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Interconnection network shown here is actually for the BBN Butterfly, but C-90 is in the same spirit.
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These machines share data by direct access.
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Potentially conflicting accesses must be protected by synchronization.
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Simultaneous access to the same memory bank will cause contention, degrading performance.
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Some access patterns will collide in the network (or bus), causing contention.
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Many machines have caches at the processors.
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All these features make it profitable to have each processor concentrate on one area of memory that others access infrequently.
| 1 |
All processors access the same memory.
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| 2 |
Advantages:
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Easy to program (correctly)
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Can share code and data among processors
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| 3 |
Disadvantages:
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Hard to program (optimally)
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Not scalable due to bandwidth limitations
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