Now that this thread is open, maybe someone can explain something... or maybe I know it already... It goes like this: A pc can only use about 3 GB of RAM because the top GB is used by the system for peripheral addressing, etc. Does that only hold true for M$ or are all PCs the same? How does one get more than 4GB onto a mobo? Do the new ones allow that? Curious -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org
On Wednesday 19 September 2007 09:49, Stevens wrote:
Now that this thread is open, maybe someone can explain something... or maybe I know it already...
It goes like this:
A pc can only use about 3 GB of RAM because the top GB is used by the system for peripheral addressing, etc.
This depends on the virtual memory hardware of the CPU chip in question. It's not the case for any of the most recent Intel chips. (I'm very unfamiliar with AMD's processors, so I can't remark on their characteristics.)
Does that only hold true for M$ or are all PCs the same? How does one get more than 4GB onto a mobo? Do the new ones allow that?
Buy a system designed for, say, the Core 2 processor series and you can put far more than 4 GB. For almost any practical (desktop) purpose the RAM capacity is unlimited. The limits come from the number of RAM slots and kind of RAM supported by the mainboard.
Curious
Note that Crucial (a RAM vendor) has announced DDR3 RAM modules and that mainboard vendors are starting to accommodate this standard, so the capacity and speed limits continue to increase. Randall Schulz -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org
Stevens wrote:
Now that this thread is open, maybe someone can explain something... or maybe I know it already...
It goes like this:
A pc can only use about 3 GB of RAM because the top GB is used by the system for peripheral addressing, etc.
(IMHO an x86 based computer is not a "pc" unless a "pc" OS is installed on it) At any rate, the x86 arch covers a lot of ground, capacity-wise: Here's a small linux/386 server: top - 10:31:03 up 395 days, 13:06, 1 user, load average: 0.89, 0.55, 0.44 Tasks: 237 total, 1 running, 236 sleeping, 0 stopped, 0 zombie Cpu(s): 0.8% us, 0.5% sy, 0.0% ni, 97.1% id, 1.5% wa, 0.0% hi, 0.0% si Mem: 4082748k total, 3697928k used, 384820k free, 90344k buffers Swap: 4198296k total, 8k used, 4198288k free, 3007020k cached Here's a medium linux/386 server: top - 10:31:35 up 395 days, 12:17, 1 user, load average: 0.94, 0.93, 0.97 Tasks: 191 total, 2 running, 189 sleeping, 0 stopped, 0 zombie Cpu(s): 5.2% us, 0.8% sy, 0.0% ni, 93.9% id, 0.0% wa, 0.0% hi, 0.0% si Mem: 7789024k total, 3423964k used, 4365060k free, 193164k buffers Swap: 8392536k total, 126452k used, 8266084k free, 727676k cached Here's a fairly good sized linux/x86_64 server: top - 10:30:39 up 399 days, 21:30, 1 user, load average: 0.53, 0.46, 0.45 Tasks: 228 total, 1 running, 227 sleeping, 0 stopped, 0 zombie Cpu(s): 0.7%us, 0.9%sy, 0.0%ni, 96.3%id, 2.0%wa, 0.0%hi, 0.0%si, 0.0%st Mem: 16443912k total, 16280288k used, 163624k free, 132800k buffers Swap: 8393952k total, 128k used, 8393824k free, 12153856k cached Joe -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org
On Wednesday 19 September 2007 10:36, Sloan wrote:
Stevens wrote:
Now that this thread is open, maybe someone can explain something... or maybe I know it already...
It goes like this:
A pc can only use about 3 GB of RAM because the top GB is used by the system for peripheral addressing, etc.
(IMHO an x86 based computer is not a "pc" unless a "pc" OS is installed on it)
What does that mean? There's no longer any real difference between personal (home), office, desktop, workstation, server or cluster operating systems. They're configured differently, but Windows, MacOS, Linux, Solaris, HP-UX, etc. are all generic enough to be used for all classes of machines. The only possible exception I can think of is that I've never heard of anyone using Windows for clusters, but I don't know they're not out there. PC is just Personal Computer. Treating it as synonymous in some way with Windows just plays into Microsoft's hands.
...
Joe
Randall Schulz -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org
Randall R Schulz wrote:
On Wednesday 19 September 2007 10:36, Sloan wrote:
(IMHO an x86 based computer is not a "pc" unless a "pc" OS is installed on it)
What does that mean? There's no longer any real difference between personal (home), office, desktop, workstation, server or cluster operating systems. They're configured differently, but Windows, MacOS, Linux, Solaris, HP-UX, etc. are all generic enough to be used for all classes of machines. The only possible exception I can think of is that I've never heard of anyone using Windows for clusters, but I don't know they're not out there.
PC is just Personal Computer. Treating it as synonymous in some way with Windows just plays into Microsoft's hands.
We're possibly at cross purposes here - but my point is that it's the OS, more than the hardware, that determines the capabilities and personality, so to speak, of a machine. I'll allow that microsoft has taken some steps towards providing a somewhat more general purpose OS, but it's peecee origins are still awkwardly apparent at times. Joe -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org
Stevens wrote:
Now that this thread is open, maybe someone can explain something... or maybe I know it already...
It goes like this:
A pc can only use about 3 GB of RAM because the top GB is used by the system for peripheral addressing, etc.
Does that only hold true for M$ or are all PCs the same? How does one get more than 4GB onto a mobo? Do the new ones allow that?
Here's a good article on the situation: http://kerneltrap.org/node/2450 There was a long thread about this on the Boston Linux Group's mailing list recently. There's a lot about the "PAE" (Physical Address Extension) kernels, as well as some discussion as to whether they were needed or not. Also, many motherboards map the area between 3 & 4gb for other duty, so even if I add another gig of RAM, it isn't clear if I'd actually see it. -- Jonathan Arnold (mailto:jdarnold@buddydog.org) Linux Brain Dump - Linux Notes, HOWTOs and Tutorials: http://www.linuxbraindump.org Daemon Dancing in the Dark, an Open OS weblog: http://freebsd.amazingdev.com/blog/ -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org
On Wednesday 19 September 2007 11:48, Jonathan Arnold wrote:
Stevens wrote:
...
A pc can only use about 3 GB of RAM because the top GB is used by the system for peripheral addressing, etc.
Does that only hold true for M$ or are all PCs the same? How does one get more than 4GB onto a mobo? Do the new ones allow that?
Here's a good article on the situation:
http://kerneltrap.org/node/2450
There was a long thread about this on the Boston Linux Group's mailing list recently. There's a lot about the "PAE" (Physical Address Extension) kernels, as well as some discussion as to whether they were needed or not. Also, many motherboards map the area between 3 & 4gb for other duty, so even if I add another gig of RAM, it isn't clear if I'd actually see it.
If the mainboard is designed to accommodate a CPU with PAE, then it should also have the option (via its BIOS configuration) to map the I/O devices somewhere much higher than the usual 3-4 GB memory hole.
-- Jonathan Arnold
Randall Schulz -- To unsubscribe, e-mail: opensuse+unsubscribe@opensuse.org For additional commands, e-mail: opensuse+help@opensuse.org
participants (4)
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Jonathan Arnold
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Randall R Schulz
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Sloan
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Stevens