Fault information gathering system for peripheral controllers in a computer system

This fault information gathering system for peripheral controllers used in computer systems has, in its internal memory (30A,40A,50A) at a peripheral controller(20), a first work area (A1,B1,C1,...) for used in normal status and a second work area (A2,B2,C2,...) used when a fault is detected as a work areas (201) for each of the modules (A,B,C,...) constituting the program and also has a tracing area (203) to store the history data of program operation and a data area (202) to keep the area information in the tracing area (203) and the first work area used when a fault is detected. The system traces the program operation and writes the history data into the tracing area (203) and, when a fault is detected by the program, switches the work area to the second work area (A2,B2,C2,...). Upon detection of a fault by the program, the area information indicating the first work area (A1,B1,C1,...) and said tracing area (203) to said data area (202). The area information written into the data area (202) is provided upon instruction from the central processing unit (10), and thereafter, the data in the first work area and the tracing area (203) are transferred to the central processing unit upon instruction from the central processing unit (10).