Microsoft Releases the Windows Operating System

With the release of Windows, a multitasking graphical user interface operating system, Microsoft began its move toward becoming the largest and most important software company in history.

Summary of Event

The story of Microsoft’s Windows operating system begins with two young computer “geeks,” Bill Gates and Paul Allen, who were childhood friends. While still students at the Lakeside School in Seattle, Washington, Gates and Allen worked for various computer companies. Gates focused on developing programs for practical uses; consequently, he and Allen built a computer that could analyze traffic patterns on Seattle streets. In 1972, they formed a company named Traf-O-Data that earned $20,000 during the 1972-1973 school year. Microsoft Corporation;Windows operating system
Windows (Microsoft)
Computers;operating systems
[kw]Microsoft Releases the Windows Operating System (Nov. 20, 1985)
[kw]Windows Operating System, Microsoft Releases the (Nov. 20, 1985)
[kw]Operating System, Microsoft Releases the Windows (Nov. 20, 1985)
[kw]System, Microsoft Releases the Windows Operating (Nov. 20, 1985)
Microsoft Corporation;Windows operating system
Windows (Microsoft)
Computers;operating systems
[g]North America;Nov. 20, 1985: Microsoft Releases the Windows Operating System[05860]
[g]United States;Nov. 20, 1985: Microsoft Releases the Windows Operating System[05860]
[c]Computers and computer science;Nov. 20, 1985: Microsoft Releases the Windows Operating System[05860]
[c]Inventions;Nov. 20, 1985: Microsoft Releases the Windows Operating System[05860]
[c]Business and labor;Nov. 20, 1985: Microsoft Releases the Windows Operating System[05860]
[c]Science and technology;Nov. 20, 1985: Microsoft Releases the Windows Operating System[05860]
Gates, Bill
Allen, Paul

A major step toward the creation of Windows came when Gates read an article in the December, 1974, issue of Popular Electronics magazine titled “Build the Altair Computer Yourself.” The existence of this inexpensive microcomputer, offered in kit form by MITS (Micro Instrumentation and Telemetry Systems), Micro Instrumentation and Telemetry Systems confirmed Gates’s belief that an inexpensive personal computer could become a reality. The problem with the Altair computer Altair was that few individuals could use it; Gates saw that the machine needed a language that would make it accessible to the general public. Gates and Allen stepped in and wrote a version of the BASIC computer BASIC (computer language) programming language that would work on the Altair.

For the purpose of working with MITS, Gates and Allen formed a business partnership named Micro-Soft in July, 1975; the company later modified the form of the name, becoming Microsoft. Gates and Allen’s goal was to develop languages for the Altair and other microcomputers, and Microsoft was the first company established to produce software for microcomputers. In the contract with MITS, Microsoft retained ownership of the language it developed for MITS. Gates promoted versions of BASIC to other companies, and orders came in from General Electric, NCR, and Citibank. Gates and Allen hired employees, and in December, 1975, Gates dropped out of Harvard to devote himself exclusively to Microsoft.

As the market for microcomputers continued to develop, as evidenced by the success of Apple, Tandy, and Commodore, executives at IBM IBM (International Business Machines) decided to study the possibility of entering the personal computer Personal computers (PC) market. The group charged with the research, which was named “Project Chess,” soon found Microsoft and Microsoft BASIC, which had become the standard in microcomputer languages. In July, 1980, IBM representatives met with Gates, Allen, and Steve Ballmer, asked many questions, and left. The next month, IBM asked Microsoft if the company could provide a BASIC program for the PC that IBM was designing by April, 1981.

In September, IBM executive Jack Sams Sams, Jack asked Microsoft to provide additional languages for IBM’s new PC: FORTRAN, Pascal, and COBOL. To do this, Microsoft needed to find an operating system. Currently the company was using the CP/M system, developed by Digital Research; however, Digital was not eager to become involved with IBM. Gates and Allen found an alternative named QDOS (for Quick and Dirty Operating System), built by Seattle Computer Products. Microsoft bought the software, paying less than $100,000 for the right to sell QDOS, renamed it MS-DOS, and relicensed it to IBM, which called it PC-DOS. Microsoft and IBM signed a contract on November 6, 1980, stating that Microsoft would provide a specified number of software programs for the “Chess” machine. Deadlines were set; however, as Gates later recalled, they were already three months behind.

Microsoft chairman Bill Gates sits on stage during an event to launch Windows 95.

(AP/Wide World Photos)

Gates also was concerned with making personal computers more “user-friendly.” IBM’s competition, Apple Computer, Apple Computer;Macintosh used an operating system that featured pictures rather than letters. PC users had to type specific letters, numbers, and punctuation marks to tell the computer what to do; users of Apple’s Macintosh computer, in contrast, used a mouse or keyboard strokes to click on pictures to give the computer commands; this graphical user interface Graphical user interface was widely successful. To aid PC users, so they would not have to work directly with DOS, which was too complicated for the average user, Gates envisioned placing a layer between MS-DOS and the user. This “interface manager” would impose a graphical interface on top of the operating system and bring uniformity to all software applications that ran under it.

Microsoft began its Interface Manager project in September, 1981. Early versions had the Manager using an alphabetical list of commands at the bottom of the screen; in 1982, this was changed to pull-down menus and dialogue boxes similar to those on the Macintosh. The Interface Manager would also display several documents simultaneously in separate “windows” on the screen. By January, 1983, Microsoft added a mouse to enable users to move windows and select options from menus. At the suggestion of Microsoft communication director Rowland Hanson, Hanson, Rowland the product received a new name: Windows.

