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Dual Systems Control Systems --  History

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Dual Systems was founded in the late 1970's, during the heyday of the S-100 bus computers. It was originally founded to produce a variety of peripheral boards (A/D and D/A converters, serial interface boards, etc.). They came out with a 68000 CPU board for the S-100 bus that was well received and so decided to specilized in the 68000 platform.

After a brief flirtation with CP/M-68K, they switched over to UNIX working with a guy called Jeff Schriebman and his then new company UniSoft Systems to port the AT&T code to their system.  UniSoft went of afterwards to redo the code for many others such as Sun Microsystems, Silicon Graphics, Apple Computer even Motorola itself.

Dual was unique in that it had used the S-100 bus as the basic backplane of its original UNIX systems, when almost everyone else who followed used Intel's
MultiBus. Dual bought S-100 boards from CompuPro, Morrow Designs, Macrotech, and other well known S-100 design houses of that time. They also designed its own SMD disk controller, a four port RS-232 serial controller, a Pertec interface 9-track tape controller, DRAM and SRAM memory boards.

When Motorola announced the 68020, Dual decided to switch system busses from S-100 to VME (a Motorola bus design; 32 address and data lines, can do 8, 16, or 32 bit transfers), and to design a multiprocessor UNIX system. The VME bus was faster than the S-100, and was better suited to multiprocessor and multiple bus-master systems than even  the Intel MultiBus II. It was also clear that the S-100 bus was reaching the end of its design life. Dual successfully designed a new CPU board around the 68020 with 512K of DRAM right on the board (VME boards are 20% bigger than S-100 boards, and do not require power regulation right on the board since bus power is regulated system-wide).

However Dual did not keep up with the market, they never produced a system with a graphics console - just a computing box for use with terminals. In the end, Dual was acquired in the late 1980's by Northstar, and their technology was sold off to whatever interested parties could be found.

Right from the start Dual made a decision to go after the high end/commercial market. They ended up with an extensive line of S-100 boards as can be seen from their catalogue. However their systems were very expensive. Complete systems ranging from $17,000 up to over $65,000. Clearly commercial systems.


Dual Systems S-100 Boards
68000 CPU    256K RAM    Clock Board   CMEM-RAM    Digital-to-Analog    Analog-to Digital    4SIO    EPROM


This page was last modified on 10/25/2013