Shared Memory
•Shared memory was claimed to be a poor model because it is does not scale
–Many vendors have sold small shared memory machines
•Some like SMPs work well (but modeled poorly by PRAM) 
•Some never worked -- KSR
•Some worked because of a technology opportunity -- slow processors with a “fast interconnect”
•Some work on small scale, but not beyond 64 processors and everyone tries to ignore that fact -- Origin-2000
–Many researchers have come up with great ideas, but they still remain unproved