  United States Court of Appeals
      for the Federal Circuit
                ______________________

                    ENFISH, LLC,
                   Plaintiff-Appellant

                           v.

   MICROSOFT CORPORATION, FISERV, INC.,
   INTUIT, INC., SAGE SOFTWARE, INC., JACK
         HENRY & ASSOCIATES, INC.,
               Defendants-Appellees
              ______________________

                      2015-1244
                ______________________

   Appeal from the United States District Court for the
Central District of California in No. 2:12-cv-07360-MRP-
MRW, Senior Judge Mariana R. Pfaelzer.
                 ______________________

                Decided: May 12, 2016
                ______________________

    ORION ARMON, Cooley LLP, Broomfield, CO, argued
for plaintiff-appellant. Also represented by JAMES P.
BROGAN, JANNA FISCHER.

   CHAD S. CAMPBELL, Perkins Coie LLP, Phoenix, AZ,
argued for all defendants-appellees. Defendants-appellees
Microsoft Corporation, Fiserv, Inc., Intuit, Inc., Jack
Henry & Associates, Inc., also represented by DAN L.
BAGATELL, THEODORE H. WIMSATT; ELIZABETH M.
BANZHOFF, AMANDA D.W. TESSAR, Denver, CO.
2                   ENFISH, LLC   v. MICROSOFT CORPORATION



    WILLIAM J. BROWN, JR., Brown, Wegner & Berliner
LLP, Irvine, CA, for defendant-appellee Sage Software,
Inc. Also represented by MATTHEW K. WEGNER, YUANJUN
LILY LI.
                 ______________________

    Before MOORE, TARANTO, and HUGHES, Circuit Judges.
HUGHES, Circuit Judge.
    Enfish sued Microsoft for infringement of several pa-
tents related to a “self-referential” database. On sum-
mary judgment, the district court found all claims invalid
as ineligible under § 101, some claims invalid as antici-
pated under § 102, and one claim not infringed. Enfish
appeals. We find that the claims are not directed to an
abstract idea, so we reverse the summary judgment based
on § 101. We find that the “pivot table” feature of the
prior art Excel product does not contain the “self-
referential” feature of the claims, so we vacate the sum-
mary judgment based on § 102. Lastly, we find no error
in the district court’s determination on non-infringement,
so we affirm the summary judgment of non-infringement.
We remand the case for further proceedings.
                            I
    Microsoft develops and sells a variety of software
products, including the product ADO.NET. At least
through the late 1990s and early 2000s, Enfish developed
and sold software products, including a new type of data-
base program.
    Enfish received U.S. Patent 6,151,604 and U.S. Pa-
tent 6,163,775 in late 2000. Both claim priority to the
same application filed in March 1995.
    The ’604 and ’775 patents are directed to an innova-
tive logical model for a computer database. A logical
model is a model of data for a computer database explain-
ing how the various elements of information are related to
ENFISH, LLC   v. MICROSOFT CORPORATION                    3



one another. A logical model generally results in the
creation of particular tables of data, but it does not de-
scribe how the bits and bytes of those tables are arranged
in physical memory devices. Contrary to conventional
logical models, the patented logical model includes all
data entities in a single table, with column definitions
provided by rows in that same table. The patents de-
scribe this as the “self-referential” property of the data-
base. ’604 patent, col. 2 ll. 44–52.
    This self-referential property can be best understood
in contrast with the more standard “relational” model.
With the relational model, each entity (i.e., each type of
thing) that is modeled is provided in a separate table. For
instance, a relational model for a corporate file repository
might include the following tables:
   document table,
   person table,
   company table.
The document table might contain information about
documents stored on the file repository, the person table
might contain information about authors of the docu-
ments, and the company table might contain information
about the companies that employ the persons.
4                    ENFISH, LLC   v. MICROSOFT CORPORATION



    Each table in the relational model contains columns
defining that table. In the corporate file repository exam-
ple, the relational model might have the following tables: 1




Using this relational model, if a database were to store
information about a document called proj.doc, a person
called Scott Wlaschin, and a company called DEXIS, then
the result might be:




    1  The figures that follow in this Background section
are adaptations of the example tables illustrated in the
patents on appeal. See, e.g., ’604 patent, Figures 3, 5, 9.
ENFISH, LLC   v. MICROSOFT CORPORATION                 5



To indicate that Scott Wlaschin is the author of proj.doc
and that he is employed by DEXIS, the relational model
uses relationships as follows:




Here, the top-most relationship explains that the value
for “Author” in the Document table refers to the “ID”
column of the Person table. Because the row for proj.doc
has AUTHOR = 1, the row in the Person table that has
ID = 1 is the author of proj.doc. By this technique, the
relational model captures information about each type of
entity in a separate table, with relationships between
those tables informing the relationships between rows in
different tables.
6                     ENFISH, LLC   v. MICROSOFT CORPORATION



    In contrast to the relational model, the patented self-
referential model has two features that are not found in
the relational model: first the self-referential model can
store all entity types in a single table, and second the self-
referential model can define the table’s columns by rows
in that same table. For example, a self-referential model
corresponding to the example relational model discussed
above might look like the following: 2




