Our applets use a lot of memory, so we have quite a bit of experience
with this.
Chances are you are not really running out of memory unless you are
allocating 32 bytes of internal representation for every byte of data
read. It's much more likely that you are bumping into limits on array
size. Netscape 4.79 would not allow you to allocate a single
dimensional array larger than 1MB. A 2D array can be much larger,
because it allocates each row separately. I'm not aware of any other
VM with this particular defect.
The default memory available for all Java's you'll encounter is at
least 64MB. The old MS VM allows 128MB by default, and Sun's VM
defaults to 64MB minimum, but 96MB on machines with more memory. Apple
defaults to 64MB in OS X. In OS 9, it depended on the user's browser
settings (which defaulted to something silly, like 4MB for the whole
browser application, and would invariably be changed by the user to a
much larger number).
This can often be changed with a control panel setting, but every VM is
different in how you achieve it. With the Sun VM and on OS X, you add
-Xmx128M (for example) to the applet parameters text type-in.
On the machine with an out-of-memory error, start up the Java console
before you visit your applet, then type "m" into the console over and
over as it loads. This should give you a better idea what's going on.
Hope that helps!
-Joshua
On May 26, 2005, at 4:39 PM, David Leader wrote:
I have just converted a java app to an applet (java version 1.1) of
size about 250Mb. This applet reads data from text files which can be
over 1 Mb in size. (These are actually files of coordinates etc. from
the human and other genome projects. The app is for serious academic
use, whereas the applet is more illustrative for use in university
teaching - and publicizing the app. on its web page.)
I set up a page with about 2 Mb of text files that worked ok (although
taking ca. 10 sec to load) on IE5.1 on Mac OS9. When I tried it on
Windows (98, XP) this failed with an out-of-memory error, although a
different page with much smaller files was OK. I cut down the size of
the files on the problem page (changed bacteria) and it now works on
Windows.
My question is, is there any way to increase the memory allocation for
an applet? I know how to do this (and with my app, which can load 40MB
text files, have to do it) for a java app on the command line, but
there isn't any command line for an applet. Looking on the Sun web
site, all I can find of relevence is a statement regarding the
(presumably Windows) plugin that "Dynamic maximum heap size is scaled
down from 128 MB to 96MB to avoid unnecessary paging on the system."
which sounds as if it might possibly explain the difference between
OS9 and Windows. But then again, what do I know about these things...
Perhaps it would help if the data were accessed in a more
sophisticated way?
David
PS I know that applets were meant to be small (and presumably the
files they use too), so you could say I shouldn't be doing this.
However, if it could be done...
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Java-dev mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription: http://lists.apple.com/mailman/options/java-dev/email@hidden
This email sent to email@hidden
_______________________________________________
Do not post admin requests to the list. They will be ignored.
Java-dev mailing list (email@hidden)
Help/Unsubscribe/Update your Subscription:
http://lists.apple.com/mailman/options/java-dev/email@hidden
