18 Jul
2016
18 Jul
'16
4:02 p.m.
On 17 July 2016 at 21:07, David Brownlee <abs at absd.org> wrote:
On 17 July 2016 at 16:09, Liam Proven <lproven at
gmail.com> wrote:
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.
--
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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.