IBM PC DOS

IBM PC DOS, short for IBM Personal Computer Disk Operating System, was special software that helped run early IBM computers and similar machines. It started in the early 1980s and was sold by IBM until the 2000s. This important system was created by Microsoft, which also sold its own version called MS-DOS to everyone. For many years, both versions worked almost the same. It wasn’t until 1993 that IBM added new features to its version, PC DOS 6.1. People often just called both types of software “DOS.”

History

The IBM team creating the IBM PC decided to get important parts, like the operating system, from outside companies. This was a big change from IBM’s usual way and helped make the IBM PC very popular. Microsoft, started five years earlier by Bill Gates, was chosen to make the operating system.

IBM wanted Microsoft to keep ownership of the software they made. IBM first talked to Microsoft in July 1980, and the official agreement was signed in November.

Even though IBM thought most people would use PC DOS, the IBM PC could also run CP/M-86 and UCSD p-System operating systems. But most people chose PC DOS.

Over time, both IBM and Microsoft made different versions of IBM PC DOS. By the time PC DOS 3.0 was finished, each company had its own team working on the operating system. In 1984, IBM shared the full details of IBM TopView with Microsoft to help them build features for Windows 2.0.

Version	Release date
1.0	August 12, 1981
1.1 (1.10)	May 7, 1982
2.0	March 8, 1983
2.1 (2.10)	November 1, 1983
3.0	September 14, 1984
3.1 (3.10)	April 2, 1985
3.2 (3.20)	April 2, 1986
3.3 (3.30)	April 2, 1987
4.0	July 19, 1988
5.0	June 11, 1991
6.1	July 26, 1993
6.3	April 27, 1994
7.0	February 28, 1995
2000	May 29, 1998

Versions

PC DOS 1.x

Microsoft changed its name to IBM PC DOS 1.0 when it came out with the IBM PC in August 1981. This first version was mostly based on an older system called CP/M-80. It worked with small disks called floppy disks and had some basic commands.

PC DOS 2.x

A new version, DOS 2.0, came out in March 1983. It added support for harder storage devices and more advanced features. This version became the base for many future operating systems.

PC DOS 3.x

When IBM made a new kind of computer in 1984, they released DOS 3.00 with it. This version added support for bigger floppy disks. Later updates fixed problems and added more features for new IBM computers.

User manual and diskette for IBM PC DOS 1.1

PC DOS 4.x

DOS 4.0 came out in July 1988. It had some new tools to make using the computer easier but also had a few problems with memory use and compatibility.

PC DOS 5

In June 1991, DOS 5 was released. It used memory more efficiently and added helpful options to commands. This was the last version that IBM and Microsoft worked on together.

PC DOS 6.1

In June 1993, IBM made its own version called PC DOS 6.1. It included new features and tools, such as better boot options and new commands.

PC DOS 6.3

Retail box of IBM PC DOS 3.30

PC DOS 6.3 came out in December and added technology to make disks smaller but hold more information.

PC DOS 7

The last version IBM made mainly for normal users was PC DOS 7, released in April 1995. It added new programming features and tools to make the computer faster.

PC DOS 2000

The newest version sold by IBM was PC DOS 2000, released in 1998. It fixed some problems and was used in special software for testing hardware.

PC DOS 7.1

PC DOS 7.1 added support for bigger disk formats and was used in some special tools and products, though it was not sold to normal users.

PC DOS as a distributed file client

In 1986, IBM announced that PC DOS could work with special systems. This helped PC programs use files stored on bigger IBM computers. By 1988, PC DOS improved, allowing programs to handle different kinds of files and folders on these big computers.