He handed it over to a computer science graduate (i.e. a non-physicist) who really liked all the modern trends in CS. Now, five years later:
1. the tarball is an order of magnitude larger
2. the input files are now all impenetrable
3. the code requires access to the outside (not possible on many superclusters)
4. he re-indented everything for no apparent reason
5. the variable names were changed, made into combined types and are much longer
6. as a result, the code is basically unreadable and nearly impossible to compare to the original formulae
7. code is duplicated all over the place
8. it now depends on unnecessary libraries (like the ones required to parse
9. it's about four times slower and crashes randomly
10. it generates wrong results in basic cases
To quote Linus Torvalds: "I've come to the conclusion that any programmer that would prefer the project to be in C++ over C is likely a programmer that I really *would* prefer to piss off, so that he doesn't come and screw up any project I'm involved with."
Fortran, apart from being a brilliant language for numerical math, has the added benefit of keeping CS graduates at bay. I'd rather have a physicist who can't program, than a CS type who can.
(Apologies to any mathematically competent computer scientists out there)