[1] SIMMON was a hypervisor, similar to the IBM CP-40 system that was being independently developed at the Cambridge Scientific Center at about that same time.
It used a novel and very efficient table-driven finite-state machine (FSM) to inject simulated errors and verify that the operating system followed the detailed specifications of actions to be taken to attempt recovery.
HOTSPOTS was an instruction trace tool written to help identify performance problem areas in IBM's MFT operating system.
These data identified the Memory Management component as consuming about 20% of CPU resources, and was used to justify a task force to try to improve the performance.
While not a specific test tool, the distorted timing relationships while running under SIMMON found a number of problems, particularly in the input/output sections.
Unless a SIMMON tool was put in place to normalize and delay I/O events, these would appear to the guest program as happening unnaturally quickly.