Looked at that a few years ago- at that time it required a customized IRIX environment to run, and Stanford was only allowed to distribute the diffs against IRIX 5.3, and not 6.2. It looks like they now have 6.4, but again can't distribute- it depends what you want to do (I can't remember what your project is) but 5.3 is definitely a more proprietary UNIX than 6.2+ is in terms of requiring IRIX specific tweaks and oddities.The upside, of course, is that your program will run on R3k (which can only run up to IRIX 5.3, generally, some IPs max out at 5.2, and the earlier machines really like 4.0.5 or less, which is even weirder to code for, especially 3.x [NeWS-based windowing system] (how's that for a run-on?)). Indys are cheap and small if you want a nice 6.2 machine, I even have a r5k in the garage if you want it for free and are anywhere near Washington state.