Re: ProDOS floppy crashes Mac O/S 7.6.1 running on a Powerbook 520c

[Tony Kavadias <tonzaggl@gmail.com>]

On Jun 19, 1:06 am, AppleCPM <a...@wilserv.com> wrote:
> Hi!
>
> On Jun 18, 8:04 am, Jayson wrote:
>
> > I can think of two possibilities. First, it could be an unused block marked
> > as used. Either Mr. Fixit or GSCopy should ask you at some point if you want
> > to free such blocks. Since Mr. Fix It couldn't fix it, the other, and more
> > disturbing, possibility is that two files are incorrectly sharing that
> > block. If this is the case, the data is almost certainly valid for only one
> > of those files. On FAT filesystems this is called cross linking, and is one
> > of the more dreaded problems, as one file has probably overwritten the other
> > file's data without even knowing it. What's worse, there's no way to know
> > which file has valid data and which one has incorrect data, so all repair
> > programs can possibly do is to give each effected file its own copy of the
> > effected areas and hope for the best.
>
>     The 520c is a waystation on the sneakernet route from this PC to a
> IIgs.  I formatted a 1.4 MB ProDOS disk on the 520c and use that to
> transfer files from this PC to the 520c.  That's because Ciderpress
> can copy files from ProDOS HD images, used with AppleWin, to a 1.4 MB
> ProDOS disk.  Then, after carrying the 1.4 MB disk upstairs to the
> 520c, I copied files to a disk image manipulated by the "IIe"
> emulator.  I was in the process of copying a couple of files to an
> 800K disk when the 520c went into limbo, accompanied by lots of noise
> from the hard drive in the 520c.  I can't remember what happened next
> but it's likely that I rebooted the 520c.  When I reinserted the 800K
> disk into the 520c, the O/S crashed.  Since the 800K disk was the
> destination for two files I wanted to transfer to a IIgs, there was
> nothing to lose by reformatting it.  That's when I discovered there
> was no way I could reformat that particular disk on the 520c.  It's
> when I took the problem disk to a IIgs that I discovered that the IIgs
> could display the directory of the disk and that the Apple II System
> Utilities program could verify the disk without any error.  At that
> point I decided what happened was deserving of a message in C.S.A2.
> That message is the start of the messages in this thread.  A lot of
> discussion could have been avoided if I had had the foresight to run
> "MR.FIXIT" on the disk, right then and there...
>
> Willi

Have you tried making a Macintosh boot disk with System 7.5.3 on it
and whatever version PC Exchange it comes with and try reading the
ProDOS floppy disk on that?  Mac OS 7.6 is not very good at using
ProDOS disks of any sort!

Later versions of Macintosh system software have had enough internal
changes to break PC Exchange under particular circumstances; for
example, System 7.5.5 no longer allows the Mac to format ProDOS floppy
disks without it causing Type 11 errors and bombing to the System
Error Handler.  When I approached Apple Developer Tech Support on a
few occasions regarding ProDOS volume compatibility with Mac OS
versions later than 7.5.5, all they could tell me was that the bugs I
submitted could not be escalated due to higher priorities, and that I
should use older system software in order to do what I need to do.
Not very helpful, I know, but that's all Apple engineering could
offer.

I recommend (if you have a night and a hard disk partition or HDD
floppy to spare) preparing an older system installation for your
PowerBook 520c (System 7.1.1 is the earliest, but I recommend System
7.5 Update 2.0) with PC Exchange 2.0.5 and using that to manage your
ProDOS floppies on a Macintosh.  However, if the problems persist,
you'll have to find out what's wrong with the ProDOS floppy on the
Apple II like how you guys have been discussing thus far.

Note that copy-protected disks or disks with customised boot sectors
or filesystem structures are also things that may cause problems with
PC Exchange.  Disk must be conformant with what ProDOS 8 1.2 or later
produces.

Just a thought.


--tonza