ms-dos operating system

-         Stands for Microsoft Disk Operating System.

-         It is a Command Line operating system, which was sometimes most common of all Personal Computer operating systems.

-         Developed by Microsoft in 1970s, it was widely used in commercial computers throughout 1980s.

-         Its main competitor, CP/M (Control Program for Microprocessors) was faded out due to IBM choosing MS-DOS for the IBM PCs.

-         Main advantages:

o    Reliability:         On properly configured systems, DOS ran well.

o    Stability:           Crashes and lockups were very rare.

-         Users needed to learn the commands needed to run DOS and once learnt, the commands were used most frequently.

-         Various limitations of DOS were figured out in late 1980s, as IBM PCs became more powerful.

-         Some of them are:

o    Only a single program could be loaded into main memory at a time, reducing the productivity that could be achieved.

o    It supports only a single user with only one processor.

o    Its blank looking screen interface made user interaction difficult.

o    DOS could only recognize 640 KB of RAM.

o    It was designed for 8-bit OR 16-bit computers, thus couldn’t take advantage of faster 32-bit computer architecture.

o    Filenames are limited to eight characters followed by three characters extension separated by a period (ex: wordfile.doc).

-         Microsoft followed its command line operating system with graphical based Windows in mid ‘80s.

-         Microsoft has MS-DOS running on top of later versions of Windows, which in fact is not a stand alone operating system.

-         It just runs as a utility.