Apple co-founder Steve Wozniak shared memories about memory on Thursday at the Flash Memory Summit in Santa Clara, California.

"The biggest decision I made in most of the projects of my life was what memory to use that's the exact right, smallest, simplest, and more importantly, the cheapest there is," Wozniak told the audience in a packed auditorium.

Even the first major commercial product he designed with co-founder Steve Jobs, the Apple II, was defined largely by memory. Facing the problem of how to refresh the characters on the screen fast enough to keep up with a microprocessor that could do a million operations per second, he came up with the idea of devoting some of the computer's dynamic memory to the display, he said.

"I let the memory that was available, the price of the memory, the efficiency of the design, which components I chose, define how fast that computer could work," Wozniak said.

He also used memory to introduce colour to the display, remembering lessons from high-school electronics class about colour TVs. Spinning four bits of memory at the right rate could produce 16 colours, he realised. That idea came to him one night as he sat at a lab table next to Jobs, who was wire-wrapping one of Wozniak's hardware designs.

Wozniak has always been known as the more geeky of the Apple co-founders, and on Thursday he recalled the contrasts between them all the way from the time they met in high school. The partnership worked out well, especially when they knew how to build their computer but couldn't afford the best memory chips, which came from Intel, Wozniak said. Jobs talked to someone he knew at Intel and got them for free. "I had always been too shy, too embarrassed, to ask for things for free," Wozniak said.

The two Steves also have different senses of humour, Wozniak said. He remembered being excited to meet Jobs, after a high-school friend had said they might get along.

"I want to meet a guy that likes electronics and likes fun, all the time," Wozniak said. "Um, he doesn't like fun that much ... I think, how many times would I see Steve Jobs just rail out in laughter like you would at good comedy, and it's pretty seldom. We did a lot of pranks together. But he wasn't really a laugher at the pranks, he more wanted to find a way to turn it into money," he said.

Wozniak has not done too badly with money himself. He's now chief scientist and a board member at Fusion-io, which makes flash storage cards that plug in to PCI Express slots in servers. The company has raised more than $100 million in funding and on Wednesday announced a deal to have its products integrated into Dell servers.

The famous technology iconoclast said Fusion-io got where it is by ignoring what everyone else in the burgeoning enterprise flash business was doing. While they flocked to SSDs (solid-state disks), which fit flash chips into a hard-disk enclosure, Fusion-io thought they had something better, he said.

"When you're in school, you're always taught that the right answer is the same answer everyone else has," Wozniak said. It's a lesson he's learned several times in years of engineering. "Clear out your mind of the way the world is today," he said.