The Convergent Technologies Operating System, also known variously as CTOS, BTOS and STARSYS, was a modular, message-passing, multi-process based operating system.
Convergent Technologies' first product was the IWS (Integrated Workstation) based on the Intel 8086 processor, which had CTOS as its operating system. This was a modular operating system with built in local area networking. CTOS supports multiple processes or threads, and message-based inter-process communication.
Companies which licensed CTOS included Burroughs (BTOS) and Bull (STARSYS). The single largest customer was Unisys, with whom Convergent Technologies merged to become one company in 1988. At its peak, CTOS had over 800,000 users worldwide.
CTOS ran on Intel Pentium computers, and could run concurrently with Microsoft Windows NT.
CTOS is no longer marketed to new customers; former major customers included Police Forces, Banks, and Airlines.
This article is based on material taken from the Free On-line Dictionary of Computing prior to 1 November 2008 and incorporated under the "relicensing" terms of the GFDL, version 1.3 or later.