The Nuxi problem

UNIX was ported to the IBM Series 1 minicomputer. The Series 1 had the same size words (two bytes) as the PDP-11, but the bytes were swapped. Hence, when the machine started up for the first time, it printed out "NUXI" instead of "UNIX". Ever since then, the "NUXI problem" has referred to byte ordering problems.
[Communications of the ACM, Vol. 26, No. 12 -- December 1983]
NUXI problem /nuk'see pro'bl*m/ /n./
Refers to the problem of transferring data between machines with differing byte-order. The string `UNIX' might look like `NUXI' on a machine with a different `byte sex' (e.g., when transferring data from a little-endian to a big-endian, or vice-versa).
[ The Jargon File v 4.0.0 ]