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[JohnCampbell]

Eddie,

You may be right with the 24 bit colour. Certainly rgb@ returns a 24 bit value range. Clearwin+ may use a 3 byte storage for each pixel, although I've never tried it. (May be I should define a type colour variable using rgb as integer*1, for my screen buffer, although I've never considered this memory to take a lot.)

One interesting thing I noticed when running the test program and monitoring with Task Manager, was that the memory demand for the program never grew by very much at all, but that may relate to the memory not being taken by the program until it is actually used, rather than only being allocated.

It all sounds like a limit of a 64k memory packet on my system, but how do the other tests reported get more than this apparent 64k limit?

( On the issue of file size, I've certainly created fixed length record fortran files up to 8gb on w2k and XP (my software limit) and I think Salford can create much larger. )

John C.

[LitusSaxonicum]

John,

Perhaps the memory packet is larger on a 2Gb system, or there may be a finite number of them, which is how they come to be odd-ish sizes (and this would account for the 2Gb systems permitting more than twice as big, as the extra Gb is free from OS encumbrances compared to the first Gb.

All speculation, of course. The proof of this hypothesis would be to turn off virtual memory. I may experiment on a spare machine tonight.

Eddie

[Heise]

John, Eddie, others,

I, too, have experienced the same issue in trying to create large graphics regions. Have you by chance isolated the particular system setting that might allow larger regions?

I have also experienced problems with calls to GET_SCREEN_DIB@ after successfully creating a large graphics region. When the size of the graphics region approaches the upper limit, GET_SCREEN_DIB@ returns 0.

Interestingly, my development machine (WinXP with 512MB RAM) allows larger regions than other machines with more memory! So, size of region allowed is not necessarily proportional to amount of RAM (as had been suggested by John's tests). As discussed, there is something else in play.

[Note: I edited this post on 19 Mar 2007 to more accurately reflect my situation after further diagnosis.]

Thanks,
David Heise