Library /sys$common/syshlp/tracehlp.hlb START, /SAVE_BUFFER_SIZE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

    /SAVE_BUFFER_SIZE=n

    The number of screens of saved lines  that  will  be  kept.   These
    lines can be examined by using the NEXT and BACK commands.

    The default value is 30.

    Only valid with /LIVE qualifier.