Library /sys$common/syshlp/SDA.HLB  —  Page Protections
    Page protections and access rights are different on Alpha and
    Integrity server systems. They are visible in output from the
    following commands:

       SHOW PAGE
       SHOW PROCESS/PAGE
       EXAMINE/PTE
       EVALUATE/PTE

    Due to system differences, there is a need to distinguish
    "Write+Read+Execute" from "Write+Read" and to distinguish
    "Read+Execute" from "Read".

    On an Alpha system, W=W+R+E and R=R+E but on an IA64 system,
    additional w and r indicators are introduced for non-execute
    cases.

    On Alpha, page protection is described by 8 bits- one Read bit
    for each mode, and one Write Bit. Therefore in the "Read" column,
    there might be KESU (read access in all modes) or K- (read access
    in Kernel mode only) or NONE (no read access). Similarly in the
    "Writ" column. Not all combinations of the 8 bits are possible
    (for example, Write access for a mode implies Read access at that
    mode and both Read and Write access for all inner modes).

    On Integrity servers, page protection is described by 5 bits, a
    combination of the Access Rights and Privilege Level fields. SDA
    interprets these with a single character to describe access in
    each mode, as follows:

    Code  Meaning

    r     Read
    w     Read, Write
    R     Read, Execute
    W     Read, Write, Execute
    X     Execute
    K     Promote to Kernel
    E     Promote to Executive
    S     Promote to Supervisor
    -     No access

    For example WRRR means Kernel mode has Read+Write+Execute access;
    all other modes have Read+Execute access.
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