Abstract: A set top box for a television receiver is configured to store and replay programming content in a data storage device such as a Winchester disc (6) under the control of data processor (8) having a main memory (9), utilizing a file system in which data can be written to and read from individually addressable regions. The addresses of the regions are held in the main memory during operation. When writing data to more than one of the regions a link is stored in one of the regions to provide data concerning the location of another of the regions that stores data from the file. The link can be used to recover the file in the event of a system crash such as a loss of power.