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

       /BUFFER_LIMIT=quota

    Specifies the maximum amount of memory, in bytes, that the
    process can use for buffered I/O operations or for temporary
    mailbox creation.

    If you do not specify a buffered I/O quota, the default value
    established at system generation time is used. The minimum amount
    required for any process to execute is 1024 bytes.

    The buffer limit quota is pooled.