Date   : Wed, 24 Dec 1997 15:37:03 +0100
From   : "Mark Usher" <marku@...>
Subject: Re: BBC hard disk

>So the board that this guy was making back in '92 was just the 1mhz bus -->
>SASI adaptor, so this should be able to handle a SASI or SCSI drive,
I don't know. I haven't seen that board or its circuit design, but the one
described in the HardDrive.zip is, yes.

> but the original Acorn Hard Drive unit was an MFM or RLL drive, much like
the
>ones used in PC XT computers?   So this is why the Adaptec card was needed?

The penny drops :-)

>What is the problem with connecting the SASI --> 1mhz Bus card into a SCSI
>drive, what are the problems?

It doesn't work when you just plug an SCSI drive in. Why, I am still looking
into it and would appreciate some thoughts from others.

> I just heard that the older large storage devices were always
>referred to as Winchester Devices, wheras now they are called just hard
disks.

Right again.

>Also, would SCSI-2 and SCSI-1 drives work on the 1mhz bus card? Or is it
>just SCSI-1, how about Ultra-SCSI or SCSI-Wide??

I think that we should really concentrate on getting an SCSI-1 to work on
the board. As SCSI-2 should be backwards compatible there shouldn't be too
much of a problem and UW, well we can always try it when the SCSI 1 works.

>>i have the file HardDisk.zip from the BBC Lives archive, and I have looked
>at the artwork of the PCB (the one in bitmap format)
>The only problem is, what are the chips used in the board?
They are listed in the parts list.

>I could probably make the board at school (would a print onto paper be
>enough?)
Not ususally. Most people print in on to an acetate to transfer onto the
board before burning it all off with acid.
>What are the dimensions of the board?
Valid point.
I would wait just a couple of weeks, as Andy is redoing the board layout on
the PC, so there will be an "optimized '97" - sort of a remix version
available fairly soon.

>Has anyone actually got/made this board?  Does anyone have a parts list for
>the board????
Yes, I have a board. The parts list is in the documenatition. RTFM :-)

Mark