Vista equivalent to the /3GB boot.ini switch

  • Thread starter Thread starter Tim Anderson
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T

Tim Anderson

My computer only has 2GB of RAM installed and I can see all of this memory
so this question has nothing to do with not being able to see installed
memory.

My question is thus:

"How do I get a LARGEADDRESSAWARE application to see more than 2GB of
virtual memory?"

On XPSP2 and Windows Server 2003, you can add the /3GB boot.ini switch to
let LARGEADDRESSAWARE applications access memory beyond the 2GB limit. I
cannot find any equivalent option in the Vista boot configuration that will
enable this. This has nothing to do with PAE (which allows access beyond the
4GB limit) and does not require a 64bit OS. This is specifically for 32bit
CPUs running a 32bit OS and there is no requirement for any specific amount
of physical RAM. How do I enable this for Vista (on a 32bit CPU and x86 OS)?

If the answer is -- "you need a 64bit OS" -- then IMO Vista is a step down
in functionality and limits functionality on very capable x86 platforms.

Thanks,
Tim
 
Tim - Quoted from your question "...to see more than 2GB of virtual
memory?".." - Virtual or RAM?
 
Quoted from my original post "My computer only has 2GB of RAM installed and
I can see all of this memory so this question has nothing to do with not
being able to see installed memory."

To restate in other words:

"How can I get an application to see more than 2GB of VIRTUAL memory?"
 
I'd guess that Vista does stuff a different way to XP. In other words:
there is no direct comparison.

Running either 32 bit or 64 bit Vista RC1 on this machine with 3 Gig of
RAM shows very similar results.
 
If an application is comiled with the /LARGEADDRESSAWARE option AND XPSP2 is
booted with the /3GB option, that application's virtual address space is 3GB
instead of 2GB regardless of how much memory you have installed. It's called
virtual memory because it does not necessarily point to any physical memory
address. Normal applications don't have this requirement but high-end,
memory intensive application do and the solution for the typical
desktop/mobile workstation is to used the aforementioned settings. Vista
does not do "stuff a different way to XP" on a 32bit CPU (which cannot run a
64bit OS -- XP, Vista, or otherwise), but there are applications that are
going to expect the XP functionality. FWIW, you can have 256MB of RAM
installed in your system, but each 32bit application has an address space of
at least 2GB or 3GB is the OS provides the option and the application is
compiled to use it. If you don't understand this distinction, it is probably
not important to you, but for the business application that are expecting to
have users loading Vista in November(?) are going to be disappointed unless
they shell out bucks for another workstation. This is not a performance
issue -- its a maximum virtual address space issue.

So far, I have not seen any response indicating that Vista x86 will support
LARGEADDRESSAWARE applications.
 
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