Author: Robert Hyatt
Date: 11:41:53 03/09/04
Go up one level in this thread
On March 09, 2004 at 11:30:44, William Penn wrote: >On March 09, 2004 at 05:28:30, Albert Bertilsson wrote: > >>I'd just like to make one thing clear, the "churning" of the harddrive(s) is >>there because of the usage of tablebases. There is nothing that can solve this, >>having larger cache for tablebases help very little because the tablebases are >>so huge and you computer search very fast. Using faster drives (like scsi) will >>increase performance because of faster tablebase access times, but the drives >>will be working constantly at peek anyway. Turn of tablebases or get used to >>drive "churning", that is you options. > >There is another option! Reduce hash table size. Then the engine speed returns >to near normal. True, it doesn't seem to affect the churning, but the engine >then runs at near normal speed - which is an important improvement. > >>Using tablesbases give you perfect solutions to some positions but the obvious >>trade of is nps, I guess that many systems don't benefit very much from >>tablebases due to the reduced search speed. > >Again, reducing hash table size tends to keep nps near normal speed, in my >experience with a souped-up Compaq Presario/XP 2400+/1G RAM running Windows XP >Home. I imagine that most systems can use tablebases OK if that is done. The >problem is that most people want to use as big a hash size as possible, but that >incorrect when the endgame approaches and tablebase access starts to be >significant - reducing the engine speed greatly. > >>If you get a lot of harddrive noise you could try mounting your drive in some >>rubber bands instead of directly in the chassi to reduce the noise a little. > >I'm not concerned about the noise. My Maxtor drives have a "quiet" mode >available if I want to use it. But it slows down access somewhat, and the noise >is also a good indicator of what the drive is doing, so I don't mind the little >extra noise. > >>/Albert > >Overall, you should be aware that such extreme hard drive churning will reduce >the lifetime of the drive significantly. Hard drives have a finite lifetime, and >can only seek so many times before the heads wear out eventually. Those who >write the code for chess tablebase access should keep this in mind, and do >whatever is necessary to improve it, and reduce the hard drive churning as much >as possible. There is really not much point to adding 6-man tablebases to most >ordinary computer systems until this churning problem is solved. >WP heads don't "wear" at all. They do not contact the disk. The seek accutator gets a work-out, and produces some extra heat, but that is all...
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