23 Nov
2005
23 Nov
'05
12:25 a.m.
On Nov 22 2005, 22:52, Tony Duell wrote:
>
> Tony Duell wrote:
> >> I'd forgotten about that; in ADFS-land, ADFS knew nothing about
device IDs -
> >> everything was ID 0 and so the host
adapter could still only
have one device
> >
> > How stupid! I wonder why they did that (after all, they allowed
for
> > multiple floppy drives on the same
controller). It's almsot as
stupid as
> > POS haeving 2 storage devices (one floppy,
one winchester)
hard-coded
> > into the OS.
I'm not sure. In fact I didn't realise it was single device; ADFS was
designed to allow 4 winchesters and 4 floppies, and the only way to
have four winchesters would be to have 2 Adaptec cards. The code to
actually handle that may not be in the ROM, though.
> Isn't SASI just single target though?
(I'd forgotten this, I was
thinking that
I thought SASI supported a total of 8 devices on the bus, like 8-bit
SCSI.
I thought so too... The Xebec manuals describe how to set the
addresses.
> So if the board (despite Acorn calling it SCSI)
is really just SASI
No, it really is SCSI. It complies with the first ANSI spec.
> ROM for the device selection code (assuming that
Acorn's board
contains the
> necessary SCSI features anyway - I think you
likely need /ATN to do
device
> selection?)
No, that's for something completely different (disconnects and
reconnects). SEL is what is used for device selection. The initiator
waits for the bus to be idle (BSY and SEL both inactive), asserts BSY
and its own ID line, and assuming nothing with higher priority also
asserts an ID line, then asserts SEL and the ID line for the desired
target. Then it releases BSY, and waits for the target to assert BSY,
at which point it releases SEL.
> You made me realise that I need to archive the
ROMs from the E01 I
have in the
I will do mine sometime too, in case they're different versions.
FWIW, I have FS 1.33 ((c)1988), FS 2.08 ((c)1989), MOS 2.07, and MOS
3.66. MOS2.07 has the string "Stacking FileStore" in it but I'm
fairly sure it came out of my E01. It also has the string "Acorn
Econet 3.68" i it, whereas MOS 3.66 has the string "Acorn Econet 3.66".
Both are mostly empty.
Somewhere amongst the Customer Services newsletters I will probably
have several FCOs that will list the released versions, or most of
them.
--
Pete Peter Turnbull
Network Manager
University of York