disk operating system (DOS).
DOS stands for disk operating system. It is a character based or command based operating system. It was the first operating system for desktop computers. Initially it was developed for IBM. Later MS-DOS was developed. Today Microsoft operating systems supports Dos. It is 16 bit operating system. It does not support multi users. It is a character based operating system means as a user to operate with computer using dos he has to work with all commands. It does not support GUI (Graphical user Interface).Many dos based games are developed.
Dos as many versions like dos 1.0, 2.0, 5.0, 5.5
Dos 6.2, 6.22, 7.0 .Dos 7.0 is available in window95 and later operating systems. Basically dos have two types of commands.
- Internal Commands
- External Commands.
What is a bootstrap loader?
It is a small program that was resided in ROM(read only memory).Whenever is system is on then automatically that the program which was written in ROM will execute itself and loads operating system from the disk. It is a part of BIOS.
Internal Commands are those commands all the commands are loaded into ram when the system is on. These commands are not resided on disk. These Internal Commands are written in COMMAND.COM. Different Internal Commands are
External Commands are those commands all the commands are resided on disk. These commands are .com, .exe, .bat both internal and external commands run from ms-dos prompt. Different types of external commands are