Acorn Econet Fileserver

Tony Duell ard at p850ug1.demon.co.uk
Tue Nov 22 16:52:33 CST 2005


> 
> 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.
> 
> 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.

> it was multiple target like SCSI just without all the device reservation like 
> SCSI)
> 
> So if the board (despite Acorn calling it SCSI) is really just SASI (or maybe 
> if it started life as a SASI project) then it could explain why the software 
> never addressed more than one target device.

Well, the Adaptec board that Acorn used in the BBC Winchester box -- 
which AFAIK was the first application for the host adapter -- certainly 
has an address jumper.

> Either that or Acorn were rather short-sighted in their software, but they 
> weren't normally known for this (typically, if the hardware would do it they 
> seemed to think that someone would actually want to do it).
> 
> Maybe it comes down to code size and there just wasn't the room in the ADFS 

That is the most likely explanation. To quote Bill Wickes 'Life is short 
and ROM is full'

> 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?)

I will see what it says in the ACW service manual. I seem to recall it 
does describe what goes on between the Host Adapter and the Adaptec board.

> 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. 
Fortunately they're socketed. I can't rememebr if you have to remove the 
floppy drives to get to them, but that's not an issue for me anyway at 
the momnet.. You do have to remove all that stupid plastic stuff around 
the case, of course.

-tony




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