==================================================================== IRON MOUNTAIN INCORPORATED, as Issuer, IRON MOUNTAIN INFORMATION MANAGEMENT, INC., IRON MOUNTAIN INTELLECTUAL PROPERTY MANAGEMENT, INC., IRON MOUNTAIN GLOBAL, LLC, COMAC, INC., IRON MOUNTAIN GLOBAL, INC., MOUNTAIN REAL ESTATE ASSETS, INC., IRON MOUNTAIN STATUTORY TRUST - 1998, IRON MOUNTAIN STATUTORY TRUST - 1999, IRON MOUNTAIN GOVERNMENT SERVICES INCORPORATED, MOUNTAIN RESERVE III, INC., NETTLEBED ACQUISITION CORP., and TREELINE SERVICES CORPORATION, as Guarantors AND THE BANK OF NEW YORK TRUST COMPANY, N.A., as Trustee SUPPLEMENTAL INDENTURE Dated as of July 24, 2006 $150,000,000 8-1/4% Senior Subordinated Notes due 2011

SUPPLEMENTAL INDENTURE

THIS SUPPLEMENTAL INDENTURE (this “Supplemental Indenture”), dated and effective as of July 24, 2006, among Iron Mountain Incorporated, a Delaware corporation (the “Company”), as the Issuer, Iron Mountain Information Management, Inc., a Delaware corporation, Iron Mountain Intellectual Property Management, Inc. (f/k/a DSI Technology Escrow Services, Inc.), a Delaware corporation, Iron Mountain Global, LLC, a Delaware limited liability company, COMAC, Inc., a Delaware corporation, Iron Mountain Global, Inc., a Delaware corporation, Mountain Real Estate Assets, Inc., a Delaware corporation, Iron Mountain Statutory Trust - 1998, a Connecticut statutory trust, Iron Mountain Statutory Trust - 1999, a Connecticut statutory trust, Iron Mountain Government Services Incorporated (f/k/a Mountain Reserve II, Inc.), a Delaware corporation, Mountain Reserve III, Inc., a Delaware corporation, Nettlebed Acquisition Corp., a Delaware corporation, and Treeline Services Corporation (f/k/a Mountain Reserve I, Inc.), a Delaware corporation (collectively, the “Guarantors”) and The Bank of New York Trust Company, N.A., as trustee (the “Trustee”).

WHEREAS, the Company, certain Subsidiaries of the Company and the Trustee are parties to an Indenture dated as of April 26, 1999 (as supplemented and in effect on the date hereof, the “Indenture”), relating to the Company’s 8-1/4% Senior Subordinated Notes due 2011 (the “Notes”);

WHEREAS, the Company, in accordance with Section 9.02 of the Indenture and in connection with an Offer to Purchase and Consent Solicitation dated July 11, 2006, sought and received the consent of the holders of a majority in principal amount of the Notes with regard to certain proposed amendments to the Indenture;

WHEREAS, pursuant to Section 9.02 of the Indenture, the Trustee is authorized to execute and deliver this Supplemental Indenture; and

WHEREAS, all conditions precedent provided for in the Indenture relating to this Supplemental Indenture have been complied with.

NOW, THEREFORE, the Company and the Trustee agree as follows for the benefit of each other and for the equal and ratable benefit of the Holders of the Notes:

ARTICLE I

Amendments

1.1          DELETION OF CERTAIN COVENANTS. The following Sections are hereby deleted from the Indenture in their entirety and shall be of no further force or effect: (i) Section 4.03 – Reports; (ii) Section 4.07 – Restricted Payments; (iii) Section 4.08 – Dividend and Other Payment Restrictions Affecting Restricted Subsidiaries; (iv) Section 4.09 – Incurrence of Indebtedness and Issuance of Preferred Stock; (v) Section 4.10 – Asset Sales; (vi) Section 4.11 – Transactions with Affiliates; (vii) Section 4.12 – Liens; (viii) Section 4.14 – Offer to Purchase upon Change of Control; (ix) Section 4.16 – Certain Senior Subordinated Debt; (x) Section 4.18 – Limitation on Sale and Leaseback Transactions; (xi) Section 5.01 – Merger, Consolidation, or Sale of Assets; and (xii) Section 5.02 – Successor Corporation Substituted.

1.2          CONTINUATION OF OBLIGATIONS. The obligations of the Company and the Guarantors under the Indenture remain in full force and effect (except as set forth in Section 1.1 hereof).