How many different families of operating systems exist in unix?

Question

I know that Mac OS, Linux, Open Solaris, and BSD are related to Unix, are there any other operating systems that are based on or related to unix? Please don't not include variants of any of that already mentioned operating systems, such as FreeBSD, Or any Linux-based distros.

Also, is there any other family of operating systems separate from Unix?

Answer 1

To add a few:

HP-UX

Solaris

AIX

Answer 2

PalmOS (hand helds)

Amiga (think they are still making a niche OS)

VMWare - more of a container, but it could be seen as a specialized OS

Brew (used on cell phones)

VAX

Mainframe

IBM OS2

** Edit **

Not sure why I didn't just go here in the first place but here is a big list of OSs:

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

Answer 3

many hardware mfgs (both system and chip) have their own (usually not free) unix variant.  e.g. aix, hp-ux, xenix, tru64, unicos, etc...

when you say "family of operating systems separate from Unix" would you include things like mainframe os?  dead/obsolete os? real-time os?