Full data set directory for magnetic tape recording media

A method for using a Full Data Set Directory (FDSD) entry, the method comprising:

• receiving, by a tape drive, a request to read a record of a data set from a magnetic recording tape;
• receiving, by the tape drive, an FDSD entry consisting essentially of information about a tape write pass in which the data set is written, a position of the data set on the tape, a record count indicating a number of records stored in the data set, and a file mark count indicating a number of file marks stored in the data set;
• determining a tape write pass and a beginning position of the data set from the FDSD entry;
• moving the tape past a previously-written data set to approximately the beginning position of the data set located in a same wrap as the previously-written data set;
• and
• reading the record from the tape.

A computer-implemented method for using a Full Data Set Directory (FDSD) for selecting a reading parameter, the method comprising:

• using an FDSD to select a parameter for reading of one or more records from a magnetic recording tape having multiple data sets written in a wrap on the magnetic recording tape, the one or more records being assembled in one of the data sets, wherein the FDSD includes an FDSD entry corresponding to the one or more records, the FDSD entry having only four entries:
• a tape write pass in which the data set having the one or more records is written, a position of the data set on the tape, a number of records stored in the data set, and a number of file marks stored in the data set;
• transmitting the parameter to a tape drive;
• and
• receiving the one or more records from the tape drive according to the parameter.