VMS was renamed OpenVMS in 1991[1] The term “Open Source” was coined in 1998 by ...

chasil · on Aug 16, 2020

Somewhat prior to then renaming, the "Open Software Foundation" was formed by a consortium including IBM, HP, and DEC.

This was done because of an uncomfortably close embrace between Sun Solaris and AT&T System V Release 4.

UNIX on DEC Alpha was originally named OSF/1.

chmaynard · on Aug 15, 2020

Hence the ambiguity.

coldtea · on Aug 15, 2020

Well, it's the Open Source that is ambiguous then, as it came later as a term...

(which, co-incidentally, is one argument of the free/libre software guys too)