For some systems in this category it will not always be possible to discuss all models of a particular product line because the number of configurations is simply too large. However, we attempt to give the representative configurations for such systems. In addition, when single-processor versions of a certain machine are available, this is regarded as a special case of a multi-processor version and the one-processor versions are omitted from the section on SM-SIMD sytems where they could have been treated.
Furthermore, we have included systems here that have a shared-memory model as a basis but that may be extended by coupling several of these systems together in a distributed memory way. The distinction is not always very clear when looking at the end product: a multi-frame DEC AlhpaServer and an HP/Convex SPP-2000 look very much alike. The difference lies in the integration. In the latter machine the distributed memory extension of multi-CPU nodes was a basis for the architecture while in the former DEC system it is more like an added feature.