Wozniak woz here

Steve Wozniak switched on his computer for the first time on Sunday, 29 June 1975.

“I didn’t realise it at the time but that day…was pivotal,” he recalls in a passage quoted on the cover of his autobiography.

“It was the first time in history that anyone had typed a character on a keyboard and seen it show up on screen right in front of them.”

This is a curious piece of hyperbole because people had typed straight onto screens before this – yet the moment was indeed pivotal. The machine that Wozniak had designed and built at the age of 24 came to be known as the Apple I and he had kickstarted the age of the personal computer.

Listen to our interview with Steve Wozniak

Computer terminals had previously timeshared mainframes using keyboards and monitors, but these were very expensive systems. Hobbyist machines such as the Altair were causing excitement among people like the young Bill Gates, but they lacked a monitor and keyboard.

“Every single computer [of this type] before the Apple I had what was called a front panel, with lots of switches, lights that flickered and push buttons. Every one since the Apple I has gone out with a keyboard,” Wozniak said in London, where he was promoting his book iWoz (£20, Headline Review).

The Apple I had no monitor because Wozniak built a gizmo that allowed it to use a TV – another first. It all amounted to the first practical, affordable, general-purpose computer

Wozniak and his friend Steve Jobs are the Lennon and McCartney of computing. Like the two Beatles, they came from the same city and formed a company called Apple (which caused no few legal hassles). And with both pairs, it is hard to imagine where one of the two would have got without the other.

Jobs went to the same school as Wozniak but is four years younger. They were drawn together by an interest in technology and a taste for pranks and japes. Wozniak delights in recalling some of these in iWoz but they must have irritated people. He recalls, for example, how he built a device to interfere with the college TV.

Wozniak was an electronics prodigy. He passed his ham radio exam at the age of 11 and was building logic circuits at 13. But he admits that by himself he would never have started Apple. “I would never have wanted to be near big-time things, big money. All I wanted to be was an engineer par excellence…

“Steve had the futuristic vision. We were best friends. He understood the technology well but nobody could design like I could. So he kept being a push for… doing things that changed the world.”

Both joined the famous Homebrew Computer Club, which became the incubator for the Apple computers. Jobs was soon selling the Apple I and encouraged Wozniak to design and build the Apple II, the machine that was to be the making of the company they founded 30 years ago on 1 April 1976.

It had colour, relatively high-resolution graphics, and it came with a Basic programming interpreter written by Wozniak, who is possibly the first and last person to design and build a general-purpose computer from scratch complete with the software for it.

“I don’t know how it happened,” he recalled of both the first two machines. “Every step I took, I had never taken before. I’d never done microprocessors. I’d never done video. I’d never done keyboards. I’d never done colour. All these great changes. Basically I knew how to combine chips very efficiently to do things that almost nobody else could do at an affordable price.”