A number produced by adding together (or otherwise combining) corresponding fields over all the records of a file, when such a total does not have any external meaning but is used solely to verify the records in the file. The hash total is amended whenever a change occurs to the relevant field; the file is verified by recomputing the hash total, and any corruption to the values in the field will be shown by a discrepancy between the stored total and the recomputed total. See also control record.