QUANTUM CORP /DE/ — Director's Dealing 2010

Apr 8, 2010

SEC Form 4 — Statement of Changes in Beneficial Ownership

Issuer: QUANTUM CORP /DE/ (QTM)
CIK: 0000709283
Period of Report: 2010-04-07

Reporting Person: GACEK JON W (Executive VP, COO, CFO)

Non-Derivative Transactions

Date	Security	Code	Shares	Price	A/D	Holdings After	Ownership
2010-04-07	Common Stock	M	50000	$1.46	Acquired	507913	Direct
2010-04-07	Common Stock	S	50000	$2.7556	Disposed	457913	Direct

Derivative Transactions

Date	Security	Exercise Price	Code	Shares	A/D	Expiration	Underlying	Ownership
2010-04-07	Non-Qualified Stock Options	$1.46	M	50000	Disposed	2010-08-22	Common Stock (50000)	Direct

Footnotes

F1: Reflects the exercise of the stock options listed in Table II of this Form 4.

F2: The sales reported in this Form 4 were effected pursuant to a Rule 10b5-1 trading plan adopted by the reporting person on February 17, 2010.

F3: The sale price reported in column 4 of Table I represents the weighted average sale price of the shares sold ranging from $2.74 to $2.77 per share. Upon request by the Commission staff, the Issuer, or a security holder of the Issuer, the Reporting Person will provide full information regarding the number of shares sold at each separate price.

F4: These options were granted under the 1999 Stock Incentive Plan of Advanced Digital Information Corporation ("ADIC") and assumed by Quantum Corporation ("Quantum") on August 22, 2006, pursuant to the Agreement and Plan of Merger between ADIC and Quantum. The options were exchanged for options to purchase Quantum stock, at the exchange ratio of 5.9756 per share.

F5: The options are fully vested and immediately exercisable.