Re: FreeBSD-6.3 only detects 3GB of RAM
fred wrote: Hello all, I am trying to fix an issue with my dual xeon ibm server, it only detects 3GB or RAM but I have 4GB: I discovered on my workstation that there is a BIOS setting to cause the motherboard to remap everything above 3GB installed RAM up above the PCI address space. Without this option set, neither x86 PAE nor amd64 could make use of my last gigabyte. Probably has nothing to do with your hardware, but just a heads-up that these things do exist. Asus P5B-Plus, 4GB PC2-6400, Intel Core 2 Duo E6550 -- Fuzzy love, -CyberLeo Technical Administrator CyberLeo.Net Webhosting http://www.CyberLeo.Net <[EMAIL PROTECTED]> Furry Peace! - http://.fur.com/peace/ ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: FreeBSD-6.3 only detects 3GB of RAM
On Thu, Mar 27, 2008 at 02:26:05PM +, [EMAIL PROTECTED] wrote: > fred writes: > > Hello all, > > > > I am trying to fix an issue with my dual xeon ibm server, it only detects > > 3GB or RAM but I have 4GB: > [...] > > I have seen this problem under Linux on IBM Intellistations (6225). > IBM pointed me to a tech document (the number of which I do not > remember) that says when the machine detects more than 3GB, it uses > some of that memory internally for ... stuff. Still, I find stealing > 1GB quite unacceptable. It's not really stealing it. It has to do with how the computer hardware handles memory mapped IO. A certain amount of memory is allocated per device which needs MMIO; in a typical computer, this could be as much as 1GB. It's mapped from the highest portion of the address space that the computer can handle--in a 32-bit environment, that means that it's mapped from 4GB on down. I haven't looked to see if it's arcitecturally the same on 64-bit machines, but if so, we'll see the same problem once we start putting more than a few terabytes of RAM in computers. Luckily, I think that day is quite a ways off, and who knows what changes will be made in computing by then. An MSDN blog actually has a decent description of the issue, including some points I didn't mention here: http://blogs.msdn.com/hiltonl/archive/2007/04/13/tbhe-3gb-not-4gb-ram-problem.aspx Erik ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
RE: FreeBSD-6.3 only detects 3GB of RAM
Thank you all for your replies. I will install FreeBSD AMD64 and test my softwares to make sure everything works as it should. Mission critical softwares are the reasons why I was sticking to 32-bit OS on my servers. freebsd/amd64 is compatible with /i386 and with linux/i386 ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
RE: FreeBSD-6.3 only detects 3GB of RAM
Thank you all for your replies. I will install FreeBSD AMD64 and test my softwares to make sure everything works as it should. Mission critical softwares are the reasons why I was sticking to 32-bit OS on my servers. -fred -Original Message- From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Ivan Voras Sent: 27 mars 2008 10:37 To: freebsd-questions@freebsd.org Subject: Re: FreeBSD-6.3 only detects 3GB of RAM fred wrote: > I have read that OPTION PAE in kernel would fix the problem but I have > also read that compiling FreeBSD AMD64 might be a better solution, any > advices before I break my current setup? Except if you have a strong reason to stick with the 32-bit kernel, use AMD64. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: FreeBSD-6.3 only detects 3GB of RAM
fred wrote: > I have read that OPTION PAE in kernel would fix the problem but I have also > read that compiling FreeBSD AMD64 might be a better solution, any advices > before I break my current setup? Except if you have a strong reason to stick with the 32-bit kernel, use AMD64. signature.asc Description: OpenPGP digital signature
Re: FreeBSD-6.3 only detects 3GB of RAM
[EMAIL PROTECTED] wrote: > fred writes: >> Hello all, >> >> I am trying to fix an issue with my dual xeon ibm server, it only detects >> 3GB or RAM but I have 4GB: > [...] > > I have seen this problem under Linux on IBM Intellistations (6225). > IBM pointed me to a tech document (the number of which I do not > remember) that says when the machine detects more than 3GB, it uses > some of that memory internally for ... stuff. Still, I find stealing > 1GB quite unacceptable. This question is answered almost once a week. Search the archives and you will find plenty of explanations, both long and short. Short version: you cannot use memory near 4 GB on 32-bit operating systems (it's a hardware limitation). You can either compile a kernel with PAE (http://en.wikipedia.org/wiki/Physical_Address_Extension) or a 64-bit version of the operating system (in FreeBSD it's called AMD64 since AMD was first to create the hardware, http://en.wikipedia.org/wiki/AMD64). signature.asc Description: OpenPGP digital signature
Re: FreeBSD-6.3 only detects 3GB of RAM
fred writes: > Hello all, > > I am trying to fix an issue with my dual xeon ibm server, it only detects > 3GB or RAM but I have 4GB: [...] I have seen this problem under Linux on IBM Intellistations (6225). IBM pointed me to a tech document (the number of which I do not remember) that says when the machine detects more than 3GB, it uses some of that memory internally for ... stuff. Still, I find stealing 1GB quite unacceptable. ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
Re: FreeBSD-6.3 only detects 3GB of RAM
I have read that OPTION PAE in kernel would fix the problem but I have also read that compiling FreeBSD AMD64 might be a better solution, any advices before I break my current setup? simply use FreeBSD/amd64 i don't understand why you don't use 64-bit system on 64-bit hardware ___ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "[EMAIL PROTECTED]"
