Date   : Sun, 21 Dec 1997 15:19:42 +0100
From   : "Mark Usher" <marku@...>
Subject: Re: SCSI Hard Drives

Crispan

>Here is the original post from 1992, from a guy making an SCSI adaptor for
>the BBC Micro with ADFS and possibly it would need 1770 control circuitry,
>remember this is from 5 years ago, so the address and phone number will
>probably be out of date!

It doesn't need a 1770 control chip. NO hard drive does. The 1770 is a
floppy controller and a hard disk attaches to the 1MHZ BUS. All BBC machines
can use a hard drive.
The OS interface is what is needed and in the BBC's case this is ADFS 1.30.
This runs quite happily alongside an 8271 floppy controller. You cannot
though use ADFS for floppies unless you upgrade the floppy controller ie. to
the 1770.
Where hard drives are concerned FORGET the floppy controller, it is of no
relevance.

>As you see, he definitly says they are SCSI and not SASI interfaces, and
>that there is only one board needed!


SASI interfaces are often referred to as SCSI interfaces so do not take this
as gospel.
I put out a message some time ago and tried to track down some of these
boards but all I have managed to come up with is the SASI controller. The
info has been posted for all and sundry at the BBC Lives. You then need to
connect this to the adaptec controller which then connects to a ST502 drive.

Now I have been experimenting in connecting an old SCSI drive directly to
the SASI board, but as yet I have not got this up and runnning. There are
alot of others on this list who are for sure more competent than me at such
things, perhaps someone else is willing to have a look ?

Mark Usher
marku@...