Date   : Fri, 05 Jan 2007 20:59:14 -0000
From   : BBCMailingList@... (Ian Wolstenholme)
Subject: Technomatic hard disk units

The ST251 is a Seagate 43MB MFM drive, 820 cylinders
and 6 heads.

Most Winchester formatters I have come across (many
of them are variants of Superform) will perform a low-
level format and then initialise the drive without the
user being able to distinguish between the two.  Some
of them do have an extra "initialise" option which will
just write a blank free space map and root catalogue
at the beginning and leave the rest untouched.

Hopefully this disc will be in this state so you can recover
what may have been on the disc before.  If it's been
low-level formatted then it's likely that a defect list
will have been saved on the drive, most formatters do
this, in a directory like $.Format or similar.  If there is
no evidence of this on the disc then you might be in
luck as to the drive only having been re-initialised.

The Advanced Disc Toolkit (ADT) ROM has a disc
sector editor which works in DFS and ADFS, including with
Winchesters.  The command is *DEX <sector>
which will bring up the contents of the requested
sector on screen.

If you haven't got ADT then it would have to be a bit
of BASIC using OSWORD &72 to issue the READ command
to the controller.

Best wishes,



Ian


----- Original Message -----
From: Jules Richardson [mailto:julesrichardsonuk@...]
To: bbc-micro@...
Sent: Fri, 05 Jan 2007 07:42:16 -0600
Subject: Re: [BBC-Micro] Technomatic hard disk units

Ian Wolstenholme wrote:
> My Technomatic hard disc is an Akhter Host Adapter plus
> Adaptec ACB4070 bridge board plus Seagate ST225 
> MFM disc.
> 
> According to the Adaptec manual, the ACB4070 is an RLL
> controller and not an MFM-and-RLL controller (that's my
> understanding of it anyway, but I could be wrong since
> it does appear to run contrary to popular belief) so I'm not
> sure how wise is it to run it with an MFM drive.

Ta for the info! (and some nice photos on your site by the way)

<background>
The unit in question is one that Adrian over at Binary Dinosaurs recently 
picked up (possibly even from a list member here) - the understanding was that 
it had some PANOS stuff on it (which makes it particularly interesting), but 
unfortunately some crisis or other meant that the previous owner formatted it.

We were speculating last night as to whether the raw data on the disk has been 
completely hosed though, or whether a formatter's likely to have just 
demolished the catalogue area and left everything else intact. That of course 
depends on what formatter was used and whether only a high-level format has 
been done. Unfortunately we ran out of time yesterday, so never got the chance 
to pull the lid on the drive casing to see what interface boards it has.
</background>

This particular drive is a ST251. I presume even with the Akhter board in 
yours, it's signal-compatible with the Acorn SCSI adapter and so ADFS will 
talk to it quite happily?

Which also begs the question: Anyone know an easy way of dragging a single 
arbitrary  sector off the drive (using the "low level" SCSI functionality in 
ADFS) and just dumping it to the screen? Picking a few sectors at random 
should be a quick test to see if there's salvageable data (rather than just 
zeros) on what ADFS thinks is a blank drive...


cheers

Jules

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