SEC Form 4

FORM 4		UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 STATEMENT OF CHANGES IN BENEFICIAL OWNERSHIP Filed pursuant to Section 16(a) of the Securities Exchange Act of 1934 or Section 30(h) of the Investment Company Act of 1940	OMB APPROVAL OMB Number: 3235-0287 Estimated average burden hours per response: 0.5
	Check this box if no longer subject to Section 16. Form 4 or Form 5 obligations may continue. See Instruction 1(b).

1. Name and Address of Reporting Person* Nierenberg Investment Management Company, Inc. (Last) (First) (Middle) 19605 NE 8TH STREET (Street) CAMAS WA 98607 (City) (State) (Zip)	2. Issuer Name and Ticker or Trading Symbol RADISYS CORP [ RSYS ]	5. Relationship of Reporting Person(s) to Issuer (Check all applicable) X Director X 10% Owner Officer (give title below) Other (specify below)
	3. Date of Earliest Transaction (Month/Day/Year) 03/16/2011
	4. If Amendment, Date of Original Filed (Month/Day/Year)	6. Individual or Joint/Group Filing (Check Applicable Line) Form filed by One Reporting Person X Form filed by More than One Reporting Person

Table I - Non-Derivative Securities Acquired, Disposed of, or Beneficially Owned
1. Title of Security (Instr. 3)	2. Transaction Date (Month/Day/Year)	2A. Deemed Execution Date, if any (Month/Day/Year)	3. Transaction Code (Instr. 8)		4. Securities Acquired (A) or Disposed Of (D) (Instr. 3, 4 and 5)			5. Amount of Securities Beneficially Owned Following Reported Transaction(s) (Instr. 3 and 4)	6. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	7. Nature of Indirect Beneficial Ownership (Instr. 4)
			Code	V	Amount	(A) or (D)	Price

Table II - Derivative Securities Acquired, Disposed of, or Beneficially Owned (e.g., puts, calls, warrants, options, convertible securities)
1. Title of Derivative Security (Instr. 3)	2. Conversion or Exercise Price of Derivative Security	3. Transaction Date (Month/Day/Year)	3A. Deemed Execution Date, if any (Month/Day/Year)	4. Transaction Code (Instr. 8)		5. Number of Derivative Securities Acquired (A) or Disposed of (D) (Instr. 3, 4 and 5)		6. Date Exercisable and Expiration Date (Month/Day/Year)		7. Title and Amount of Securities Underlying Derivative Security (Instr. 3 and 4)		8. Price of Derivative Security (Instr. 5)	9. Number of derivative Securities Beneficially Owned Following Reported Transaction(s) (Instr. 4)	10. Ownership Form: Direct (D) or Indirect (I) (Instr. 4)	11. Nature of Indirect Beneficial Ownership (Instr. 4)
				Code	V	(A)	(D)	Date Exercisable	Expiration Date	Title	Amount or Number of Shares
Stock Options (Right to pruchase)	(1)	03/16/2011		A		1,300		(2)	03/16/2018	Common Stock	1,300	(2)	1,300	I	The D3 Family Fund, LP(3)(4)
Stock Options (Right to pruchase)	(1)	03/16/2011		A		5,100		(2)	03/16/2018	Common Stock	5,100	(2)	5,100	I	The D3 Family Bulldog Fund, LP(3)(4)
Stock Options (Right to pruchase)	(1)	03/16/2011		A		600		(2)	03/16/2018	Common Stock	600	(2)	600	I	The D3 Family Canadian Fund, LP(3)(4)

1. Name and Address of Reporting Person* Nierenberg Investment Management Company, Inc. (Last) (First) (Middle) 19605 NE 8TH STREET (Street) CAMAS WA 98607 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer X Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* Nierenberg David (Last) (First) (Middle) 19605 NE 8TH STREET (Street) CAMAS WA 98607 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* D3 Family Fund, LP (Last) (First) (Middle) 19605 NE 8TH STREET (Street) CAMAS WA 98607 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* D3 Family Bulldog Fund, LP (Last) (First) (Middle) 19605 NE 8TH STREET (Street) CAMAS WA 98607 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

1. Name and Address of Reporting Person* D3 Family Canadian Fund, LP (Last) (First) (Middle) 19605 NE 8TH STREET (Street) CAMAS WA 98607 (City) (State) (Zip) Relationship of Reporting Person(s) to Issuer Director X 10% Owner Officer (give title below) Other (specify below)

Explanation of Responses:

1. The stock options have an exercise price of $8.11.

2. David Nierenberg was appointed to the Board of Directors of the issuer effective March 16, 2011. In connection with his appointment, Mr. Nierenberg was granted 7,000 stock options, which vest as follows: (a) One-third of the total option shares shall vest and be exercisable after one year, and (b) thereafter, in equal monthly increments over the two succeeding years. These stock options are held for the benefit of the reporting persons identified above in Table II of this Form 4.

3. Additionally: (a) The D3 Family Fund, L.P. owns 727,510 shares of common stock, (b) The D3 Family Bulldog Fund, L.P. owns 2,742,682 shares of common stock, (c) The D3 Family Canadian Fund, L.P. owns 256,095 shares of common stock, and (d) The DIII Offshore Fund, L.P. owns 801,176 shares of common stock.

4. Each of the reporting persons disclaims beneficial ownership of these securities except to the extent of the reporting person's pecuniary interest therein.

Remarks:

	David Nierenberg, President, Nierenberg Investment Management Company, Inc. (NIMCO)	03/17/2011
	David Nierenberg, President, NIMCO, General Partner of The D3 Family Bulldog Fund, LP	03/17/2011
	David Nierenberg	03/17/2011
	David Nierenberg, President, NIMCO, General Partner of The D3 Family Canadian Fund, LP	03/17/2011
	David Nierenberg, President, NIMCO, General Partner of The D3 Family Fund, LP	03/17/2011
	** Signature of Reporting Person	Date
Reminder: Report on a separate line for each class of securities beneficially owned directly or indirectly.
* If the form is filed by more than one reporting person, see Instruction 4 (b)(v).
** Intentional misstatements or omissions of facts constitute Federal Criminal Violations See 18 U.S.C. 1001 and 15 U.S.C. 78ff(a).
Note: File three copies of this Form, one of which must be manually signed. If space is insufficient, see Instruction 6 for procedure.
Persons who respond to the collection of information contained in this form are not required to respond unless the form displays a currently valid OMB Number.