> > I can happily load a 300MB image with the IMAQ Readfile VI, but when I > try to load larger images (eg 500MB), labview gracefully shuts down > with a "Not enough memory for requested operation" error > (-1074396159). The first thing I did was increased my RAM from 1GB to > 2GB but this made absolutely no difference. > > Would love to know how I can use a little more of the memory that I > have installed!
And when the OSes and applications move to 64 bit addressing, we should all be able to. Until then, you are working awfully close to the amount of VRAM that NT can give the process. NT is a 32 bit OS, which lets it address 4GB. I believe that it will only give each process 2GB, and half that is reserved for stack space. I'm not certain about that number since I've also heard that each process gets 2GB of data/code, and 2GB of stack. And it is also possible to reconfigure the NT kernel to give processes a different amount of stack upon creation, though I've never looked at how to configure it. Anyway, my point is that you are reaching a limit of the OS virtual memory system. When this happens, you can't rely on it, and the application has to handle it. Since LV doesn't know much about your application, it is actually up to the person writing the diagram. As I mentioned before, the options are to work on a portion of the data at a time. Process the top 200MB of the image, then the next 200MB, ... Then combine the results. This of course may involve overlapping the data being processed, all depending on what processing is going on. This is done all the time on time acquired waveforms, where the infinite or very long waveform is chopped, windowed, processed, and the results are then combined. It makes the algorithm more complex, but reality often encourages people to do clever things. If you will be more specific about the contents of the image and the analysis, there is almost always a way. There are tons of algorithms that trade space for time and allow for processing to be done incrementally on huge datasets, but they get very specific and can't always be used in the general case. Greg McKaskle
