4gb address space limitation for i386
I have an IBM xSeries 350 4xPIII with 5.5gb of RAM, and see that only about 3.5gb is being used under the i386 port. I've been looking through the archives to try and figure out what the root of the problem is and I amn't quite sure I know which part of the situation is the real problem. Is it a limitation of the i386 port? That is to say, if there were a specific PIII (i686?) port, would this problem be overcome? Or is it a hardware limitation? Is it necessary to use a not-clean method to access the extra address space (is this what PAE is?), and there's no clean way around it, regardless of the port? I was looking at building a PAE kernel, but was discouraged by the lack of usb and certain SCSI support, both of which I'd really like to have (in the case of SCSI, need to have). Is this lack of support because of an inherent difficulty in the hardware, or could it be overcome in a stable way with modification of the device driver code? My basic (and very hypothetical) question - if I had unlimited time and knowledge (I have limited both), what direction would I take to get access to all 5.5gb of RAM on this particular computer? Thank you, Bob ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: 4gb address space limitation for i386
Youre pretty much going to require an AMD setup for that. On 8/30/07, User Bobby <[EMAIL PROTECTED]> wrote: > > I have an IBM xSeries 350 4xPIII with 5.5gb of RAM, and see that only > about 3.5gb is being used under the i386 port. I've been looking through > the > archives to try and figure out what the root of the problem is and I amn't > quite sure I know which part of the situation is the real problem. > > Is it a limitation of the i386 port? That is to say, if there were a > specific PIII (i686?) port, would this problem be overcome? Or is it a > hardware limitation? Is it necessary to use a not-clean method to > access the extra address space (is this what PAE is?), and there's no > clean > way around it, regardless of the port? > > I was looking at building a PAE kernel, but was discouraged by the lack of > usb and certain SCSI support, both of which I'd really like to have (in > the case of SCSI, need to have). Is this lack of support because of an > inherent difficulty in the hardware, or could it be overcome in a > stable way with modification of the device driver code? > > My basic (and very hypothetical) question - if I had unlimited time and > knowledge (I have limited both), what direction would I take to get access > to all 5.5gb of RAM on this particular computer? > > Thank you, > Bob > ___ > freebsd-questions@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-questions > To unsubscribe, send any mail to " > [EMAIL PROTECTED]" > ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
RE: 4gb address space limitation for i386
Hello: > -Original Message- > From: [EMAIL PROTECTED] [mailto:owner-freebsd- > [EMAIL PROTECTED] On Behalf Of User Bobby > Sent: Thursday, August 30, 2007 2:32 PM > To: freebsd-questions@freebsd.org > Subject: 4gb address space limitation for i386 > > I have an IBM xSeries 350 4xPIII with 5.5gb of RAM, and see that only > about 3.5gb is being used under the i386 port. I've been looking > through the > archives to try and figure out what the root of the problem is and I > amn't > quite sure I know which part of the situation is the real problem. > > Is it a limitation of the i386 port? That is to say, if there were a > specific PIII (i686?) port, would this problem be overcome? Or is it a > hardware limitation? Is it necessary to use a not-clean method to > access the extra address space (is this what PAE is?), and there's no > clean > way around it, regardless of the port? > > I was looking at building a PAE kernel, but was discouraged by the lack > of > usb and certain SCSI support, both of which I'd really like to have (in > the case of SCSI, need to have). Is this lack of support because of an > inherent difficulty in the hardware, or could it be overcome in a > stable way with modification of the device driver code? > > My basic (and very hypothetical) question - if I had unlimited time and > knowledge (I have limited both), what direction would I take to get > access > to all 5.5gb of RAM on this particular computer? > > Thank you, > Bob You may just have one issue or you may have two. There is a 4 Gig limit to 32-bit Operating Systems (not just FreeBSD), so you either have to run a 64Bit system (which you can't) or fake it using PAE. You may also be running into the PCI-Hole which requires memory to map PCI devices. This can suck up anywhere to about 1/2 a Gig of RAM. PAE is definitely "at your own risk" and everything I've read about the potential ramifications (including complete loss of data) compel me to stick with the regular, non-PAE configuration on i386 systems. But, someone else may have had better luck and set your mind at ease. Regards, Mike ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: 4gb address space limitation for i386
On Thu, Aug 30, 2007 at 05:32:09PM -0400, User Bobby wrote: > I have an IBM xSeries 350 4xPIII with 5.5gb of RAM, and see that only about > 3.5gb is being used under the i386 port. I've been looking through the > archives to try and figure out what the root of the problem is and I amn't > quite sure I know which part of the situation is the real problem. > > Is it a limitation of the i386 port? That is to say, if there were a > specific PIII (i686?) port, would this problem be overcome? Or is it a > hardware limitation? It is a hardware limitation. > Is it necessary to use a not-clean method to access > the extra address space (is this what PAE is?) That is exactly what PAE is for. >, and there's no clean > way around it, regardless of the port? Correct. > > I was looking at building a PAE kernel, but was discouraged by the lack of > usb and certain SCSI support, both of which I'd really like to have (in the > case of SCSI, need to have). Is this lack of support because of an > inherent difficulty in the hardware, or could it be overcome in a stable > way with modification of the device driver code? All drivers could potentially be made to work correctly together with PAE. For some of them it would probably require substantial and non-trivial modifications to the driver code. > > My basic (and very hypothetical) question - if I had unlimited time and > knowledge (I have limited both), what direction would I take to get access > to all 5.5gb of RAM on this particular computer? Use a PAE-enabled kernel. Fix the drivers you need that do not currently work correctly with PAE (or persuade/bribe/blackmail/hire somebody else to fix the drivers.) -- Erik Trulsson [EMAIL PROTECTED] ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: 4gb address space limitation for i386
User Bobby wrote: Ok thank you all for your replies. I'm thinking I can't use amd64 on a PIII, right? So, given that I'm stuck with this particular piece of hardware, my only real option is to begin down the long and scary road of PAE. Yes? Bob On Thu, 30 Aug 2007, [EMAIL PROTECTED] wrote: On Thu, 30 Aug 2007, User Bobby wrote: I have an IBM xSeries 350 4xPIII with 5.5gb of RAM, and see that only about 3.5gb is being used under the i386 port. I've been looking through the archives to try and figure out what the root of the problem is and I amn't quite sure I know which part of the situation is the real problem. Is it a limitation of the i386 port? That is to say, if there were a specific PIII (i686?) port, would this problem be overcome? Or is it a hardware limitation? Is it necessary to use a not-clean method to access the extra address space (is this what PAE is?), and there's no clean way around it, regardless of the port? I was looking at building a PAE kernel, but was discouraged by the lack of usb and certain SCSI support, both of which I'd really like to have (in the case of SCSI, need to have). Is this lack of support because of an inherent difficulty in the hardware, or could it be overcome in a stable way with modification of the device driver code? My basic (and very hypothetical) question - if I had unlimited time and knowledge (I have limited both), what direction would I take to get access to all 5.5gb of RAM on this particular computer? Thank you, Bob It's a limitation of the basic i386 architecture; you have to use i386 with PAE, or better yet use amd64, because those architectures support memory address sizes beyond 32-bits. Cheers, -Garrett Correct. -Garrett ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
