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.
About the writing...There appears to be a paragraph or two missing at the beginning of the article that sets the scene. The first sentence starts with "Most computers at that time". I guessed the setting was the late 1980s.
I was trying to understand who the players were. Mentioned were " Wilson, Furber and the rest of the team" but no context.
I noticed an inaccuracy about the IBM PC processor. The first PC used the 8088, the 8-bit data-bus version of the 8086.
Wait...I just noticed at the bottom of the article a page button where it says page 3 of 3. I arrived from a LinkedIn discussion group. I don't see paging buttons at the top of the article.
Extremely well done story, Peter. I enjoyed it. "It took four clock ticks to run a (68000) memory cycle." That told me something I didn't know about the evolution and inherent advantage of the ARM architecture, which I assume took one tick. Charlie Babcock, InformationWeek
The core of ARM was that it had to be cheaper than an off the shelf processor or else Acorn went bust. Thats why when Robin Saxby took over he needed to find a customer for the core as Acorn were not buying enough to keep going. Nokia told people to licence this as they were not paying for someone elses IP as it would mean GSM handset were going to be too expensive. TI licenced it and there history was written
Back in the days I worked at an early computer store, we ran a set of BASIC benchmarks originally published in BYTE magazine on the other computers in our store after we found our numbers agreed with BYTE's list of computers they ran on.
I further wrote a program to sort and rank the results (this being the days before VisiCalc) and one item I tracked (but did not sort on) was the processor the syetem used.
Were were looking to see who wrote the better BASIC interpreter, but were surprised when we saw processor stratification instead.
The 1 MHz 6502s were faster than the 4 MHz Z-80s, followed by the 4 MHz 8080s.
Looking into it, aside from the pipelined instructions, loads took 3 cycles on a 6502 while the Z-80 took 6, and the condition code was set automatically by the load instead of requiring another instruction like the Intels, I felt it was the reduced number of registers (6502 A, X & Y) (Z-80 A, BC, DE, HL + mirror set) helped as well. From my experience programming S/370 Assembler, I had seen too many cases of registers being swapped around, just to make use of register sets already being used, or for special purpose use, which in the end did not do much but chew up clock cycles. Given the reduced number of registers on the 6502, you made use of them for good purpose, you didn't calculate a value and let it hang in a register for K's of execution later until you whipped it out of seemingly nowhere (making debugging harder as well).
That made the 6502 far more efficient than the Intel processors, even though they ran at 4x the clock rate.
Yes I recall my days at ACORN and interaction with Herman, Roger and Steve.
I even recall Herman & my discussion about the daily calendar product that was to have 16 charter LCD displays from Hitachi and use there RT chip who we were connected with very closely for memory parts for our BBC and Electron
What a group and what an innovation company from the day one joined…looking back it was love of my life as I have not come across another company like it for pushing the envelope on daily bases. Gopro may today’s such leader
At ACORN, each one of us was doing 5 projects at any one time from network to making mouse using CCD sensors. I even tacked a research storage device where there head moved spirally to the center with removable 2in cartridge. This is before the 3.5in Discs became the norm
Oh I still have an Electron and it still boots-up and runs Basic, 6502 Assemble like no other product today to hack code in 5min and run 2MHz assembly in Basic. What a concept
Only good memories of my carrier and working with Herman, Roger Wilson (Sophie Wilson) and off course Chris Curry who we started a company called GSI out of his 40 bedroom Manson in Croxton Village together with Ram Banerji
ZahidOh I still have an Electron and it still boots-up and runs Basic+6502 Assemble like no other product today
The first project I worked on used the BBC microcomputer to do 3D spherical trigonometry using radio signals in real time to compute location - sort of a poor man's GPS.
What was astonishing was how fast floating point code written in Basic would run on this 8 bit 6502. I guess this was due to hand-crafted C or assembler floating point routines embedded in ROM but I still don't really understand how they made interpreted code run so quickly.
Join our online Radio Show on Friday 11th July starting at 2:00pm Eastern, when EETimes editor of all things fun and interesting, Max Maxfield, and embedded systems expert, Jack Ganssle, will debate as to just what is, and is not, and embedded system.