[rwmj]

It is not available on all arches though.

Although in practices the arches that lack a native OCaml compiler don't matter.

In RHEL we ship OCaml natively for everything except S/390 and AArch64. AArch64 will be important, but since hardware doesn't exist in a form you can buy for servers, we're happy to wait for upstream to implement this. We'll probably help them out with hardware too.

Edit: We maintain our own PPC64 backend.

[avsm]

Xavier Leroy committed experimental native AArch64 support to OCaml trunk over the summer. I'm planning to add it to the OPAM package testing pool as soon as I get my hands on some Calxeda (or other) hardware.

https://github.com/ocaml/ocaml/tree/trunk/asmcomp/arm64

[apaprocki]

We actively use/used OCaml in production on SPARC/Solaris, POWER/AIX, HP-UX/IA64. (The optimized compiler wouldn't build on AIX.)

[rwmj]

Various backends for less used architectures are maintained out of tree, eg here:

https://github.com/retired-camels/ocaml

[jgw25]

There's an AIX port of 3.12.1

http://ocaml-ports.geschenker.net/ocaml-aix.html