o Compatibility issues with previous Performer releases:

  IRIS Performer release have a number of 3 fields: Major.Minor.Maint
  Maintenance releases are binary compatible with all versions of
  the same Major.Minor base release.  For example, 2.0.1, 2.0.2, 2.0.3
  and 2.0.4 are all binary compatible with each other and are
  all binarcy compatible with their base release, 2.0.  Maintenance
  releases contain bug fixes and the highest maintenance number will
  be the most recent release.  Different Major.Minor releases are not
  binary compatible; ie: IRIS Performer 2.0 is not binary compatible
  with IRIS Performer 2.1.  For this reason, IRIS Performer releases
  include compatibility libraries from previous releases (properly
  versioned and suffixed for the IRIX environment) so that old
  IRIS Performer applications will continue to run without re-linking.
  
  Performer compatibility issues with IRIX 5.3:

  Applications created with IRIS Performer 2.0 using IRIX 5.3 also
  run under IRIX 6.1 and later IRIX releases in 32-bit mode.  The
  32-bit applications created using IRIX 5.3 will not make use of
  64-bit address space and other MIPS III/IV features provided by the
  IRIS Performer N32 and N64 development environment under IRIX 6.2
  and later operating system releases.

  Note that applications built on an IRIX 6.1 or 6.2 systems are not
  guaranteed to run properly on 5.3 systems, due to changes in
  structures used by system libraries. (This is true even for
  applications that do not use IRIS Performer-- applications built on
  later versions of IRIX may not run on earlier ones).  Therefore to
  produce an O32 executable that will run on all SGI systems 5.3 and
  later, the compiling must be done on an IRIX 5.3 system.

  Performer compatibility issues with IRIX 6.1:

  Applications created with IRIS Performer 2.0 under IRIX 6.1 can be
  compiled and linked for 32-bit IRIX 5.3-style execution (known as
  Old 32-bit mode, or O32) only.  IRIS Performer programs built for
  the two new executable types (N32 and N64) are not operable on
  pre-6.2 systems -- specifically, they will not run on IRIX 5.3 or
  6.1 systems.

  O32 IRIS Performer programs will run on IRIX 6.1. However, the
  OpenGL development environment of IRIX 6.1 is not as full featured
  as the 32-bit OpenGL of IRIX 5.3 or IRIX 6.2. This can cause both
  low-performance and lack-of-feature problems for developers
  creating OpenGL applications. For this reason, developers are
  advised to build only IRIS GL applications on IRIX 6.1 systems or
  to upgrade to IRIX 6.2 for access to its enhanced 32-bit and 64-bit
  OpenGL development environment.

  Performer compatibility issues with IRIX 6.2:

  IRIS Performer 2.0 and 2.1 are compatible with IRIX 6.2 and later 
  IRIX relases.  Applications can be developed for all three execution 
  modes: O32, N32, and N64.
  The IRIX 6.2 32-bit and 64-bit OpenGL implementations have the
  RealityEngine feature extensions and performance enhancements found
  in IRIX 5.3. For this reason, developers are urged to use IRIX 6.2
  or later rather than IRIX 6.1 for OpenGL development. As mentioned
  above, IRIS Performer applications built in either N32 or N64 mode
  will not run on IRIX 5.3 or 6.1 systems, and, in general,
  applications should not be run on earlier versions of IRIX than the
  machine on which they are compiled.

  Applications using Performer 1.2/IRIX5 are binary compatible with
  machines running Irix 5.2, 5.3, 6.0, and later IRIX releases
  without relinking.

  IRIS Performer 1.0 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
  1.0 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 1.0 binary compiled and linked under IRIX
  releases earlier than 4.0.5F will 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.