Library /sys$common/syshlp/pca$help.hlb DISPLAY, Qualifiers, /SIZE  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /SIZE:n

    Changes the maximum size of a normal output display to n lines.
    If more than n lines are written to the display, the oldest lines
    are lost as the new lines are added. If you omit this qualifier,
    the maximum size is not changed.