RCM

Possibly the First Network Operation System and Local Area Network


While working for Xerox at the Eastern Technology Center in Rockville, Maryland I worked on a project to provide a laboratory automation system to Astral Pharmaceutical. Astral's requirements were not met by any of Xerox's standard operating systems so I convinced my boss to let me write a new OS that would meet the needs of Astral, as well as other laboratory and process control applications. The result of this project was the Remote Computer Monitor (RCM) that allowed bare-bones computers (no hard disks, almost no peripherals) to use the hardware resources of a host computer as if they were local devices. Tying the computers together was a device we called an Inter-Computer Data Link (ICDL). Xerox designated the device the Model 7907M. In modern terms, it was a Local Area Network (LAN).


In July of 1974, two Xerox 530 computers and an ICDL were shipped to Astral as a pilot project. One computer had a hard disk and other peripherals. It ran a conventional operating system (OS). The second Xerox 530 computer had a lot of analog to digital (ADC) and digital to analog (DAC) converters but only a teletype as a local I/O device. That computer ran RCM. The project was a great success and Astral wanted to add more RCM-based systems.


Unfortunately Xerox left the computer buisness shortly after the system was delivered. That left Astral without a computer supplier, so they turned to a local company, Digital Equipment Corporation (DEC). Xerox provided DEC with documentation and source for RCM so that DEC could provide support for Astral.

The following year DECNET, which has been hailed as the first network operation system, was released.


And now you know the rest of the story.