Date   : Mon, 27 Apr 2009 11:43:19 +0100
From   : michael.firth@... (michael.firth@bt.com)
Subject: ADFS Drive Numbers

> -----Original Message-----
> From: 
> bbc-micro-bounces+michael.firth=bt.com@... 
> [mailto:bbc-micro-bounces+michael.firth=bt.com@...
> .uk] On Behalf Of Ian Wolstenholme
> Sent: 27 April 2009 11:20
> To: bbc-micro@...
> Subject: Re: [BBC-Micro] ADFS Drive Numbers
> 
> There aren't any jumpers on the host adapter boards I have, and I
> don't want to go messing about cutting anything on them!  It 
> seems like
> the host adapter will only listen to a controller board with 
> ID 0 and the
> controller board will only listen to discs with IDs of 0 or 
> 1.  It looks like
> I can't plug a second Winchester disc into the back of the 
> first one, even
> changing the drive ID of one of them, presumably because both host
> adapters are trying to be mapped into the same area of RAM.
> 
> I would have thought this would have been possible, though.  
> Presumably
> it wasn't beyond the bounds of possibility when the Acorn 
> Winchester Discs
> came out that some installations (like large Econets) might have two
> Winchesters connected to the same BBC server?
> 
> Having said that, I remember occasionally at School trying to 
> log on in the
> computer room and receiving "User not known" and the teacher 
> remembering
> that the Girls' Winchester was plugged in, and going to the M128 and
> unplugging it and connecting the Boys' Winchester!  (Which 
> was bigger by
> the way!)
> 
> Could I perhaps connect two controllers to the same host adapter board
> with a 50-way cable with two headers?
> 
> I've successfully connected two Winchesters to the same 
> Adaptec controller
> previously. I was going to do this yesterday to take a backup 
> of the Technomatic
> (probably not the most logical thing to do given the hardware 
> problems, but
> by far the most straightforward!)
> 
> However, like all best laid plans, I found that I only have 
> two "loose" Winchesters
> here.  All the other ones have gone into storage, and the two 
> here were formatted
> on an ACB4000, so I can't read them on the Technomatic's 
> ACB4070 to see if
> there's anything on them before I overwrite them!
> 
> Best wishes,
> 
> 
On the Adaptec board there should be one 34 way header, and two 20 way headers
- see the picture here:

http://www.dmc12.demon.co.uk/retrotech/largeimages/ABCScsiMFM.JPG

The extra 20 way header you need is the one in between the existing 20 way
header going to the hard drive and the 34 way header going to the hard drive.

To connect up two ST506 drives to the Adaptec controller, you need to connect
the 34 way header in parallel to both drives, and one 20 way header to each
drive.

To do this you'll need a version of the 34 way cable with one header to connect
to the Adaptec board, and two edge connectors to connect to the hard drives,
plus two of the standard single 20 way IDC to edge connector cables.

As an alternative, on JGH's site, there is a backup utility for copying a
SCSI hard drive to an IDE one:

http://www.mdfsnet.f9.co.uk/Info/Comp/BBC/IDE/ADFS/

The only thing is that you'll need an IDE interface that can have its address
changed, and I don't think the Retroclinic ones support this.

Regards

Michael