Library /sys$common/syshlp/dbg$help.hlb DEBUG, System Management, System Resources  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    The kernel and main debugger communicate through global sections.
    The main debugger communicates with up to 8 kernel debuggers
    through a 65-page global section. Therefore, the system global-
    page and global-section parameters (GBLPAGES and GBLSECTIONS,
    respectively) might need to be increased. For example, if 10
    users are using the debugger simultaneously, 10 global sections
    using a total of 650 global pages are required by the debugger.