Aahh yes - but IRIS x000 don't run IRIX, they run GL2-W with the MEX windowing system. Verry different, verry interestink... Might I suggest 4D1-3.3.2 (IRIX 3.3.2) on a PI - 4D1-3.x had a NeWS based windowing-system, among the few NeWS systems released standard (I'm not even sure which SunOS Sun's NeWS came with - SunOS 3 was SunView, SunOS 4 was OpenWindows (NeWS+X11, but not strictly NeWS). IRIX 5.3 should go on one machine (5.3+XFS should you be lucky enough to find it). This will allow you to run COFF binaries. The other one (R4k) should run an IRIX 6.x release. The 3000 with GL2-W3.6 would fit in quite nicely...