Eclipse MV

The Eclipse MV/8000 was the first in a family of 32-bit minicomputers produced by Data General during the 1980s. Codenamed Eagle during development, its architecture was a new 32-bit design backward compatible with the previous 16-bit Eclipse series. The development of the computer and the people who worked on it were the subject of Tracy Kidder's book The Soul of a New Machine. The MV/8000 was succeeded by the MV/6000, MV/8000-II, MV/2000, MV/2500, MV/4000, MV/10000, MV15000, MV/20000, MV/30000 and MV/40000. Later models such as the MV/40000 were SMP systems with hot-swappable components.

The Eclipse MV was a 32-bit CISC architecture with a 4GB address space. The 4GB address space was divided into eight rings of 512MB each with a privilege mechanism mapped onto the rings. The outermost ring, ring-7, was the least privileged. The inner-most ring, ring-0 was the most privileged. The AOS/VS operating system supported the notion of lightweight "tasks" as well as processes. A single process could start various tasks that would all share a global address space (similar to modern "threads"). Tasks were very easy to use from Data General's FORTRAN compiler, and allowed faster context switching than using full processes.

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