The following MPMs currently exist:

  prefork ....... Multi  Process Model with Preforking (Apache 1.3)
  mpmt_os2 ...... Multi Process Model with Threading on OS/2
                  Constant number of processes, variable number of threads.
                  One acceptor thread per process, multiple workers threads.
  winnt ......... Single Process Model with Threading on Windows NT
  event ......... Multi Process model with threads.  One acceptor thread,
                  multiple worker threads, separate poller threads for idle
                  connections and asynchoneous write completion.
  worker ........ Multi Process model with threads.  One acceptor thread,
                  multiple worker threads.
  netware ....... Multi-threaded MPM for Netware