QUANTUM CORP /DE/ — Director's Dealing 2010

Jul 1, 2010

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: QUANTUM CORP /DE/ (QTM)
CIK: 0000709283
Period of Report: 2010-07-01

Reporting Person: BRITTS WILLIAM C (EVP, Sales & Marketing)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2010-07-01	Common Stock	M	25000	—	Acquired	660662	Direct
2010-07-01	Common Stock	F	18185	$1.86	Disposed	642477	Direct
2010-07-01	Common Stock	A	140000	—	Acquired	782477	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2010-07-01	Restricted Stock Units	$	M	25000	Disposed	2010-07-01	Common Stock (25000)	Direct

Footnotes

F1: Reflects the partial vesting of Restricted Stock Units (RSUs) granted on 6/30/2007. The vested RSUs converted to shares of Common Stock on a 1-for-1 basis

F2: Surrender of shares to satisfy tax withholding obligations upon vesting of RSUs granted on 06/30/2007 and on 07/01/2008.

F3: RSUs will vest in equal installments on 07/01/2011, 07/01/2012 and on 07/01/2013.