Computer Chess Club Archives




Subject: Re: is the

Author: Robert Hyatt

Date: 06:28:26 07/24/98

Go up one level in this thread

On July 24, 1998 at 08:06:59, Tom Kerrigan wrote:

>On July 23, 1998 at 19:39:40, Roberto Waldteufel wrote:
>>the graphics overhead of Windows. When there are no other applications open, it
>>seems strange to me that Windows does not automatically allocate RAM instead of
>>slow-access disc space. I could understand it if I were multitasking other
>No, you missed the point.
>Windows does not allocate RAM. It allocates memory space. It probably does some
>work to make sure that a lot of the memory allocated is already in RAM, but when
>you allocate 40MB and you only have 64MB RAM, that's a very hard thing to do.
>That's why you see so much swapping.

however, if the memory management is done *right* then active programs page in,
inactive programs page out, and the paging stops, assuming (a) the active
program can actually fit into real memory and (b) that there are not more active
programs than can actually fit into real memory.  Playing chess should have one
compute-bound process and the rest should slowly "go away" to disk.

in any case, the "paging" should be a flurry as most people see when they ask
"Why does crafty take 10 secs to make the first book move, and then  0 seconds
for the next 20 on my win95 machine, while on your linux box it can make the
first 20 moves in 0 seconds?"

Unix (linux) has to page in every page of executable code one time, as it is
referenced by the program during execution.  For non-initialized data, there is
no paging I/O at all...  it just allocates pages *as they are referenced and not
before* and gives them to the program via the memory management hardware map.

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