Date : Fri, 25 Jul 2003 15:44:59 +0100 (BST)
From : Jules Richardson <julesrichardsonuk@...>
Subject: Re: Weird batch of BBC stuff.
> I've just obtained a weird batch of stuff from an educational source. It
> came to me as a job lot so I'm not sure if it's supposed to operate together
> or if all the parts are distinct.
Sounds like it might be two seperate systems - possibly a Domesday setup plus
something else - maybe part of a video editing suite?
I haven't physically seen one of the Domesday sets for a few years now so can't
remember exactly what they involve now.
I'd be interested to hear anything that you find out about it anyway (I love
collecting obscure Acorn kit! :-) plus details of what's inside the cases for
the two machines. Any chances of being able to put some photos up somewhere?
> SCSI to Male 9 PIN D-Type plug (SCSI end fits the SCSI connectors on Cumana
> MO and CD-ROM drives).
> 25 PIN D-Type Male to 9 PIN D-Type female (25 PIN end fits RS-232C port on
> back of laserdisk players)
Hmm. The smallest number of pins you can get away with running SCSI over is
more then 9; you'll need 8 lines just for the data. Looking at the connections
for the Apple 25-way SCSI connectors, 6 of those are signal ground so you could
just get away with 20. Maybe it could be bastardised with a few less (making
assumptions about certain signals at both ends), but still more than 9...
I always thought - at least for a Domesday setup - that the players were SCSI.
The host was a Master I believe, and was equipped with a SCSI controller
(mounted internal or external, I'm not sure) presumably running via the 1MHz
bus. Maybe I'm misremembering and those Sony players were custom built by Sony
the drives may well have been SCSI internally but with a SCSI-serial
conversion board mounted within the player.
Is the Cumana drive SCSI? If so - and the BBC's look stock from the outside -
it sounds like you're missing a SCSI controller :-( Maybe it's more serious
than that, and you're missing an entire machine - the BBC's might only have
been used essentially as terminals for controlling software. The drives might
well have hooked up to something that you don't have.
Anyone else able to shed some like on this? As I say it's been a few years
since I've seen a Domesday system so can't remember details now, and that's
even if this is anything to do with one of those...
cheers
Jules
====
Backward conditioning: putting saliva in a dog's mouth in an attempt to make
a bell ring.
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