Date   : Sat, 11 Jan 1997 18:07:33 +0000
From   : Mike Tomlinson <mike@...>
Subject: Re: Hard disc interfacing

In message <Pine.LNX.3.95.970111165123.8849A-
100000@...>, Gelfling <pjh28@...> writes
>Does anyone know the standard (if there is a standard) pin labelling for
>winchester drives, and which connection goes to which pin on the 1MHz bus?
>The type of drive I'm considering buying is an old and big PC drive, about
>5x10x20 cm, and has a 34-way (I think) PCB connector at the back, possibly
>also a power connector somewhere but I haven't been able to inspect it
>properly.

You can't just use a "big and old PC drive" straight off.

Winchester drives for the BBC use a two-stage conversion process. The
1Mhz bus is connected via a host adapter board to an Adaptec SCSI-to-MFM
converter, to which a standard MFM hard drive is connected.

Software consists of talking to the host adapter, which addresses the
Adaptec board, which then converts SCSI commands into C-H-S (cylinder,
head, sector) requests to the hard disc.

You would be much better off looking for a secondhand Acorn Winchester,
or one of the derivatives from Technomatic, Viglen, Watford, etc..  They
all operated on the same principle.


-- 
Mike Tomlinson
Tijd is geld.