Solaris has been a 64-bit operating system for longer than I can recall. In addition to supporting 64-bit applications, Solaris also supports 32-bit applications, and is capable of running as a 32-bit entity on 32-bit platforms. If you need to see if 32- or 64-bit applications are supported on a given platform, you can run isainfo with the “-v” option:
$ isainfo -v
64-bit sparcv9 applications
vis
32-bit sparc applications
vis v8plus div32 mul32
If you would like to see which hardware capabilities (e.g., MMX extensions) are available, you can run isalist:
$ isalist
pentium_pro+mmx pentium_pro pentium+mmx pentium i486 i386 i86
If you are curious what the optimal instruction set is for your platform, you can run optisa with the output of isalist as the argument:
$ optisaisalist``
pentium_pro+mmx
Tis all about knowing what your platform is capable of!