<PAGE>
EXHIBIT 5.1
[LATHAM & WATKINS LETTERHEAD]
October 18, 2000
JNI Corporation
9775 Towne Centre Drive
San Diego, California 92121
RE: REGISTRATION STATEMENT ON FORM S-1, FILE NO. 333-45934;
5,175,000 SHARES OF COMMON STOCK, PAR VALUE $.001 PER SHARE
-----------------------------------------------------------
Ladies and Gentlemen:
In connection with the Registration Statement on Form S-1
(File No. 333-45934) filed by JNI Corporation, a Delaware corporation (the
"Company"), with the Securities and Exchange Commission (the "Commission") on
September 15, 2000, as amended by Amendment No. 1 thereto filed with the
Commission on September 26, 2000 and Amendment No. 2 thereto filed with the
Commission on October 18, 2000 (the "Registration Statement"), under the
Securities Act of 1933, as amended (the "Act"), you have requested our opinion
with respect to the matters set forth below. The Registration Statement relates
to the registration of 5,175,000 shares of common stock of the Company, par
value $.001 per share, 1,000,000 of which are being offered by the Company (the
"Company Shares"), 3,500,000 of which are being offered by certain stockholders
of the Company (the "Selling Stockholder Shares") and 675,000 of which may be
purchased by the underwriters pursuant to an over-allotment option granted by
certain stockholders of the Company (the "Over-Allotment Shares," and together
with the Company Shares and Selling Stockholder Shares, the "Shares").
If the underwriters exercise the over-allotment option in
full, 42,872 of the Over-Allotment Shares will be newly issued shares of
common stock of the Company issued upon exercise of certain stock options
held by executive officers of the Company and 632,128 of the Over-Allotment
Shares will be currently outstanding shares of common stock of the Company.
The Company Shares together with the 42,872 Over-Allotment Shares to be newly
issued shares of
<PAGE>
LATHAM & WATKINS
JNI Corporation
October 18, 2000
Page 2
common stock of the Company are referred to herein as the "New Shares." The
Selling Stockholder Shares together with the 632,128 Over-Allotment Shares to be
outstanding shares of common stock of the Company are referred to herein as the
"Outstanding Shares."
In our capacity as your counsel in connection with such
registration, we are familiar with the proceedings taken and proposed to be
taken by the Company in connection with the authorization, issuance and sale of
the Shares, and for the purposes of this opinion, have assumed such proceedings
will be timely completed in the manner presently proposed. In addition, we have
made such legal and factual examinations and inquiries, including an examination
of originals or copies certified or otherwise identified to our satisfaction of
such documents, corporate records and instruments, as we have deemed necessary
or appropriate for purposes of this opinion.
In our examination, we have assumed the genuineness of all
signatures, the authenticity of all documents submitted to us as originals, and
the conformity to authentic original documents of all documents submitted to us
as copies.
We are opining herein as to the effect on the subject
transaction only of the General Corporation Law of the State of Delaware,
including statutory and reported decisional law thereunder, and we express no
opinion with respect to the applicability thereto, or the effect thereon, of any
other laws, or as to any matters of municipal law or the laws of any local
agencies within any state.
Subject to the foregoing and the other qualifications set
forth herein, it is our opinion that, as of the date hereof:
1. The New Shares have been duly authorized, and, upon
issuance, delivery and payment therefor in the manner contemplated by the
Registration Statement, will be validly issued, fully paid and nonassessable;
and
2. The Outstanding Shares have been duly authorized and
validly issued and are fully paid and nonassessable.
We consent to your filing this opinion as an exhibit to the
Registration Statement and to the reference to our firm contained under the
heading "Legal Matters."
Very truly yours,
/s/ LATHAM & WATKINS