Architecture and operating system design of the M/sup 2/ Database Machine

The paper discusses the architecture and operating system design of the M/sup 2/ Database Machine. The primary design goal of the M/sup 2/ is to provide a cost-effective solution to large database processing. The M/sup 2/ architecture is essentially a bus-based two-level hierarchical multiprocesser with a shared-memory multiprocessor structure at the lower level and a shared-disk structure at the higher level. The main distinction of the M/sup 2/ architecture is the high-bandwidth message-passing bus that forms the backbone of the second level, the higher level, of the hierarchy. The high bandwidth of the message-passing bus extends the scalability of the M/sup 2/ architecture to more than one hundred CPUs. Another distinction of the M/sup 2/ Database Machine is its system software. The M/sup 2/ incorporates a directory-base coherence protocol in its distributed file system. The directory-based coherence protocol allows efficient file sharing at the page or file block level.<>