Subject:   -12- Binary Compatibility on different releases
Date: 8 Apr 1994 00:00:01 EST

  IRIS Performer requires IRIX 4.0.5 or later.  Because IRIX 4.0.5F
  added several new GL calls to support RealityEngine features, an
  application that uses GL routines or tokens found only in 4.0.5F and
  later does not run properly under 4.0.5, 4.0.5B, or 4.0.5C.  When run
  on these earlier IRIX releases, an IRIS Performer application making
  calls to GL functions or using GL tokens that are undefined in the
  run-time environment cause run-time errors or undefined behavior.

  An IRIS Performer binary compiled and linked under IRIX releases
  earlier than 4.0.5F, run under IRIX 4.0.5F and later, but some
  RealityEngine features are not directly accessible to the
  application.  An application can still access RealityEngine features
  supported automatically or explicitly through IRIS Performer when
  linked with IRIS Performer shared libraries.

  Running a IRIS Performer application built with IRIX 4.0.5 on IRIX
  5.X is not recommended.  In particular, multiprocess applications
  cannot take advantage of all processors.  Also, because IRIX 4.0.5's
  relaxed shared memory accounting was replaced by a despotic and
  stricter regime under IRIX 5.2, a Performer application built on
  4.0.5 will need a much larger amount of swap space to be allocated up
  front unless PFTMPDIR is used to specify a memory mapped file.