    This self-referential table stores the same information
that is stored by the example relational model shown
above. However, all of the information about documents,
persons, and companies are stored in a single table.
    Further, an additional row is included in the self-
referential table: the row beginning with ID = #4. This
row has values of TYPE = “field” and LABEL = “Employed
By.” Such a row with TYPE = “field” is a special row,
because it defines characteristics of a column in that same
table. In this case, the row with ID = #4 corresponds to
the penultimate column, which is denoted by also mark-
ing that column with the ID of #4. The row with ID = #4
defines a single characteristic of the corresponding col-
umn, viz., its label. Because the row with ID = #4 has
LABEL = “Employed By,” we know that the corresponding
column is labeled “Employed By,” as seen in the penulti-
mate column. In other situations, the row might define
other characteristics of the column, such as the type of


    2  The following diagram is a simplified version of
Figure 3 of the ’604 patent.
ENFISH, LLC   v. MICROSOFT CORPORATION                       7



data that the column can hold, e.g., text, integer numbers,
or decimal numbers. Because the patent describes a
model where the table’s columns are defined by rows in
that same table, it is “self-referential.” See ’604 patent,
col. 2, ll. 59–65.
     The patents teach that multiple benefits flow from
this design. First, the patents disclose an indexing tech-
nique that allows for faster searching of data than would
be possible with the relational model. See, e.g., ’604
patent, col. 1 ll. 55–59; id. at col. 2 l. 66–col. 3 l. 6. Sec-
ond, the patents teach that the self-referential model
allows for more effective storage of data other than struc-
tured text, such as images and unstructured text. See,
e.g., ’604 patent, col. 2 ll. 16–22; col. 2 ll. 46–52.
    Finally, the patents teach that the self-referential
model allows more flexibility in configuring the database.
See, e.g., ’604 patent, col. 2 ll. 27–29. In particular,
whereas deployment of a relational database often in-
volves extensive modeling and configuration of the vari-
ous tables and relationships in advance of launching the
database, Enfish argues that the self-referential database
can be launched without such tasks and instead config-
ured on-the-fly.    See Oral Argument at 1:00–2:15
http://oralarguments.cafc.ucsourts.gov/default.aspx?fl=20
15-1244.mp3; see also ’604 patent, col. 7 ll. 10–22. For
instance, the database could be launched with no or only
minimal column definitions. Then, as a new attribute of
information is encountered, such as an email address, an
“Email” column could be added simply by inserting a new
row of TYPE = “field” and LABEL = “email.” The addition
of this new row can then instigate the database to create
a new, corresponding column. The addition of a new row-
defining-a-column to the previous example might result in
the following:
8                    ENFISH, LLC   v. MICROSOFT CORPORATION




    In 2012, Enfish filed suit against Microsoft in district
court in California, alleging that Microsoft’s ADO.NET
product infringes the ’604 and ’775 patents. ADO.NET
provides an interface by which software applications can
store, retrieve, and otherwise manipulate data stored in a
database. Enfish alleges that ADO.NET creates and
manipulates self-referential tables as part of its opera-
tion.
    Five claims are at issue in this appeal: claims 17, 31,
and 32 of the ’604 patent; and claims 31 and 32 of the ’775
patent. The district court entered summary judgment on
these claims as follows: all claims invalid under 35 U.S.C.
§ 101 as directed to an abstract idea; claims 31 and 32 of
both patents invalid under 35 U.S.C. § 102(b) as antici-
pated by the prior public sale and use of Microsoft’s Excel
5.0 product; and claim 17 not infringed by ADO.NET.
   Enfish appeals each of these summary judgments.
We have jurisdiction under 28 U.S.C. § 1295(a)(1).
                             II
    This court reviews a grant of summary judgment un-
der the standard of review of the regional circuit. See
Taurus IP, LLC v. DaimlerChrysler Corp., 726 F.3d 1306,
1322 (Fed. Cir. 2013). The Ninth Circuit reviews a grant
of summary judgment de novo. See Oswalt v. Resolute
Indus., Inc., 642 F.3d 856, 859 (9th Cir. 2011). Summary
judgment is only appropriate if “there is no genuine
dispute as to any material fact and the movant is entitled
to judgment as a matter of law.” FED. R. CIV. P. 56(a). In
reviewing summary judgment, “[t]he evidence of the non-
movant is to be believed and all justifiable inferences are
to be drawn in [the non-movant’s] favor.” Anderson v.
Liberty Lobby, Inc., 477 U.S. 242, 255 (1986).
    On appeal, Enfish challenges the district court’s grant
of summary judgment on § 101 invalidity, § 102 invalidi-
ENFISH, LLC   v. MICROSOFT CORPORATION                      9



ty, and non-infringement. We address each argument in
turn.
                             III
    We turn first to the district court’s determination that
the claims at issue do not claim patent-eligible subject
matter, which we review de novo. See OIP Techs., Inc. v.
Amazon.com, Inc., 788 F.3d 1359, 1362 (Fed. Cir. 2015).
     Section 101 provides that a patent may be obtained
for “any new and useful process, machine, manufacture,
or composition of matter, or any new and useful improve-
ment thereof.” 35 U.S.C. § 101. This court, as well as the
Supreme Court, has long grappled with the exception that
“[l]aws of nature, natural phenomena, and abstract ideas
are not patentable.” Ass’n for Molecular Pathology v.
Myriad Genetics, Inc., --- U.S. ----, 133 S. Ct. 2107, 2116
(2013) (quoting Mayo Collaborative Servs. v. Prometheus
Labs., Inc., --- U.S. ----, 132 S. Ct. 1289, 1293 (2012)).
Supreme Court precedent instructs us to “first determine
whether the claims at issue are directed to a patent-
ineligible concept.” Alice Corp. Pty Ltd. v. CLS Bank Int’l,
--- U.S. ----, 134 S. Ct. 2347, 2355 (2014). If this threshold
determination is met, we move to the second step of the
inquiry and “consider the elements of each claim both
individually and ‘as an ordered combination’ to determine
whether the additional elements ‘transform the nature of
the claim’ into a patent-eligible application.” Id. (quoting
Mayo, 132 S. Ct. at 1298, 1297).
    The Supreme Court has not established a definitive
rule to determine what constitutes an “abstract idea”
sufficient to satisfy the first step of the Mayo/Alice in-
quiry. See id. at 2357. Rather, both this court and the
Supreme Court have found it sufficient to compare claims
at issue to those claims already found to be directed to an
abstract idea in previous cases. “[The Court] need not
labor to delimit the precise contours of the ‘abstract ideas’
category in this case. It is enough to recognize that there
10                    ENFISH, LLC   v. MICROSOFT CORPORATION



