[Scott Dorsey]

Laurence Payne NOSPAMlpayne1ATdsl.pipex.com wrote:

Sure. As much AS POSSIBLE. Are you suggesting PT or Windows affords
data caching the same priority as it gives program code?

It's not data caching. It's virtual memory. It's done by Windows, and
the application has no control over it.

That
whenever a program accesses a data file larger than available RAM,
core will be swapped to disk in the interests of caching every last
possible byte of data? I think not :-)

No, you have it backwards. The program has a large address space that is
available for it to use. It is larger than the physical core space on
the computer. When a program goes to access memory that is not currently
swapped in, it swaps a page out to the page file, and swaps in one that
contains the memory block the application wants. In this way, the program
sees a very large address space without the computer actually needing to
have so much space in core.

Are you maybe falling into the common trap of thinking Virtual Memory
= paging file?

The paging file PLUS the physical memory IS the virtual memory space
available. This is early-1970s technology we are talking about here.

Many systems that are designed for realtime applications have very different
memory management, because on realtime operating systems the application
tells the operating system how much time it's willing to spend on each task
and the OS schedules things appropriately so all processes can meet deadline.
That's mid-1980s technology, and you will see it applied in realtime systems
today like pSOS and BeOS.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."