The precise platforms are: x86_64, ppc64 (big endian) & s390x.

I think what is more interesting are the platforms that are not in that list. Internally we build for 32 bit i686, ppc (32 bit) and s390, but AFAIK we don't release those. We also don't build for ARM 32 bit (but aarch64 will be in future[1]).

Of course this is a lot less than Debian, but we have to carefully choose what we are able to support for customers. This is not a throw-it-at-the-wall approach.

[1] http://rwmj.wordpress.com/2014/03/04/red-hat-64-bit-arm-deve...

AFAIK the main reason we still build the 32-bit stuff is to ship multilib packages for their 64-bit siblings.

Thanks for not realeasing the 32bit arch, makes package building and management considerably easier!

Not so fast - I believe CentOS is planning a 32-bit SIG. I'm sure it won't get near the adoption a Red Hat blessed distribution would get (even considering how 32-bit is on its way out), but it exists.