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                                                                   EXHIBIT 10.15

                               SECOND AMENDMENT TO
                                CREDIT AGREEMENT

        THIS SECOND AMENDMENT TO CREDIT AGREEMENT (the Amendment), dated as of
June 28th, 2000, is made by and between LANDMARK SYSTEMS CORPORATION, a Virginia
corporation (the "Borrower"), and SUNTRUST BANK, a Georgia banking corporation,
successor by merger to CRESTAR BANK (the "Bank").

                                    RECITALS

        The Borrower and the Bank are parties to the Credit Agreement, dated as
of March 30, 1999, as amended by the First Amendment to Credit Agreement, dated
as of June 21, 1999, between the Borrower and the Bank (as further amended,
modified or supplemented from time to time, the "Credit Agreement"). Capitalized
terms defined in the Credit Agreement shall have the same defined meanings when
such terms are used and undefined in this Amendment.

        The Borrower and the Bank have agreed to extend the Termination Date,
subject to the terms and conditions of this Amendment. Accordingly, for valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the
Borrower and the Bank agree as follows:

        1.      The Termination Date is extended to June 30, 2001.

        2.      The Borrower and the Bank agree that each reference in the Loan
Documents to the Credit Agreement shall be deemed to be a reference to the
Credit Agreement as amended hereby, and each reference in the Loan Documents to
the Termination Date shall be deemed to be a reference to the Termination Date
as extended hereby. To the extent of a conflict between the terms of this
Amendment and the terms of any other Loan Document, the terms of this Amendment
shall control.

        3.      The Borrower acknowledges and agrees that this Amendment only
amends certain terms of the Loan Documents and is not a novation, and the
Borrower ratifies and confirms the terms and provisions of, and its obligations
under, the Credit Agreement and each other Loan Document in all respects. The
Borrower acknowledges and agrees that there are no defenses, counterclaims or
setoffs against any of its obligations under the Loan Documents.

        4.      The Borrower represents and warrants that this Amendment has
been duly authorized, executed and delivered by it in accordance with
resolutions adopted by its Board of Directors. All representations and
warranties made by the Borrower in the Loan Documents are incorporated by
reference in this Amendment and are deemed to have been repeated as of the date
of this Amendment with the same force and effect as if set forth in this
Amendment, except that any representation or warranty relating to any financial
statements shall be deemed to be applicable to the financial statements most
recently delivered to the Bank in accordance with the provisions of the Loan
Documents. The Borrower agrees that nothing in this Amendment shall require the
Bank to grant any further amendments of the Loan Documents.



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        5.      The Borrower agrees to pay all costs and expenses incurred by
the Bank in connection with this Amendment, including, but not limited to,
reasonable attorneys' fees.

        6.      This Amendment shall be governed by the laws of the Commonwealth
of Virginia, without reference to conflict of laws principles.

        7.      This Amendment may be executed by the parties individually or in
any combination, in one or more counterparts, each of which shall be an original
and all of which together constitute one and the same instrument.

WITNESS the following signatures.

                                       LANDMARK SYSTEMS CORPORATION,
                                       a Virginia corporation

                                       By:        /s/ F. S. ROLANDI
                                          --------------------------------------
                                       Name:          F. S. Rolandi
                                            ------------------------------------
                                       Title:             VP/CFO
                                             -----------------------------------


                                       SUNTRUST BANK,
                                       a Georgia banking corporation, successor
                                       by merger to CRESTAR BANK

                                       By:       /s/ CHARLES YOULES, VP
                                          --------------------------------------
                                       Name:          Charles Youles
                                            ------------------------------------
                                       Title:         Vice President
                                             -----------------------------------



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