NPWDEF alters files in much the same way that ResEdit can. Therefore, all the standard warnings about doing things with ResEdit apply to NPWDEF. Work on duplicate copies and back up your files before running NPWDEF. Above all, be careful and see the disclaimer.
What it does
NPWDEF (short for No Purge WDEFs) deals with a potential source of instability in the Mac OS. If an application or control panel uses a custom resource of type 'WDEF' that is purgeable, the application could crash under certain circumstances. Vik Rubenfeld reported this problem on comp.sys.mac.programmer October 8, 1996, and received a reply from Apple. I have included that posting below. The problem reportedly becomes more acute under low memory conditions and System 7.5. NPWDEF sets all resources of type 'WDEF' that it finds to unpurgeable, thus eliminating this possible problem. You could use ResEdit to fix all your files by hand, but NPWDEF can fix all the files inside a folder or disk at one time.
You probably have an application or two on your hard drive that has a purgeable WDEF, for example, Microsoft Word and Microsoft Excel. Note that although the System file contains purgeable WDEFs, the problem does not apply to it.
To use it
NPWDEF is fully drag and droppable; simply drag and drop any file, folder or disk onto the icon, and NPWDEF will set all WDEFs it finds that are purgeable to be unpurgeable. Or choose 'Open' from the File menu and choose the desired disk, folder or file. NPWDEF will search and examine all enclosed subfolders and files. NPWDEF can't modify files that are already open, so it won't work on open applications or the active System file.
NPWDEF should run on any Mac that is running System 7.
NPWDEF lets you know what it's doing and tells you about any files it finds that have purgeable WDEFs. If there is sufficient interest, I will add a log file and an option just to scan for purgeable WDEFs, rather than just forcing them to be unpurgeable. If you would like this feature, let me know at the contact address below.
Disclaimer
Normally an app relies on a resource being unpurgeable rather than purgeable, but it is entirely possible that some application depends on having a purgeable WDEF. I can't imagine why someone would do it that way, but it is possible. Therefore, using NPWDEF could actually make your app more unstable.
Also, as noted in the warning above, NPWDEF messes with resources. It could do something to your system that will make it worse rather than better. It could even hammer your disk so badly that you lose everything on it. I honestly don't think it will, but I don't know for sure and can't test it beyond a couple of Macs I have. I certainly haven't tested it on very many different versions of the Mac OS or with all the extensions and applications out there. At any rate, use this software at your own risk! Be careful. Back up important data.
Distribution
No Purge WDEFs 0.5 is copyright 1996 Sterling Augustine
No Purge WDEFs is freeware, but I retain the copyright. When distributing it, you must include a copy of this file. If NPWDEF is included in any software compilation distributed for money, such as a CD-ROM, the distribution must send me a copy of the compilation.
Contacting me
Snail mail
Sterling Augustine
100 Norman St.
Lafayette, LA 70508
Email
Sterling_Augustine@shodor.org
Version History
0.5b1 October 11, 1996: First Public Release
Vik Rubenfeld's Orginal Posting with the reply from Troy Gaul
