Video boards were already around for microcomputers when Acorn was doing this work, obviously being elements in their earlier System range. The Cromemco Dazzler was a famous early example which led to a range of steadily more sophisticated products used in the broadcast realm. I suppose the Prisma graphics boards for the Beeb had broadly the same role. There was also the Pluto range of boards available for a number of different systems.Sounds like a mistake from acorn, I think the pc graphics cards have shown that dedicated graphics subsystems processors/memory was the way ahead.
What happened was that video capabilities became decent enough to design into a system from the start, as opposed to leaving it to an expansion card, and then you have the video system tied to the main processor, as we see in the Beeb and Electron. Since manufacturers were usually looking to introduce new models as a way of providing new features, also hopefully providing them with a stream of new sales as new buyers were tempted and previous buyers upgraded, this might not have been regarded as a deficiency. Putting the graphics support in the core product also made it more attractive and might have helped drive the total system cost down for a system configured for graphics.
However, Acorn doubled down on using the Beeb as a platform for other systems, notably the Acorn Business Computer, which didn't lend itself to keeping up with the progression in graphical capabilities seen in other systems. They did the same thing with the Archimedes: develop a system with better graphics than the competition that were also built-in, initially delivering a better experience, but necessitating some kind of updated product some time in the future. And, indeed, just as it took about six years to get from the Beeb to the Archimedes, it took about seven years to get from the Archimedes to the Risc PC.
Although one could look at this Proton architecture and claim that it is really just the Beeb architecture we all know and recognise with just a bit of relabelling, if the assignment of the video system had been different, it would have taken the product along a different path. Since the BBC had various requirements, it seems plausible that Acorn changed the architecture to offer a lower cost base system featuring the 6502 and video system, leaving the second processor for Z80 and CP/M support to meet those requirements.
Statistics: Posted by paulb — Sat Dec 07, 2024 12:56 pm