While entertaining, I'm left with the following question: if not UNIX, then what? Are there any successful non-UNIX-y OSes that are worth checking out? I may embarrass myself here, but I was under the impression that BSD, Plan 9, Solaris and HP-UX were all UNIX-y ...
The coherency of VMS (and the VAX platform) is quite amazing -
Coherent command line interfaces, API's, documentation, hardware, and software, even down to coherent part numbering made by a single company, from small workstations up to larger scale minis, and nearly transparent clustering.
I mention VAX specifically, since by the time Alpha arrived, DEC was competing in a much different environment, and was subsequently merged, etc etc etc.
IBM and other mainframe-ey OS's, though definately arcane, have some amazing facilities (parallel sysplex.. multi architecture systems that are completely redundant and hot-swappable) and capabilities since the late 60s/70s which are only now being caught upto in crude and hackish form at the present time with commmercial PC servers.
BeOS had some cool concepts.