[LON-CAPA-admin] Problems with mimetex_valign on 2.8.0

[loncapa_admin]

Hi,

I've just been putting our set of servers through their paces before going into production, and I noticed that the Change Math Pref page was choking on the display of the mimetex box.  Safari 3.2.1 would leave the iframe empty and report an error
"http://kepler.johnabbott.qc.ca/res/adm/pages/math_example.tex?inhibitmenu=yes&texengine=mimetex -> lost network connection"
while Firefox would try to download a 0-byte length file math_example.tex.  A little further investigation found that this could cause big problems if the math display preference were set to mimetex or default.

We're running something of an unusual configuration, Fedora 9 running on ppc64 powermacs.  The LON-CAPA specific packages have been built from source, while all the other packages are up-to-date.  Since this is an unsupported architecture, I'm not sure if this is Fedora 9- or ppc64-specific, or just some weird quirk that happens on Mondays.  I have been able to (I think) narrow down the problem.

The mimetex.cgi binary is compiled correctly, and working (tested this by pointing browser to http://kepler.johnabbott.qc.ca/cgi-bin/mimetex.cgi?x^2+y^2, as well as calling mimetex.cgi from the command line).

A bit of digging led to the following discovery:  commenting out lines 249 through 279 of lontexconvert.pm (in effect forcing the variable $valign to be 0, bypassing the socket creation steps) gives a working mimetex (minus the vertical alignment, I presume).

Has anyone else noticed this behaviour?

Cheers,


Michael Dugdale
Department of Physics
John Abbott College
21275 Lakeshore Road
Ste. Anne de Bellevue, Québec
H9X 3L9

(514) 457-6610 X 5888
loncapa_admin at johnabbott.qc.ca
michael.dugdale at johnabbott.qc.ca