Reading: * H.T. Kung and John T. Robinson. "On Optimistic Methods for Concurrency Control." TODS, June, 1981. In Red Book. I wasn't around this day to take notes. I took notes the following day summarizing the discussion of optimistic concurrency control. Sorry! =OCC= ==OCC vs. Locking== OCC - More concurrency - No deadlocks - Aborts - in resource-limited setting, overhead of aborts + retries make OCC slower than locking. Locking - Deadlocks So no one really uses OCC, since it is wasteful of resources that will be aborted, and requires too much computation on attempting commit. ==OCC in Hardware== Since we have so many cores coming up in the multicore revolution, we can use a few cores to perform verification before modifying memory. Pro: If two processes will rarely Con: Doesn't make a program without much concurrency magically concurrent.