is no meaningful distinction between the concept of risk
hedging in Bilski and the concept of intermediated set-
tlement at issue here.” Alice, 134 S. Ct. at 2357; see also
OIP Techs., 788 F.3d at 1362. For instance, fundamental
economic and conventional business practices are often
found to be abstract ideas, even if performed on a comput-
er. See, e.g., OIP Techs., 788 F.3d at 1362–63.
    In setting up the two-stage Mayo/Alice inquiry, the
Supreme Court has declared: “We must first determine
whether the claims at issue are directed to a patent-
ineligible concept.” Alice, 134 S. Ct. at 2355. That formu-
lation plainly contemplates that the first step of the
inquiry is a meaningful one, i.e., that a substantial class
of claims are not directed to a patent-ineligible concept.
The “directed to” inquiry, therefore, cannot simply ask
whether the claims involve a patent-ineligible concept,
because essentially every routinely patent-eligible claim
involving physical products and actions involves a law of
nature and/or natural phenomenon—after all, they take
place in the physical world. See Mayo, 132 S. Ct. at 1293
(“For all inventions at some level embody, use, reflect,
rest upon, or apply laws of nature, natural phenomena, or
abstract ideas.”) Rather, the “directed to” inquiry applies
a stage-one filter to claims, considered in light of the
specification, based on whether “their character as a
whole is directed to excluded subject matter.” Internet
Patents Corp. v. Active Network, Inc., 790 F.3d 1343, 1346
(Fed. Cir. 2015); see Genetic Techs. Ltd. v. Merial L.L.C.,
2016 WL 1393573, at *5 (Fed. Cir. 2016) (inquiring into
“the focus of the claimed advance over the prior art”).
    The Supreme Court has suggested that claims “pur-
port[ing] to improve the functioning of the computer
itself,” or “improv[ing] an existing technological process”
might not succumb to the abstract idea exception. See
Alice, 134 S. Ct. at 2358–59. While it is true that the
Court discussed improvements to computer-related tech-
nology in the second step of its analysis in Alice, see id. at
ENFISH, LLC   v. MICROSOFT CORPORATION                     11



2355–60, that was because the Court did not need to
discuss the first step of its analysis at any considerable
length, see id. at 2356 (“Petitioner acknowledges that its
claims describe intermediate settlement . . . .”), id. at
2357.
    We do not read Alice to broadly hold that all im-
provements in computer-related technology are inherently
abstract and, therefore, must be considered at step two.
Indeed, some improvements in computer-related technol-
ogy when appropriately claimed are undoubtedly not
abstract, such as a chip architecture, an LED display, and
the like. Nor do we think that claims directed to software,
as opposed to hardware, are inherently abstract and
therefore only properly analyzed at the second step of the
Alice analysis. Software can make non-abstract im-
provements to computer technology just as hardware
improvements can, and sometimes the improvements can
be accomplished through either route. We thus see no
reason to conclude that all claims directed to improve-
ments in computer-related technology, including those
directed to software, are abstract and necessarily ana-
lyzed at the second step of Alice, nor do we believe that
Alice so directs. Therefore, we find it relevant to ask
whether the claims are directed to an improvement to
computer functionality versus being directed to an ab-
stract idea, even at the first step of the Alice analysis.
      For that reason, the first step in the Alice inquiry in
this case asks whether the focus of the claims is on the
specific asserted improvement in computer capabilities
(i.e., the self-referential table for a computer database) or,
instead, on a process that qualifies as an “abstract idea”
for which computers are invoked merely as a tool. As
noted infra, in Bilski and Alice and virtually all of the
computer-related § 101 cases we have issued in light of
those Supreme Court decisions, it was clear that the
claims were of the latter type—requiring that the analysis
proceed to the second step of the Alice inquiry, which asks
12                   ENFISH, LLC   v. MICROSOFT CORPORATION



if nevertheless there is some inventive concept in the
application of the abstract idea. See Alice, 134 S. Ct. at
2355, 2357–59. In this case, however, the plain focus of
the claims is on an improvement to computer functionali-
ty itself, not on economic or other tasks for which a com-
puter is used in its ordinary capacity.
    Accordingly, we find that the claims at issue in this
appeal are not directed to an abstract idea within the
meaning of Alice. Rather, they are directed to a specific
improvement to the way computers operate, embodied in
the self-referential table. See supra at 6. Specifically,
claim 17 of the ’604 patent recites:
     A data storage and retrieval system for a comput-
     er memory, comprising:
         means for configuring said memory according
     to a logical table, said logical table including:
            a plurality of logical rows, each said logi-
        cal row including an object identification
        number (OID) to identify each said logical
        row, each said logical row corresponding to a
        record of information;
            a plurality of logical columns intersecting
        said plurality of logical rows to define a plu-
        rality of logical cells, each said logical column
        including an OID to identify each said logical
        column; and
        means for indexing data stored in said table.
ENFISH, LLC   v. MICROSOFT CORPORATION                      13



