After the Beeb - the Electron and the Acorn Business Computer (1983 to 1985).

Despite the popularity of the Beeb, it was a relatively expensive machine to buy. To address this problem, Acorn introduced a cut-down version of the Model B. This machine was the Acorn Electron.

The Electron was developed by Acorn during 1983, with the aim of releasing it in time for the Christmas rush. In terms of hardware it was similar to the Beeb, and used the same processor, the 6502A, operating system and BASIC variant (BBC BASIC II). However, much of the functionality of the Electron was contained in a single ULA, thus cutting down manufacturing costs. The other main difference between the BBC Micro and the Electron was that the Electron did not have the extra circuitry to display the Beeb's teletext mode. There were also a number of other hardware differences.

Although the basic Electron only came with six ports (power supply in, TV out, video out, RGB monitor out, cassette interface and expansion connector) it was relatively easy to expand, mainly due to Acorn's Plus 1 and Plus 3 add-ons. The Plus 1 plugged in to the expansion connector and added two cartridge slots, a printer interface and the ability to add extra ROMs to the system. The Plus 3 was a complete 3.5" disc drive system that also plugged directly in to the expansion slot. A Plus 1 could then be added using an expansion slot on the back of the Plus 3. This device also came with an uprated power supply unit, to cope with the extra demands made by the floppy drive. Even after the original Plus 1 and Plus 3 were no longer available, a number of other companies, particularly Slogger and PRES, were still manufacturing peripherals that made use of the expansion connector.

In the end, however, the ULA took too long to develop, and the Electron was released too late to take full advantage of Christmas 1983. By Christmas 1984, the Electron has been largely superseded, and it never enjoyed the popularity of its larger brother, although a number of enhanced Electrons did find their way in to Interflora shops, as the "Interflora Messenger".

Following the problems with the Electron, Acorn was in serious financial trouble, and in 1984 the company was rescued by Olivetti. To help revive flagging sales of the BBC Micro a new stop-gap revision was introduced, known as the Model B+. This was basically a BBC Model B with a number of glitches cured and 64 Kb or 128 Kb of RAM. While this machine was not at popular as the original machines, it still managed to sell somewhere in the region of 28,000 units.

At around this time, Acorn started looking at a previously unknown market - that of business machines. The result was the introduction of the Acorn Business Computer range in 1984 and 1985. These machines were based on the Model B+, housed in a different case with an integral monitor and separate keyboard. What made them different was the inclusion of a variety of second processors and associated operating systems. There were a total of eight machines in the range, both discless and hard disc based, and with between 64 Kb and 4096 Kb of RAM. All machines consisted of a 6502 processor with a "parasite" second processor. The available second processors and operating systems were a 32016 running PANOS, an 80286 running various versions of DOS and a Z80 running CP/M. The most successful machine in the range was the 32016-based Model 210, later known as the Cambridge Workstation. This contained 4096 Kb of RAM, and was supplied with a 10 Mb hard disc. By default it was supplied with PANOS, but Xenix was also used on this machine. Eventually some of the second processors used in the ABC range were released as second processors for the existing range of BBC Micros. Of these the Z80-based solution became the most popular.

At the end of 1985 Acorn were in serious need of a new machine. The BBC Micro range was looking dated, and the Electron and ABC range was not selling as they perhaps had hoped. Fortunately, a new 6502-based machine was in development, that it was hoped would revive Acorn's fortunes - the BBC Master.

Next: The next generation - The BBC Master series (1986).

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Robert McMordie

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