Date   : Tue, 18 Mar 2008 20:31:28 +0000
From   : pete@... (Pete Turnbull)
Subject: Disc drive power

On 18/03/2008 13:54, Jules Richardson wrote:

> There's no 'smarts' on a standard Shugart-a-like floppy drive - it needs 
> something to tell it when to step the heads and read/write data. So you still 
> need some sort of microprocessor solution to copy between two drives (although 
> doubtless something could be bodged with a handful of LS-TTL chips :-)

I read Ian's post as meaning he hoped to connect a 3.5" drive at the 
same time as a 5.25", ie both connected to a computer (eg a Beeb) at the 
same time, not that he was thinking of copying drive-to-drive with 
nothing elsde involved.

> * Hmm, you're not forgetting that the BBC has +12V available on the AUX power 
> connector are you? I have/had several beebs over the years with external 
> drives that were powered from this connector. I'm not sure you could quite get 
> away with two 5.25" drives powered this way (the load might be too high), but 
> 3.5" + 5.25" might be OK.

It has +5V, +12V, and -5V.  Acorn's original dual 80-track drives, which 
were full-height Olivetti units, ran off the aux power connector quite 
happily, though they weren't particularly power-hungry by the standards 
of the day.

-- 
Pete                                           Peter Turnbull
                                               Network Manager
                                               University of York