LOCS: An EDP Machine Logic and Control Simulator

The new EDP Machine Logic and Control Simulator, LOCS, is designed to facilitate the simulation of data processing systems and logic on the IBM 7090 Data Processing System. With this simulator, it will be possible to operate and execute commands in a manner comparable to that of a hardware version of the machine being simulated. The inputs to LOCS consist of a description, coded in LOCS language, of the machine to be simulated and a set of test programs coded in either the procedure language of the test problems (e.g., FORTRAN), or in the instruction language of the simulated machine. If a procedure language is used, a suitable translator program coded in machine language must be included to translate the test programs into machine code. The outputs of LOGS consist of the performance statistics, computation results, and diagnostic data which are relevant to both the test programs and the design of the simulated machine. This paper first describes the LOCS System including a description of LOCS inputs and outputs as well as an outline of the procedure one must follow to use LOCS. Next, the method of using LOCS is illustrated by an example of the complete simulation of a simple conventional binary data processing machine; and following this, a summary of current status.