X0303 4 2010-12-17 1 0001373671 Isilon Systems, Inc. ISLN 0001439716 Godwin Mary E. 3101 WESTERN AVENUE SEATTLE WA 98121 0 1 0 0 VP Operations Common Stock 2010-12-17 2010-12-17 4 U 0 217 33.85 D 6600 D Common Stock 2010-12-21 2010-12-21 4 U 0 6600 33.85 D 0 D Right to Buy (Common Stock) 4.9 2010-12-21 2010-12-21 4 D 0 166520 D 2009-07-09 2018-08-05 Common Stock 166520 0 D Right to Buy (Common Stock) 7.36 2010-12-21 2010-12-21 4 D 0 115000 D 2011-02-09 2020-02-09 Common Stock 115000 0 D Right to Buy (Common Stock) 2.57 2010-12-21 2010-12-21 4 D 0 80720 D 2010-05-01 2019-05-15 Common Stock 80720 0 D Includes 217 shares acquired under the issuer's Employee Stock Purchase Plan on December 6, 2010. Pursuant to the terms of the merger agreement between issuer, EMC Corporation and a subsidiary of EMC, this restricted stock unit was cancelled on the effective date of the merger in exchange for a cash payment equal to the offer price of $33.85 per share. Pursuant to the terms of the merger agreement, (i) 68,082 shares under this option were cancelled on the effective date of the merger in exchange for a cash payment equal to, on a per share basis, the offer price of $33.85 less the exercise price, and (ii) 98,438 shares under this option were assumed and exchanged for an option to purchase shares of EMC common stock. Pursuant to the terms of the merger agreement, this option was assumed and exchanged for an option to purchase shares of EMC common stock. Pursuant to the terms of the merger agreement, (i) 18,220 shares under this option were cancelled on the effective date of the merger in exchange for a cash payment equal to, on a per share basis, the offer price of $33.85 less the exercise price, and (ii) 62,500 shares under this option were assumed and exchanged for an option to purchase shares of EMC common stock. Keenan M. Conder, Attorney in Fact 2010-12-21