The Legacy of MS-DOS [Editorial]
By on July 27th, 2011

MS-DOS, the humble little operating system that was instrumental in establishing Microsoft’s dominance over the PC industry, turns 30 today. On July 27, 1981, Microsoft bought the rights for QDOS (Quick and Dirty Operating System). QDOS went on to be rebranded as MS-DOS (Microsoft Disk Operating System), which then went on to dominate the market for nearly fifteen years.


Colored Beginning

MS-DOS helped Microsoft blossom into a software giant that became both feared and hated for its often aggressive and sometimes illegal tactics. However, even before Microsoft was a household name, and even before Microsoft was a monopoly, Microsoft was no stranger to sneaky and clever business strategies. In those days, CP/M (Control Program for Microcomputers) by Gary Kildall of Digital Research, Inc. was the dominant OS, and IBM initially wanted to use it on their forthcoming PCs. However, talks broke down due to Kildall’s refusal to sign a non-disclosure agreement (although more colorful versions of the story are often told in tech folklore).

The next company that IBM approached was Microsoft, which had little experience in developing operating systems. Microsoft decided to license QDOS written by Tim Paterson, a Seattle Computer Products employee. Sneakily enough, Microsoft initially hid its IBM deal from Seattle Computer and managed to acquire the rights for less than $100,000. QDOS, which is often alleged to be virtually identical to CP/M, would soon succeed in obliterating the latter. However, the smartest decision that Microsoft took was to convince IBM to allow it to hold on to the rights for marketing DOS. As a result, Microsoft would go on to earn hundreds of millions in revenues over the next several years.

Rapid Growth

MS-DOS 1.0: Released as PC-DOS with IBM PCs (source)

On August 12, 1981, IBM introduced its new personal computer, the IBM 5150 PC. It featured a 4.77-MHz Intel 8088 CPU, 64KB RAM, 40KB ROM, one 5.25-inch floppy drive, and PC-DOS 1.0 (Microsoft’s MS-DOS).

MS-DOS-AdvertisementNext year, Microsoft released MS-DOS 1.25, the first edition of its OS that ran on non-IBM machines. Throughout the 1980s Microsoft continued to iterate DOS, even though Windows, which featured a GUI (Graphical User Interface), was released in 1985. Initial versions of Windows were designed as add-ons that could be launched from DOS.

In 1983, MS-DOS 2.0 was released. It was virtually rewritten from scratch and added features like directories (a tree-structured file system) and support for 360 KB floppy disks. The following year saw the introduction of MS DOS 3.0 and MS DOS 3.1, which boasted of support for 1.2 MB floppy disks, bigger (than 10 MB) hard disks, and networking. 3.5-inch 720 KB floppy disk drive support arrived in 1986 with MS DOS 3.2.

MS-DOS 4.0 introduced in 1988 was a major step forward in many ways, but it also turned out to be bit of a disaster. It introduced DOS Shell, and support for a graphical interface. Unfortunately, it was also horrendously buggy.

Gradual Decline

Throughout the decade Microsoft faced competition from Digital Research’s DOS Plus, and later from DR-DOS. Microsoft also collaborated with IBM to develop OS/2, which was seen as a successor of DOS. However, emboldened by the increasing popularity of Windows, Microsoft decided to stop backing OS/2, and released Windows 3.0 in 1990. In the same year, Microsoft became the first software company to reach $1 billion in annual sales. Before that, in 1986, Microsoft took complete ownership of DOS from Seattle Computer Products through a legal settlement of $925,000.

In 1991, MS-DOS 5.0 was released along with the extremely popular QBASIC. MS-DOS 6.0 was released in March 1993, and was criticized due to its controversial DoubleSpace disk compression feature that was copied from Stacker. This feature was dropped next year in MS-DOS 6.21 due to a lawsuit from Stacker.

In 1994, Microsoft announced that it would stop selling DOS separately in preparation for the launch of Windows 95, which would become the first standalone Windows OS. Although Microsoft stopped selling DOS, it continued to live on as Command Prompt within Windows. With both Windows 95 and 98 it was even possible to invoke DOS mode without booting into Windows. MS-DOS 8, which was introduced in Windows ME, and continues to be shipped with Windows till date, was the final version of MS-DOS.


MS-DOS attained popularity because its relative ease of use, flexibility, and configurability. However, it also had its idiosyncrasies. Perhaps the most (in)famous aspect of DOS was the error prompt Abort, Retry, Fail?. As any DOS user would testify, this single error prompt could drive anyone to insanity. Not only did it appear with an annoyingly high frequency, but it was also frustratingly pointless. Retry often didn’t do anything productive, and abort was invariably the sole option left for the user. The Fail option, which was supposed to allow programs to recover from errors, failed with alarming regularity to yield the desired result.

MS-DOS-FailAbort, Retry, Fail?is one of the first pop-culture contributions from Microsoft, and in many ways the precursor to our love-hate relationship with the BSOD (Blue Screen of Death). However, that is not the only unfortunate resemblance between Microsoft of today and Microsoft of 1980s. Here’s a super weird MS-DOS 5 update promo video released by Microsoft. It’s painful to watch, but is still less disturbing than the Zune advertisement that Microsoft released a few years back.

Microsoft’s DOS wasn’t really Microsoft’s, and it will probably be overdramatic to claim that MS-DOS changed the PC industry forever. The fact is that if Microsoft hadn’t supplied MS-DOS to IBM, IBM probably would have found another similarly capable alternative. However, DOS did change the fortunes of Microsoft forever. By the mid 80s, more than 80% PCs were running MS-DOS due to its affordability, ubiquity, and superior hardware compatibility. The success of IBM PCs powered by MS-DOS also helped standardize the PC architecture. MS-DOS was the giant on whose shoulders Windows flourished. MS-DOS was the giant on whose shoulders Microsoft flourished.

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Author: Pallab De Google Profile for Pallab De
Pallab De is a blogger from India who has a soft spot for anything techie. He loves trying out new software and spends most of his day breaking and fixing his PC. Pallab loves participating in the social web; he has been active in technology forums since he was a teenager and is an active user of both twitter (@indyan) and facebook .

Pallab De has written and can be contacted at

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