SecProbe.io

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549

       DIVISION OF
CORPORATION FINANCE

  Mail Stop 3030
November 25, 2008
 VIA U.S. MAIL AND FAX (408) 731-1893

 James W. Sullivan Chief Financial Officer Mosys, Inc. 755 N. Mathilda Avenue, Suite 100 Sunnyvale, California 94085

 Re: Mosys, Inc.
  Form 10-K for the year ended December 31, 2007
  Filed March 17, 2008   File No. 000-32929
Dear Mr. Sullivan:

We have reviewed your filings and have th e following comments.  Where indicated, we
think you should revise your document in response to these comments.  If you disagree, we will
consider your explanation as to why our commen t is inapplicable or a revision is unnecessary.
Please be as detailed as necessa ry in your explanation.  In some  of our comments, we may ask
you to provide us with information so we may better understand your disclosure.  After
reviewing this information, we may raise additional comments.

Please understand that the purpose of our re view process is to assist you in your
compliance with the applicable disclosure requir ements and to enhance the overall disclosure in
your filing.  We look forward to working with you in these respects.  We welcome any questions
you may have about our comments or any other aspect of our review.  Feel fr ee to call us at the
telephone numbers listed at the end of th is letter.

James W. Sullivan
Mosys, Inc.
November 25, 2008 Page 2  Form 10-K for the Year Ended December 31, 2007

 Financial Statements, page 50

 Note 1. The Company and Summary of Si gnificant Accounting Policies, page 54

 Revenue Recognition, page 56

Royalty, page 58

1. We note from your disclosure that in 2006 you began recognizing revenue from two
types of prepaid royalties, pre-production royalties and pos t-production royalties, and the
revenue related to both type s of royalties is recognized upon execution of the related
contract. Based on your disclosure  it is unclear to us why you believe it is appropriate to
recognize the revenue in its entirety upfront at execution of the contract in accordance
with the guidance in SAB Topic 13A. Please provide  us with the specific terms of your of
agreements with regards to these prepaid royalties and the amounts of related revenue you recognized in 2006 and 2007. Please cite  the specific accounting guidance upon
which you based your accounting.
 2. In this regard, if material, pl ease tell us how you considered the prepaid royalties as part
of your Results of Operations discussion in  Management’s Discussion and Analysis. We
note your current disclosure stat es that you generally recognize royalties in the quarter in
which you receive the licensee’s report.
 Note 4. Asset Acquisitions, page 64

 3. We note that one of the components of purchas ed intangible assets  related to your 2007
asset purchases is an assembled workforce.  Please tell us why you be lieve this allocation
is appropriate based on the guida nce in paragraph 39 of SFAS 141.
 Form 10-Q for the Quarter Ended September 30, 2008

Note 1. The Company and Summary of Si gnificant Accounting Policies, page 6

Investments, page 9
 4. We note that as of September 30, 2008, you had classified $8.3 million (net of $0.9
million in unrealized losses) of your auction ra te securities as long-term investments due
to the disruption in the credit markets that resulted in widespread failed auctions. We also note that you used Level 3 inputs to measure the fair value of the auction rate securities
because there has not been a successful auction since February 2008.  Please address the
following:

James W. Sullivan
Mosys, Inc.
November 25, 2008 Page 3
• Please note that paragraphs 32 and 33 of SFAS 157 require an entity to describe the
inputs and the information used to deve lop those inputs for both recurring and
nonrecurring fair value measurements using significant unobservable inputs (Level
3).  Please explain to us in  greater detail about the methodology and the assumptions
you employed to measure the auction rate securities.  Refer to FSP FAS 157-3 for
further guidance.  Further, please expand your disclosure to address our concern in
future filings.

• Also in this regard, please explain to us and expand your disclosure in future filings
why the decline in the fair value of the auct ion rate securities ha s not been other-than-
temporary.  Refer to FSP FAS 115-1 for further guidance.

5. We note that approximately 36% of your cash equivalents and available for sale
securities were measured based on level 2 inputs. Your discussi on regarding the inputs
used to measure fair value does not appear to be specific to your inve stments. Please tell
us more about the inputs used, including how you obtain these inputs, what they represent
and how you are able to corroborat e these prices. For example, tell us and revise future
filings to disclose if your level 2 assets  were valued using models, other pricing
methodologies or were directly or indirectly observable through co rrelation with market
data.
 6. In this regard, please consider revise your Crit ical Accounting Policies in future filings to
discuss significant assumptions and estimates made by management in determining fair
value.
 Item 9A. Controls and Procedures, page 20

 7. We note your disclosure that your principa l executive officer and principal financial
officer concluded that your disclosure contro ls and procedures were effective “to ensure
that information required to be disclosed by us  in the reports filed or submitted by us with
the SEC is recorded, processed, summarized and reported within the time periods specified in the SEC’s rules and forms.”  If you elect to include any qualifying language as to the effectiveness conclusion in your future filings, such language should include, at a minimum, but only if true, that your officer s concluded that your disclosure controls
and procedures are effective to ensure that information required to be disclosed by you in
reports that you file or submit under the Exchange Act is recorded, processed,
summarized and reported within the time peri ods specified in Secu rities and Exchange
Commission rules and forms and
 is accumulated and communicated to your management,
including your principal executive officer and principal financial officer, or persons
performing similar functions, as appropriate to allow timely decisions regarding required
disclosure.  See Exchange Act Rule 13a-15(e)  for the complete definition of “disclosure
controls and procedures.”  A lternatively, if true, your disclosure could simply indicate
that your officers determined th at your “disclosure controls and procedures are effective”

James W. Sullivan
Mosys, Inc. November 25, 2008 Page 4
 without any further qualifications  or attempts to define t hose disclosure controls and
procedures.  As appropriate, please amend your filing and respond to these comments within 10
business days or tell us when you will provide us  with a response.  Pleas e furnish a cover letter
with your amendment that keys your responses to our comments and provides any requested
information.  Detailed cover lette rs greatly facilitate our review .  Please understand that we may
have additional comments afte r reviewing your amendment and responses to our comments.

We urge all persons who are responsible for th e accuracy and adequacy of the disclosure
in the filing to be certain that the filing includes all information re quired under the Securities
Exchange Act of 1934 and that they have provi ded all information investors require for an
informed investment decision.  Since the compa ny and its management are in possession of all
facts relating to a company’s disclosure, they are responsible for the acc uracy and adequacy of
the disclosures they have made.
In connection with responding to our comment s, please provide, in writing, a statement
from the company acknowledging that:
‚ the company is responsible for the adequacy and accuracy of the disclo sure in the filing;

‚ staff comments or changes to disclosure in response to staff comments do not foreclose
the Commission from taking any action with respect to the filing; and

‚ the company may not assert staff comments as a defense in any proceeding initiated by the Commission or any person under the federa l securities laws of  the United States.

In addition, please be advise d that the Division of Enfo rcement has access to all
information you provide to the sta ff of the Division of Corporati on Finance in our review of your
filing or in response to our comments on your filing.
 You may contact Andri Boerman at (202) 551-3645 or Julie Sherman at (202) 551-3640
if you have questions regarding comments on the financial statements and related matters.
Please contact Celia Soehner at  (202) 551-3463 or Mary Beth Br eslin at (202) 551-3625 if you
have questions on other comments.  In this rega rd, do not hesitate to contact me at (202) 551-
3554.           S i n c e r e l y ,             A n g e l a  C r a n e           B r a n c h  C h i e f