In article <37BDD20B.AAF0364A@ndirect.co.uk> , Steve <sjl### [at] ndirectcouk>
wrote:
> When parsing a scene that needs to swap for a few days it sounds
> asthough the machine is working something out, placing an answer
> to that in the swap file, reading that answer in order to find
> out where an object goes or something, deleting that answer, and
> putting the object place info inot the swap file and then
> starting over again for the next object.

I think you misunderstand what a swap file does: When physical memory gets
low the operating system (not POV-Ray!) will store some blocks of memory on
a mass storage device (usually harddisk) and adjust the memory map of the
CPU so the larger memory still appears to be there even for the processor.
When it tries to access memory that is on disk, an exception handler (= a
function) of the OS will be called and it will move some other blocks of
memory to disk and move those needed from disk to memory. This processes is
completely transparent to POV-Ray as it is to any other application.

> Would it be possible to have POV use memory until it's full and
> then instead of starting to swap, putting say the last ten
> percent of memory into the swap file and there fore having ten
> percent of memory to play with unitl it's full and doing the same
> again over and over rather than constantly reading and writing to
> the swap file.

As said before, the swap file is managed by the operating system. Most
operating system memory managers can determine efficiently which blocks of
memory to move to disk and which are needed often and therefore should stay
in memory.

> I don't know if this would be possible or not, but it would speed
> those types of render up considerably.

While a specialized memory manager could surely squeeze out a few percent,
it would basically require to write a whole operating system as memory
management is obviously one of the core functions of any OS!


    Thorsten


____________________________________________________
Thorsten Froehlich, Duisburg, Germany
e-mail: tho### [at] trfde

Visit POV-Ray on the web: http://mac.povray.org

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