Exhibit 1



                             JOINT FILING AGREEMENT

     In  accordance  with Rule 13d-1 (f) under the  Securities  Exchange  Act of
1934,  as amended,  the  undersigned  hereby  agree to the joint filing with all
other Reporting Entities (as such term is defined in the Schedule 13G) on behalf
of each of them of a statement on Schedule 13G  (including  amendments  thereto)
with respect to the Common Stock,  $.01 par value per share, of Acmat Corp., and
that this  Agreement  be  included  as an  Exhibit to such  joint  filing.  This
Agreement  may be  executed  in any number of  counterparts  all of which  taken
together shall constitute one and the same instrument.

                  IN  WITNESS  WHEREOF,  the  undersigned  hereby  execute  this
Agreement this 14th day of March, 2001.

                                            EQSF ADVISERS, INC.

                                            By:/s/ MARTIN J. WHITMAN
                                            --------------------------
                                            Martin J. Whitman
                                            Chairman, President and Chief
                                            Executive Officer

                                            M.J. WHITMAN ADVISERS, INC.

                                            By:/s/ MARTIN J. WHITMAN
                                            --------------------------
                                            Martin J. Whitman
                                            Chairman and Chief Executive Officer

                                            /s/   MARTIN J. WHITMAN
                                            --------------------------
                                             Martin J. Whitman