This special parameter is use by VSI and is subject to change.
    Do not change this parameter unless VSI recommends that you do so.
    On Alpha and Integrity servers, CRD_CONTROL can be used to expand
    the function defined by CRDENABLE.

    CRD_CONTROL is a bit mask for corrected read data (CRD) soft
    error control flags. These flags control the use of CRDERROR
    routines.

    On Alpha and Integrity servers, the following bits are defined:

    Bit    Description

    0      Enables CRD processing for all systems.

    1      Enables scrubbing (rewriting) of the memory location that
           induced the CRD.

    2      Enables page replacement of the pages that exhibit
           repeated CRD errors.

    3      Forces all memory pages to be included in the PFN
           database. On systems that contain more than 512 megabytes
           of memory, all memory is mapped by the PFN database by
           default. This bit allows the mapping to occur on systems
           with less than 512 megabytes of memory.

    4      Enables extended CRD handling, if available.

    5      Enables loading of driver and process for handling server
           management events. Platform-specific code usually sets
           this bit if the required hardware and firmware support are
           available.

    6      Disables CRD throttling.

    7      Disables System Event Log (SEL) polling.

    16-31  Reserved for platform-specific error-handling control.

    On Alpha and Integrity servers, the default setting is 22, which
    enables scrubbing, page replacement, and extended CRD handling.