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Project Chess: The Story Behind the Original IBM PC

Anyone who uses a desktop or laptop computer owes it all to the first IBM PC, which set a standard for the industry 40 years ago. This is its story.

Michael J. Miller
By Michael J. Miller 

On August 12, 1981, IBM introduced the IBM Personal Computer. This wasn't the first PC, but it did create the standards that in many ways have dominated personal computing for most of the past 40 years, including an open architecture, an Intel architecture processor, and a Microsoft operating system.

Perhaps the most important decision IBM made about the PC was not producing it within its existing infrastructure but instead leaving it to a relatively small group of mavericks in Boca Raton, Florida.

That project started as the outgrowth of a presentation that William C. "Bill" Lowe, laboratory director of IBM's Entry Level Systems (ELS) unit in Boca Raton, made before IBM's Corporate Management Committee, including IBM President John Opel and Chairman Frank Cary, in July 1980. By this point, there were a number of popular personal computers on the market, including the Apple II and a raft of machines running the CP/M operating system.

Portrait of William Lowe, from IBM/InfoCast, at the annual PC Forum, Naples, Florida, February 21-24, 1988. (Photo by Ann E. Yow-Dyson/Getty Images)
William Lowe in 1988

Cary had apparently liked the idea of a personal computer for years, but IBM's famous bureaucracy couldn't be convinced. Instead, it created products that were too big, too expensive, and too corporate-focused to reach a mass market, like the Datamaster and the IBM 5100.

But Lowe convinced the committee that a small group focused on putting together pieces from the outside industry, rather than creating something new within IBM, could indeed create a new computer within a year. He got permission and recruited a group of 12 engineers as part of what would become known as "Project Chess."

In the next month, Lowe's task force had several meetings with other players in the young industry and made a number of key decisions. One was to sell IBM's personal computer through ComputerLand and Sears, Roebuck retail stores in addition to offering it through IBM's own commissioned sales staff.

Jack Sams, who would head software development, was contacting software companies, including Microsoft. The group chose to use an "open architecture," licensing the central processing unit (CPU) and most of the other hardware components from outside IBM.

The team apparently was pulled together very quickly, and on August 8, 1980, Lowe and two engineers, Bill Syndes and Lew Eggebrecht, demonstrated a prototype to the Corporate Management Committee. It approved the basic plan and gave Project Chess the go-ahead to create a personal computer, code-named Acorn.

According to the 1993 book Gates,Gates, by Stephen Manes and Paul Andrews, the plan for the prototype had 32K of read-only storage (ROS, which everyone else calls ROM), 16K of RAM, a six-slot open bus, and a variety of options, including RAM expandability up to 256K, a printer adapter, the choice of a color or monochrome display, 8-inch disk drives, an optional floating point processor, and an auxiliary user interface (joystick). The 8-inch drives would be replaced by 5-¼-inch drives, and six slots would go down to five. Otherwise, the specs were nearly identical to what the final machine would offer.

Lowe, who would shortly leave Entry Systems Division to run IBM's larger facility in Rochester, Minnesota, picked Philip D. "Don" Estridge, another longtime IBM employee who worked at the Boca Raton labs, to run the project. Estridge would go on to be called the "father of the PC."

Estridge recruited a team that included Syndes, who headed engineering; Dan Wilkie, who was in charge of manufacturing; and H.L. "Sparky" Sparks, who headed sales and marketing. The next few months saw a whirlwind of activity, including signing Microsoft to provide the languages and the operating system (more about that shortly).

By the end of 1980, the team had 150 employees, and by January 1981, the machine was first demonstrated within the company. Later versions were distributed to other software companies, allowing for the creation of such initial packages as the VisiCalc spreadsheet, a series of accounting programs from Peachtree Software, and a word processor called EasyWriter from Information Unlimited Software (IUS).

On August 12, 1981, almost exactly a year after Project Chess was given the go-ahead, IBM introduced the IBM Personal Computer 5150—which was almost immediately dubbed the IBM PC—at multiple press conferences, from New York to Chicago, where I saw it.

That original IBM PC had some great features and some clear limitations. It had a 4.77MHz Intel 8088 processor, trumpeted as a "high-speed 16-bit microprocessor," but the PC had only an 8-bit data bus. Initially, the machine came with 16K RAM on the motherboard standard, expandable to 64K, but its processor was capable of more, because its 20 address bits permitted the PC to address 1 megabyte of physical memory, which was a huge leap forward at that time. While the PC could display graphics, you had to buy an optional graphics card to do this, because the base machine had only a monochrome adapter. Of course, the advertised price didn't include a monitor or even a serial or parallel port.

Sold at ComputerLand outlets and Sears Business Centers, the initial PC had a base price of $1,565, including an 8088 CPU, 16K of RAM, and no floppy disk or monitor, but the ability to plug in your home TV and a cassette recorder. I'm not sure anyone ever bought one in that configuration. More typically, a system with 64K of RAM, and a single-sided, 160K floppy disk drive had a list price of $2,880.

Limitations aside, by the time it arrived on store shelves that October, the IBM PC was an immediate hit. It was helped by a brilliant marketing campaign featuring the Little Tramp, the character Charlie Chaplin popularized in movies such as Modern Times.

The company originally estimated it would sell 250,000 units over a five-year period, but some members of the development team have reported that the company built and delivered that many systems in certain months.

After the success of the IBM PC, IBM eventually moved to bring the PC division back into the IBM fold. Estridge was placed into a corporate vice president role within IBM. Lowe, who left the PC project soon after its founding, returned to head the Entry Systems Division. Estridge died in a plane crash in August 1985. By that point, the PC architecture created by the Boca Raton team had already become the industry standard, resulting in thousands of applications, a huge variety of add-in boards, and PC-compatible machines from dozens of vendors.

For more information, check the best books on the early history:

For more, check out PCMag's full coverage of the 40th anniversary of the IBM PC:

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