[flygoat]

I'm planning to do something low-level, just wonder that how stable is IRIX's syscall ABI?
Is there any major syscall breakage between versions?

Knowing that *BSDs are breaking syscall ABI all the time, while Linux won't break syscall ABI, what's the position for IRIX?
I saw IRIX5 is used in ELF to identify ABI even for IRIX6.5 binaries, does it mean IRIX's syscall ABI is stable since IRIX5?

Perhaps the easiest way to figure that out is diff includeds under sys/ between versions. Just want to know if anybody have relevant information.

[Raion]

The syscall stability of IRIX between 6.5.16 and up is essentially reasonably stable yes. All of the 6.5 derivatives are very close to each other but at one point they added some extensions which makes a lot of binaries that are compiled for newer versions incompatible.

6.2, 5.3 etc. Are much different under the hood

[robespierre]

Binaries compiled for IRIX 5.3 will run unchanged on all versions of 6.2 and 6.5. The kernel uses different interfaces based on the ABI of the process (applications compiled for 5.3 use the "O32" ABI).

[Raion]

Right, as long as they're not COFF it'll work fine on IRIX, but it won't work fine in the other direction