Method and apparatus for simulating I/O devices.

摘要

A computer system comprises a CPU (101), a main memory (102), and a plurality of I/O Processors (IOPs) (111-118), coupled to each other by a system I/O bus (105). The IOPs perform slave processing functions relating to I/O devices. A simulation protocol is defined for the IOPs, whereby the host CPU can command an IOP to execute a simulation script. The simulation script defines one or more I/O devices to be simulated, and specifies a simulated workload associated with the devices. The IOP executes the simulation script by sending simulated input streams to the host and receiving output destined for the simulated I/O devices from the host on the system I/O bus. An IOP may simulate multiple I/O devices, and may simulate I/O devices concurrently with servicing real I/O devices. In typical use, one or more applications programs will execute on the CPU concurrently with the execution of one or more simulation scripts in the IOPs attached to the system I/O bus. The behavior of the system under such conditions can be used for capacity planning forecasts, for developing and debugging the application software, for reproducing and diagnosing intermittent error conditions, or for performing other tasks in which it is necessary to determine the characteristics of the system under hypothetical conditions.