Lexmark X644E Technical Reference Manual page 227

resolution
— resolution integer
queries the resolution for the current print job. An integer is returned on the
stack:
300 dpi is set to On
300
600 dpi is set to On
600
1200 dpi is set to On
1200
This operator is equivalent to executing the following PostScript emulation
sequence:
currentpagedevice /HWResolution get 0 get
Error: stackoverflow
revision
— revision integer
queries the Revision system parameter. An integer is returned on the stack to
indicate the revision level.
Error: stackoverflow
4-34
PostScript