Le 13/08/2015 07:04, Mike Horvath a écrit :
> My computer just locked up due to lack of memory. I got a black screen
> and had to reboot. Is this supposed to happen? Shouldn't POVray be
> switching over to virtual memory?

The system is in charge of virtual memory. Povray is just an application 
with sometime huge need of memory.

>
> Windows 7 Pro x64
> 8GB RAM
> POV-ray 3.7.0.msvc10.win32
>
> Not sure how much swap memory got used up during the render.

Next time, open the task manager before starting the render, to see how 
it goes.

The handling of swap (virtual memory) by most OS can be such a slow down 
with random access that it turns super-speedy processor into very slow 
snail. Some operating system do not even have protected special pages of 
memory for themselves (excepted the swap routine... if you swap that 
part of memory on disk, you're dead soon), and that might include the 
data to draw the display: so, when refreshing the picture, such as when 
moving the mouse and asking a redraw to all applications when exiting 
screen-blank-economy mode (or other), it would need to access a lot of 
pages while an active process is still asking a hell lot of other 
pages... so refreshing the screen would take hours... hence your black 
screen.

Usually swap is used with huge documents (photos or movie, or even 
texts) whose only a tiny part need to be access at once, and the 
distribution of the data is such that the accessed part for the current 
task is usually a small set of continuous portions of the memory, so 
putting the remainder of the memory on the disk is invisible to the user 
(and the program is waiting 99.9% for user's interaction, so reaction 
time is not impacted).

Povray with a huge scene is not like that: it takes all the CPU it can 
for rendering, and want to access unpredictable locations all the time. 
You might help to keep the reaction time for the user in a reasonnable 
area by using less cpu-cores (via the -WT option), if at least you have 
more than one true cores.

Some operating systems can enforce a memory limit per process: once 
reached, they kill the offender without negotiation.

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