PURPOSE: To execute efficiently writing to a peripheral storage device of a control table by constituting a titled system so that writing of the control table related to a job is executed in accordance with a policy of recovery of an electronic computer center and a degree of importance of the job.

CONSTITUTION: The titled system is constituted so that a recovery instructing value (a) of a center can be designated by an initializing parameter, etc. of a system, and also at every job, a recovery instructing value (b) of its job can be designated by a job control sentence. Also, a degree of unnecessity of recovery Ci is determined in advance so as to correspond to a processing step. An operating system 2 calls a wirte processing 4 whenever a job control table existing on a main storage device is changed. The write processing part 4 compares the degree of unnecessity of recovery Ci of the processing step in that time point, with the recovery instructing value (b) of the job, and only in case of (b)≥Ci, the job control table on the main storage device is written to a peripheral storage device.