Date   : Wed, 12 Oct 2005 23:03:26 +0100
From   : jgh@... (Jonathan Graham Harston)
Subject: Re: 3.5" Floppy For A Master

Jeff Gaines <jeff@...> wrote:
> I have read Andy Davis's article on converting an Amiga or ST external
> drive, I'm not sure that having a 5.25" BBC floppy helps any because
> if I understand it the BBC drive runs on 5 volts and ordinary floppies
> need 12v and 5v. I kept the powered case I had, designed to hold 2
> floppies, until I had a clean out last year, b*gger, b*ugger, b*gger!
 
All Acorn machines have an auxilary power socket that gives you 5v
and 12v to power a disk drive (or other equipment) from. Just plug
the disk drive data lead into the disk drive socket and the power
lead into the power socket.
 
As far as a BBC/Master is concerned, a disk drive is a disk drive
is a disk drive.
 
An 8271 as used in a BBC with DFS 0.xx or 1.xx can only do single
density, giving a maximum of 400K per disk. A 1770 as used in the
Master or the BBC B/B+ with DFS 2.xx can also do double density,
giving a maximum of 640K per disk.
 
DFS 1.20 has a couple of timing problems with 3.5" drives that are
fixed in DFS 1.21.
 
You should only use double density/blue/single hole 3.5" disks,
not high density/black/two hole disks, unless you want data
deterioration. The magenetic media has different coercivity, and
though you may be able to successfully persuade a machine to write
to a disk, you will have no guarantee that any data so written
will be re-readable.
 
> Can anybody think of any type of external enclosure available nowadays
> that has built in power and that I could persuade a floppy drive into?
 
There's a black ABS enclosure, approximately 95x35x100mm, sold by
Maplin that's just the right size to mount a 3.5" drive in. I
can't find it in my catalogue at the moment, and I didn't make a
note of the order code last time I dispatched one.
 
> Or a way of making use of the 5.25" floppy?
 
Put it in a 5.25" drive?
 
> I could be the proud possessor of a Master soon-ish with no way of
> getting any apps on to it :-( I do have my old cassette recorder with
 
As to 720K DOS floppy. Use Sprow's DOSFS on the Master.
 
-- 
J.G.Harston - jgh@...                - mdfs.net/User/JGH
There are three food groups: brown, green and ice cream.