The cause was a heart attack, his daughter, Michelle Marshall, said.

Apple and other companies had been selling personal computers for several years when IBM began looking for ways to get involved in the business in the late 1970s. The company had long dominated corporate and government mainframe computing by using proprietary software and in-house production. But it was hardly nimble, and its leaders believed it would be left behind if it took its typical years to reach production.

In 1980, Mr. Lowe, who had joined the company as a product test engineer in 1962, right after college, pitched an improbable idea: He would form a team that would build a personal computer in a year. How? The team would bypass IBM's proprietary development model and instead use parts and software made by a growing industry of outsiders. Even IBM seemed surprised when, a year later, the company pulled it off.

On Aug. 12, 1981, the company introduced the IBM Personal Computer, also known as the 5150. It used an operating system called MS-DOS 1.0, made by a little-known company from Washington State named Microsoft. It ran on an Intel 8088 microprocessor and cost $1,565, not including a monitor.

"Two decades earlier, an IBM computer often cost as much as $9 million and required an air-conditioned quarter-acre of space and a staff of 60 people to keep it fully loaded with instructions," according to a history on the company's website. "The new IBM PC could not only process information faster than those earlier machines, but it could hook up to the home TV set, play games, process text and harbor more words than a fat cookbook."

IBM's entry into personal computing, however belated, was a huge success.

The company had never before had a presence in retail stores. Now customers could buy an IBM computer at Sears — presuming Sears was not sold out. Microsoft, Intel and other companies whose products were used benefited tremendously, beginning their transformation from obscure tech companies into household brands.

Collaboration became common in the computer industry. Four years after introducing the IBM Personal Computer, IBM and Microsoft agreed to develop software jointly that would not be exclusive to IBM machines.

"We are committed to the open architecture concept, and we recognize the importance of an open architecture to our customers," Mr. Lowe said of the collaboration in 1985.

But the commitment to open architecture and off-the-shelf parts had another consequence. Other manufacturers, like Compaq and Dell, began building "IBM compatible" machines, also called clones, that were often better and cheaper. They took on the same colloquial name given to the 5150: PC.

Mr. Lowe became a lightning rod for criticism as IBM tried to fend off scores of competitors and develop new hardware and software. For a while, he provided backing to Steven P. Jobs, who was developing his NeXT computer platform after leaving Apple in 1985.

But in 1988, three years after Mr. Lowe became president of the company's Entry Systems Division and two years after he became a corporate vice president, he left IBM, taking a job at Xerox to help it expand its manufacturing lines beyond basic copy machines.

"My being here isn't so much a reflection on IBM," Mr. Lowe said from his new offices at Xerox. "I feel I still had runway there, but this seemed like such a great opportunity."

In 1991, he became president of the Gulfstream Aerospace Corporation, the maker of corporate jets, and he later held executive positions at New England Business Services and the Moore Corporation, another business services company.

William Cleland Lowe was born on Jan. 15, 1941, in Easton, Pa. He attended Lafayette College in Easton on a basketball scholarship and graduated with a degree in physics. He was the first in his family to graduate from college.

In addition to Ms. Marshall, his survivors include his wife, Cristina; four other children, Gabriela, Daniel, Julie Kremer and James; and 10 grandchildren.