Date   : Tue, 23 Nov 2010 18:38:18 +0000
From   : pete@... (Pete Turnbull)
Subject: Harddisc fakery using a microcontroller

Mark Usher wrote:
>> Um, the E01 uses the same ACB4000/MFM drive combo used by the Acorn
>> (and
>> other) Winchester drives for the Beeb.
> 
> Not quite. The Host Adapter board plugs straight into a SCSI drive RO652. No
> ACB4000 involved. I've just hooked up a Seagate ST2209N to it which also
> seems to work quite well. 
> Perhaps the host adapter is slightly different to the Beeb one and ATN has
> actually been implemented!

Sadly not.  The Filestore circuit diagrams and service manuals make that 
clear.

>> The E01S is SCSI.
>> RO652 is just the hard drive model, the E01/E01S is hard drive agnostic.
> 
> Yup, and the E01S is plugged straight into the drive, skipping the host
> adapter.

Yes, the difference between E01 and E01S is basically that the little 
host adapter was moved from the hard drive box to the Filestore "disc 
controller" box and the "Filestore Expansion Bus" connector was replaced 
by a SCSI bus connector.  The difference between E20 and E20S/E40S/etc 
was that the connection was directly to a SCSI bus, the host adapter was 
removed (to the E01S) and you could stack up to four drives on the SCSI 
bus connections.  Both E20 and E20S use native SCSI drives, without an 
Adaptec bridge board.

-- 
Pete                                           Peter Turnbull
                                               Network Manager
                                               University of York