. 4. It doesn't support some symbols as file name and extensions like \,/, . , ! , | , , , etc.
MS-DOS accepts two types of commands which are Internal DOS commands and External DOS Commands.
Internal DOS command:
Those commands which are included in COMMANDCOM file and which can be run from any drive prompt are the internal DOS commands. Internal DOS commands always remains at the computer memory after booting so we can run from every drive prompt.
Sn Command Switch Function Syntax 1. CLS To Clear screen Drive: CLS C:\CLS 2. REN To Rename File. Drive: REN {Old filename} {New filename} C:\REN ram sita 3. DIR /P To display a list of the files and directories in page wise order. Drive: DIR/switch C:DIR/P /W To display a list of the files and directories in width wise order. Drive: DIR/switch C:DIR/W /AD: Directories /AR: Read Only /AH: Hidden /AS: System /AA: Archive To display a list of the files and directories with specific attributes. Drive: DIR/Switch C:DIR/AD C:DIR/AR C:DIR/AH C:DIR/AS C:DIR/AA 4. COPY To copy  file. Drive: Copy {source} {Filename} {Destination} C:COPY {ram} A: 5. MOVE To move  file. Drive: Move {source} {Filename} {Destination} C:MOVE ram A: 6. DEL To delete file Drive: DEL {Filename} C:DEL ram 7. COPY CON To create new file. Drive: COPY CON {Filename} C:COPY CON ram 8. TYPE To view the contents of the file. Drive: TYPE {Filename} C:TYPE ram 9. DATE To view the system date. Drive: DATE C:DATE 10. TIME To view the system time. Drive: TIME C:TIME 11. MD or MKDIR To create new directory. Drive: MD {Directory name} C:MD ram 12. CD or CHDIR To change directory. Drive: CD {Directory name} C:Windows\Desktop\CD ram .. To close directory one by one. Drive: Path: CD.. C:Windows\Desktop\CD.. \ To close all the open directory at once. Drive: Path: CD\ C:Windows\Desktop\CD\ 13. RD or RMDIR To remove empty directory. Drive: RD {Directory name} C:RD ram 14. VER To view the version of the DOS. Drive: VER C:VER 15. VOL To view the volume label of the DOS. Drive: VOL C:VOL 16. PROMPT To Change Drive prompt. Drive: PROMPT {Switch} $G Grater than C:PROMPT $G $L Less than C:PROMPT $L $B Pipe sign C:PROMPT $B $Q Equal sign C:PROMPT $Q $V MS DOS Version C:PROMPT $V $D Date C:PROMPT $D $P$G Default/ Original C:PROMPT $P$G $P Drive and path C:PROMPT $P $T Time C:PROMPT $T $$ Dollar sign C:PROMPT $$