Kendall Square Research (KSR) was a supercomputer company headquartered originally in Kendall Square in Cambridge, Massachusetts in 1986, near Massachusetts Institute of Technology (MIT). It was co-founded by Steven Frank and Henry Burkhardt III, who had formerly helped found Data General and Encore Computer and was one of the original team that designed the PDP-8. KSR produced two models of supercomputer, the KSR1 and KSR2.
The KSR systems ran a specially customized version of the OSF/1 operating system, a Unix variant, with programs compiled by a KSR-specific port of the Green Hills Software C and FORTRAN compilers. The architecture was shared memory implemented as a cache-only memory architecture or "COMA". Being all cache, memory dynamically migrated and replicated in a coherent manner based on the access pattern of individual processors. The processors were arranged in a hierarchy of rings, and the operating system mediated process migration and device access. Instruction decode was hardwired, and pipelining was used. Each KSR1 processor was a custom 64-bit reduced instruction set computing (RISC) CPU clocked at 20 MHz and capable of a peak output of 20 million instructions per second (MIPS) and 40 million floating-point operations per second (MFLOPS). Up to 1088 of these processors could be arranged in a single system, with a minimum of eight. The KSR2 doubled the clock rate to 40 MHz and supported over 5000 processors. The KSR-1 chipset was fabricated by Sharp Corporation while the KSR-2 chipset was built by Hewlett-Packard.