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 under the control of data processor having a main memory, utilizing a file system in which data can be written to and read from individually addressable regions. The profile in the persistent data structure includes a statement signature to identify the query statement, and an action to tune the statement. A chunk hash of each chunk is calculated to provide chunk hashes that are stored as entries in a hash table.