This command will delete image buffer number 'buf' and discard its contents. The memory needed to hold an image or spectrum is not pre-assigned when the VISTA program is compiled, instead it is allocated dynamically by the system when a new image is read in or created. By allocating ``virtual memory'', VISTA can work efficiently by only using as much system memory at one time as required. The DISPOSE command is used to free this memory when the image is no longer needed or when VISTA has run out of memory for assigning images to other buffers. If you want to save the image, it should be written to disk or tape first with the WD command before using DISPOSE.
You can delete several image buffers at once by putting their numbers on the command line, up to a maximum of 20. The DISPOSE ALL command will clear out the contents of all image buffers, releasing all of the dynamically allocated memory.
VISTA may sometimes respond with the message 'No virtual memory available' when trying to load or create an image. To make room for the new image, use DISPOSE to delete an unused image buffer or two. This frees up more memory, allowing you to proceed.
If you DISPOSE of images that you will no longer need, the VISTA program may run faster, especially if there are many users on the system or if you are working with large (>2048x2048 images).