MIPSpro is not included in the default software library from SGI. What is included is the "IRIX Development Libraries" and "IRIX Development Foundations" which provide the headers, static libraries, and a few development tools (but not compilers). For IRIX 5.3, the full IDO (with C compiler) is downloadable from ftp.sgi.com, for IRIX 6.2 the IDF/IDL parts are on ftp.sgi.com (IRIX 6.2 did not ship with the development tools and headers as standard). Many versions of MIPSpro function as "nagware" and will still compile while you're waiting for your license Origin running the latest MIPSpro compilers. No official hobbyist program, there just isn't any return in it for SGI (the MIPS-based IRISes were discontinued in December).