Date   : Fri, 24 Nov 2006 06:02:34 -0600
From   : julesrichardsonuk@... (Jules Richardson)
Subject: BBC Disk Drive?

bill carr wrote:
> Hoping that somebody on the list might be able to help...
> 
> I have recently purchased some BBC disks along with 3 ICL brand disk drives 
> on eBay.
> 
> http://cgi.ebay.co.uk/ws/eBayISAPI.dll?ViewItem&item=160048450516&ssPageName=ADME:B:EOIBSA:UK:11
> 
> The one problem that I have now is that the connector into the drive is a 37 
> pin affair and not the standard (?)  bbc type that slips onto the disk 
> drive's motherboard.  Is there any way to buy/build an adaptor/cable which 
> will make these drives usable?  Or are ICL drives totally different 
> internally? It would be a shame for them to be useless, as they are in great 
> condition.

Hmm, looking at the image in the URL, they *look* (as far as it's possible to 
tell) like standard drives (I'd wondered if you'd accidentally bought 
something for one of ICL's workstation systems - they made some really oddball 
stuff)

I suppose a standard floppy disk connection is 34 pins, so a 37 pin connector 
is the closest match using a stock D-shell type. Of course, half of the pins 
on a standard floppy drive are ground, and it was typical for a manufacturer 
to leave a few of those out and use a smaller connector for external drives 
(e.g. Amiga) - but maybe ICL used the whole lot.

Personally, I'd pull the cases off the drives and check the connector on the 
drive itself. I bet it's standard, and the *quickest* way of hooking them up 
would be to ditch the 37-pin connector/cable and just hook up using a scrap 
floppy cable from a PC (undo the PC's twist in the cable, of course, so that 
it's straight-through). Quickest isn't necessarily the most elegant or robust, 
though :-)

How do the drives get power, incidentally? If there's no way of supplying 
power to them, then the obvious is that they're routing the power lines over 
the same 37-pin connector (the spec for D-type connectors allows for 
surprisingly large amounts of current)

It all makes me wonder where these drives came from, though. I wonder if ICL 
had some kind of 'distribution box' which brought the connections on the 
underside of the beeb out to a separate unit to make them more accessible 
(I've wondered about doing such a thing myself, but got worried about maximum 
cable lengths - particularly for the 1MHz bus and Tube).

cheers

Jules

-- 
And if eight out of ten cats all prefer whiskas
Do the other two prefer Leslie Judd?