At this stage Acorn did not exist as a company. Acorn was initially the
trading name of Hauser's company, Cambridge Processor Unit Ltd., Wilson
recalls. "Even before I graduated in 1978 I had an offer of employment,"
Wilson remembers it was for a salary of 1200 pounds a year. "It was a
bad salary even then," reminisces Wilson, but it allowed the pursuit of
an interest in digital design.
"The System 1 we had on Veroboard
and there was a racking system. We had a number of boards; a computer
board, a floppy disk controller board and so on. As Acorn System 1 went
through a number of iterations it built up a following in the industrial
sector, Wilson recalls; a first showing for some of the embedded
capabilities that ARM processors would later have.
It was at
about that time Chris Curry left Sinclair and came to work at Acorn
bringing Steve Furber with him although Furber was not yet an employee,
as he continued studying at the university for a PhD and only worked for
Acorn part time.
Meanwhile Hauser's hopes for Acorn continued to
grow. In 1980 the Acorn Atom home computer was available in either kit
of assembled form, again based on the 6502.
"The Acorn Atom was a
repackaging of the industrial subsystems we had developed," said
Wilson. "It included a BASIC interpreter that I had written, but it also
included some design faults. We needed to do a professional version of
the Atom. Andy Hopper [later Professor Andy Hopper of Olivetti Research
and Cambridge], wanted a workstation to run all the high-end languages
while Chris Curry wanted something just a little better [than Atom] that
would be commercial," recalls Wilson.
"I suggested a two-part design with an I/O processor and a language processor. Proton was the project name," said Wilson.
Proton project led to the now infamous pitch by Acorn in 1981 to build a
computer for the U.K.'s national television service, the BBC. The BBC
wanted to commission an affordable home and schools computer on which
they could demonstrate programming and computer science in a series of
Hauser phoned up Wilson one Sunday in 1981 and asked
if it would be possible to turn the Proton plans into a working
prototype by the following Friday for a visit by the BBC. For once
Wilson told Hauser "no!"
Wilson recalls that Hauser said:
"That's a pity," but seemed to accept the answer. Hauser then phoned up
Furber asking the same question but adding that Wilson had indicated it
might be possible. Furber's initial reaction had been the same as
Wilson's but he agreed that if Wilson thought it doable there was no
harm in trying.
There followed four days of long hours, frantic
work, calling in favors from semiconductor suppliers to get hold of
sample parts, blowing of custom uncommitted logic arrays (ULAs), and
wire-wrapping boards with hundreds of posts and thousands of
connections. "There was a great deal of debugging on the Thursday using
an in-circuit emulator based on an Acorn System 5," recalls Wilson.
led to the incident of the machine failing to boot and rejecting all
attempts to diagnose the problem late into Thursday evening until, in
desperation, Hauser suggested disconnecting the emulator. At which point
the prototype sprang into life.
Even on the Friday morning
Wilson was still writing the video software to get the machine to
display a raster but nonetheless the BBC executives who had specified
their home computer should be based on the Z80 processor, gave the
contract to Acorn and their 2-MHz 6502 based design.
years the making of the BBC computer, which achieved a penetration of
80 percent in U.K. schools, was the making of Acorn Computers.
what was it about that 8-bitter, that kept Wilson and the Acorn design
team loyal to it. "The key was it was easy to comprehend and to design
stuff around it," said Wilson.
"We'd built up a very good
understanding of the 6502 over the years and we knew it allowed a fast
memory interface," Wilson said.
Click on image to enlarge.
The 6502-based BBC computer