Stock Trading History of Greylock Xi Limited Partnership

The following table details the trading activities (stock purchases, stock sales, and stock option exercises) reported to the Securities and Exchange Commission (SEC) by insider Greylock Xi Limited Partnership since year 2005. The trader's CIK number is 1136545. At the time of this reporting, Greylock Xi Limited Partnership is the 10% Owner of Data Domain, Inc. . (stock ticker symbol DDUP). See this page for all insider trading activities at Data Domain, Inc. .

Stock purchases, sales, and option exercises reported by insider *Greylock Xi Limited Partnership* since 2005.
Trade Date	Symbol	Company Name (Issuer)	Trade Type	Shares	Price ($)	Value ($)
2008-02-28	DDUP	Data Domain, Inc.	Sale	875,606	20.00	17,512,120
2007-12-03	DDUP	Data Domain, Inc.	Sale	83,718	25.89	2,167,459
2007-11-21	DDUP	Data Domain, Inc.	Sale	914,423	25.89	23,671,028

Insider trading activities including stock purchases, stock sales, and option exercises listed in the above table cannot be completely guaranteed as to their accuracy. For more information regarding the trades made by Greylock Xi Limited Partnership (10% Owner of Data Domain, Inc. at the time of this reporting) see the Securities and Exchange Commission (SEC) website.