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RAMFILES 1 or 0 ?

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Old   February 28, 2003, 08:22
Default RAMFILES 1 or 0 ?
  #1
Ossi
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Hi, does anybody know what is the difference in writing the temporary files to the disc (RAMFILES 1) or not writing (RAMFILES 0) ? At least it takes some space when the files are written to the disc but other than that, are there any pros if not writing the temporary files to the disc ?
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Old   February 28, 2003, 10:52
Default Re: RAMFILES 1 or 0 ?
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Marc
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Hey Ossi.
If not writing them to disk, you have to keep them somewhere. They will be kept in RAM, thats why the fuction is called RAMFILES. It will be significant faster to keep the files in memory, but unfortunately you will need very much physical memory (depending on the size of the job).
Greetings, Marc
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Old   February 28, 2003, 10:59
Default Re: RAMFILES 1 or 0 ?
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Ossi
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Thanks ! Ossi
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Old   February 28, 2003, 11:25
Default Re: RAMFILES 1 or 0 ?
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Steve
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If you're doing some really Noddy model for testing purposes (a few hundred cells perhaps), RAMFILES=1 really speeds things up.

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Old   March 1, 2003, 01:17
Default Re: RAMFILES 1 or 0 ?
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cjtune
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At any rate, you wouldn't want to run out of RAM. Things become really slow (by one to two orders or magnitude) when the temporary data 'spills' over to your hard disk swap file(s).

So at the limiting condition of having barely enough RAM, is it better to have RAMFILES=1 or =0?
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Old   March 1, 2003, 14:50
Default Re: RAMFILES 1 or 0 ?
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steve
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Using ramfiles is as fast or faster than not when you do not run out of physical memory. If you run out of physical memory and start swapping, then using ramfiles is usually significantly worse. The reason is that the data put on the scratch files is put there intelligiently when its not likely to be used for a while. If you just let the system swap, it really cannot match the intelligience of a programmer who knows exactly what data is needed and when. If your are marginal on ram, I would suggest not using ramfiles.
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Old   March 2, 2003, 02:38
Default Re: RAMFILES 1 or 0 ?
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cjtune
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Makes sense... otherwise why have the RAMFILES variable at all?
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