Transition of platforms in british education 3195

On 1 Apr 2006 19:03:49 GMT

The Apple was quite a bit earlier than the BBC and *much* higher quality. The BBC was designed down to a price, at which it unfortunately could not be manufactured. Which is why Acorn went into a sudden stock price nose dive before being bought up nice and cheap by Olivetti.

The original aim of the BBC contract (eventually awarded to Acorn after the Newbrain failed to get into production in time) was for a Z80 based machine that could run CP-M (perhaps with the aid of optional extras if necessary to get the base machine price down to the target). The contract for this was originally awarded to Newbury Labs and the Newbrain1 was designed to fill the bill - however to get that down to price required the main logic to be on ULAs which Ferranti were never able to produce. When the Newbrain stretched way past the required delivery date the contract went open again with less restrictive requirements and Acorn dusted off the old Proton design (a never released successor to the Atom) and with a promise of a Z80 card to run CP-M filled the original requirement along with a "business version" made by another company2.

The Acorn BBC had a number of design issues - including the complete failure of the original design to fit into the board space (despite some very inventive layout) which was eventually cured by removing part of the Econet circuitry to an external box. The vidproc ULA which ran too hot (and produced pyjama stripes) necessitating the "case support" heatsink, and the presence of a floppy controller chip which was listed as obsolete by the manufacturer before the first BBC left the factory.

Despite all that it was succesful enough and popular enough to bring Acorn to their knees.

1 I worked on the Newbrain when the existence of the BBC contract was a fairly closely held secret - we weren't supposed to know who the suits that kept turning up were.

2 The Torch Communicator - a BBC B, Z80 card, modem, two floppy drives and a colour monitor all in a nice heavy steel case with a detached keyboard. I was the principal hardware engineer for that and the designer of the CPN clone of CP-M (which existed primarily because once I understood the details of the CP-M filesystem I refuse point blank to implement anything so kludgy).

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