MacOS 10.4.8 Causes IDL Segmentation Fault

QUESTION: Last night I upgraded my MacOS to 10.4.8 and now every time I run IDL from X11 it crashed with a segmentation fault. Does anyone know anything about this?

ANSWER: As of 4 November 2006, things are still a little uncertain as to what this might be. Karl Schultz has looked into it, and he presented this preliminary appraisal to the IDL newsgroup.

Yes, I've been looking at this recently, and have collected some hopefully useful information.

IDL PPC binaries of any release now appear to crash when running on an Intel Mac under Rosetta emulation with OS X 10.4.8. The problem didn't occur with OS X 10.4.7. The crash logs indicate a crash in libXt. Since the *only* change made to the environment where I observed all of this was upgrading from 10.4.7 to 10.4.8, I am inclined to suspect the Apple update to 10.4.8.

Some web searching reveals that there are more than a few problems with the 10.4.8 upgrade on Intel Macs. One person reported a similar crash with Matlab 7.1 under the same conditions. The report indicated that the Matlab crashes started after the upgrade to 10.4.8 was applied. Same situation, same problem, I think. One could also extend this thought to the possibility that any PPC binary X11 application running under Rosetta on an Intel based OS X 10.4.8 might crash.

Therefore IDL users of versions prior to 6.3 probably should not upgrade their Intel Macs to 10.4.8.

IDL 6.3 users should really get the Intel binaries for IDL that are available from ITTVIS. Not only would this relieve this particular 10.4.8 problem, but the Intel binaries run faster on the Intel Mac.

The PPC-based hardware does not seem to be adversely affected by this OS X upgrade.

I'm going to go ahead and report this problem to Apple, and all we can do is hope that they'll take the time from the Leopard schedule to release a patch for this seemingly defective OS X upgrade.

That's the best I can do for now.

November 2, 2006 Update:

Apple has come up with an update to Mac OS 10.4.8. Several IDL users have reported that the update fixes the memory corruption bug and allows PPC X11 clients to run normally.

An even easier way to get the update is to run Software Update on your Mac, according to Ken Bowman. You will see:

   X11 Update 2006         1.1.2          51 MB

This is different from the XCode security update.

Setting up Your OS X Computer for Science

Several people have asked me for additional information about setting up their Macintosh computers for science applications. I can recommend OS X for Astronomers as a site with useful information.