The OASIS Operating System (renamed THEOS in about 1985) was originally distributed starting in 1977 by Phase One Systems in Oakland, CA.

Today (2003) Phase One Systems publishes software development tools for THEOS(R) systems.

Also, Phase One Systems licenses a porting tool called CET Basic. CET Basic is compatible with THEOS BASIC, MultiUser BASIC, OASIS BASIC, and UX-BASIC. This means you can keep most of your existing source code, and using W/32 BASIC, recompile your THEOS, OASIS, or UX-BASIC programs to work under additional operating systems such as Windows95/98/NT/2000, Linux or SCO UNIX.

THEOS is a registered trademark of THEOS Software Corporation.

Phase One Systems can be reached at http://www.PhaseOneSystems.com.