An image forming apparatus has a feeder for feeding a sheet, an image forming unit for performing an image formation job so as to form an image on a sheet fed from the feeder, a controller for interrupting a current image formation job, performing an interrupt image formation job, and resuming the current image formation job after completion of the interrupt image formation job. Such code masking, referred to as \u201cobfuscation,\u201d is useful to prevent unwanted parties from making copies of an original author’s software, obtaining valuable information from the software for purposes of breaking into a program, stealing secrets, making derivative works, etc. The proposed solution adds a monitor that periodically measures a responsiveness of each resource. A Ta2O5 dielectric layer is formed on the bottom electrode and forming a top electrode on the Ta2O5 dielectric layer. The control unit is further operable to program a delay line based upon the delay between the clock signals and based upon internal operational signals correlated with the clock signals. Control of the substrate permittivity further allows the user to control surface plasmon propagation from the source input grating along the interface to a drain output grating, to achieve a transistor-like effect for the surface plasmon.