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Philip Donald Estridge

June 23, 1937 Jacksonville, Florida USA
August 2, 1985 Dallas, Texas USA

Donald Estridge (courtesy Carol Lambert)

Philip Don Estridge's official portrait IBM



PC; computer; IBM


Developed the IBM PC with a team of 12 other engineers (a/o.: Dr. Glenn S. Dardick)


The personal computer enjoys the ubiquity it does because of one man: Philip "Don" Estridge. An IBM employee since 1959, Estridge headed up the skunk works in Boca Raton, Fl., that in 1981 launched the IBM PC. Estridge made the decision—revolutionary for that time and place—that the machine would be made from off-the-shelf, easily obtainable parts and that the design specification would be made public. Estridge and his wife Mary Ann died in the Aug. 2, 1985, in the crash of a Delta Airlines L-1011, which was hit by wind shear while landing at Dallas-Fort Worth Airport.

Estridge's longtime friend, neighbor and coworker Jan Winston, now retired but still consulting with IBM, talked to CIO about the colleague he still misses.

Don and I lived next door to each other in Boca Raton. It was a sleepy town in those days, not sophisticated like it is today. Then, it was only old people and IBM employees. You could stand outside watching the kids play and have a departmental meeting. Our families were very close well before the PC project started; he and I had worked together on the Series 1 project, IBM's first minicomputer. Because we had different responsibilities, we were often in contention on that project, but there was no stress in our friendship.
Don was very humane, with a wonderful sense of humor and a charming personality. He combined a manic drive with tremendous respect for his people, recognizing all that they were sacrificing during the PC project. When the PC took off, it was like a rocket ride, and he did a wonderful job of exerting executive leadership. And he was a technically competent visionary. Don had a very broad view of where computer business was going technically as well as the importance of computers to the economy and to society as a whole.
Would the world today surprise him? Its magnitude would. Our first sales projections estimated selling 250,000 units over three years. The executives wondered what we were smoking because the best-selling IBM computer had sold only 25,000 over three to five years. We always said to ourselves that the technology would grow by leaps and bounds because of applications like VisiCalc. We knew there was going to be e-mail too. But the broad acceptance of the computer, the way it embedded itself in our everyday lives and the explosion of the Internet, is an order of magnitude beyond what we were thinking about in the early '80s(1)




June 23, Born in Jacksonville, Florida USA. His father was a professional photographer.


Attended St. Paul's School from Kindergarten through eight grade; Jacksonville, Florida, USA(12)


Graduated from Kenny High school Jacksonville, Florida, USA(12)


May Ann Estridge
courtesy Carol Lambert
Married to Mary Ann Hellier on September 13th, from this marriage three children were born: Patricia Ann, Mary Evelyn and Sandra Marie.(12)


Completed a BS in electrical engineering at the University of Florida
Estridge joined IBM as a junior engineer in Kingston New York and held positions in the Federal Systems Division, participating in the construction of SAGE(11)


Moved to Washington.
Working on the manned and unmanned programming support for NASA /Goddard Space Flight Center


Estridge moved to Boca Raton, Florida, USA. Joined the General Systems Division and from 1975 - 1979 he was series/1- a mini computer - programming manager


Had responsibility for the development of a Series/1 integrated product until 1980


Becomes manager of Entry Level Systems - Small system in Boca Raton, Florida USA. Responsible for the development of small microprocessor-based systems for 'tiny' business and personal use.

At the end of 1980, IBM decided to truly compete in the rapidly growing low-cost personal computer market. The company established what was then called the Entry Systems Division, located in Boca Raton, Florida, to develop the new system. This small group consisted of 12 engineers and designers under the direction of Don Estridge; the team's chief designer was Lewis Eggebrecht. The division developed IBM's first real PC. (IBM considered the 5100 system, developed in 1975, to be an intelligent programmable terminal rather than a genuine computer, even though it truly was a computer.). Nearly all these engineers had been moved to the new division from the System/23 DataMaster project, which in 1980 introduced a small office computer system that was the closest predecessor to the IBM PC. (3)



January - Estridge's organization has grown from 12 to 135 people

July - Appointed director Entry Systems Business in July and responsible for the IBM Personal Computer

It struck me that what the company really needs today is a good skunk works. IBM's Don Estridge started one in 1981 in Boca Raton, Fl., in an old, leaky-roofed warehouse with malfunctioning air-conditioning. Eighteen months later, the PC was ready for the market. (4)
To invent the IBM PC, IBM created three secret research teams who competed against each other. The winner was the research team headed by Philip "Don" Estridge in Boca Raton, Florida. His team examined everything created by the other microcomputer companies (Apple, Radio Shack, Commodore, etc.) and combined their best ideas, to produce a relatively low-cost computer.

Don's team developed the IBM PC secretly. IBM didn't announce it to the public until August 12, 1981.(2)

"What we discovered was that the way people responded emotionally to PC's was more important than what the computer actually did." -Don Estridge.

Because IBM introduced the PC it gave this machine respectability ("stamp of approval"). Thus making it possible to market the machine also to small businesses.


January - Appointed division director Entry Systems Business Unit

March - System Products Division vice president and general manager Entry Systems.


August - President of the newly formed Entry Systems Division

Apple Computer's Steve Jobs offers IBM's Don Estridge the position of president of Apple Computer, for US$1 million per year, US$1 million signing bonus, and US$2 million to buy a house. Don Estridge turns it down. (13)


January - IBM vice president

August - Estridge's organization has now 9.500 people on its pay roll

Nearly a million PC 's have been sold


March - IBM vice president, manufacturing

August 2, died in a plane crash near Dallas, Texas USA together with his wife Mary Ann.(13)

Don Estridge died in a plane crash on August 2, 1985 The Delta Airlines L-1011 (Lockheed 1101 "Tristar") in which he traveled crashed because of a "wind shear", according to official reports.(14,15) Others say because of a crashed computer system at flight control.

By all rights, the first IBM personal computer fair, held in San Francisco over the weekend of Aug. 26-28, ought to have been a wildly joyful celebration honoring Philip D. Estridge, president of IBM's Entry Systems Division. Estridge, after all, is the man who brought to market the IBM PC, a product that has shattered all sales records(10)and won over the marketplace as no other computer ever has. Yet, listen to Don Estridge, as he addressed a session of software designers and hardware vendors about the PC:

"There's a question that keeps coming up, like waves on the beach: 'What do I use one for?'"(6)


Honors and Awards





IBM archives, Carol Lambert





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