These key functions are enabled when an optional hard disk is installed:Job Building, Printer lockout, storage used by Application Solutions such as FormsMerge Job Buffering (print spooling), email spooling, font and macro storage, User-based billing, Job Park (through a power-off and power-on cycle), hard disk-related administration (Disk wiping, Disk encryption, Disk diagnostics).The 'Disk Encryption' function provides a randomly generated encryption key used to encrypt all data stored on the hard disk. This key generated by each printer is unique to that specific printer.With 'Printing Lockout' a disk may also be locked with a user PIN. This prevents any submitted jobs from printing. All held jobs are stored on the hard disk until it is unlocked. 'Disk Encryption' should be used with this setting.