Date   : Wed, 24 Nov 2010 07:49:48 +0000
From   : pete@... (Pete Turnbull)
Subject: Harddisc fakery using a microcontroller

Mark Usher wrote:
> Egg... Face :-) sorry, been a very very long day today, and an even
> longer one tomorrow. I'm even top posting too!

Tsk, tsk! but I know the problem.  I've been known to misread things too 
so don't worry about it :-)

> People had always surmised since the 90s that the host adapter board
> doesn't work directly with a scsi drive due to lack of ATN
> implementation. Yet here we are with the very board working quite
> happily with a scsi drive.

Yep.  I remember seeing a partly dismantled Filestore on Laurie 
Hardwick's bench with two SCSI disks hanging off it when he was 
developing the stacking filestore with Bruce.

> I don't think though the circuit diagram for the host adapter is
> included in the filestore service manual.

Actually it is, at least in my (ring-bound) copy but it's petty poor 
quality.  Page 28 has the interface pinout table, though, and pp26-30 
have the signal descriptions and description of how they're used in bus 
phases.

-- 
Pete                                           Peter Turnbull
                                               Network Manager
                                               University of York