FlexOS

FlexOS was a modular real-time multi-user multi-tasking operating system (RTOS) designed for computer-integrated manufacturing, laboratory, retail and financial markets. It was developed by Digital Research's Flexible Automation Business Unit in Monterey, California since 1986 and was marketed since January 1987 as a reengineered derivation of Digital Research's Concurrent DOS 286 multiuser multitasking operating system.

Overview

FlexOS was re-written in C for higher portability across hardware platforms, and it featured very low interrupt latency and fast context switching.

The original protected mode FlexOS 286 version 1.0 was designed for host machines equipped with 286 CPUs, and with adaptations for NEC V60, NEC V70 and Motorola 68000 processors planned. FlexOS 286 executables using the system's native INT DCh (INT 220) application program interface had the filename extension .286. A CP/M API front end (FE) was available as well, using the extension .CMD for executables. (A filename extension of .68K was reserved for FlexOS 68K, presumably derived from Concurrent DOS 68K as of 1986.)