Mac PC Exchange Woes for CD-ROM Burning

Date: Fri Dec  4 16:32:25 MST 1998
From: David Cain <bite-me-spamboy@mindspring.com>
Subject: Mac PC Exchange Woes for CD-ROM Burning

Toast supports long filenames, but versions of PC Exchange in Apple systems up to System 8.1 do not correctly support them, and System 8.1's PC Exchange is broken, too.

The upshot is, if you're using, say, a Jaz disk to quickly test your Xplat project (handy, since you can quickly move the whole volume back and forth between machines), and if you're on a system < 8.1, then you'd better use 8.3 filenames, lest PC Exchange truncate them to that MYFILE~1.DXR gibberish. PC Exchange 2.2 and System 8.1 don't truncate them, but don't exactly work, either.

It's worth noting here that ALL versions of PC Exchange I've encountered since MacOS 7.5 have been broken in one way or another:

Versions < 2.1.1 (fixed in 2.1.1 - System 7.6) suffer from the evil "infinite folder recursion" bug (every new folder becomes a system folder which contains the contents of the root of the disk, which contains the new folder which is a system folder, which contains the root of the disk, which contains...) that will completely hose the file/folder structure of a disk (only way out is to salvage what you can and reformat).
Versions < 2.2 (changed in 2.2 - System 8.1) don't handle long filenames properly.
Version 2.2 (System 8.1) mangles long filenames on locked volumes (my notes below - long).

Also, if you're using a Novell network (We are, don't ask me why. Did at every shop I've worked in since 1994, too), you are still restricted to 8.3 names for files transferred to Novell servers (this gets really messy 'cause Macromedia's Xtras don't even follow the 8.3 convention).

The upshot is that on the verge of 1999, it's STILL only safe to use 8.3 filenames for work to be delivered on Win95.

PC Exchange 2.2 mangles long filenames on locked volumes

The basics:
PC Exchange 2.2 cannot distinguish between long filenames whose first 6 characters and file extension are identical IF the PC volume on which they reside is locked prior to insertion into any Mac.

For myself, a multimedia developer burning Mac/PC discs with Toast, this will be a constant problem. The bug could affect hundreds, thousands of files, or perhaps just a few files buried somewhere in 650 MB of data. Either way, it takes a lot of time to diagnose.

I ALWAYS lock my PC volumes before insertion into a Mac drive so PC Exchange doesn't get a chance to write garbage FILEID.DAT, RESOURCE.FRK, FINDER.DAT files and folders all over my PC disks.

Background

For long filenames, PC Exchange 2.2 now uses the Windows method of placing long filenames in the 8.3 namespace. For example, "macintosh files.txt" would look like "MACINT~1.TXT" if viewed in a DOS window. Note that only the first 6 characters of the name and the file extension match the actual filename.

Steps to repro:
Given 3 files with long filenames on a PC:

DestinationUnknown.txt
Destin FL tax ofc.txt
Destiny-mix.txt

the 3 files appear thus in the DOS environment:

DESTIN~1.TXT
DESTIN~2.TXT
DESTIN~3.TXT

Place the 3 files on an otherwise completely empty PC disk (Jaz and Zip tested - I'm assuming any volume will demo this behavior).

Write-protect the PC disk

Insert in a Mac running MacOS 8.1 with PC Exchange 2.2

You can see the files, but only one of the 3 will open. The other 2 give an alert message which indicates that the files cannot be found. (Toast will also catch this situation in its verification step).

If you perform these same steps, but instead do NOT write protect the disk, PC Exchange scans the disk, writes FINDER.DAT, FILE ID.DAT and RESOURCE.FRK files and folders all over the disk. Once this has been done, the Mac will be able to find and open all the files. Haven't tested whether this operation requires that you eject the disk after removing write protection (with Iomega tools, for example) in order to be able to open the files.

Files which do NOT have long names, but which DO have the first 6 characters identical:

YELLOWBK.TXT
YELLOWAT.TXT
YELLOWWH.TXT

Are correctly opened by PC exchange under the circumstances which cause long filenames to break.

Have not tested for behavior with long folder names.

Workarounds:

Unprotect PC volumes and allow PC Exchange to scan and write on your PC disks. Then spend all afternoon poring through 650 MB of data and removing the garbage files when you bring the disk back to the PC. Yuk

Stick to 8.3 filenames

if burning CDs is your main goal, and you have all day to kill, differentiate the filenames on the PC side somewhere in the first 6 characters:

1DestinationUnknown.txt
2Destin FL tax ofc.txt
3Destiny-mix.txt

and then rename the files to their original names in Toast for the burn to the CD.

Clocks go slow in a place of work - minutes drag and the hours JERK!

= the Clash - Magnificent Seven =