The BBC Micro turns 30
The 8-bit 1980s dream machine
The BBC Micro – the machine which, along with the Sinclair ZX Spectrum, epitomised the British home computer boom of the early 1980s – was launched 30 years ago tomorrow.
Unveiled on 1 December 1981 as the Model A and Model B, the BBC Micro would go on to sell over 1.5 million units before the last of the line was discontinued in 1994.
The BBC Micro was designed and manufactured by Acorn, a Cambridge-based computer company founded by Chris Curry and Herman Hauser on 5 December 1978 as Cambridge Processor Unit (CPU).
Curry had quit working for Clive Sinclair's Science of Cambridge (SoC), where he had developed the MK14 microcomputer kit. Sinclair was less enthusiastic about the project than Curry, who came to believed that the only way to take the product to the next stage – to build and sell a computer for home use – was to do so outside of SoC.
Hauser, a physics researcher at Cambridge University, agreed. He was aware of the many young, talented computer scientists and engineers working at the university and was able to help CPU quickly tap into this resource.
CPU first developed a controller for Ace Coin Equipment's one-armed bandits, funding the work on the Acorn Microcomputer – later called the Acorn System 1 – which was launched in March 1979.
During the following months, Sinclair began work on the ZX80. Unlike the motherboard-and-not-much-else MK14 and System 1, the ZX80, although sold primarily as a kit the user would assemble, was designed as a cased product with the potential to appeal to a much broader audience than electronics hobbyists.
That move, in turn, may well have inspired Curry to drive the development of the next Acorn machine, the Atom. Seeing the possibilities, Curry and Hauser recast CPU as Acorn. And, a year later, in March 1980, the Atom was launched as the first Acorn Computers machine, combining a case with an integrated keyboard – with moving keys, unlike the ZX80's flat ones – and what was essentially a System 3 motherboard within.
And with the Atom's launch, Acorn's development team began work on its successor, codenamed Proton, a machine they hoped would be a more serious machine than the one-up-on-Sinclair Atom.
Meanwhile, the state broadcaster was taking an interest in the world of microcomputers...
Next page: Corporation Street
Re: i'm off for a walk down memory lane...
Only shame is you can't go and do it in WHSmith, Boots, Laskey's, etc any longer
What the article doesn't mention is the BBC's operating system. Unusually for most micros of the age, which mostly consisted of a CPU and some RAM in a box with just enough Basic to let you write programs, the BBC actually had one. It was simple and elegant and very modular: the OS ROM lived in the top 16kB of address space, then you had a paged bank of application ROMs living in the next 16kB section, and the bottom 32kB was shared RAM.
Application ROMs could consist of standalone utilities, proper applications (like the excellent BBC Basic, or word processors like Wordwise or View), file systems (like the fast and simple DFS, the slower but much more sophisticated ADFS, the network file system NFS, etc), and so on. The OS would seamlessly page from one to the other, so an application ROM could make file system calls which would get delegated to the currently selected file system even though they both lived in the same place at the same time. It was even possible to open file descriptors to more than one file system at a time and copy from one to the other!
The OS system call API was fast, capable, well-documented and sufficiently abstract to allow some really neat things: the Tube second processor interface allowed system calls to be executed via RPC from a *completely different computer*. Tube second processors really were CPUs in a box; no I/O other than the connection to the BBC, no ROM other than the RPC stub. So you got 64kB of RAM and maximum perforfmance, with all the fiddly I/O overhead handled by the BBC itself, now acting as a dedicated and extremely capable I/O processor.
And the Tube wasn't limited to 6502s --- they also made Z80, 32016, 68000 second processors, all using that same system call interface. Even the ARM chip, now a juggernaut taking over the world, started life as a second processor connected to a BBC micro!
(I don't believe they ever tried system call RPC via Econet, but it would have been an interesting experiment.)
It's a shame that Acorn's master plan fell through. After the Electron debacle, they regrouped and produced the BBC Master, which was an excellent machine in many ways but not a patch on the machine that *could* have been. With better marketing, we could by now be using BBC-descended multiprocessor systems instead of PCs...
I knew a whole two people with a Beeb, about 20 - 30 of us with Speccies and even an Oric user.
But never once heard of anyone wanting a an Electron; a Spectrum 128 / QL, C64's yes but an Electron?
Ahh I miss those day. BBC's are Pants Spectrums rule! No Spectrums are toys, BBC are proper computers.
Shame we don't have any of that childish behavior 30 years on.