Separations between the end of one data file and the beginning of the next data file are recognized, without utilizing an entire data storage block by means of a controlling program for a peripheral recording device monitoring the control information headers of helically stored data on a recording tape. When files are stored on the recording tape, the controlling program increments an increase of a file section number by one and increments to zero a data block number at the beginning of a new data file. When the recording device is reading the recording tape and there is detected an incrementation of the file section number and a zero value for a data block number, a recognition is made that this data indicates the end of one data file and the beginning of another data file.