John Ellenby, a British-born computer engineer who played a critical role in paving the way for the laptop computer, died  in San Francisco. He was 75. Mr. Ellenby’s pioneering work came to fruition in the early 1980s, after he founded Grid Systems, a company in Mountain View, Calif. As chief executive, he assembled an engineering and design team that included the noted British-born industrial designer William Moggridge.

• The team produced a clamshell computer with an orange electroluminescent flat-panel display that was introduced as the Compass. It went to market in 1982. The Compass is now widely acknowledged to have been far ahead of its time.

• “The Grid Compass was the first successful clamshell laptop computer,” said Marc Weber, a historian at the Computer History Museum in Mountain View.It went on to become a valuable tool for big corporations, government spies, White House and Pentagon officials, and even astronauts, surviving the midair explosion of the space shuttle Challenger in which seven people died.

• The Compass came with advanced, and expensive, data storage capacity called bubble memory and was accordingly pricey, originally selling for $8,150 ($20,325 today). As a result, it found an enthusiastic market not with consumers but rather in Washington.

• John Ellenby was born in Corbridge, in northern England, on Jan. 9, 1941, to Conrad Ellenby, a zoologist, and the former Mary McCarraher, a biologist. He studied economics and geography at University College London and spent a year in the early 1960s studying at the London School of Economics, where he encountered mainframe computers.