VMS Help EXCHANGE, INITIALIZE, Qualifiers  *Conan The Librarian (sorry for the slow response - running on an old VAX)

1 - /ALLOCATION

       /ALLOCATION=n

    Specifies the allocation of a new virtual device file in terms
    of 512-byte blocks. The allocation specified is the number you
    entered as n. If you do not specify the /ALLOCATION qualifier
    when you create a new virtual device file, the default allocation
    is 494 blocks, the size of a single-density diskette. The maximum
    allocation is 65,536 blocks.

    A virtual device file is usually the size of a standard device
    supported by both RT-11 and OpenVMS. These sizes are as follows:

    Device    Blocks

    TU58      512
    RX01      494
    RX02      494 (single density)
    RX50      800
    RX02      988 (double density)
    RX33      2400
    RL02      20480
    RK06      27126
    RK07      53790

    You can also use the /ALLOCATION qualifier to reduce the size
    of a physical device. For example, if you want to prepare
    an RL02 disk but have only an RK07 device available, you can
    initialize the RK07 to a volume of 20,480 blocks. When the RL02
    is available, you can transfer the files to the RL02 knowing they
    will fit on the smaller device.

2 - /BADBLOCKS

       /BADBLOCKS[=RETAIN]

    Performs a bad block scan of the volume before initialization. A
    file named FILE.BAD is created on top of each bad block or group
    of bad blocks encountered on the device, preventing any future
    use of the bad areas.

    If a bad block is found in either the boot block or the volume
    directory, the volume is not usable and EXCHANGE displays
    an error message. If the bad block is in a directory segment
    other than the first, you might be able to use the volume by
    reinitializing it with a smaller number of segments (see the
    /SEGMENTS qualifier description).

    If you specify /BADBLOCKS=RETAIN, EXCHANGE uses the device's
    existing bad block information, instead of performing a bad block
    scan. Therefore, initializing takes less time. If you do not
    specify RETAIN, EXCHANGE writes a pattern on each block of the
    volume, then reads each block to verify that the block is usable.
    EXCHANGE prints a list of the bad blocks found on the device.

    RK06, RK07, and RL02 disk volumes support bad block replacement.
    Therefore, Compaq recommends that you use the /REPLACE=RETAIN
    qualifier for these volumes. If you use the /BADBLOCKS qualifier
    with a volume initializied previously with the /REPLACE
    qualifier, EXCHANGE deletes the bad block replacement table and
    performs a new bad block scan. If you use /BADBLOCKS=RETAIN with
    such a volume, EXCHANGE uses the FILE.BAD files created during
    the volume initialization.

3 - /CREATE

    Specifies that a virtual device is to be created and initialized.
    The specification is a file name; if a file type is not given,
    EXCHANGE applies the default type of DSK.

4 - /DENSITY

       /DENSITY=density-value

    Specifies, for magnetic tape volumes, the density in bytes per
    inch (bpi) at which the tape is to be written.

    For magnetic tape volumes, the density value specified can be 800
    or 1600, as long as the density is supported by the magnetic tape
    drive. If you do not specify a density value for a blank tape,
    the system uses a default of the lowest density supported by the
    tape drive.

    For the RX02 dual-density diskette drive, use the DCL command
    INITIALIZE/DENSITY=SINGLE or INITIALIZE/DENSITY=DOUBLE to
    reformat the diskettes to a different density; then use the
    EXCHANGE command INITIALIZE to create the RT-11 directory
    structure.

                                   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.

5 - /EXTRA_WORDS

       /EXTRA_WORDS=n

    Specifies, for RT-11 volumes, the number of extra words to add
    to each directory entry, in addition to the required seven words.
    The ability to increase the length of directory entries is useful
    for some RT-11 applications. Increasing the size of the directory
    entries reduces the number of entries that fit in each directory
    segment.

6 - /MESSAGE

       /MESSAGE
       /NOMESSAGE

    Controls whether or not EXCHANGE displays a message that the
    volume was initialized. The default is determined by the /MESSAGE
    qualifier entered with the EXCHANGE command when EXCHANGE was
    activated.

7 - /REPLACE

       /REPLACE=RETAIN

    Retains, when an RT-11 volume is initialized, the bad block
    replacement table and any existing FILE.BAD files.

    The RETAIN option is required; EXCHANGE cannot build a
    replacement table for a volume. The RT-11 system builds and
    uses the table based on specific hardware error conditions. The
    OpenVMS I/O system is different, and cannot be relied upon to
    generate exactly the same error conditions. Therefore, it is not
    possible for EXCHANGE to generate the same replacement table that
    would be generated by RT-11.

    If no replacement table is present, the qualifier /REPLACE=RETAIN
    is equivalent to /BADBLOCKS=RETAIN.

8 - /SEGMENTS

       /SEGMENTS=n

    Defines, for RT-11 volumes, the number of 2-block directory
    segments to allocate for the directory. The number of segments
    in the directory establishes the number of files that can be
    stored on a device. The system allows a maximum of 72 files
    per directory segment and 31 directory segments per device. The
    argument n represents the number of segments; the valid range for
    n is from 1 to 31 (decimal). The default values for n depend on
    the device type, as follows:

    Device    Segments

    TU58      1
    RX01      1
    RX02      1 (single density)
    RX02      4 (double density)
    RX50      4
    RX33      16
    RL02      16
    RK06      16
    RK07      31

9 - /VOLUME_FORMAT

       /VOLUME_FORMAT=option

    Defines the physical format of the volume to be processed.

    The EXCHANGE command INITIALIZE is not valid for Files-11
    devices.