I wish I could find a link to the page because I hate to talk without evidence but the page I saw suggested that the version of Java compiled for 64 bit machines still retains the same memory limit per process as the 32 bit one. Since it was per process it's quite possible that just spawning threads is enough to get by the limit, but without digging into the Sun website I couldn't tell you.
As you say, your Java App is 32 bit, and what this means I think (relating it to the above) that the memory limit for it may be 3 GB regardless of whether you're using a PAE kernel or not.

Penny has dropped on this.

I can't tell whether you understand (probably you do). A 32 bit program under a 64 bit kernel can use pages anywhere in the total ram. Even if you had hundreds of GB of physical ram (far more than a 32 bit PAE kernel can access) a 32 bit program can still have its pages distributed anywhere in ram. If you had 400GB of ram, a hundred different processes each running a 32 bit program could each use a different 4GB, all at the same time.[/QUOTE]

And this. Thank you.



That sums it up very well for me. Thank you. I'll run with the 64 bit version. If gvSIG has too many issues running on 64bit, can I install the 32bit version over the top of it?

Edit: I initially misunderstood you and thought you meant switching gvSIG versions within a 64 bit Linux. But I guess you mean replacing a 64 bit Linux with 32 bit. That is the same as installing from scratch. It is difficult to keep whatever programs and files you installed after Linux in place across a reinstall of Linux, so typically you would back up any of your own work before reinstalling and then reinstall any separate programs after reinstalling Linux.

In Debian based distributions (such as Ubuntu) it may be a little trickier, than it ought to be, to install a 32 bit program in a 64 bit OS (It is smoother in Red Hat based distributions). But it is unlikely to be terrible hard to install.

All the complications (if any) are at install time. Once a 32 bit program is properly installed in a 64 bit Linux, it runs just as smoothly (or better) than it would in a 32 bit Linux.

If you have some trouble installing a 32 bit program in 64 bit Ubuntu, I suggest you ask for help here, rather than give up on it and switch to 32 bit Ubuntu.

I also would not suggest selecting a Red Hat based distribution for the minor advantage that installing 32 bit programs in a 64 bit OS is easier. Red Hat based distributions are all less beginner friendly than Ubuntu.

Yes, I meant to abandon 64 bit OS & go to 32. gvSIG performs OK in my XP 32bit, I had hoped for better performance, but as it will only run at 32 on a 64 system any performance boost would only come from having to compete less for RAM. so for this application, the difference would be less noticeable than the other applications running at 64 bit..

I followed some instructions to convert Ubuntu to Lubuntu (System > Administration > Synaptic Package Manager. Then type “Lubuntu” In the search field. Double-click on lubuntu-core and install it) and now have the LXDE desktop but seems to be same Ubuntu (just nagged to upgrade to 12.04) under it. Is this correct? Have I now got Ubuntu+LXDE (more overhead) or has Lubuntu replaced Ubuntu? How can I tell? I did notice AMD64 in the download stuff so it has gone for 64bit.

I haven't "moved in" on the Linux boot so haven't got any data or other stuff that I need to backup/keep, so I can wipe or overwrite this with no problems. All my data is on a NAS (another thing to deal with-mounting that).

I'll persevere with 64bit then if help is on hand...
Whatever I'm running at present didn't shine with Minecraft last night (R&R time). Quite an interesting benchmark really as it uses masses of resources both RAM & CPU. I'll be trying gvSIG next

Thanks for that concrete advice - duly noted

Ta.
Gotta look at this....Will try on other PC.
BTW, why not SOHO?

Why not Vector SOHO? Well, I found it a bit tiresome to have to download and burn two disks rather than one. You can always add the extra software yourself, and get exactly what you want, rather than multiple video players. Also I remembered that there'd been some problem or other — and so there had been:
http://www.linuxquestions.org/review...p/product/2202

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Thank you. I suppose if you were rolling it out over a few PCs it would save a bit of effort but tailoring your downloads has more appeal.

Moved to new post.
Not sure that the original question is closed yet though...

@mogmog: This is a new qn, different are entirely to the original one; I'd recommend asking the Mods (via the Report button) to use it to start a new thread, or just mark this threads a SOLVED and start a new one.

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