EXHIBIT 99.1



                                    EXHIBIT B

                             JOINT FILING AGREEMENT


             The undersigned acknowledge and agree that the foregoing statement
on Schedule 13G is filed on behalf of each of the undersigned and that all
subsequent amendments to this statement on Schedule 13G shall be filed on behalf
of each of the undersigned without the necessity of filing additional joint
acquisition statements. The undersigned acknowledge that each shall be
responsible for the timely filing of such amendments, and for the completeness
and accuracy of the information concerning him or it contained therein, but
shall not be responsible for the completeness and accuracy of the information
concerning the other, except to the extent that he or it knows or has reason to
believe that such information is accurate.


Dated this 10th day of April, 2001.

                             The TCW Group, Inc.
                             By:
                                  /s/ Linda D. Barker
                                  --------------------------------------------
                                  Linda D. Barker
                                  Authorized Signatory







                             Robert Day
                             By:
                                  /s/ Linda D. Barker
                                  --------------------------------------------
                                  Linda D. Barker
                                  Under Power of Attorney
                                  dated November 6, 2000 on file with
                                  Schedule 13G for Retek, Inc.
                                  dated November 8, 2000.


                                       B-1