Well, AT&T/SysV regarded themselves as the 600 pound gorilla in the room, and Sun as the young upstart punk kid, so in building a joint system, everything "compromised" by just doing it the SysV way.

/bin & /usr/bin was populated by SysV tools with SysV options, with the particularly incompatible command line options of "ps" that plague it and clones of it to this day.

There were still Sun/BSD bin tools hidden away somewhere for use by the desperate, but they were deprecated and weren't in the search path of one's coworkers etc. etc.

I remember there being a lot of pressure to adopt SysV "streams", which from 20,000 feet sounded very powerful but were actually a nightmare -- not according to me, since I managed to avoid them, but according to later accounts of people I knew at AT&T.

And of course there were similar changes to libraries and man pages and /etc and init and etc.

I cut my teeth on BSD, contributing in small ways to its earliest development, and I considered it an improvement over vanilla Bell Labs/AT&T Unix -- not just NIH; BSD introduced the fast file system and demand paging and the "more" command (later incarnation "less").

AT&T on the other hand responded with a very strong case of Not Invented Here; they really seriously did not want to retrofit improvements like that. And tried to do various clones, like "pg" to replace "more", which was so awful it couldn't even page backwards, just to give some idea.

System III had a few new features but mostly sucked, due to that attitude, and System V was more or less more of the same.

Sun OS took all of the BSD improvements (ok, 7 options to "cat" is arguable, but whatever) and added more nice stuff, like NFS and RPC (RPC got a lot of flak, but originally there really was no alternative) and "Yellow Pages" (later renamed to NIS/Network Information Services for trademark reasons).

NeWS was a breakthrough in windowing, based on postscript rendering to screens (although not the same as Display Postscript), and was quite brilliant.

In creating a common standard, the compromise was to throw away or hide the majority of the BSD and Sun OS improvements in order to, basically, just let AT&T do things their own inferior way.

NFS was already becoming an industry standard, so it didn't go away, but NeWS did, in favor of the incredibly bad "Common Desktop Environment" GUI standard, which was a step backwards relative to all X11 offerings, not just relative to the breakthrough NeWS.

The alternative, Motif, had a ridiculously complex and clumsy API that took vast amounts of boilerplate programming to get anything done. Dark times for GUIs.

http://en.wikipedia.org/wiki/Common_Desktop_Environment

[In my first draft I mixed that up with Open Look, a sign of fuzzy memory]

I haven't thought about it in ages, so there are likely a bunch of other things I'm not remembering, but the net result was a standard that was far less pleasant to program to or to do system administration on -- plus many instances of dual standards.

Chuck above was hit by similar nastiness in the kernel itself; I wasn't dealing much with kernel internals at the time, but from what I heard, it was perhaps even worse there.

If Sun OS had merged with Plan 9, that would have actually advanced the world, rather than retarding it.