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Memory issues

Ram assigned to the MacLispix application.
Memory is assigned to MacLispix using the Get Info box in the finder. MacLispix can run on 8 Meg or less, if only smaller images are processed. get info system dialog box


 Images use two kinds of memory - Mac heap and Lisp heap. The Image arrays are stored in the LISP heap. The scaled copy of the arrays are also stored in the LISP heap, while the pixmap, what is actually seen on the screen, is stored in the Mac heap.
 Printout- use Info->Print Memory Quotas buttons and click on Monitor window.printout for memory button

To save memory, the default is not to display images, thus saving space that would be taken by the scaled image array and the pixmap. MacLispix, since it is written in LISP, uses dynamic memory allocation. Both the Lisp heap and the Mac heap can be reused, if one discards the images. An important exception may be this: the Mac Heap is taken from the LISP heap as memory is needed, and stays there even when the image window is closed. The moral is not to show too many large images at once, or else the LISP heap will all disappear into the mac heap, and MacLispix will run out of memory.

In the event of seeing the GC cursor repeatedly, or getting a message that macLispix has run out of memory, it probably be necessary to restart MacLispix. Occasionally, it is possible to quickly close some images and regain enough memory to continue to work.

To monitor the memory being used click the Heap button. This will show the amounts of heap space used. Pay particular attention to the last figure on the right - the amount of free LISP heap memory remaining. Displayed images use Mac heap space. Image arrays use Lisp heap space. The Mac heap will grow as more images are displayed by taking over free Lisp heap space, but the reverse will not occur. In other words, when image arrays run out of room, space cannot be recovered by deleting image windows - only by erasing image arrays. The only way to get more LISP heap space is to restart MCL. The best way to avoid the problem is to minimize the number of images displayed at once, or, more specifically, to minimize the total image window area at any given time.


Image memory

The memory taken by the raw data for each image is listed by the Info button:

The above listing shows the window title (or the image name), which by default is the file name from which the image was read. Next is the pixel data type. (Unsigned-byte 8) is the usual byte image format. Note that this does NOT indicate whether or not the image is a gray scale image, or a false colored image using an LUT. (Unsigned-byte 16) images are sometimes known as 'integer images', but there are other types of integer images than this. The last collumn is the memory requirement in Kbytes (kilobytes = 1024 bytes).


When the image is actually displayed, additional memory is used for the pixmap, and sometimes for a scaled version of the image. (The memory requirement for a bit image, for example, is about an order of magnitude larger than the size of the original data array.)

For special types of images, such as the blobber, superblobber, EDIF spots, and stacks, each image window uses considerably more memory.