Question

I need to know how much physical memory a windows machine has, using Perl.

I’ve tried using Win32::SystemInfo. However this module states the following caveat:

On Intel x86 computers with more than 2 GB and less than 4 GB of memory, the MemoryStatus function will always return 2 GB for TotalPhys. Similarly, if the total available memory is between 2 and 4 GB, AvailPhys will be rounded down to 2 GB.

So on a machine which has 2-4 GB of physical memory, I get a false answer.

Is there a way to get the correct amount of physical memory? Perhaps another module? Or directly using Win32::API?

Edit: From the comments people gave here, it looks like the limitation is in the Win32 API , and not specific to Win32::SystemInfo. However, the OS does know exactly how much physical ram is available, so there must be a way to extract that information. If not in Perl then maybe in another language?

Answer 1

As stated in the comments, this is an issue of GlobalMemoryStatus, as it can return answers up to 2GB. And GlobalMemoryStatusEX which solves this issue of the 2GB limit, but only works on 64 bit systems (as far as I can tell).

In the end I’m using the following Perl code, which uses Win32::OLE and WMI class Win32_PhysicalMemory, which returns the correct amount of physical memory even on 32bit systems:

use strict; use warnings; use English; use Win32::OLE qw( EVENTS HRESULT in ); use Readonly;  sub get_physical_memory {     my $machine                         = shift || '.'; # Default to local machine     my Readonly $WMI_MEMORY_CLASS_NAME  = 'Win32_PhysicalMemory';     my Readonly $MEGABYTE               = 1024*1024;      my $WMI =          Win32::OLE->GetObject( 'winmgmts:{impersonationLevel=impersonate,(security)}//$machine/' ) || die 'Could not get Win32 object: $OS_ERROR';     my $total_capacity                  = 0;      foreach my $object ( in( $WMI->InstancesOf( $WMI_MEMORY_CLASS_NAME ) ) ) {         $total_capacity += $object->{Capacity};     }      my $total_capacity_in_mb            = $total_capacity / $MEGABYTE;     print 'Total Memory : $total_capacity_in_mb \n';     return $total_capacity_in_mb; }