    Pursuant to 35 U.S.C. § 112 ¶ 6 (2006), the district
court construed the “means for configuring” language as
requiring a four-step algorithm: 3
   1. Create, in a computer memory, a logical table
   that need not be stored contiguously in the com-
   puter memory, the logical table being comprised of
   rows and columns, the rows corresponding to rec-
   ords, the columns corresponding to fields or at-
   tributes, the logical table being capable of storing
   different kinds of records.
   2. Assign each row and column an object identifi-
   cation number (OID) that, when stored as data,
   can act as a pointer to the associated row or col-
   umn and that can be of variable length between
   databases.
   3. For each column, store information about that
   column in one or more rows, rendering the table
   self-referential, the appending, to the logical table,
   of new columns that are available for immediate




   3    “Construction of a means-plus-function limitation
includes two steps. ‘First, the court must determine the
claimed function. Second, the court must identify the
corresponding structure in the written description of the
patent that performs the function.’” Noah Sys., Inc. v.
Intuit Inc., 675 F.3d 1302, 1311 (Fed. Cir. 2012) (quoting
Applied Med. Res. Corp. v. U.S. Surgical Corp., 448 F.3d
1324, 1332 (Fed. Cir. 2006)). And “the corresponding
structure for a function performed by a software algo-
rithm is the algorithm itself.” EON Corp. IP Holdings
LLC v. AT & T Mobility LLC, 785 F.3d 616, 621 (Fed. Cir.
2015). The parties do not dispute this construction on
appeal.
14                    ENFISH, LLC   v. MICROSOFT CORPORATION



     use being possible through the creation of new
     column definition records.
     4. In one or more cells defined by the intersection
     of the rows and columns, store and access data,
     which can include structured data, unstructured
     data, or a pointer to another row.
J.A. 325.
    The district court concluded that the claims were di-
rected to the abstract idea of “storing, organizing, and
retrieving memory in a logical table” or, more simply, “the
concept of organizing information using tabular formats.”
J.A. 321 (emphasis omitted). Likewise, Microsoft urges
the court to view the claims as being directed to “the
concepts of organizing data into a logical table with
identified columns and rows where one or more rows are
used to store an index or information defining columns.”
Appellee’s Br. 17. However, describing the claims at such
a high level of abstraction and untethered from the lan-
guage of the claims all but ensures that the exceptions to
§ 101 swallow the rule. See Alice, 134 S. Ct. at 2354
(noting that “we tread carefully in construing this exclu-
sionary principle [of laws of nature, natural phenomena,
and abstract ideas] lest it swallow all of patent law”); cf.
Diamond v. Diehr, 450 U.S. 175, 189 n.12 (1981) (caution-
ing that overgeneralizing claims, “if carried to its ex-
treme, make[s] all inventions unpatentable because all
inventions can be reduced to underlying principles of
nature which, once known, make their implementation
obvious”).
    Here, the claims are not simply directed to any form
of storing tabular data, but instead are specifically di-
rected to a self-referential table for a computer database.
For claim 17, this is reflected in step three of the “means
for configuring” algorithm described above. For both
pairs of claims 31 and 32, this is reflected in other claim
language, discussed infra at 20. The necessity of describ-
ENFISH, LLC   v. MICROSOFT CORPORATION                   15



ing the claims in such a way is underscored by the specifi-
cation’s emphasis that “the present invention comprises a
flexible, self-referential table that stores data.” ’604
patent at Abstract; see also id. at col. 2 ll. 44–46 (“The
present invention improves upon prior art information
search and retrieval systems by employing a flexible, self-
referential table to store data.”).
    The specification also teaches that the self-referential
table functions differently than conventional database
structures. According to the specification, traditional
databases, such as “those that follow the relational model
and those that follow the object oriented model,” ’604
patent, col. 1 ll. 37–40, are inferior to the claimed inven-
tion. While “[t]he structural requirements of current
databases require a programmer to predefine a structure
and subsequent [data] entry must conform to that struc-
ture,” id. at col. 2 ll. 10–13, the “database of the present
invention does not require a programmer to preconfigure
a structure to which a user must adapt data entry.” Id. at
col 2 ll. 27–29. Moreover, our conclusion that the claims
are directed to an improvement of an existing technology
is bolstered by the specification’s teachings that the
claimed invention achieves other benefits over conven-
tional databases, such as increased flexibility, faster
search times, and smaller memory requirements. See id.
at col 2 ll. 23–27; see also Openwave Sys., Inc. v. Apple
Inc., 808 F.3d 509, 513–14 (Fed. Cir. 2015) (finding that a
specification’s disparagement of the prior art is relevant
to determine the scope of the invention).
    In finding that the claims were directed simply to “the
concept of organizing information using tabular formats,”
J.A. 321 (emphasis omitted), the district court oversimpli-
fied the self-referential component of the claims and
downplayed the invention’s benefits. The court deter-
mined that the patents’ self-referential concept could be
satisfied by creating a table with a simple header row.
But that is simply not the case. For example, step three
16                   ENFISH, LLC   v. MICROSOFT CORPORATION



