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: BARRETT BARBARA (Senior VP, Human Resources)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2010-07-01	Common Stock	M	11666	—	Acquired	141347	Direct
2010-07-01	Common Stock	F	11925	$1.86	Disposed	129422	Direct
2010-07-01	Common Stock	A	70000	—	Acquired	199422	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2010-07-01	Restricted Stock Units	$	M	11666	Disposed	2010-07-01	Common Stock (11666)	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.