Developed by: IBM y Microsoft
Launched: 1981

The disk operating system for IBM PCs, which IBM commissioned from Microsoft.
Since Microsoft didn't have such a system, it bought QDOS from Tim Paterson for a ridiculously low price, and with its sales, it became a giant in the industry.

PC DOS versions

Year	Ver.
1981	1.0
1982	1.1It allowed data to be written on both sides of a floppy disk, thus doubling the capacity of the IBM machine.
1983	2.0Created for the IBM PC/XT, the first PC to store data on a hard drive.
1984	2.1Created for the launch of the IBM PCjr.
1984	3.0Created for the IBM PC/AT, a computer with Intel's 80286 processor.
1988	4.0A version for i386 that would be the embryo of OS/2.
1991	5
1993	6.1
1995	7.0
1998	2000Version 7.0 revised to support Y2K.
2003	7.1Support for FAT32.