memory limit and the 64-bit era

Posted by Michael Held on Apr 04, 2007; 1:16pm
URL: http://imagej.273.s1.nabble.com/memory-limit-and-the-64-bit-era-tp3699808.html

hi,

I want to start the often discussed "memory limit" discussion in the
light of 64-bit processors again.

we have tested ImageJ on a 64-bit Intel P4 with Windows XP 64-bit
(Windows 2003 Server) on board and after an *extremely* painful search
we found the Java 64-bit for Windows (search the web for
'jre-1_5_0_11-windows-amd64.exe' which perfectly works for Intel's P4
64-bit and should for Core(2)Duo as well).
we used the latest ImageJ 1.38n and modified ImageJ.cfg to run under the
new 64-bit JVM.

so far we could allocate 3GB (-Xmx3000m) on a machine with 2GB
physically (which will be upgraded soon), but ImageJ file import crashed
after 1.85GB (instead of 1.7GB) with the "out of memory" exception (both
'About ImageJ' and TaskManager showed an allocation about 3GB).

we will test and report further.

does anybody know why ImageJ has a general 4GB limit? I just guess that
any memory offset used in ImageJ is a good old 32-bit unsigned integer.
if so, are there plans to upgrade ImageJ for the 64-bit era?
(browsing of *large* datasets acquired by 5D microscopy is still one of
the major limitations in the life-sciences)

hope to start a discussion here...
cheers,
michael

--
Michael Held, Dipl.-Inf.
ETH Zurich
Institute of Biochemistry
HPM E17, Schafmattstrasse 18
8093 Zuerich, Switzerland
Phone: [phone], Fax: [phone]
[hidden email]