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

[AppleCPM <a2@wilserv.com>]

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