>I believe it has something to do with 16bit/32bit operating systems, and yes I agree one can use unsigned file sizes.
>
>Maybe just a correction, I believe it is not 2Gb file sizes, but actually 2Gb records. X# allows 4Gb records and file size only limited by max file size the OS can handle, which if my memory serves me right is 4Tb.

It was the filesize too, at least for LLFF (low level file functions, for those who forgot) and various other methods of output into files.