Unisys Corporation

Grace Jui-Yen Lin

Howard J Keller

Derek William Paul

An emulated computer system includes an instruction processor which directly executes a set of native instructions. Stored in a memory, which is coupled to the instruction processor, are a plurality of foreign user programs and a foreign operating system, each of which is a compilation of foreign instructions and data. Also stored in the memory is an emulator program which is a compilation of the native instructions that interprets the foreign instructions, and a native operating system which is a compilation of the native instructions under which the emulator program is run. To diagnose faults in this emulated computer system, a heterogeneous diagnostic program is provided in the memory, which is a compilation of the native instructions that reads the foreign user programs and foreign operating system from the memory and stores them in a reformatted form on a magnetic media. The heterogeneous diagnostic program is initiated in response to the occurrence of a user selectable event which indicates the presence of a defect in the foreign operating system or foreign user programs. Execution of the heterogeneous diagnostic program occurs while the native operating system is running and while one or more native user programs run under the native operating system.

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Mission Viejo, CA, United States of America

Grace Jui-Yen Lin