The vmstatus operator

systemdict

- vmstatus level used maximum

This a standard PostScript operator; we're just documenting some notes and restrictions.

level is the current depth of save nesting.

used and maximum give the memory used for PostScript VM and the available memory, in bytes. However, the values returned are limited to 2 GiB, regardless of the actual amount of used and available memory. This is because values larger than 2 GiB cannot be represented by a PostScript integer.

used is given for either local or global VM, depending on the current allocation mode. See the PostScript spec for details. maximum is the same value for both modes, as the memory is available for either.

Note that PostScript VM is only a minor part of the memory usage of the RIP, as for example, the display list including images, and the rasters for transparency groups and the output page are not managed by PostScript. The available memory is more useful as it will be available for any purpose, not just VM. Note however, that there are many caches and data stores that the RIP can and will automatically compress or purge in low memory. It's generally not advisable or necessary to write memory management code in PostScript to try to second-guess the RIP.