Path: utzoo!utgpu!jarvis.csri.toronto.edu!mailrus!tut.cis.ohio-state.edu!ucbvax!AC.DAL.CA!BRIGHT
From: BRIGHT@AC.DAL.CA (BOB BRIGHT)
Newsgroups: comp.sys.atari.st
Subject: Re: Problem with TOS recognizing media changes
Message-ID: <8903251343.AA15964@ucbvax.Berkeley.EDU>
Date: 25 Mar 89 05:25:00 GMT
Sender: daemon@ucbvax.BERKELEY.EDU
Organization: The Internet
Lines: 45

In reply to a posting of mine concerning strange TOS behaviour when
attempting to read non-existent subdirectories, clf3678@ultb.UUCP (C.L.
Freemesser) writes:

>The problem you are having with your drive is not uncommon.
>I am assuming you have the Chinon drive in your STFM (it has the eject
>button underneath the disk slot).
>
>First off, Chinon drives are the pits.  Recent ST's have had HUGE
>problems with these drives.  Atari wisely stopped using them and went to
>Sony drives.
>
>The actual problem is that the disk-eject device the drive has, which
>tells the computer that a new disk has been inserted), has failed.  It
>is a very common problem.  It can be fixed, but the easiest way to fix
>this is to replace the drive with a GOOD mech.  The drive will probably
>fail on you soon.  If your computer is still under warrantee, get a new
[...]

I don't think that you read my posting very carefully. Yes, the drive in my
520STfm is a Chinon; and no, I don't think that the problem is with the
drive's eject/write-protect detection.  I've been reading this group for a
while, so I've heard all about the problems with those insidious Chinon
drives.  (I was under the impression, though, that the problem with media
change recognition when Atari started using the Chinon drives was due to the
way the Chinon's write-protect mechanism was wired up.  Is _failure_ of the
write-protect mechanism, rather than a wiring glitch, really all that common?)

As I noted in the original posting, my machine recognizes media changes just
fine, _except_ when I try to read a non-existent subdirectory on a disk that
has at least one other folder on it.  When I do that, no amount of swapping
disks in and out of the machine will cause <esc> to read a new directory. The
symptoms are thoroughly replicable, and moreover this is the _only_
circumstance in which I've ever noticed a problem with media changes.  And
there's also that curious behaviour when I try to read a non-existent
subdirectory on a disk that has no other folders: every fourth press of <esc>
_forces_ a re-read of the disk, though I haven't taken it out of the drive.

Correct me if I'm wrong, but this sure sounds like TOS-related behaviour to
me.  BBB

Bob Bright <BRIGHT@DALAC.BITNET>
Philosophy Dept.
Dalhousie University
Halifax, NS  B3H 3J5  (902) 424-3810