Design and Use of Fault Simulation for Saturn Computer Design

A system of IBM 7090 Data Processing System computer programs was developed for the purpose of normal and/or fault simulation of the Saturn computer. This paper will describe the design of the simulator and cite several applications in the development of the Saturn computer. The architecture, plus several important characteristics of the simulator, are presented. These include the Design Automation input interface, the logic selection procedure, failure injection, the compilation procedure, logical simulation and functional simulation. The ability to simulate up to 4000 Saturn instructions in either normal and/or fault environments (up to 33 faults per IBM 7090 run) will be demonstrated. Simulation of single, multiple, solid or intermittent faults, plus an automated statistical analysis of intermittent fault simulation results, will be presented. The IBM 7090 execution time of a compiled logic simulator can be prohibitive. To minimize running time several programming techniques were utilized, including logic block ordering (to allow single pass simulation), parallel fault simulation, stimulus bypassing, and functional simulation. These techniques are described. Several special forms of simulator output were developed. The use of this output and the applications of the simulator are presented, including design verfication, test program evaluation, generation of a test point catalog, disagreement detector network evaluation, disagreement detector placement, intermittent failure analysis.