Abstract: The present invention is a methodology for developing high-assurance computing elements. The method may comprise one or more of the following steps: (a) receiving a plurality of requirements detailing intended behavior of a high-assurance computing elements; (b) creating a model based on the requirements; (c) generating higher order language (HOL) code based on the model; (d) simulating the behavior of the computing elements from the HOL code; (e) generating test cases based on the model; (f) translating the model into a verification tool-specific format; and (g) formally verifying the model using a verification tool.

Abstract: The present invention is a methodology for developing high-assurance microcode. The method may comprise one or more of the following steps: (a) receiving a plurality of requirements detailing intended behavior of microcode (b) creating a model of microcode behavior; (c) generating microcode based on the model; (d) generating test cases based on the model; (e) simulating the behavior of the microcode; (f) translating the model into a verification tool-specific format; and (g) formally verifying the model using a verification tool.

Abstract: A method of verifying properties of a source program includes creating a directed multigraph from the source program. The directed multigraph is then minimized by identifying removable vertices in the multigraph. Based on the minimization of the directed multigraph, the source program is transformed by inlining variables in the source program to produce a transformed program. The transformed program is then model checked using a model checking tool in order to verify properties of the source program.

Abstract: A system and method for sensing the positioning the printhead in one or more of a standby position, a wipe position, and a printing position uses electrical signals from a drive motor as an indicator of whether the printhead has properly moved to a desired position. As the printhead is tilted to a print position, a first position electrical signal is detected by sampling a resistance on the torque motor at a first time. A second position electrical signal is determined by sampling another resistance on the motor at a second time. A slope is calculated between the first position sample and the second position sample. The calculated slope is analyzed to determine whether the printhead is operating properly. Thus, the need for standalone sensors to determine the positioning of the printhead is eliminated.

Abstract: A system and method for determining proper positioning of the printhead as it travels between first and second positions by sampling an electrical resistance signal of a motor during tilting of the printhead, calculating an average of specified samples at a time, and comparing the calculated average to a predetermined threshold to determine whether the printhead is operating properly. Thus, the need for sensors to determine the positioning of the printhead is eliminated.