Quite a few operating systems were available for the VAX. (Open)VAX originally called VAX/VMS was DEC’s flagship operating system. A stripped down version called MicroVMS was available for a short time for the MicroVAX I, II and 2000. Later versions of VMS , Ultrix and VAXeln had an optional Graphical User Interface (GUI). Also, a few varieties of UNIX were available including the proprietary ULTRIX, BSD including NetBSD which is still being currently updated, and AT&T UNIX System, and Research UNIX.