Total Physical Memory

[Guest]

Hello out there

I just noticed that Windows 2000 and also windows 2003 server incorrectly
reports how much physical memory there is installed in a server - You can
either see it as the properties on "This computer", taskmanager or f.ex. this
small script with the cscript engine:

strComputer = "."
Set objSWbemServices = GetObject("winmgmts:\\" & strComputer)
Set colSWbemObjectSet = _
objSWbemServices.InstancesOf("Win32_LogicalMemoryConfiguration")

For Each objSWbemObject In colSWbemObjectSet
Wscript.Echo "Total Physical Memory (kb): " & _
objSWbemObject.TotalPhysicalMemory
Next

it reports 3.2GB mem in a Dell 2800 server with 4GB RAM - I have run this
script on several different hw-platforms with similary result. Anyone got an
idea why?

regards /ti

 

[Bob I]

The short answer is "Because PCI address space is unavailable to use."
Long version
http://www-307.ibm.com/pc/support/site.wss/document.do?lndocid=MIGR-40247

 

[Guest]

Hi again

Thanks for the answer - I had something like this in mind but I thought it
is a bit huge area to dedicate to the PCI bus. If I look in the
device-manager and look at the resources for the PCI bus it occupies from
D0000000H - FEBFFFFFH - which looks like my lost memory. But is this memory
used by the PCI bus for data-transfer or is this just "unavalibly" because
the PCI devices are memory-mapped into this area - eg: is this 3/4GB RAM lost
or still used ?

 

[Guest]

Jusat a extra note: we have just tried to boot one of the servers - with no
more than 4GB physical memory installed - with the /PAE switch on (according
for some tip from Dell Support) - and certainly - now is all the installed
memory recoigniced by the OS. I just wonder - this switch changes the way the
OS translate the logical adresses - with PAE enabled, the operating system
moves from a two-level linear address translation to a three-level address
translation. The extra layer of translation is what provides access to
physical memory beyond 4 GB. Instead of a linear address being split into
three separate fields for indexing into memory tables, it is split into four
separate fields; a 2-bit field, two 9-bit fields, and a 12-bit field that
corresponds to the page size implemented by Intel Architecture (4 KB).
But - my mem is all belove the 4GB limit - do we have some bug somewhere
here if servers do not have PAE enabled ? Are these pages behind the PCI bus
lost for the OS if we do not have PAE enabled?

regards /ti

 

[Bob I]

Sorry, you are past my knowledge of the memory issue now. Have you tried
installing more than 4 GB memory?

 

[Guest]

hi again
no - I am quite happy if it these stupid servers just could recognize my
4GB, which should be possibly, without advanced options..