AIX Version 4.3 Differences Guide

Chapter 2. AIX Kernel Enhancements
This chapter examines the changes in the AIX base kernel that are new with AIX
Version 4.3.
2.1 Binary Compatibility
The AIX architecture and development teams place a very high priority on
ensuring that binary compatibility exists for customers who want to migrate their
applications to later versions of AIX. The following sections explain the extent of
this compatibility and the few areas where problems may arise.
2.1.1 Compatibility between AIX Version 4 Releases
Applications written using earlier releases of AIX Version 4 (Release 1 or Release
2) for RS/6000 POWER, POWER2, POWER3, and PowerPC-based models, can
be executed on AIX Version 4 Release 3 without recompilation for the same and
newer models in that processor family (POWER, POWER2, POWER3, or
PowerPC). The exceptions to this statement are applications using:
• Non-shared compiles of AIX shared libraries
• Features explicitly described as non-portable by IBM in the AIX Version 4
reference manuals
• Undocumented AIX internal features
• X11R5 server extensions (AIX Version 4.3 Only)
• Applications compiled using POWER2-, POWER3-, or PowerPC-specific
compiler options but executed on models other than POWER2, POWER3, or
PowerPC.
Note: Applications compiled on a given release level of AIX Version 4 may not
operate properly on systems running an earlier release of AIX Version 4.
Any program intended to run in all environments, POWER, POWER2, POWER3,
and PowerPC (601 and newer PowerPC processors), must be compiled using the
common mode option of the compiler. Programs compiled to exploit POWER2
technology must be run on POWER2-based processors. Programs compiled to
exploit POWER3 technology must be run on POWER3-based processors.
Programs compiled to exploit PowerPC-based technology must be run on
PowerPC-based processors. Existing binaries do not need to be recompiled to
operate on the target processors.
64-bit applications produced using AIX Version 4 Release 3 on any of the 32-bit
processor models, or the 64-bit processor models, will execute without
recompilation on the 64-bit processor models. 32-bit applications produced using
AIX Version 4 Release 3 on either 32- or 64-bit processor models will execute
without recompilation on both models.
2.1.2 X11 Compatibility
The AIX 4.3 X-server has been upgraded to the X Consortium Release 6 version
of X (commonly known as X11R6). The libraries shipped by IBM with X11R6 are
backward-compatible, and the client applications that access these libraries will
© Copyright IBM Corp. 1998 13