why does Sun JVM have a hard max mem limit of 93meg on 2gig pc with no setting done

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Mistton - 19 Apr 2007 03:39 GMT

have a several PCs running WinXP SP2 and W2k SP2 latest patches. all have AMD
or Intel chips with at least 1 gig ram.

have Java applet that at times requires ~250 meg of ram. on some boxes it
runs in less than 1 min on other takes over 30 mins.

on ones with 30 mins i notice mem never goes over 150 meg ram usage in task
manager even when box has 600 meg free. on boxes with 1 min time it goes to
250 megs and finishes.

i have tried all versions of Sun JVM from 1.4.2 to 1.6

i went to http://www.duckware.com/support/javahelp.html and noticed that on
boxes that are fast in the Java VM: Your Java VM reports the following
diagnostic information: section in max mem it said >128 meg or >256 etc

on slow boxes its says max memory: 93 meg.

there are no settings in the java plugin

can anybody please explain

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Andrew Thompson - 19 Apr 2007 06:30 GMT

>have Java applet that at times requires ~250 meg of ram.

>can anybody please explain

Please help the reader by including upper case letters
at the start of each sentence, and a question mark at
the end of questions. You would not want to make it
hard for us, would you?

As far as the memory and applets goes - I don't know,
*but* you might fix the entire problem by launching the
applet using web start, which also allows you to specify
memory settings.

Here are examples of:
1) Launching an applet.
<http://www.physci.org/jws/#jtest>
2) Requesting extra memory for an application.
<http://www.physci.org/jws/#giffer>

Signature

Andrew Thompson
http://www.athompson.info/andrew/

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Mistton - 19 Apr 2007 11:50 GMT

>..
>>have Java applet that at times requires ~250 meg of ram.
[quoted text clipped - 16 lines]
>2) Requesting extra memory for an application.
><http://www.physci.org/jws/#giffer>

Sorry it was written after a 16 hour day of work dealing major
production problems.

The issue is some PC with same OS image and settings have a hard limit of 93
meg. In the Java Console it never goes above that. Others have a soft limit.
We understand that we can change the settings on a PC to increase it, but we
have 100s of PCs all over the country that are having this issue. We really
want to determine why this is occurring get to the root cause.

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Joshua Cranmer - 19 Apr 2007 22:12 GMT

> The issue is some PC with same OS image and settings have a hard limit of 93
> meg. In the Java Console it never goes above that. Others have a soft limit.
> We understand that we can change the settings on a PC to increase it, but we
> have 100s of PCs all over the country that are having this issue. We really
> want to determine why this is occurring get to the root cause.

Two questions:
1. Are you sure that the OS image is really the same?
2. If software isn't the problem, then hardware is: I suspect that the
machines have different hardware (or configuration for the hardware)
which is causing this problem, if the answer to #1 is an unqualified yes.

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Mistton - 20 Apr 2007 14:54 GMT

>> The issue is some PC with same OS image and settings have a hard limit of 93
>> meg. In the Java Console it never goes above that. Others have a soft
[quoted text clipped - 8 lines]
>machines have different hardware (or configuration for the hardware)
>which is causing this problem, if the answer to #1 is an unqualified yes.

1 - Yes exact same image

2 - I have now detected this on PCs and notebooks and servers under w2k win
2003 server, win xp sp2, from IBM and others, with AMD and Intel chips and all
types of different hardware

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why does Sun JVM have a hard max mem limit of 93meg on 2gig pc with no setting done

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