of the algorithm described above explains that the table
stores information related to each column in rows of that
very same table, such that new columns can be added by
creating new rows in the table. See J.A. 325 (describing
four-step algorithm); see also ’604 patent, col. 2 ll. 53–65
(describing “the present invention”, including a descrip-
tion where “columns are entered as rows in the table and
the record corresponding to a column contains various
information about the column,” thereby “render[ing] the
table self-referential”). It is beyond debate that this is
more than simply a header row.
     Moreover, we are not persuaded that the invention’s
ability to run on a general-purpose computer dooms the
claims. Unlike the claims at issue in Alice or, more re-
cently in Versata Development Group v. SAP America,
Inc., 793 F.3d 1306 (Fed. Cir. 2015), which Microsoft
alleges to be especially similar to the present case, Appel-
lee’s Br. 18, see also Oral Argument at 15:40–18:15, the
claims here are directed to an improvement in the func-
tioning of a computer. In contrast, the claims at issue in
Alice and Versata can readily be understood as simply
adding conventional computer components to well-known
business practices. See Alice, 134 S. Ct. at 2358–60;
Versata Dev. Grp., 793 F.3d at 1333–34 (computer per-
formed “purely conventional” steps to carry out claims
directed to the “abstract idea of determining a price using
organization and product group hierarchies”); see also
Mortgage Grader, Inc. v. First Choice Loan Servs. Inc.,
811 F.3d 1314, 1324–25 (Fed. Cir. 2016) (claims attaching
generic computer components to perform “anonymous
loan shopping” not patent eligible); Intellectual Ventures I
LLC v. Capital One Bank (USA), 792 F.3d 1363, 1367–69
(Fed. Cir. 2015) (claims adding generic computer compo-
nents to financial budgeting); OIP Techs., 788 F.3d at
1362–64 (claims implementing offer-based price optimiza-
tion using conventional computer activities); Ultramer-
cial, Inc. v. Hulu, LLC, 772 F.3d 709, 714–17 (Fed. Cir.
ENFISH, LLC   v. MICROSOFT CORPORATION                     17



2014) (claims applying an exchange of advertising for
copyrighted content to the Internet); buySAFE, Inc. v.
Google, Inc., 765 F.3d 1350, 1354–55 (Fed. Cir. 2014)
(claims adding generic computer functionality to the
formation of guaranteed contractual relationships). And
unlike the claims here that are directed to a specific
improvement to computer functionality, the patent-
ineligible claims at issue in other cases recited use of an
abstract mathematical formula on any general purpose
computer, see Gottschalk v. Benson, 409 U.S. 63, 93
(1972), see also Alice, 134 S. Ct. at 2357–58, or recited a
purely conventional computer implementation of a math-
ematical formula, see Parker v. Flook, 437 U.S. 584, 594
(1978); see also Alice, 134 S. Ct. at 2358, or recited gener-
alized steps to be performed on a computer using conven-
tional computer activity, see Internet Patents, 790 F.3d
1348–49 (claims directed to abstract idea of maintaining
computer state without recitation of specific activity used
to generate that result), Digitech Image Techs., LLC v.
Electrs. For Imaging, Inc., 758 F.3d 1344, 1351 (Fed. Cir.
2014) (claims directed to abstract idea of “organizing
information through mathematical correlations” with
recitation of only generic gathering and processing activi-
ties).
    Similarly, that the improvement is not defined by ref-
erence to “physical” components does not doom the claims.
To hold otherwise risks resurrecting a bright-line ma-
chine-or-transformation test, cf. Bilski v. Kappos, 561
U.S. 593, 604 (2010) (“The machine-or-transformation test
is not the sole test for deciding whether an invention is a
patent-eligible ‘process.’”), or creating a categorical ban on
software patents, cf. id. at 603 (“This Court has not indi-
cated that the existence of these well-established excep-
tions gives the Judiciary carte blanche to impose other
limitations that are inconsistent with the text and the
statute’s purpose and design.”). Much of the advancement
made in computer technology consists of improvements to
18                   ENFISH, LLC   v. MICROSOFT CORPORATION



software that, by their very nature, may not be defined by
particular physical features but rather by logical struc-
tures and processes. We do not see in Bilski or Alice, or
our cases, an exclusion to patenting this large field of
technological progress.
    In sum, the self-referential table recited in the claims
on appeal is a specific type of data structure designed to
improve the way a computer stores and retrieves data in
memory. The specification’s disparagement of conven-
tional data structures, combined with language describing
the “present invention” as including the features that
make up a self-referential table, confirm that our charac-
terization of the “invention” for purposes of the § 101
analysis has not been deceived by the “draftsman’s art.”
Cf. Alice, 134 S. Ct. at 2360. In other words, we are not
faced with a situation where general-purpose computer
components are added post-hoc to a fundamental econom-
ic practice or mathematical equation. Rather, the claims
are directed to a specific implementation of a solution to a
problem in the software arts. Accordingly, we find the
claims at issue are not directed to an abstract idea.
    Because the claims are not directed to an abstract
idea under step one of the Alice analysis, we do not need
to proceed to step two of that analysis. See id. at 2355.
We recognize that, in other cases involving computer-
related claims, there may be close calls about how to
characterize what the claims are directed to. In such
cases, an analysis of whether there are arguably concrete
improvements in the recited computer technology could
take place under step two. Here, though, we think it is
clear for the reasons stated that the claims are not di-
rected to an abstract idea, and so we stop at step one. We
conclude that the claims are patent-eligible.
                            IV
    Alternatively, Microsoft encourages us to affirm the
invalidity of claim 17 on the ground of indefiniteness.
ENFISH, LLC   v. MICROSOFT CORPORATION                    19



