A history of ARM, part 1: Building the first chip

The world was on top of Acorn Computers. There was going to be trouble soon.

The small UK company won a contract to make a computer for a national television show. The company was on pace to sell more than one million units.

The world of computers was evolving. The market for cheap 8-bit micros was getting saturated. The IBM PC and the upcoming Apple Macintosh promised more power and ease of use. The company didn't have a lot of money for research and development.

A seed of an idea

One of the designers of the micro was aware of the problem. She added a slot called the "Tube" that could be used to connect to the central processing unit. The computer's original 6502 chip could be used for other tasks if aCPU took over.

She should choose what processor she uses. Wilson and co-designer Steve Furber looked at various 16-bit options. None were very good.

Wilson told the Computing History Museum that they could see what all the processors did and didn't do. They did not use the memory system well. They weren't easy to use, and they weren't fast. We wanted to get to a power level where we could achieve the same results if we wrote in a higher level language.

What was the other option? Was it possible for a small computer to make its own processor? Wilson and Furber went to Israel to find out what happened. A lot of expensive equipment was seen by them. They suspected that such a task was beyond them.

They went to the Western Design Center. The company was making a successor to the 6502 called the 65C618. A few engineers and some students made diagrams using old Apple II computers and bits of sticky tape while Wilson and Furber were there.

It seemed like it could be done. The graphics and input/output chips were built by Wilson and Furber. The designs were simpler and had less parts.

Upper management atAcorn supported their efforts despite the challenges. They went much further than that. The team received copies of IBM research papers about a new and more powerful type of processor from the co- founder. "Reduced instruction set computing" was the name of it.