:As promised, here is Miguel's answer.
Miguel's answer is excellent. For the non-SGI'ers on the list
I just would like to add:
1) IRIX has many features that important customers require
(e.g. trusted IRIX capabilities, real time scheduling
and many more) that actually make it slower than Linux
(in general). As a vendor SGI is committed to support
these features from low end to high end for a long time
to come. IRIX is big. Linux is smaller and faster.
Once we have Linux running and we'll start running simple
benchmarks you'll see this very clearly. Another big feature
for our customers is XFS. Linux doesn't support a safe file
system, IRIX does (try to turn off your Linux box and you
lost a lot of stuff, unlike on IRIX with XFS.
2) IRIX needs to run on machines that are incredibly different:
from uniprocessors through SMP (which Linux is now getting at)
to the S2MP model (no shared bus: Origin family) every feature
added to support S2MP (the Origin line) may potentially complicate
and slow down the uP desktop case. SGI customers demand
one source base. They want to compile on O2 and run on Origin.
Linux is just starting to get a feel for how complex is SMP
vs. uP so it'll naturally run great on a uP but wouldn't be
able to take advantage of the most scalable architecture of
the Origins. As we've learned this requires rewriting large
parts of your kernel from scratch. Which is why SGI is doing
3) IRIX runs only on SGIs and to get upgrades you need to
pay for support. Linux runs on many platforms. It is free
The common source base gives it a great advantage for people
who have mixed envs. It is affordable and ideal for hackers.
it has a big and fast growing following.
4) IRIX has no chance of beating M$oft. Linux doesn't either
but it has a bit more. Just kidding.
The guy who said "SGI has hundreds of highly paid engineers
tuning IRIX to run fast on MIPS" simply misses the issues.
They are much more complex than that.
Both Linux and IRIX have their place. Each of them is good
at different things. People should have a choice between SGI
taking care of all their needs and the alternative to have
full control of their software.
Linux on SGI should prosper.