[sf-perl] [OT] cygwin memory question

Jordan Share jshare at krotus.com
Sat Jul 24 09:10:47 PDT 2010

On 7/22/2010 11:10 AM, David Alban wrote:
> greetings,
> configuring new laptop for work.  installed:
> CYGWIN_NT-5.1 L-SFA-524320 1.7.5(0.225/5/3) 2010-04-12 19:07 i686 Cygwin
> on a laptop running windows xp professional.
> windows' task manager shows physical ram to be 4 gb (3594060 kb) but
> the free command seems aware only of half of that:
> $ free
>               total       used       free     shared    buffers     cached
> Mem:       2097151          0    2097151          0          0          0
> -/+ buffers/cache:          0    2097151
> Swap:      2095104     140184    1954920
> i tried googling and looking through some cygwin docs.  i haven't
> found my question addressed.  what i'm finding is the way to increase
> the heap size for a given process, but that doesn't address my
> question.
> can anyone point me to anything that would help me get cygwin to
> recognize all four gb of memory?
> thanks,
> david
> p.s.  hmmm...  could cygwin be using half of the memory as swap...?

It might be an artifact of the fact that any given 32bit process can 
only address (by default) 2GB of RAM on 32bit windows? (There is a 
workaround up to 3gig, with special boot options).


Also, fwiw, most of the time, 4GB under 32bit windows is kind of a 
waste, because a large part of the address space is being used for DMA 
for your video card anyway.  (For instance, you probably have 512meg of 
video memory, if windows is only showing you about 3.5gigs of available 
RAM, as you indicate).


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