Date   : Wed, 24 Dec 1997 12:20:59 +0000
From   : Crispin Boylan <viewtronix@...>
Subject: Re: BBC hard disk

At 08:57 24/12/97 +0100, you wrote:
>Mike
>
>>Just looking at my hard disc on my Master, the components are
>>
>>Acorn badged PSU 5v 3.5a 12v 3.0a
>>1mhz bus connects to an interface board (can't see this easily)
>>Board connects to another board marked Adaptec ACB 4000 (SCUSI ?)
>>This connects to drive : NEC D5146H
>>
>>Do these part numbers mean anything to anyone ?
>
>
>Yes, the board that plugs into the 1mhz bus is the host adapter. If it is an
>Acorn winchester unit then it will probably be the Acorn board, otherwise
>Viglin etc etc or even home made is possible. This is the board that is
>described in the HardDrive.zip at the BBC Lives.
>
>The Adaptec board allows this SASI host adapter to communicate with the NEC
>drive that is RLL not SASI or SCSI. The NEC is a 5.25 ST506/412(1.3)RLL
>drive. Heads 4 Cylinders 615 and Sectors 17. Formatted capacity of 40.0MB.
>
>The adaptec board acts really as a "translator", like comparing attaching an
>SCSI drive to an IDE interface on a PC, you'd need something to go between.
>
>What we're are stumbling on at the moment is attaching this SASI host
>adapter that plugs into the 1MHZ bus to a SCSI drive which should be pretty
>much backwards compataible to it's forerunner SASI, without using an adaptec
>4000 board (which is only for ST506 drives).
>
hi
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, 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?   

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

Also, is a Winchester Disk the same as a Hard Disk, I'm pretty much sure
they are, but I just heard that the older large storage devices were always
referred to as Winchester Devices, wheras now they are called just hard disks.

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??

Thanks.


See ya!
Crispin Boylan
viewtronix@...
http://easyweb.easynet.co.uk/~viewtronix
"If there's a bright centre to the universe, we're on the planet that is
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