Date   : Sun, 17 Apr 2005 13:49:17 +0000
From   : Jules Richardson <julesrichardsonuk@...>
Subject: Re: KeyBoard, Winchester Hard Drive

On Sun, 2005-04-17 at 14:27 +0100, Richard Gellman wrote:
> If you're willing to put in a little soldering time, you can bodge
> one.
> 
> Basically, the Acorn SCSI interface (which connected the 1Mhz bus to
> the Adaptec ACB4000 (or similiar) board, which in turn connected a
> SCSI interface to a winchester drive) is actually made of out extra-
> ordinarily low-level components. Essentially, its a group of logic
> circuits that expand the 1Mhz Bus into a 50pin SCSI bus.

Actually, the Acorn SCSI interface is the only really difficult bit to
get hold of - I've only seen one in the last few years. But I usually
pick up 4 or 5 ST506-interface drives a month, and come across SCSI-
>ST506 bridge boards every few weeks. There's a lot still about, lurking
in cupboards...

> Once this is built, you should be able to connect a SCSI drive [1] to
> the business end, format [2] it, and away you go.
> 
> [1] There was discussing about SCSI drives and their suitability for
> the BBC Micro. Not all will allow reformatting to 256 byte sectors.
> However, since they are cheap enough to get (at the lower capacities
> anyway) from ebay, its worth trying if you go down this route.
> 
> [2] The Acorn formatters may not want to deal with the hard drive in
> question, given that a limited range of drives were made. In
> particular, things like "2Gb" may scare it. You may have investigate
> formatting the drive manually, i.e. a BASIC program and a large number
> of OSWORD calls. Documentation is available for this.

Can't remember now, but do the various SCSI->ST506 boards support a
standard "format unit" command, or was this specific (via vendor unique
extensions) to each type of bridge board? If the latter then the Acorn
formatters won't work except with the right kind of bridge board...

As for SCSI drives capable of 256 bytes / sector, it'd be interesting
for someone to do some experimenting. It wouldn't surprise me if none of
the 3.5" SCSI drives support it though :-(

cheers

Jules