The Bi-Weekly British Backtrack - The BBC Micro
by, 09-03-2010 at 01:16 PM (587 Views)
The BBC Micro Computers
Welcome to another one of my UK based articles under a new name, the Bi-Weekly British Backtrack which kind of gives the game away. We will try to keep to a bi-weekly schedule and we will be coming from Britain, but we won't always cover British items. Anyway, next up is a decidedly British product, this time we're looking at the British Broadcasting Corporation Microcomputer System, or the BBC Micro for short.
The BBC Micro was a series of computers that were designed and built by the company Acorn Computers for the BBC Computer Literacy Project that was run by the BBC. They were designed with education in mind and they were renowned for being rugged, expandable and for having a great operating system which made them ideal for use in schools.
I actually almost ended up with an Acorn computer for several reasons, they looked as cool as hell and futuristic with the monitor being built in similar to something like the Apple Lisa but much more rounded and sleek looking. Pester power won through in the end though and despite the Acorn being more education oriented I persuaded my dad that the Commodore 64 was the way to go but the BBC Micro in its day was a great system.
Acorn had to put in a tender for the Literacy Project because they wanted to build a computer system that would accompany the BBCs TV programmes and literature, and when they won the contract they named the computer the BBC Micro and it became very popular in schools. They changed Acorn's fortunes and they also became popular in many homes as well, despite having a comparitively high price tag.
The Model A was initially priced at £235 and the Model B £335 but these prices rose almost immediately to £299 and £399 respectively because of increased costs and that put them way over the price tag for their competitors. I remember my Commodore 64 costing £250 but it came with everything, Computer, Cassette Deck, Joystick and Games.
Acorn forecast that its total sales would be around 12,000 units, but eventually, wait for it, more than 1.5 million BBC Micros were sold.
Being fully aware that their costs were high in comparison Acorn made a cheaper option which was a largely compatible but cut-down version intended for games. The 32K Acorn Electron had games written specifically for it, and it's one of these that I almost got, but those games could also usually be run on the BBC Model B.
There were actually twelve models produced and the term "BBC Micro" is usually used to refer to the first six of them, and those six were the Model A, Model B, Model B+64 and Model B+128, the Master 128 and the Master Compact. The later six models were referred to as the Archimedes series.
So what was the BBC Computer Literacy Project and why was it so important? Well, in the early 1980s the project began in response to a very influential ITV documentary series called The Mighty Micro. In that series Dr Christopher Evans from the National Physical Laboratory predicted the computer revolution, and he forecast that it was going to have a huge effect on the economy, on industry and on the lifestyles of people in the UK.
The BBC wanted their project to jump on this bandwagon and they wanted a computer that would be able to demonstrate various tasks and they would feature it in their 1981 documentary series called The Computer Programme. The list of topics covered by The Computer Programme included programming, graphics, sound and music, Teletext, controlling external hardware and artificial intelligence. They drew up plans for a computer spec they wanted to use and began to look for somebody to build it for them. Remember the name Sir Clive Sinclair from the C5 review? Well Sinclair was asked about supplying the computer and he offered them one called the NewBrain Micro but it was rejected so the BBC met with other companies including Dragon and of course Acorn.
The Acorn team had already been working on an upgrade to their existing Atom microcomputer known as the Proton which included better graphics and a faster CPU. The machine was only in prototype form at the time, but the Acorn team worked through the night to get a working Proton together to show to the BBC. The Acorn Proton was the only machine to come up to the BBC's specification, and actually exceeded it in nearly every aspect.
So for obvious reasons it was Acorn's machine that was released as the BBC Microcomputer in late 1981 and became affectionately known as the Beeb (a term often used to refer to the BBC itself) and it was to become very popular in the UK, especially, as I mentioned, in the education sector.
Now, commonly among computers released around this time, including the Sinclair ZX Spectrum and the Commodore 64, both released later in 1982, demand greatly exceeded supply, and it was months before some customers received the machines they had ordered. There was a brief attempt to launch the machine in the US which failed. The version of BASIC III had been modified to accept the American spellings of words like COLOR but unfortunately the height of the graphics display was reduced from 256 scan lines per field to 200 to suit NTSC TVs and that had a huge effect on running the applications meant for British computers. After the US launch failed, the remaining machines were remade for the British market and sold off.
Really the success it had in the UK can be largely attributed to its adoption by the education system as a whole, and it was used by many schools to deliver their courses on Computer Literacy and Information Technology.
Some Commonwealth countries, like India, started their own Computer Literacy programs and they also used the BBC Micro which further increased the sales figures for Acorn.
A company called Research Machines had, until this time, been the primary provider of educational computers but one of the main advantages which helped the BBC Micro in the educational market was its durability. Compared to the Spectrum and the Commodore 64 it was far more solidly built and more than up to the task of putting up with some of the rough treatment it got in schools.
So let's dig into the specs a little bit and compare some of the range. The Model A had 16 KB of user RAM, while the Model B had 32 KB. A feature that the Micro shared with other 6502 based computers such as the Apple and the early Commodore models was that the RAM was clocked twice as fast as the CPU at 4 MHz, with alternating access given to the CPU and the video display circuits. This meant that the Micro had a fully unified memory address structure with no speed penalties. Most of it's competitors with memory-mapped display did suffer from CPU speed penalties depending on the actions of the video circuits, for example the Amstrad CPC and the ZX Spectrum. Some took a different approach and kept the video memory completely separate from the CPU address pool such as the MSX.
