DUMPSTYLE specifies the method of writing system dumps.

    DUMPSTYLE is a 32-bit mask, with the following bits defined.
    Each bit can be set independently. The value of the system
    parameter is the sum of the values of the bits that have been
    set. Remaining or undefined values are reserved for HP use only.

    Bit              Mask       Description

    0                00000001   0 =  Full dump (SYSGEN default).
                                     The entire contents of physical
                                     memory are written to the dump
                                     file.
                                1 =  Selective dump. The contents of
                                     memory are written to the dump
                                     file selectively to maximize
                                     the usefulness of the dump file
                                     while conserving disk space.

    1                00000002   0 =  Minimal console output.
                                1 =  Full console output (includes
                                     stack dump, register contents,
                                     and so on).
    2                00000004   0 =  Dump to system disk.

                                1 =  Dump off system disk (DOSD) to
                                     an alternate disk. (See the HP
                                     OpenVMS System Manager's Manual
                                     for details.)

    3 (Alpha and     00000008   0 =  Do not compress.
    Integrity
    servers)
                                1 =  Compress. (VAX systems do not
                                     support dump compression.)

    4 (Alpha and     00000010   0 =  Dump shared memory.
    Integrity
    servers)
                                1 =  Do not dump shared memory. (VAX
                                     systems do not support shared
                                     memory.)

    5 - 14                           Reserved for HP use only.

    15 (VAX only)    00008000   0 =  Disable use of bits 16 - 27.
                                     (Specific to VAX 7000s.)
                                1 =  Enable use of bits 16 - 27.

    16 - 27 (VAX     0FFF0000        Range of DOSD unit numbers. (VAX
    only)                            systems do not support shared
                                     memory.)

    28 - 31                          Reserved for HP use only.

    If you plan to enable the Volume Shadowing minimerge feature on
    an Alpha or Integrity servers disk, be sure to specify DOSD to an
    alternate disk.

                                   NOTE

       On Alpha and Integrity servers, you can save space on
       the system disk and, in the event of a crash, save time
       recording the system memory, by using the OpenVMS Alpha
       and Integrity servers dump compression feature. Unless
       you override the default AUTOGEN calculations (by setting
       DUMPSTYLE in MODPARAMS.DAT), AUTOGEN uses the following
       algorithm:

       o  On a system with less than 128 MB of memory, the system
          sets the DUMPSTYLE to 1 (a raw selective dump) and sizes
          the dump file appropriately.

       o  On a system with 128 MB of memory or greater, the system
          sets the DUMPSTYLE to 9 (a compressed selective dump),
          and creates the dump file at two-thirds the value of the
          corresponding raw dump.

    Examples:

    The mask of 00000006 directs the system to send a full dump, with
    full console output, off the system disk (to the alternate disk).

    For a VAX 7000, a mask of 00098006 directs the system to send a
    full dump with full console output to the DOSD whose unit number
    is 9.

    On Alpha and Integrity servers, the mask of 00000009 directs the
    system to compress a selective dump with minimal console output.

    DUMPSTYLE has AUTOGEN and DYNAMIC attributes.