Other companies were also rushing to produce products with a windowing environment. When VisiCorp announced it would be shipping its windowing environment software to customers and Quarterdeck, a new software publisher, announced its windowing product, Gates decided to announce Windows to the press. On November 10, 1983, at the COMDEX computer dealers’ trade show in New York City, he announced Microsoft’s development of Windows, “a graphical user interface to cover DOS,” and stated that by the end of 1984, Windows would be operational on more than 90 percent of all MS-DOS computers. However, the complexity of the project had been underestimated. In October, 1984, Microsoft announced a new release date for Windows of June, 1985.

Windows became Microsoft’s most important project, with more than twenty programmers working on it day and night. The long delay in its release led many to assert that Windows was mere “vaporware”—software that is promoted or advertised before it is commercially available, often to forestall potential customers’ adoption of competing software already on the market. Finally, after 110,000 programming hours, Windows 1.01 was released on November 20, 1985.


It was always important to Bill Gates that computers be accessible to the “everyday” user, not restricted to experts or used solely by business. To that effect Microsoft created Windows. Windows 1.0, which was a graphical extension of MS-DOS, fell somewhat short of expectations, and Windows 2.0 was functional but certainly not revolutionary. Windows 3.0 (released in 1990), however, went far beyond the Macintosh in multitasking and, thanks to a burgeoning PC market, Microsoft sold approximately ten million copies in less than two years. The Windows 3.0 profits allowed Microsoft to release Windows 3.1 and then Windows for Workgroups, geared toward corporations and the predecessor to Windows NT.

Windows NT (New Technology), released in 1993, was a completely different product line with the look and feel of Windows 3.1 on the surface, but the underlying code and the resources needed to run the operating system were far beyond those of the typical home PC. NT 3.1 was also the first version of Windows to be a true 32-bit environment. Windows NT and Windows became completely different product lines as NT took on Novell and UNIX for the server market and Windows continued to dominate the home PC market. Following the split, NT went on to have four major releases, with NT 3.51 and 4.0, Windows 2000, and Windows 2003; all were immensely successful. Windows had three major releases with Windows 95, Windows 98, and Windows ME (Millennium Edition).

Windows 95 was the release that made Microsoft a corporate giant, selling over a million copies in the first four days after its release. It was largely built on a 32-bit platform, rather than the 16-bit MS-DOS platform, allowing for better, faster, and more secure file and disk management. “Win95” also introduced the Start button and taskbar, which became fixtures in all subsequent Windows releases, including the NT and CE lines. The Windows 95 Plus! Pack, released a few months later, integrated the Internet Explorer browser into Windows as Microsoft set its sights on overtaking Netscape for Internet browser market share.

The Windows 98 and 98SE releases continued to distance the operating system from its MS-DOS roots and strengthened Microsoft’s online presence through tighter Internet integration. Windows 98, SE, and Plus! included the new Windows Messenger (instant messenger competitor to America Online, or AOL), an updated MSN (Microsoft Network, also a competitor to AOL for Internet access), Windows Media Player, and the new Internet Explorer 5.0 browser, which would soon vanquish Netscape.

Windows ME, released in 2000, was considered an upgrade to Windows 98. The release bridged Windows 98 and the forthcoming Windows XP. Stability issues and the lack of any new innovative features, however, led some critics to label ME “Mistake Edition.” The failure of ME to appease hungry consumers led many to move to Windows 2000 (NT 5.0), which was technically a commercial product but offered the stability and security that consumers were looking for.

The Windows and NT product lines merged with Windows XP, which was built on top of NT’s 32-bit architecture. XP was the longest-running Windows line, lasting from 2001 until the release of Windows Vista in January, 2007. A number of XP releases occurred during that period, including XP’s 64-bit operating system, something unheard of in the MS-DOS days.

Each new release of Windows made Microsoft stronger, and the company’s domination of software bled into hardware as new Windows releases subsequently needed more powerful and smarter hardware to run the software. All major releases of Windows had massive effects on the manufacturers of PCs and computer peripherals.

Gates was off by a few years when he stated that Windows would be operational on more than 90 percent of all MS-DOS computers by late 1984, but Windows eventually operated more than 95 percent of all computers in the world. Windows grew to power not only the majority of desktop computers, but also a sizable number of servers and a large and growing segment of consumer electronics. MS-DOS was retired in 2000 with the release of Windows XP and became a distant memory with the release of Windows Vista in 2007. Microsoft Corporation;Windows operating system
Windows (Microsoft)
Computers;operating systems

Further Reading

  • Andrews, Paul. How the Web Was Won: Microsoft from Windows to the Web. New York: Broadway Books, 1999. Discussion of Microsoft focuses primarily on the years 1990-1999 and the company’s developing Internet presence.
  • Donston, Deb. “Twenty Years of Windows: How One Operating System Came to Dominate Computing—and What’s Next.” eWEEK, November 14, 2005, 43-52. Selected analysts discuss the impact of Windows over the twenty years following the first version’s introduction.
  • Tsang, Cheryl D. Microsoft First Generation: The Success Secrets of the Visionaries Who Launched a Technology Empire. New York: John Wiley & Sons, 2000. Focuses on the people who worked with Gates and how they contributed to the company.
  • Wallace, James, and Jim Erickson. Hard Drive: Bill Gates and the Making of the Microsoft Empire. New York: John Wiley & Sons, 1992. Provides background on the development of Windows, the personnel involved, and the problems incurred.

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