Cache Operation
Each cache controller keeps a table that tracks all modified blocks residing in same column.
- Tables are identical for processors in the same column.
If need to discover where a remote block is, put the read request on the ROW bus
- Guaranteed that some processor on the row will have a cache entry for that block since each processor knows about all blocks on its column.
Assume requesting processor is P00 (Prc), and data is in processor P11 caches. Then processor P01 will repeat request on column bus 1, get data from P11, and then place data on Row bus.