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                                                                   EXHIBIT 10.21


                           AMENDMENT TO LOAN DOCUMENTS


BORROWER:             VIXEL CORPORATION
ADDRESS:              11911 NORTHCREEK PARKWAY S.
                      BOTHELL, WASHINGTON  98011

DATE:                 JUNE 21, 1999

        THIS AMENDMENT TO LOAN DOCUMENTS is entered into between GREYROCK
CAPITAL, a division of NationsCredit Commercial Corporation (formerly Greyrock
Business Credit) ("GBC"), whose address is 10880 Wilshire Blvd., Suite 1850, Los
Angeles, CA 90024 and the borrower named above ("Borrower").

        The Parties agree to amend the Loan and Security Agreement between them,
dated November 26, 1997 (as amended, the "Loan Agreement"), as follows,
effective on the date hereof. (This Amendment, the Loan Agreement, any prior
written amendments to said agreements signed by GBC and the Borrower, and all
other written documents and agreements between GBC and the Borrower are referred
to herein collectively as the "Loan Documents". Capitalized terms used but not
defined in this Amendment, shall have the meanings set forth in the Loan
Agreement.)

        1.      Credit Limit. Section 1 of the Schedule, which presently reads
                as follows:

                "1. CREDIT LIMIT (Section 1.1): An amount not to exceed the
                lesser of $12,500,000 or the sum of (a) and (b) below:

                        "(a) The unpaid principal balance of the Term Loan in
                        the original principal amount of $7,500,000 being made
                        concurrently herewith by GBC to Borrower (the `Term
                        Loan') and evidenced by the Secured Promissory Note
                        (`Term Note') made by Borrower to the order of GBC,
                        being executed and delivered to GBC concurrently
                        herewith; plus "(b) Loans (the "Revolving Loans") in an
                        amount not to exceed the lesser of (i) $5,000,000 at any
                        one time outstanding, or (ii) 80% of the amount of
                        Borrower's Eligible Receivables (as defined in Section 8
                        above)

                "The Term Loan shall be made concurrently, in one disbursement.
                GBC shall have no obligation to disburse the Term Loan if, at
                the date of the disbursement, any Event of Default or event
                which, with notice or passage of time or both, would constitute
                an Event of Default has occurred and is continuing. "The Term
                Loan shall bear interest and be repayable on the terms set forth
                in the Term Note. The Term Loan once repaid may not be
                reborrowed. The Term Loan and the Revolving Loans constitute
                `Loans' for all purposes of this Agreement." is amended to read
                as follows:


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                "1. CREDIT LIMIT (Section 1.1): An amount not to exceed the
                lesser of $15,000,000 or the sum of (a) and (b) below:

                        "(a) The unpaid principal balance of the Term Loan in
                        the original principal amount of $7,500,000 made by GBC
                        to Borrower (the `Term Loan') and evidenced by the
                        Secured Promissory Note (`Term Note') made by Borrower
                        to the order of GBC; plus

                        "(b) Loans (the "Revolving Loans") in an amount not to
                        exceed the lesser of (i) $7,500,000 at any one time
                        outstanding, or (ii) 80% of the amount of Borrower's
                        Eligible Receivables (as defined in Section 8 above)

                "The Term Loan shall bear interest and be repayable on the terms
                set forth in the Term Note. The Term Loan once repaid may not be
                reborrowed. The Term Loan and the Revolving Loans constitute
                `Loans' for all purposes of this Agreement."

        2.      Extension. The date "SEPTEMBER 30, 1999" in Section 4 of the
Schedule (as previously amended) is hereby amended by replacing said date with
the date "SEPTEMBER 30, 2000."

        3.      Fee. In consideration for GBC entering into this Amendment, the
Borrower shall pay GBC a fee in the amount of $175,000 (the "Transaction Fee"),
which shall be paid in installments of $14,583 per month, beginning July 31,
1999, and continuing on the last day of each month thereafter until paid in
full. Said fee shall be deemed fully earned and part of the Obligations on the
date hereof, shall be in addition to all interest and other fees, and shall be
non-refundable. Notwithstanding the foregoing, if Borrower shall terminate the
Loan Agreement and shall pay and perform in full all Obligations on or before
December 31, 1999, and no Event of Default shall have occurred and be
continuing, then GBC shall accept $100,000 as full payment of the Transaction
Fee.

        4.      Representations True. Borrower represents and warrants to GBC
that all representations and warranties set forth in the Loan Agreement are true
and correct.

        5.      General Provisions. This Amendment, the Loan Agreement, and the
other Loan Documents set forth in full all of the representations and agreements
of the parties with respect to the subject matter hereof and supersede all prior
discussions, representations, agreements and understandings between the parties
with respect to the subject hereof. Except as herein expressly amended, all of
the terms and provisions of the Loan Agreement and the other Loan Documents
shall continue in full force and effect and the same are hereby ratified and
confirmed.


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Borrower:                              GBC:

VIXEL CORPORATION                      Greyrock Capital, a Division of
                                       Nationscredit Commercial Corporation


By /s/ Kurtis L. Adams
   --------------------------------
      President or Vice President      By /s/ Signature Illegible
                                          -------------------------------------
                                       Title
                                             ----------------------------------
By /s/ Kay Church
   --------------------------------
      Secretary or Ass't Secretary

                                     CONSENT

        The undersigned, guarantor, acknowledge that its consent to the
foregoing Agreement is not required, but the undersigned nevertheless does
hereby consent to the foregoing Agreement and to the documents and agreements
referred to therein and to all future modifications and amendments thereto, and
any termination thereof, and to any and all other present and future documents
and agreements between or among the foregoing parties. Nothing herein shall in
any way limit any of the terms or provisions of the Continuing Guaranty of the
undersigned, all of which are hereby ratified and affirmed.

                                       ARCXEL TECHNOLOGIES, INC.

                                       By /s/ Kay Church
                                          --------------------------------------
                                       Title Controller
                                             -----------------------------------