REAL-32
Intelligent Micro Software, Logan Industries, Inc.: Solutions through Software, MacroCom MaxFrame, MAZE Technology: Access Control System Solutions, Multiuser-DOS
RxDOS
Dissecting DOS: A Code-Level Look at the DOS Opera, RxDOS, RxDOS Downloads, RxDOS, Source Code DOS Clone, Samsung Computer Division: Products: RxDOS Series
S&H Computer Systems, Inc.
Makes TSX-32 general purpose, multiuser, multitasking, text-based, non-graphical, DOS compatible RTOS, coded for x86 platforms. Supports realtime use, embedded devices.
Technosoftware, Inc.
RTXDOS-16 (DOS compatible) and RTXDOS-32 (WIN32 compatible) real-time OSs for embedded PCs. Modular systems with TCP/IP, WEB server, Process IO, OPC Toolkit, and IEC1131.