BNU.COM is both a FOSSIL driver (TSR) and a utility which can
    manipulate the resident   version   of   itself.    On  first
    successful loading, it will terminate  and  leave  the driver
    portion of itself   (only   about  5K  or  so   plus   buffer
    requirements) resident, and  allocate  communication  buffers
    for each of the enabled ports (typically  using 14K for a one
    port install when  'diagnostics' mode is enabled).   It  then
    captures and utilises  the  system's  INT 14H (communications
    services) vector and services  requests  for  all  FOSSIL and
    non-FOSSIL aware programs using the INT 14H interface.

    BNU will NEVER  load  itself  more than once,  unless  within
    different tasks when    using    a   multitasker,   such   as
    PC-MOS/386(tm), DESQview(tm), DoubleDOS(tm) or VM/386(tm).

    This documentation assumes a working knowledge of MS-DOS, and
    no effort is made to explain MS-DOS  functions,  commands  or
    setup.  Some familiarity  with  BBS or mail capable  software
    and other FOSSIL drivers will definitely be an advantage, but
    not required.