Library /sys$common/syshlp/bkm$help.hlb Density 6250  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    Set Tape Density to 6250 bpi

    Turn on this option if you have a tape device that can operate at
    6250 bits per inch.  "Bits per inch" refers to the format density of
    data storage for a tape.