Date   : Fri, 23 Jan 2004 19:03:03 -0000
From   : "Ken Lowe" <kglowe@...>
Subject: Re: IDE Interface for BBC

All this talk of HDDs and Beebs inspired me to have a dig in my loft....

Dom Wright Wrote
> I'm sure I looked into this a few years back (and failed).  I've just
given
> it a go with and old Maxtor 500MB drive and remembered why I stopped.
>
> The Acorn card seems to connect pin 34 of the SCSI bus directly to +5v
> (mine is an Issue 2 card).
> The Adaptec ACB4000 doesn't use this pin at all, but the other specs
> for SCSI that I have seen seem to indicate that this pin should be
> grounded.  Hence the power supply is shorted and shuts down immediately.
>
> Is it worth me cutting the track to pin 34 on the Acorn board?
>

I have a Viglen Host Adapter connected to a Fujitsu M2681 240MB (I think)
SCSI drive. I had to cut this track on my Viglen board to make it to work
with my drive.

> I'd like to give it a go, then see if I can get superform to
> format the drive with 256 byte sectors, or try and write something
> to do it.

Yes, it won't work with 512 byte sectors. I wrote a program (based on the
format program which came with my original Viglen Winchester) to change my
Fujitsu drive from 512 byte sectors to 256 byte sectors (block length). I
found a document on the Fujitsu website describing how to change block
length from 512 to 256 using MODE SELECT 0x15 (I'm not sure if this is
specific to the Fijitsu drive I have, but I've still got the info if
anybodys interested). It was then necessary to issue a FORMAT UNIT 0x04
command using this same program, which reformatted with the specified block
length. Once the low level format was complete, I initiated a high level
format to the SCSI disk again. This created the Free Space Map (sectors 0 &
1) and root directory (sectors 2 thru 6) on the HDD, and I now have a 120MB
drive (it may still be 240MB - I'm not sure if I lost half the space by
changing block length from 512 to 256, but I defined the drive as 120MB in
the free space map, to be on the safe side). The HDD worked great after
that. I think I should still have the format programs on my HDD somewhere if
anybody is interested. I haven't booted it up in a few years though.

Ken.