Author: Matthew Hull
Date: 15:36:13 07/22/03
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On July 22, 2003 at 18:25:39, Robert Hyatt wrote: >On July 22, 2003 at 17:43:03, Matthew Hull wrote: > >>On July 22, 2003 at 17:27:37, Bob Durrett wrote: >> >>> >>>While using Chessbase 8, I use an analysis engine. Until today, that analysis >>>engine has been Fritz 8. Today I purchased Shredder 7 and ran Chessbase 8 using >>>Shredder 7 as the analysis engine. After allowing the analysis engine to look >>>at a position for a few minutes, I copied the Shredder line to the notation and >>>then switched to Fritz 8. The question I have is whether or not the contents of >>>the hash table used by Shredder would then be used by Fritz. The first thought >>>would be that switching engines would erase the Shredder hash table(s) and set >>>up new empty Fritz hash table(s). But does it have to be that way? >> >> >>The hash table is part of the program's memory address space. Each program has >>it's own address space. There is no sharing of this space between chess >>engines. Most modern operating systems take care that one address space does >>not access another program's address space, as this would defeat the goals of >>system stability and program reliability in spectacular ways. >> >>Regards, >>Matt >> >> > >Yes, but a program +could+ do this without knowing. IE let the GUI >create (allocate) the hash table. It could use shmget/shmat to create >a _shared_ block of memory that another engine could use once the first >engine is terminated. Or it could use mmap() to do the same thing. It >is highly doubtful it is done, of course, but it _is_ possible. Absolutely. This is done in OS/390 (cross memory services, I think it is called), usually between something (IMS/CICS) and DB2. Matt > > > >>> >>>Is there some simple test a user could perform to determine whether or not the >>>two engines would use the same hash table where the contents put in by one >>>engine would then be used by the other? >>> >>>Does this make any sense? >>> >>>Bob D.
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