According to Microsoft, the previously-recited four-step
algorithm is not a sufficient structure for the claimed
function of “configuring said memory according to a
logical table.”
    For a claim element recited in means-plus-function
format, “the specification must contain sufficient descrip-
tive text by which a person of skill in the field of the
invention would ‘know and understand what structure
corresponds to the means limitation.’” Typhoon Touch
Techs., Inc. v. Dell, Inc., 659 F.3d 1376, 1383–84 (Fed. Cir.
2011) (quoting Finisar Corp. v. DirecTV Grp., Inc., 523
F.3d 1323, 1340 (Fed. Cir. 2008)). “[W]hile it is true that
the patentee need not disclose details of structures well
known in the art, the specification must nonetheless
disclose some structure.” Biomedino LLC v. Waters Techs.
Corp., 490 F.3d 946, 952 (Fed. Cir. 2007) (quoting Default
Proof Credit Card Sys. v. Home Depot U.S.A., Inc., 412
F.3d 1291, 1302 (Fed. Cir. 2005)).
    The district court found that the four-step algorithm
sufficiently identified a structure for a person of skill in
the art to implement the function of “configuring said
memory according to a logical table.” We agree. Step one
of the four-step algorithm relies on well-known techniques
in the database arts for setting up a table in computer
memory. Microsoft does not allege that an ordinary
artisan would not understand the algorithm. Steps two
through four then provide particular details for modifying
some such well-known configuration in accordance with
the disclosed invention. The fact that this algorithm
relies, in part, on techniques known to a person of skill in
the art does not render the composite algorithm insuffi-
cient under § 112 ¶ 6. Indeed, this is entirely consistent
with the fact that the sufficiency of the structure is
viewed through the lens of a person of skill in the art and
without need to “disclose structures well known in the
art,” Biomedino, 490 F.3d at 952.
20                   ENFISH, LLC   v. MICROSOFT CORPORATION



    Therefore, we do not find claim 17 invalid on this al-
ternative ground.
                             V
    Because we find the claims patent-eligible under
§ 101, we now turn to the issue of validity under § 102.
The district court found claims 31 and 32 of both patents
anticipated under § 102. Claim 31 of the ’604 patent is
exemplary:
     A method for storing and retrieving data in a
     computer memory, comprising the steps of:
         configuring said memory according to a logical
     table, said logical table including:
            a plurality of logical rows, each said logi-
        cal row including an object identification
        number (OID) to identify each said logical
        row, each said logical row corresponding to a
        record of information;
            a plurality of logical columns intersecting
        said plurality of logical rows to define a plu-
        rality of logical cells, each said logical column
        including an OID to identify each said logical
        column; and
            wherein at least one of said logical rows
        has an OID equal to the OID to a correspond-
        ing one of said logical columns, and at least
        one of said logical rows includes logical col-
        umn information defining each of said logical
        columns.
As seen, claim 31 recites a method involving configuring a
memory “according to a logical table,” with that logical
table specified in some detail. Notably, the logical table
must have a row and a column that have the same ID
value. This language of the “wherein” clause embodies
the self-referential property explained supra at 6.
ENFISH, LLC   v. MICROSOFT CORPORATION                   21



    The district court found the claims anticipated under
§ 102(b) by the Microsoft Excel 5.0 software program.
Excel 5.0 is a version of the well-known spreadsheet
program that was in public use at latest by early-1994.
The district court focused on the “pivot table” feature of
Excel 5.0 as anticipating the claims. A pivot table is a
type of data-summarization table that a user can prompt
the Excel program to generate, based on a preexisting
table of raw data. For instance, a user may begin with a
table of raw sales data as follows (only a subset of the
entire table is shown below):




J.A. 7722. The example table has rows for sales by a
particular salesperson of a particular product in a particu-
lar region, among other attributes. The user can prompt
Excel to create a pivot table, such as the following:




J.A. 7722. This pivot table has row labels corresponding
to salespersons and column labels corresponding to types
of product. The cells of the pivot table sum the “Sales”
column of the raw data table based on its intersection of a
particular salesperson and a particular type of product.
22                   ENFISH, LLC   v. MICROSOFT CORPORATION



For instance, salesperson Buchanan has sold $67,566
worth of dairy products.
    The district court found this pivot table feature of Ex-
cel 5.0 to anticipate claim 31, including the self-
referential property embodied in the language of “wherein
at least one of said logical rows has an OID equal to the
OID to a corresponding one of said logical columns.” The
district court noted that a cell in the row of the raw data
table, (e.g., “Dairy”) was also the label of a column in the
pivot table, (again, “Dairy”). J.A. 283–84. Microsoft’s
expert exemplified this position by showing that the
addition of the “Housewares” row to the raw data table,
like so:




J.A. 7723, would result in the addition of a “Housewares”
column to the pivot table, like so:




