On 17 July 2016 at 21:07, David Brownlee <a...@absd.org> wrote: > On 17 July 2016 at 16:09, Liam Proven <lpro...@gmail.com> wrote: >> In 1987 or so, the early Archimedes like the A305 and A310 came with >> ST-506 controllers and 20-40MB Conner drives. The expensive >> workstation-class models -- Dick mentions having an A500, but that was >> a series, not a model. > > The A500 was the development prototype which pre-dated the A310 > (originally with pre-multiply ARM1 CPUs). Only a 100 or so made. I > think they used pretty much the same Hitachi HD63463 as the (optional > podule for the) A300 series which I think was DMA capable. > >> There was, later (1990), the A540: >> >> http://chrisacorns.computinghistory.org.uk/Computers/A540.html >> >> This was the Unix R260, but shipping with RISC OS instead of RISC iX. >> >> The A540 came with a snazzy SCSI HD: >> >> http://www.apdl.org.uk/riscworld/volumes/volume9/issue2/blast20/index.htm > > The A540/R260 was a completely different class of machine, with an > ARM3 and the ability to take multiple memory (each with memory > controller) cards. > >> ... but then it was the thick end of three thousand quid. >> >> Back in '87, I suspect Dick had an A310 or something, with an ST-506 >> drive & Arthur (i.e. RISC OS 1 -- an ARM port of the BBC Micro's MOS >> with a desktop written in BBC BASIC). >> >> So I suspect no DMA... but I don't know. > > Think of it as an A310 with integrated disk controller, in a big metal > box with a lot more soldered wires internally :-p > > Acorn kept them in internal service for white a while, including for > development versions of RISC OS 3 with the multitasking filer.
Fascinating -- thanks for that! OK, so the HD controller chipset was DMA capable, but did Arthur take advantage of that fact? I note that the first PDF datasheet I find for that chip is on Peter Howkin's Martuan site. Pete is a friend of mine and maints RPCemu as well as the open-source version of CDE, and is a major Acorn expert. Said datasheet indicates that the HD63463 needs an accompanying HD63450 DMA controller for DMA operation. -- Liam Proven • Profile: http://lproven.livejournal.com/profile Email: lpro...@cix.co.uk • GMail/G+/Twitter/Flickr/Facebook: lproven MSN: lpro...@hotmail.com • Skype/AIM/Yahoo/LinkedIn: liamproven Cell/Mobiles: +44 7939-087884 (UK) • +420 702 829 053 (ČR)
