Date   : Sun, 09 Sep 2001 15:47:37 +0100
From   : "Colin Fraser" <colinf@...>
Subject: Re: XFER

> -----Original Message-----
> From: owner-bbc-micro@...
> [mailto:owner-bbc-micro@...]On Behalf Of Michael McConnell
> Sent: 09 September 2001 12:08
> To: Colin Fraser
> Cc: 'BBC mailing list'
> Subject: RE: [BBC-Micro] XFER
>
> That strikes me as odd - I know there are issues with 5.25in
> discs, but
> 3.5in should be fine...
>
> Are you trying to use an HD disc as a DD one? This as I've
> discovered is
> prone to failure...

I was trying to read and write 720k disks on a very recent floppy drive.
It just wouldn't do it, either with HD or DD media.
I thought it might have been a BIOS problem on my PC, but when I swapped out
the new floppy drive for an older drive I knew I had successfully used for
720k disks in the past, it worked OK.
Probably the new drive couldn't handle the write clock required for 720k.

Floppy drive manufacturers seem to be reducing costs by stripping down the
electronics to the bare minimum, and in some cases only supporting 1.4M
disks.
I have modified a number of floppy drives for use in old Akai S900 samplers,
which requires changing some of the jumper settings on the drive board.
These jumpers are also disappearing, presumably also to save costs.
It's getting to the point where I'm stockpiling a few older 3.5 inch drives
as spares...

BTW HD disks can be used succefully in DD drives, but may lose data.
HD disks use a magnetic surface that requires a higher strength magnetic
field to write them.
Data longevity will be reduced if you write them with only DD strength.
This should not be a problem if you write a HD disk at 720k format in an HD
drive, as the density select switch should enable the higher write current,
even tho' the disk is being formatted 720k style.

Colin f