Parallel Computer Architecture

946 CHAPTER 12 Future Directions

out the earlier, more exotic parallel machine designs. These three major segments

evolved in a predictable, evolutionary fashion, each with their market segment,

while the microprocessor marched forward from 4 bits to 8 bits to 16 bits, bringing

with it the personal computer and the graphics workstation.

In the mid-1980s, the microprocessor reached a critical threshold where a full 32-

bit processor fit on a chip. Suddenly, the entire picture changed. A complete comput-

er of significant performance and capacity fit on a board. Several such boards could

be put in a system. Bus-based cache-coherent SMPs appeare ...