J.A. 7724. On its face, this would seem to have the effect
of adding a column based on a newly added row, which is
in some ways a characteristic behavior of the self-
referential table disclosed in the patents.
    But finding this feature to anticipate the claims re-
quires an inappropriately broad reading of the claims.
Claim 31 is directed to configuring memory “according to
ENFISH, LLC   v. MICROSOFT CORPORATION                       23



a logical table.” While we have held that the use of a
singular indefinite article with a claim feature may sup-
port an interpretation of “one or more” of those claim
features, see, e.g., Free Motion Fitness, Inc. v. Cybex Int’l,
Inc., 423 F.3d 1343, 1350 (Fed. Cir. 2005), the context of
claim 31 shows that this is not such a case. The remain-
der of claim 31 describes rows and columns without
providing any suggestion that a second table has been
introduced. The specification makes clear that the inven-
tion is directed to the arrangement of a single, logical
table, particularly, a row defining a column in that same
table. See, e.g., ’604 patent, col. 2, ll. 31–41; id. at col. 2,
ll. 44–52; id. at col. 7 ll. 10–22; id. at Figure 3; see also
Oral Argument at 1:45–2:15; id. at 27:00–29:30. There-
fore, the “at least one of said logical rows” and the “corre-
sponding one of said logical columns” must both be in the
same logical table. 4
    But the district court read the features of claim 31 on
a row from the raw data table and a column from the
pivot table. This fails to show the feature of claim 31
having identical IDs for a row and a column in the same
table. Fundamentally, having a row in one table refer-
ence a column in another table is not a “self-referential”
table at all, but something more like “referential tables”
or “tables that refer to one another.”
    The fact that the raw data table and the pivot table
are present on the same spreadsheet is of no consequence.
The district court appears to have grounded its reasoning



    4   To be clear, we do not hold that the claims are di-
rected exclusively to a database with a single, self-
referential table. Rather, the claims recite a single, self-
referential table, regardless of any other tables that may
be present in the same database.
24                   ENFISH, LLC   v. MICROSOFT CORPORATION



on the fact that the two tables show up together on a
single spreadsheet:




J.A. 7724. But the spreadsheet is no more than the
medium on which the two separate tables are presented.
Two separate tables drawn on one sheet of paper are still
two separate tables.
     Therefore, Excel 5.0 fails to include the claimed single
table having a row defining a column in that same table.
Identification of one element, the row, in one table and
another element, the column, in another table is insuffi-
cient for anticipation. Anticipation requires “that the
reference describe not only the elements of the claimed
invention, but also that it describe those elements ‘ar-
ranged as in the claim[.]’” Net MoneyIN, Inc. v. VeriSign,
Inc., 545 F.3d 1359, 1371 (Fed. Cir. 2008) (quoting Finisar
Corp. v. DirecTV Grp., Inc., 523 F.3d 1323, 1334 (Fed. Cir.
2008)).
    For this reason, the district court erred in granting
summary judgment of anticipation. Given our claim
construction and the disclosure in Excel 5.0, the pivot
table feature of Excel 5.0 does not anticipate claim 31 of
ENFISH, LLC   v. MICROSOFT CORPORATION                   25



the ’604 patent. Claim 32 of the ’604 patent and claims 31
and 32 of the ’775 patent require the same “self-
referencing” feature by way of the matching-ID language.
Therefore, we find that the pivot table feature of Excel 5.0
also does not anticipate those claims.
                             ***
    Enfish encourages us to consider whether Microsoft is
estopped from asserting an Excel 5.0 invalidity defense
due to an inter partes review instituted at the U.S. Patent
and Trademark Office at Microsoft’s request. Because we
find that Excel 5.0 does not anticipate the claims, we see
no reason to address this issue. If on remand the district
court permits a new invalidity contention based on a
different feature of Excel 5.0 or some other related prior
art, then we leave the estoppel issue to the district court
to consider in the first instance.
                             VI
     We now turn to the issue of infringement. The dis-
trict court found that Microsoft’s accused product,
ADO.NET, does not infringe claim 17 of the ’604 patent.
The district court reached this conclusion by finding that
ADO.NET does not perform the “means for indexing”
recited in that claim. Claim 17, in abbreviated form,
recites as follows:
   A data storage and retrieval system for a comput-
   er memory, comprising:
       means for configuring said memory according
   to a logical table . . . and
       means for indexing data stored in said table.
    Enfish raises two arguments against the district
court’s summary judgment of non-infringement: first
against the claim construction for “means for indexing,”
and second for the application of that claim construction
to the ADO.NET product.
26                     ENFISH, LLC   v. MICROSOFT CORPORATION



                               A
    The district court interpreted the “means for index-
ing” under 35 U.S.C. § 112 ¶ 6 (2006). Such a claim
element “shall be construed to cover the corresponding
structure, material, or acts described in the specification
and equivalents thereof.” § 112 ¶ 6. And, as noted above,
“the corresponding structure for a function performed by a
software algorithm is the algorithm itself.” EON, 785 F.3d
at 621. The district court identified the function of the
“means for indexing” as “indexing data stored in the
logical table.” J.A. 270. The district court accepted
Enfish’s proposal of the following algorithm as the corre-
sponding structure:
     1. Extract key phrases or words from the applicable
        cells in the logical table.
     2. Store the extracted key phrases or words in an in-
        dex, which is itself stored in the logical table.
     3. Include, in text cells of the logical table, pointers to
        the corresponding entries in the index, and in-
        clude, in the index, pointers to the text cells.
J.A. 270, 338, 2543–49.
     On appeal, Enfish now contests the district court’s re-
liance on this three-step algorithm as the corresponding
structure for the “means for indexing.” Enfish argues
that it never meant for all three steps to be required, but
instead that some of the steps or parts of the steps may be
optional. Specifically, Enfish argues that the correspond-
ing structure does not necessarily require both “pointers
to the . . . index” and “pointers to the text cells” in step 3,
i.e., “bi-directional” pointers.     Appellant’s Br. 61–63.
Enfish asserts that because the specification shows both
an embodiment with uni-directional pointers and an
embodiment with bi-directional pointers, the district court
erred in identifying the three-step algorithm with bi-
directional pointers as the only corresponding structure.
ENFISH, LLC   v. MICROSOFT CORPORATION                   27



     The district court did not err in its construction. En-
fish’s primary support for its position is the fact that
Figure 11 of the patents shows uni-directional pointers
(i.e., from the index to the text cells), whereas Figure 14
shows bi-directional pointers (i.e., in both directions
between the index and the text cells).




