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Old 08-02-2012, 10:35 AM   #16
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Quote:
Originally Posted by mogmog View Post
I haven't delved into it but Minecraft (popular with certain factions in our household), which runs on Java, has a 64bit version - suggests some sort of 64bit capability or fudge?
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.
 
Old 08-02-2012, 10:41 AM   #17
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nearly there!

Quote:
Originally Posted by johnsfine View Post
The 3.x GB limit is a limit of physical ram per system, which you need to understand is very different from virtual ram per process. The 3.x GB limit of physical ram per system is a limit on non PAE 32 bit kernels and a limit (regardless of kernel) on some motherboards.
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.



Quote:
I'm not sure how that person measured ram use (it is much harder to measure than you would expect). I think those results are wrong. It depends a lot on the specific programs involved, but generally the increase in ram use for 64 bit is much smaller than that post claims. Also, it doesn't scale up: The increase is primarily in the program's overhead, not in the memory it uses for its actual task. So a program like gimp might need many MB more to work with a low res photo in 64 bit than it needs in 32 bit and that might be a significant percentage of its small memory use. But if you work with giant high res photos and need GB of ram, the difference between 64 bit and 32 bit will be a similar total number of MB rather than a similar %.

If I had under 1GB of ram, I would consider the increase in ram overhead of 64 bit to be a big reason to stack with 32 bit. At 3GB or more physical per system, I think the extra ram use of 64 bit isn't worth worrying about.
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?
 
Old 08-02-2012, 11:34 AM   #18
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Quote:
Originally Posted by mogmog View Post
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.

Last edited by johnsfine; 08-02-2012 at 11:42 AM.
 
Old 08-03-2012, 08:08 AM   #19
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Quote:
Originally Posted by johnsfine View Post
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.
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.

Quote:
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.
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).

Quote:
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'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

Quote:
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.
Thanks for that concrete advice - duly noted
 
Old 08-03-2012, 08:11 AM   #20
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I Tthought I was nearly there...

Quote:
Originally Posted by DavidMcCann View Post
Vector now has a 64-bit version, so you could consider that for everything. Don't bother with Vector SOHO, Vector Standard is just fine.
Ta.
Gotta look at this....Will try on other PC.
BTW, why not SOHO?
 
Old 08-03-2012, 11:00 AM   #21
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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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Old 08-09-2012, 03:47 PM   #22
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why not Vector SOHO

Quote:
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:
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.
 
Old 09-04-2012, 12:25 PM   #23
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Two steps forward, one step back....

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

Last edited by mogmog; 09-08-2012 at 02:49 AM. Reason: Moved to new post
 
Old 09-04-2012, 07:26 PM   #24
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@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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