Date   : Wed, 20 Jul 2005 01:23:56 +0100
From   : jgh@... (Jonathan Graham Harston)
Subject: Re: floppy discs

"BeebMaster" <beebmaster@...> wrote:
> Actually this doesn't seem to happen as I've just tried it on my Cumana
> 40/80 drive set to 40 track and it carried on quite happily after track 39,
> although having run it a few times it seems as if there may be a built in
> idiot mechanism on the drive to prevent the head being damaged because it
> does give a clunk-click sort of sound for every track after 40.
 
Most drives tend to have two track switches. On that detects the
head arriving at track zero, and one that detects the head
reaching the maximum track the drive can reach. On hitting these
switches the drive refuses to step any further. On getting to
track zero the TRACK0 line on the drive connector is also
asserted.
 
Note that a lot of drives don't have anything that stops them
stepping past the maximum track other than the physical end of the
stepper.
 
-- 
J.G.Harston - jgh@...                - mdfs.net/User/JGH
RISC OS Choices System - http://mdfs.net/Software/RISCOS