Vuescan Memory Allocation error

[Bruceh]

I'm getting the error:

"Unable to allocate XXX MBytes of memory.
Try increasing the amount of virtual memory."

I'm using Windows 2000 Pro and increased Virtual memory
without any success.

Could there be a problem with Vuescan?

 

[degrub]

How much real memory are you working with ? You really don't want to be
using virtual memory (ie swapping to disk). WHat size Mb images are you
working with ?

Frank

 

[Bruceh]

I'm maxed out with 512MB ram. I know that I'll be swapping in these
large scan situations, but I can live with it. The images are *big*.

bruce

 

[Bart van der Wolf]

I'm maxed out with 512MB ram. I know that I'll be swapping in these
large scan situations, but I can live with it. The images are *big*.

How big? Are you scanning full res, full size on a flatbed scanner? That'll
be BIG! The operating system needs to have enough of a predefined virtual
diskspace to cope with that. You can see the resulting filesize in the
VueScan statusbar.

Bart

 

[Kurt Stege]

I'm getting the error:

"Unable to allocate XXX MBytes of memory.
Try increasing the amount of virtual memory."

I'm using Windows 2000 Pro and increased Virtual memory
without any success.

Could there be a problem with Vuescan?

Yes and no. I have seen the same problem on my computer.
This happens, when the size of the processed images
increases. (In my case, it happened while batch processing
a bunch of already scanned raw files from disk.)

I guess, it is a problem of memory fragmentation, of
fragmentation of virtual memory! Windows only support
2 GB of virtual memory for each process. That is a built
in constant you can't change. (The CPU using 32-bit-addresses
has an address range of 4 GB, but Windows uses the other
2 GB for system memory shared between severall/all processes.)

When allocating (and freeing) really huge memory blocks,
we are talking here about a half giga byte or more for
one raw image (and maybe a second memory block for a
processed copy), vuescan will get problems with the
fragmentation of the address space (as said, only 2 giga bytes).

Workaround: Restart vuescan. The new process beginns with an
fresh unfragmented memory.


By the way, the message from Windows is not quite correct.
You can't increase the size of virtual memory. That is fixed
at two giga bytes per process. You can increase the size
of physical available memory (physical ram and space in swap
file). But that will not help in this case...

Regards,
Kurt.

 

[Bruceh]

Yes and no. I have seen the same problem on my computer.

This happens, when the size of the processed images
increases. (In my case, it happened while batch processing
a bunch of already scanned raw files from disk.)

I guess, it is a problem of memory fragmentation, of
fragmentation of virtual memory! Windows only support
2 GB of virtual memory for each process. That is a built
in constant you can't change. (The CPU using 32-bit-addresses
has an address range of 4 GB, but Windows uses the other
2 GB for system memory shared between severall/all processes.)

When allocating (and freeing) really huge memory blocks,
we are talking here about a half giga byte or more for
one raw image (and maybe a second memory block for a
processed copy), vuescan will get problems with the
fragmentation of the address space (as said, only 2 giga bytes).

Workaround: Restart vuescan. The new process beginns with an
fresh unfragmented memory.

By the way, the message from Windows is not quite correct.
You can't increase the size of virtual memory. That is fixed
at two giga bytes per process. You can increase the size
of physical available memory (physical ram and space in swap
file). But that will not help in this case...

Thanks for the explanation Kurt!

bruceh