Author: Komputer Korner
Date: 15:36:43 07/29/98
Go up one level in this thread
On July 29, 1998 at 13:20:09, Tom Kerrigan wrote: >On July 29, 1998 at 08:08:01, Komputer Korner wrote: > >>"Current Win 95 versions load programs by first copying the executable file into >>disk cache memory, as shown in "Windows 95, Windows 98 Unaligned." From there, >etc. > >Yes, of course, this is how a disk cache works. > >You're making a huge issue about some sort of waste of memory that simply does >not exist. Windows uses free memory as a disk cache. Yes, the program is loaded >into this memory, but why do you care? The memory wouldn't be used for anything >if this didn't happen. > >Now to hash tables... > >A hash table isn't part of a chess program's code. It isn't loaded from >anywhere. It doesn't have anything to do with the Windows disk cache. At no >point in time is it duplicated. Does this help clear things up? > >The reason you can't use 100% of your memory for hash tables is because the >program needs memory to run. So does the operating system. > >Another reason you can't use X megabytes of memory for hash tables is because >that's just not how they work. Hash tables in chess programs have 2^x entries. >If you tell my program to use 127 MB for its hash table, it will use 64 MB, >simply because of the way things are addressed in the table. > >KK, I wouldn't get so pissed off at you if you posted questions about how things >worked, but when you write posts full of BS and pass it off as honest >information about computers, you might screw up other people. > >Cheers, >Tom Tom, I am only pointing up what I see. You know far far more than I do on these matters. The amount of memory that the OS and the program needs to run is peanuts compared to the sizes of hash tables. Nimzo 98 takes up to 106Mb for a hash table in WIN NT on my 144Mb system. Nimzo 3.5 takes up to the same amount in WIN 95 if you have 144Mb of RAM and without swapping. However on a system with only 40Mb of RAM, one cannot load more than about 18 Mb of RAM for a hash table in Nimzo 3.5 without terrible swapping on every move. Thus WIN 95 must grab about 20Mb of RAM for itself when it forms it's page file. The WIN 95 System Monitor is a sorry excuse for a reporting tool compared to the WIN NT 4 Task Manager but here are the findings after starting WIN 95 and Nimzo 3.5 on a system with 144 Mb of RAM. Allocated memory- 161.7Mb Free Memory- 16K Other Memory- 42.4 Mb Swapfile Size - 18.5 Mb Swapfile in use- 2.7Mb Diskcache size- 23.7Mb Locked Memory- 27.4 Mb Swapfile defective- 0 Swappable memory- 119.2Mb Now if anything is more confusing than this I haven't seen it. That is one of the reasons why I like to stay in the WIN NT 4 environment. After shutting down Nimzo 3.5 , the amounts of the above table change to the following: Allocated memory-55.2Mb Free Memory- 105.2Mb Other Memory- 42.3Mb Swapfile Size - 2.7Mb Swapfile in use- 2.7Mb Diskcache size- 23.6 Mb Locked Memory- 26.9 Mb Swapfile defective- 0 Swappable memory- 12.8Mb When I shut down WIN 95, and restart the numbers there are very small changes in the numbers except that Swapfile size and Swapfile in use drop to 0 and Free Memory drops to 102.2 Mb. So it is all very confusing but it seems that unless you limit the vcache size in Windows system.ini WIN 95 will take some of your precious memory for itself. It seems that from the Free Memory numbers, WIN 95's system monitor doesn't know what the hell is going on. Maybe nobody knows. We do know that if you limit the vcache, some other input-output operations will be drastically affected so that isn't a satisfactory solution. But what is clear is that this drastically limits systems with smaller amounts of memory.ie: Systems with less than 64Mb of RAM. On my other WIN 95 system with 40 Mb of RAM, the amount of RAM clearly isn't enough. Perhaps some programs round up to the next hash table size instead of rounding down and that would help to explain what happens (massive swapping)when I try to create 20Mb hash table or more on my system with 40 Mb of RAM. -- Komputer Korner
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