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RE: memory usage

From: lacall <lacall@micron.com>
Date: Wed, 14 Apr 1999 16:28:26 -0400 (EDT)
Message-ID: <B1272D4045CBD111A96E0020AFFBF32D03DB7C9B@ntxchange03.micron.com>
To: "'Christopher William Turner'" <cwturner@cycom.co.uk>, "'www-jigsaw@w3.org'" <www-jigsaw@w3.org>
Here's my understanding; anyone can jump in w/ corrections...
Physical memory refers to RAM that is found in silicon DRAM chips on your
PC. Virtual memory is disk space that operating systems use to emulate
physical memory, when there isn't enough physical memory to go around. Maybe
Win98 needs more than 32 MB of memory, so it uses all the physical memory
first (hence 0 for "memoria fisica no usada"--if I didn't know spanish I'd
be less helpful :), and >65MB for "memoria asignada"--since some of the 65
used is actually "virtual" memory, or just disk space that's been allocated.
This "virtual memory" disk space is located in a special file called a swap
file, and this is true for both Windows and Linux and probably most OS'es.

Forgive me if I'm saying things you already know....

The memory usage in my WinNT task manager (don't have linux ps or win98
handy) is divided between "Mem Usage" and "VM Size", which I believe to mean
"physical memory used by this process" and "virtual memory used by this

Does that help any?

Luke Call
EDM Group
Micron Technology, Boise 

-----Original Message-----
From: Christopher William Turner [mailto:cwturner@cycom.co.uk]
Sent: Wednesday, April 14, 1999 2:16 PM
To: lacall; 'www-jigsaw@w3.org'
Subject: Re: memory usage

I have tried using the standard "Monitor de sistema" microsoft tool to
memory and I don't understand the results. The "Memoria fisica no usada" is
always close to 0 and the "memoria asignada" is above 65Mbytes on my 32Mb
memory machine!

Do *not* try disabling virtual memory. My machine failed to reboot after I
did this
"insufficient memory errors". So it seems that my windows needs 65Mbytes
just to
(and presumably swaps to achieve it)!. I managed to recover by holding down
control key during restart and selecting "modo prueba de fallos" (test of
mode) and
then reenabling the virtual memory. Don't try this at home.

I think the microsoft tool is poorly documented but then I don't understand
memory or ps stats either!.

Please can someone tell me how to measure and interpret memory use or cpu
by a java process on Linux and  Windows?

Chris Turner, http://www.cycom.co.uk/
Received on Wednesday, 14 April 1999 17:28:01 UTC

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