COMA-BC: a cache only memory architecture multicomputer for non-hierarchical common bus networks

The use of multicomputer systems as opposed to multiprocessors allows one to build machines with good performance quality through the use of computers connected to general purpose networks. This type of system is more flexible, cheaper and its use is very common. However, multicomputer systems are based on message passing as a programming paradigm, which makes the programming, to a large degree, more difficult. The authors propose a multicomputer system, COMA-BC, based on a bus type interconnection network governed by hardware coherence. Such a system provides a programming model with shared, dynamic variable types in which the data migrates to those nodes that need it. The implementation of the abstraction of a space with shared addresses in a physically distributed substratum of memory is carried out through a snoopy type coherence protocol in which directory information has been used to reduce the traffic in the interconnection network. They have carried out an efficiency study for the execution of applications of the set SPLASH-2, based on the construction of an emulator in a multicomputer environment