[Shiunbird]

Raion, the book I'm using to learn, Advanced Programming in the UNIX environment, covers a lot all the differences. I have the Third Version, and it is so cool that it even covers modems and serial comms very thoroughly.
I have a modem at home waiting to be installed, that I will add to my rack as means of remote access in case I'm away, my two ISPs are down and there's no way else to get in. (I carry a Jornada 720 with me during long journeys, and it has a modem)

I couldn't recommend the book enough. It is a great read even if you are not a programmer or trying to learn.

I plan to get for Christmas the second edition - it is from the 90s, so it should cover more extensively IRIX and HP-UX. The Third Edition uses a lot of macos, Linux and solaris as reference and mentions others mostly en passant.

TruHobbist, do you write using your SGI and cross build? I've been using SoftBench on HP-UX. I fell in love with it. Plus the C8000 is waaaaaay quieter than the Octane. I tend to use remote X when I'm using Cosmo - it's the application I use the SGI mostly for at the moment.