Dave et al, I found the issue I was seeing with boost::filesystem::file_size() a few weeks ago, but figured I should post it here (now that i'm back from Burning Man and all that) in case anyone else is interested. It's not the fault of Boost -- it's gcc. On PPC Macs, compiling using --fast makes boost::filesystem::file_size() return a bad value, though on Intel Macs, --fast is fine. It might be a gcc (or maybe Apple's specific version of gcc) bug, or maybe --fast indeed works differently on PPC and x86. I found it interesting :-)
Note the OP said Intel and PPC. The processor type is the only determinant of byte ordering that I know of.
But some processors have switchable byte ordering for data access. See the Bi-endian hardware entry in:
Yow, PPC is one of those. Sorry!
Regards, John Falling You - exploring the beauty of voice and sound http://www.fallingyou.com