Systems Engineering Laboratories

Systems Engineering Laboratories was founded in Fort Lauderdale, Florida, in 1962 to design and build 32-bit realtime computer systems. Realtime computers are used for process control and monitoring, and to accommodate these applications they must include architectural features allowing them to respond quickly to external stimuli such as switch closures in a power plant. Systems Engineering Laboratories (also called SEL) was founded at the beginning of the breakout of computers from 16-bit to larger architectures. In fact, another computer company founded in Fort Lauderdale at about the same time, Modular Computer (or MODCOMP), was initially a 24-bit computer manufacturer.

SEL's first computers, such as the 810A, the 8500, and the 8600, used wire-wrap technology to create the numerous system boards and backplane (called a swingplane). Components were low-scale transistor-transistor logic (TTL) integrated circuits comprising a few transistors per chip, and core memory was used. In 1976, the SELbus was introduced with the Model 32/55 computer. The CPU of the 32/55 was composed of three wire-wrapped boards bolted together. The bus speed was 26.6 megabytes per second, which was a record at the time of its introduction. The use of a bus instead of a wire-wrapped backplane simplified manufacturing, lowered costs, and made system enhancements easier. Multilayer printed circuit boards were introduced with the 32/57 about a year later, and single-board CPUs were introduced shortly thereafter. The SEL 32 series became extremely popular in many technical markets such as aircraft simulation and oil exploration.

Later, in the early 1980s, SEL introduced a system based on emitter-coupled logic (ECL) technology called the Thunderbird. The CPU for this system was about a dozen boards because of the ECL chip footprint. As a result, CPUs could only be placed at each end of the SELbus, limiting computer systems to two CPUs.

SEL had a proprietary operating system called Real Time Monitor (RTM) which, although extremely fast, had limited user interface. It supported a console for command entry, but no additional users. When the SEL32 systems were introduced, SEL created another operating system called MPX which supported multiprocessing and multiple users. Later, in the early 80s, SEL adopted the Unix operating system.

SEL was purchased by Gould in 1982 and was operated essentially unchanged as the Gould Computer Systems Division. Later, in 1995, Encore computer corporation bought the computer division from Gould. The last operations of Encore were closed down in 2003.