PURPOSE: To make the data gathering matched to fault contents possible, by setting optionally the recording mode and the freezing mode of a history memory.

CONSTITUTION: A freeze condition detecting means 7 detects the fault occurrence or the like in a data processing system to generate a freeze command signal. A freeze trigger timing means 8 generates a freeze trigger signal FRZ after a certain delay fro the arrival of the freeze command signal on a basis of the signal from a freeze mode setting means 6. The non-freeze trigger signal inverted FRZ of the output of the means 8 has value 1 normally to permit a signal WRT instructing the record processing to be sent to a history memory 5 through an AND gate 4. However, when the freeze command signal is inputted to the means 8, the inverted FRZ becomes 0, and the gate 4 stops the passage of the signal WRT hereafter not permit the record processing of the memory 5. Thus, timing of recording and freezing of the memory 5 are set optionally.