Different Types of Operating Systems:- MS DOS

2. Different Types of Operating Systems:- MS-DOS

Different Types of Operating Systems:- MS-DOS

• MS-DOS

   MS-DOS was developed by Microsoft as a single-user operating system working on a Personal Computer. DOS has character user Interface (CUI) where the user has to type commands from the keyboard to execute any task. When the operating system program is loaded into the memory process is known as Booting. Booting is of two types:

   (1) Cold Booting: When we start the computer by pressing the power switch on the system unit, the operating system is loaded from disk to the memory. This type of booting is called cold Booting.

   (2) Warm / Hot Booting: Hot booting is done when the computer comes into the "no-respond" state. In this state, the computer is rebooted by using the Reset button or pressing a key combination of Alt + Ctrl + Del keys from the keyboard.

   For DOS booting process, following three programs are very important :-

   (a) MS DOS

   (b) IO.SYS

   (c) COMMAND.COM

   DOS has got inverted tree directory structure. The main directory which contains system files is known as the root directory.

   DOS has two types of commands:-

   (1) Internal Commands

   (2) External Commands

   Internal Commands are loaded into the memory when the operating system is loaded. These commands are included in COMMAND.COM. Some of the internal commands are DIR, CLS, MKDIR, VER, DATE, TIME, CD.

   External commands are not loaded with the operating system. These commands are loaded separately and have an extension of .exe or .com. Some examples of, external commands are ATTRIB, FORMAT, DELTREE, SCANDISK.

   DOS Supports to wild card characters * and?

   '*' Asterisk Mark stands for any number of characters.

       Generally, they are limited to 8 characters in DOS.

   '?' Question Mark Stands for any single character.

• For Example:-

   To find out the list of all the files whose name starts from C followed by any number character the command will be:-

   DIR C * . *

   To find the name of the file starting from C and followed by a single character, the command will be:-

   DIR C ? . *