The BBC Micro had a number of extra I/O interfaces such as serial and parallel ports, an 8-bit general purpose digital I/O port, a port that supported four analogue inputs, a light pen input, and switch inputs. It also had an expansion connector known as the "1 MHz bus" that meant you could hook up extra hardware.
You could expand it with extra ROM chips, either 4 on the PCB or 16 with expansion hardware, and these extra ROM chips could be accessed via paged memory. An Econet network interface and a disk drive interface were also available as options but rarely requested, neither was the proprietary interface called the "Tube" which allowed a second processor to be added, but the Tube was later used in third-party add-ons, including a Zilog Z80 board and disk drive that allowed the BBC machine to run CP/M programs, and it allowed Acorn to use ARM CPU-equipped BBC Micros as software development tools when they created the Acorn Archimedes series.
One of the software titles that ran on the Tube was an enhanced version of Elite, and this game was simply massive on the Beeb. Another was a CAD package that required a second 6502 Processor and a 5-dimensional joystick called a "Bitstick".
The Model A and the Model B were built on the same PCB and a Model A could be upgraded to a Model B without too much difficulty. Model A users that wanted to run Model B software only needed to add the extra RAM and a chip and snip a link so it could be done without soldering, but to do a full upgrade with all the external ports as well you would need to solder the connectors to the motherboard.
Some of the faults that the Beeb would suffer from included the early model power supplies overheating, and a flaw in the manufacturing process meant that a big percentage of Model Bs produced a buzzing noise from the built-in speaker, but you could reduce it a little by adding a resistor.
The new Model B+ arrived in 1985 and it had increased RAM of 64 KB and floppy disk support as standard, but unfortunately, or rather stupidly, it wasn't compatible with some original BBC B programs and games. The problem was that the original Intel 8271 floppy disk controller had been replaced by the Western Digital 1770 and it was mapped to different addresses. There were 8271 emulators but they were only good for basic operation and weren't up to playing games. One such well known example was the game Repton Infinity from Superior Software which refused to run on the B+. The game was re released several times before a version fully compatible with both systems was made.
The Beeb had a large software library ranging from games to educational titles including, as I mentioned, Elite, which was the game's original release, and as the early BBC Micros allowed machines to be networked, and many schools and universities built Econet networks, there were several network multiplayer games created. Not many of them were successful, presumably because they targeted neither the home or the educational market, more a mixture of the two. The exception to the rule was a tank game called Bolo.
The built-in operating system, Acorn MOS, had an extensive API that interfaced with all the standard peripherals, all the ROM-based software and the screen too, and you could program things like vector graphics, keyboard macros, cursor-based editing, sound queues and envelopes, things that were usually restricted to BASIC. Acorn tried to dissuade programmers from accessing the hardware and system variables directly and recommended the use of official API calls. One of the main reasons for this was so that programs would still work if and when they were moved over to the Tube processor but it also had the side effect of making software more portable and compatible across the Acorn range of computers.
The built-in BBC BASIC, that sat on one of the ROM chips, was pretty much ahead of its time and made the Beeb much more suited to the education sector because users could write extensive programs without having to use unstructured languages or machine code. Something not true of its competitors.
In 1986 the BBC Master series appeared which offered memory sizes from 128 KB and several other improvements on the original 1981 model, although it was still based on the 6502 architecture. In 1985 though, Acorn had produced their own 32-bit RISC CPU, the ARM2, and were working on building a personal computer around it. That would eventually be released in 1987 as four different models in the Archimedes series, with the two lower-specced models being released as BBC Microcomputers, and the last model, the BBC A3000, was released in 1989 but the Archimedes range failed to live up to the same success that the Beebs had.
Back at the end of the last Millenium I was an HGV Driver and I was working on a contract with the Cadbury-Schweppes group, and I used to collect lots of loads of chocolate and packaging from the main factory in Bourneville, and as late as 2001 when I was last there, the warehouse and despatch offices were using BBC Micros and Dot Matrix printers, but sadly I don't remember which models they were.
Wikipedia will tell you that as late as 2005 there are still many BBCs in use, and a BBC B+ was observed running the communications link in an unattended water pumping station in Oxhey in 1995. They still run interactive displays in museums across the country, and Jodrell Bank was reported to still be using a BBC Micro to steer its 42ft radio telescope in 2004.
Musician Vince Clarke from Pop bands Depeche Mode, Yazoo, and Erasure used a BBC Micro, and later a BBC Master, with the UMI music sequencer to write many of his songs, and in his Pop videos you can either see a BBC Micro or it will be providing the text and graphics.
Queen also used the UMI Music Sequencer on their record A Kind of Magic and the UMI gets a mention in the CD booklet.
Obviously the BBC would use their branded computers as well and they provided graphics and sound effects for many early 1980s BBC TV shows such as one called The Adventure Game, and this show's BBC had a plastic box that covered the BREAK key on the keyboard so that the contestants wouldn't press it by accident. Another kids show that used one was the quiz show "First Class" where the onscreen scoreboard was powered by a BBC Micro nicknamed "Eugene". A more famous example was Doctor Who which used Beebs for special effects during the 1980s.
Remember in the Prestel article where I told you what Teletext was? Well the BBC would often use a BBC Micro to host it's Teletext pages.
So I hope that's given you some insight into the BBC Micro range of computers and how they came about, what they did, why they were so important and what they still do today, even professionally in some cases. Until next time, hopefully in 2 weeks, see if you can find one for sale on Game Gavel.