GB1444314A - Trace arrangem ent for simulation device - Google Patents

Abstract

1444314 Data processing system INTERNATIONAL STANDARD ELECTRIC CORP 29 Jan 1974 [31 Jan 1973] 04072/74 Heading G4A A data processing system includes two operational computers 1A, 1B each with an associated data store 8A, 8B, and a simulation computer 6 arranged to simulate the activity of a group of peripheral devices and to cause operational (status) data to be written by a selected one of the operational computers into its store following completion of the execution of an instruction and to access the stored data and transfer it to a peripheral store 12 associated with the simulation computer where it is available for further processing. The arrangement simulates operation in a real system comprising computers 1A, 1B and a group of peripherals and traces the operation of computers 1A, 1B. The storage of status data may be initated following completion of the first instruction after receipt of the order, by the nth occurrence of a given instruction address, or following execution of a specified instruction. The arrangement includes a timing system including counters which are rendered inoperative when status data is being saved &c. so as to maintain track of the simulated real operation of computers 1A, 1B. The peripheral store 12 may be a magnetic tape device, the memories 8A, 8B may be magnetic cores, and a backing memory 9, e.g. a magnetic drum, is provided. The computers have associated manual input peripherals.