’604 patent, Figure 11 (“TEXT CELLS” and “LIST”
markup our own).




’604 patent, Figure 14 (“TEXT CELLS” and “INDEX”
markup our own). Although Figures 11 and 14 do in fact
illustrate a sort of dichotomy akin to that proffered by
Enfish, the discussion of those figures in the specification
reveals that any such dichotomy is false. The list 250 in
Figure 11 is not an index at all; it is an intermediate
compilation of keyword values used in the process of
forming the index. See generally ’604 patent, col. 12–14.
The specification notes that, even at the stage of forming
list 250, the text cells contain references to the keywords
28                   ENFISH, LLC   v. MICROSOFT CORPORATION



contained therein, in the form of “anchors.” Id. at col. 12
ll. 16–34. When the index is ultimately formed, as illus-
trated in Figure 14, the index entries contain references
to the text cells, and the text cells, through the use of the
anchors, contain references to the index. See id. at col. 14
ll. 10–17. That is, the specification presents Figure 14 as
index entries in the self-referential table that result from
a process that began with the keyword extraction step
illustrated in Figure 11. The figures are not alternative
embodiments.
    Therefore, we find no error in the district court’s use
of Enfish’s own-identified three-step algorithm as the sole
equivalent structure for the “means for indexing.”
                             B
     Using the three-step algorithm, the district court de-
termined that ADO.NET does not perform either step two
or step three. For step two, the district court determined
that there was no genuine issue of fact that ADO.NET
does not store the text value of a keyword in the index,
but rather just a reference to that value. For step three,
the district court determined that there was no genuine
issue of fact that ADO.NET does not store a pointer from
the text value to the index, but stores a pointer to some
other object. Enfish argues that the district court erred in
its findings as to both step two and step three.
    For an accused product to practice a claim element in-
terpreted under § 112 ¶ 6, the accused product must
perform the identical function using an identical or equiv-
alent structure. See Odetics, Inc. v. Storage Tech. Corp.,
185 F.3d 1259, 1267 (Fed. Cir. 1999). Step two requires
storing the “extracted key phrases or words” in an index.
However, as the district court explained, it is uncontested
that ADO.NET does not store the actual text values in the
index, but rather stores references to the cells containing
those text values. J.A. 340–41; Appellant’s Br. 66. Step
three requires including, in the cells with the text values,
ENFISH, LLC   v. MICROSOFT CORPORATION                     29



pointers to the “corresponding entries in the index.”
Again, it is uncontested that ADO.NET does not store
pointers as such. Instead, it stores pointers to other
objects that, by use of a further chain of pointers, may be
resolved to the index. J.A. 341–43; Appellant’s Br. 69.
Therefore, ADO.NET does not use the identical “corre-
sponding structure,” i.e., the three-step algorithm, dis-
closed in the specification.
     As such, ADO.NET can only infringe claim 17 if its
algorithm for performing indexing is an equivalent to the
three-step algorithm identified above. An accused struc-
ture is “equivalent” to a disclosed structure if the differ-
ences between the two are insubstantial. See Odetics, 185
F.3d at 1267. The district court concluded that the failure
to store actual text values in the index (i.e., the difference
at step two) combined with the failure to use pointers
from the text values to the index (i.e., the difference at
step three) render the three-step algorithm and the
ADO.NET indexing algorithm substantially different.
J.A. 343–44. The district court found that at least one
disclosed organization scheme for the index, i.e., alphabet-
ically for fast name searching, may not be possible if the
actual text values are not stored in the index. The district
court found that the bi-directional pointers allow the
performance of associative queries, which the patents
describe as being a key benefit of the invention. On
appeal, Enfish attempts to argue that the differences in
step two and step three do not exist, but fails to explain
how those differences are insubstantial if we agree with
the district court that they do exist, which we do. There-
fore, finding no argument to the contrary, we conclude
that ADO.NET’s indexing algorithm is not an equivalent
of the three-step algorithm of claim 17.
    Because ADO.NET does not use the identical or
equivalent structure as disclosed in the patents for the
“means for indexing,” we find that ADO.NET does not
infringe claim 17.
30                   ENFISH, LLC   v. MICROSOFT CORPORATION



                           VII
    Based on the foregoing, we reverse the district court’s
grant of summary judgment based on § 101 and conclude
that all five claims on appeal are patent-eligible. We
vacate the district court’s grant of summary judgment
based on § 102 and conclude that both pairs of claims 31
and 32 are not anticipated by Excel 5.0 pivot tables.
Lastly, we affirm the district court’s grant of summary
judgment of non-infringement and conclude that
ADO.NET does not infringe claim 17. We remand the
case to the district court for further proceedings.
      REVERSED-IN-PART, VACATED-IN-PART,
       AFFIRMED-IN-PART, AND REMANDED
     No costs.
