[OS X TeX] The Font Cache Problem

[Richard Koch]

Folks,

Many of you are aware of the following bug: you'll be running one or  
more TeX front ends and/or utilities and suddenly the mathematical  
symbols will disappear in the preview output. Further inspection shows  
that a different font without these symbols has been substituted for  
the correct font. Once one application has the problem, other TeX apps  
also have font problems, even if closed and restarted. To fix the  
problem, it is necessary to reboot the machine or use a utility to  
clear the font cache.

The problem seems to be caused by incorrect data written into the font  
cache by Apple system software. Most users never run into the problem,  
while others have persistent trouble. We have inspected source files  
from the unfortunate users, and the sources appear to be absolutely  
straightforward TeX code using standard TeX fonts.

This morning a user provided a possible clue. I'd like people on this  
mailing list (with the problem) to see if his clue is consistent with  
their own use of TeX.

This user had two machines running Leopard, a PPC and an Intel  
machine. He only had the problem on the Intel machine. If he rebooted  
and just ran a few standard TeX apps, he was fine. But he used  
Equation Editor and/or Equation Service for a while, the problem would  
surface. (Is Equation Service a separate app, or just a service  
provided by Equation Editor?)

Then he noticed that his Equation Editor used PPC code and was running  
under Rosetta. He managed to find the source code and compile it under  
Intel, and then the problem vanished.

He concluded that the real culprit is Rosetta. I tend to agree. Cocoa  
apps call Apple system software to image PDF data, and that system  
software in turn calls font machinery. So it is very hard to imagine  
how a bug in application code could cause problems in the font cache.  
But a Rosetta bug makes perfect sense.

If your own experiences confirm this connection, we'll finally be able  
to report the problem to Apple.

Dick Koch
koch at math.uoregon.edu