Library /sys$common/syshlp/uafhelp.hlb MODIFY, Qualifiers, /BIOLM  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /BIOLM=value

    Specifies a buffered I/O count limit for the BIOLM field of the
    UAF record. The buffered I/O count limit is the maximum number
    of buffered I/O operations, such as terminal I/O, that can be
    outstanding at one time. The default is 40 on VAX systems and 150
    on Alpha systems.