/sys$common/syshlp/helplib.hlb INITIALIZE, Qualifiers, /DENSITY  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /DENSITY=density-value

    Allows you to specify the format density value for certain tapes
    and disks.

    For magnetic tape volumes, specifies the density in bits per inch
    (bpi) at which the magnetic tape is to be written. The density
    value specified can be 800 bpi, 1600 bpi, or 6250 bpi, as long as
    the density is supported by the magnetic tape drive.

    If you do not specify a density value for a blank magnetic tape,
    the system uses a default density of the highest value allowed
    by the tape drive. If the drive allows 6250-, 1600-, and 800-bpi
    operation, the default density is 6250 bpi.

    If you do not specify a density value for a magnetic tape that
    has been previously written, the system uses the density of the
    first record on the volume. If the record is unusually short, the
    density value will not default.

    The /DENSITY qualifier does not apply to any TF tape device.

    Valid tape density values are:

    Keyword     Meaning

    DEFAULT     Default density
    800         NRZI 800 bits per inch (BPI)
    1600        PE 1600 BPI
    6250        GRC 6250 BPI
    3480        IBM 3480 HPC 39872 BPI
    3490E       IBM 3480 compressed
    833         DLT TK50: 833 BPI
    TK50        DLT TK50: 833 BPI
    TK70        DLT TK70: 1250 BPI
    6250        RV80 6250 BPI EQUIVALENT
      NOTE: Only the keywords above are understood by TMSCP/TUDRIVER
        code prior to OpenVMS Version 7.2. The remaining keywords
            in this table are supported only on Alpha systems.
    TK85        DLT Tx85: 10625 BPI - Cmpt III - Alpha only
    TK86        DLT Tx86: 10626 BPI - Cmpt III - Alpha only
    TK87        DLT Tx87: 62500 BPI - Cmpt III - Alpha only
    TK88        DLT Tx88: (Quantum 4000) - Cmpt IV - Alpha only
    TK89        DLT Tx89: (Quantum 7000) - Cmpt IV - Alpha only
    QIC         All QIC drives are drive-settable only - Alpha only
    8200        Exa-Byte 8200 - Alpha only
    8500        Exa-Byte 8500 - Alpha only
    DDS1        Digital Data Storage 1 - 2G - Alpha only
    DDS2        Digital Data Storage 2 - 4G - Alpha only
    DDS3        Digital Data Storage 3 - 8-10G - Alpha only
    DDS4        Digital Data Storage 4 - Alpha only
    AIT1        Sony Advanced Intelligent Tapes - Alpha only

    To format a diskette on RXnn diskette drives, use the
    INITIALIZE/DENSITY command. Specify the density at which the
    diskette is to be formatted as follows:

    Keyword     Meaning

    single      RX01 - 8 inch
    double      RX02 - 8 inch
    dd          double density: 720K - 3 1/2 inch
    hd          high density: 1.44MB - 3 1/2 inch
    ed          extended density: 2.88MB - 3 1/2 inch

    If you do not specify a density value for a diskette being
    initialized on a drive, the system leaves the volume at the
    density to which the volume was last formatted.

                                   NOTE

       Diskettes formatted in double density cannot be read or
       written by the console block storage device (an RX01 drive)
       of a VAX-11/780 until they have been reformatted in single
       density.

       RX33 diskettes cannot be read from or written to by RX50
       disk drives. RX50 diskettes can be read from and written to
       by RX33 disk drives; they cannot be formatted by RX33 disk
       drives.