Systems Engineering Laboratories was founded and incorporated in Fort Lauderdale, Florida in 1959,[1][2] and were involved in the beginning of the breakout of minicomputers from 16-bit to larger architectures, with a 24-bit model in 1966.

This left the company consisting primarily of their real-time group (the original SEL core) and returned to this business niche after renaming themselves Encore Real Time Computing.

Compro Computer Services, Inc continue trading as Encore in Europe, COMPRO continues the tradition of long-term product support by offering replacement solutions (e.g., the Legacy Computer Replacement System, or LCRS) that emphasize backward-compatibility coupled with future-proofing.

The use of a bus instead of a wire-wrapped backplane simplified manufacturing, lowered costs, and made system enhancements easier.

The SEL 32 series became extremely popular in many technical markets such as aircraft simulation, oil exploration, electric power system control, and the beginnings of computer animation.

In the early 1980s, SEL introduced a system based on emitter-coupled logic (ECL) technology code named the Thunderbird.

[citation needed] The CPU for these system ballooned to about a dozen boards because of the low-density ECL chip footprint.

The ECL circuitry consumed huge amount of current at a very low voltage; the cabinets of the larger models contained extra rack space which held stacks of 400-amp power supplies, and heavy-gauge wiring leading to the backplane.

Encore used the real-time reflective memory design from Gould along with their 88100 based systems and Umax OS to create a line of high-density storage devices.

Known as the Infinity-90 product these acted as large SANs for Unix, Windows and mainframe computers with data sharing capabilities.

SEL had a proprietary operating system called Real Time Monitor (RTM) which, although extremely fast, had limited user interface.

(However, clever programmers soon discovered that by customizing search paths, they could mix utilities, system calls and libraries from both environments.)