Date   : Fri, 14 Oct 2005 10:37:09 +0100 (BST)
From   : Tim Fardell <tim.fardell@...>
Subject: Re: 3.5" Floppy For A Master

On Fri, 14 Oct 2005, Eelco Huininga wrote:

> Hmmm I always thought HD drives could be switched between the DD and HD 
> modes by an extra input signal (pin 2 I think). So if drives auto-detect 
> the density of floppydisks, what is this signal for then?

I had a Compaq-branded drive that actually examined the disk to determine
whether it was HD or DD, ignoring the sensing hole. The LED would be red
for DD and green for HD, and it would allow you to format any type of disk
to any format :-) I wish I still had that drive :-(

Incindentally, I have made a lot of use of HD disks in DD drives, and have 
yet to experience any problems with them.