VMS Help RUN, Process, Qualifiers, /IO_BUFFERED  *Conan The Librarian (sorry for the slow response - running on an old VAX)

       /IO_BUFFERED=quota

    Specifies the maximum number of system-buffered I/O operations
    that the created process can have outstanding at any one time.

    The default quota is the quota established at system generation
    time. The minimum required for any process to execute is 2.

    The buffered I/O quota is nondeductible.