The Free On-line Dictionary of Computing (19 January 2023):

NUXI problem

    /nuk'see pro'bl*m/ The problem of
   transferring data between computers 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).

   See also middle-endian, swab, and bytesexual.

   [Jargon File]

   (2001-06-12)


The Jargon File (version 4.4.7, 29 Dec 2003):

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). See also middle-endian, swab, and 
    bytesexual.