proc bind proc                          replace operator names in proc by
                                        operators

- null null                             push null on operand stack

- usertime int                          return time in milliseconds

- pagecount int                         returns number of pages printed
                                        since machine was built

* - jobname string                      returns name of current job

* - product string                      returns name of printer

* - revision string                     returns postscript interpreter
                                        software revision level

* - version string                      interpreter version

* old new setpassword bool              sets system administrator password

* int checkpassword bool                true if int is current password