VMS Help Sys Parameters, DBGTK_SCRATCH  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    (Alpha only) DBGTK_SCRATCH specifies how many pages of memory
    are allocated for the remote debugger. This memory is allocated
    only if remote debugging is enabled with the 8000 boot flag.
    Normally, the default value is adequate, but if the remote
    debugger issues an error message, you should increase this
    value. See Writing OpenVMS Alpha Device Drivers in C for more
    information. (This manual has been archived but is available on
    the OpenVMS Documentation CD-ROM.)