Most PC and workstation SMPs use a bus interconnection strategy as depicted in
Figure 17.5. It is instructive to look at an alternative approach, which is used for a recent
implementation of the IBM zSeries mainframe family [SIEG04, MAK04],
called the z990. This family of systems spans a range from a uniprocessor with one
main memory card to a high-end system with 48 processors and 8 memory cards.
The key components of the configuration are shown in Figure 17.6: