Toon, You could stick with the coding which people could read on 32 bit systems( which is what Portland group has done, and what is done on the SGI mips machines). This is to use a 4 byte integer for the record length, which is a mighty large single record. This would only inconvenience the pioneers, who expect to have arrows in their back anyway. It would also allow all the existing g77, etc. generated unformatted files to be used as is. Having arrived on the frontier at this point, obviously I would be making this arguement, but as part of the appeal of the opterons is that you can go gently into the 64bit computing world, moving toward a consistent format with the existing standard makes sense to me (especially since I can't imagine having a single record of such a large size). Is this code I could possibly get in and hack myself? I suspect not, since c is my second language, but if it would be something I could get involved in and make a positive contribution towards, I would attempt it. ( I might also see if I could implement a byteswapping option). However, having said that, and looking realisticly at my aptitude and my amount of free time available, it's kind of like my 8 year old offering to drive me somewhere. At any rate, I appreciate your response, and all the work that has gone into those compilers. My contributions have been limited to purchases of books from FSF, and I do appreciate them. Cheers Mike