Lessons Learned from Porting

• In my experience, most portability problems come from programmer laziness, expressed as ambiguity.

• Bad assumptions about objects all being 32 bits!

  • IA-64 is “LP64” Integers 32 bits, Long and Pointers 64
  • Compiler “implicit declaration” warnings are really errors

• Mixing PIC and non-PIC at linker time is a bad idea...

• Not all platforms have all features

  • Serial consoles on servers
  • No sound hardware on mainframes

• New architectures MUST track development kernel and toolchain revisions, or upstream maintainers ignore them