Encore Computer
| Company type | Private |
|---|---|
| Industry | Computer hardware |
| Founded | 1983 |
| Founder | Kenneth Fisher, Gordon Bell, Henry Burkhardt III |
| Defunct | 1997 |
| Fate | Sold Storage Products Group to Sun Microsystems in 1997; acquired by Gores Technology Group in 1998; later acquired by Compro Computer Services in 2002 |
| Headquarters | Marlborough, Massachusetts , United States |
Area served | Worldwide |
Key people | Kenneth Fisher, Gordon Bell, Henry Burkhardt III |
| Products | Multimax parallel computers, Encore-91, Infinity 90 line, Infinity R/T Model 300, Series 90 RT 3000 workstation, RSX processor |
| Parent | Gores Technology Group (from 1998), Compro Computer Services (from 2002) |
Encore Computer Corporation was a U.S.-based computer firm operating between 1983 and 1997, headquartered in Marlborough, Massachusetts. As an early innovator in the parallel computing arena, Encore introduced multiple system architectures beginning in 1985 but did not achieve the same level of market recognition as rivals such as Pyramid Technology, Alliant, Sequent, and FLEX.
The company was established in 1983 by Kenneth Fisher (previously CEO of Prime Computer), Gordon Bell (former engineering VP at Digital Equipment Corporation and creator of the VAX), and Henry Burkhardt III (co-founder of both Data General and Kendall Square Research). Their objective was to develop massively parallel computing systems utilizing off-the-shelf processors. The Multimax, their inaugural product released in September 1985, ranked among the earliest commercial machines incorporating bus snooping, which facilitated effective shared memory access across multiple CPUs.
History
In 1988, Encore expanded by acquiring Systems Engineering Laboratories (SEL) from Nippon Mining. Founded in 1961 and once part of Gould Electronics, SEL specialized in advanced electronics for industrial monitoring and military flight simulation. Due to U.S. restrictions on foreign ownership of defense-related enterprises, Nippon Mining divested SEL’s computing division, effectively incentivizing Encore to take over the unit.
Aligning with industry developments, Encore embraced RISC processors, opting for the Motorola 88000. The Encore-91, introduced in late 1991, featured configurations with two (9102) or four (9104) CPUs running at 25 MHz. This design progressed into the Infinity 90 line (beginning with the Infinity 90/ES in 1994), scaling up to support as many as 2,045 Motorola 88110 CPUs at 50 MHz. Nevertheless, Motorola’s strategic pivot away from the 88000 architecture towards PowerPC processors disrupted Encore’s planned product trajectory.
Shifting focus toward high-performance real-time systems, Encore launched the Infinity R/T Model 300 equipped with the Alpha 21064 CPU in late 1994. Simultaneously, they introduced the single-processor Series 90 RT 3000 workstation running OSF/1, designed either for standalone operation or integration as a node within parallel configurations.
Encore also engineered the RSX, a customized RISC processor capable of functioning as a conventional cluster node or operating in CONCEPT/32 compatibility mode to emulate legacy custom real-time hardware—likely originating from the SEL acquisition. The company maintained ongoing support for system upgrades dating back to models introduced in 1975.
Gradually, Encore divested portions of its computing operations; notably, its Storage Products Group was sold to Sun Microsystems in 1997.
Gores Technology Group
In 1998, Gores Technology Group purchased Encore and rebranded it as "Encore Real-Time Computing," concentrating on real-time computing solutions and leveraging the original SEL foundation.
Compro Computer Services
Compro Computer Services acquired Encore Real-Time Computing in 2002. While most international offices outside the U.S. continue operating under the Encore brand, Compro provides ongoing support for SelBUS-based SEL, Gould, and Encore systems, offering upgrades through the Legacy Computer Replacement System (LCRS) hardware emulator.
An example of an Encore Multimax system donated by the Naval Postgraduate School is currently preserved at the Computer History Museum.
Specifications
The initial Multimax system accommodated between one and ten pairs of 10 MHz National Semiconductor NS32032 processors, featuring a 32-bit CISC architecture comparable to the Motorola 68000. Subsequent versions upgraded to NS32332 and NS32532 processors, which offered increased clock speeds. The last Multimax model based on National Semiconductor technology was the 500, introduced in 1989. Every version operated on BSD, System V Unix, or Mach, each adapted specifically for parallel processing. Development of the NS32032 series by National Semiconductor ended shortly after the launch of the model 500.