I'm starting to do some development work on my iBook; the code is just number-crunching code, and has to be portable between Linux (i386) and OS X. (The target platform is actually Linux, but that's not where I'm doing the development). Anyway, one of my programs does a bunch of calculations and then writes out binary format files that contain lots of numbers and some characters. (Other programs read these files in.) If I run the same program on my Linux box and my iBook and md5sum them, I find the output files have different md5 fingerprints which is worrisome. Is this just a symptom of the internal representation of numbers/characters being different on the two boxes? Or is it something potentially serious?