UNIX for Dummies Questions & Answers

I thought SCO OpenServer was 100% free for non-commercial use?

Double check that, last time I checked, Oracle did, not Novell
Yes. There are several other Illumos based operating systems around. They aren't strictly Unix compliant but are probably close.

Unfortunately not, there was at one time a '2 user' license available to students.

No it is not discontinued. It is alive and well.

Oracle acquired SMI, not Novell.

HP-UX is still very much for sale and kept up-to-date. HP also sell Linux systems.
IBM have a very strong focus on Linux systems as well as AIX.
It was Oracle who took over Sun Microsystems.
Novell are now owned by Attachmate and still own SUSE Linux.

Apple OS/X has X86 versions but normally only runs on Apple hardware.

SCO, Novell and Microsoft are spending a worrying amount of time in court regarding unix and Linux patents. Microsoft are also doing deals with Oracle on the same subject. When you consider that Microsoft once owned Xenix (which is the root of SCO unix and Unixware) and that Windows NT is part-VMS (pre-unix) you do wonder what Microsoft are up to.

True from an economic view, but Xenix was written by Microsoft and sold to SCO. SCO then acquired a Unix System V 3.2 license, and because of the original deal with Microsoft had to provide backwards compatibility with Xenix.

It wasn't.
Unix was written by AT&T. Microsoft licenced unix from AT&T but could not call it "unix" which AT&T retained. At the same time IBM took out a better licence with AT&T which is why IBM spend less time in the courts.

Sarcastic note: Apart from the MSDOS bootstrap and some basic MSDOS commands, what has actually been written by Microsoft which has not been replaced by products written by rival companies where Microsoft have bought the rights or the entire company?