  United States Court of Appeals
      for the Federal Circuit
               ______________________

       PAPST LICENSING GMBH & CO. KG,
                  Appellant

                          v.

    SAMSUNG ELECTRONICS AMERICA, INC.,
      SAMSUNG ELECTRONICS CO., LTD.,
                   Appellees
            ______________________

                     2018-1777
               ______________________

    Appeal from the United States Patent and Trademark
Office, Patent Trial and Appeal Board in No. IPR2016-
01733.
                 ______________________

                Decided: May 23, 2019
               ______________________

   GREGORY S. DONAHUE, DiNovo Price LLP, Austin, TX,
argued for appellant. Also represented by NICOLE E.
GLAUSER, CHRISTOPHER V. GOODPASTOR.

   PATRICK J. KELLEHER, Drinker Biddle & Reath LLP,
Chicago, IL, argued for appellees. Also represented by
CARRIE ANNE BEYER; NIKOLA COLIC, Washington, DC.
                ______________________

    Before DYK, TARANTO, and CHEN, Circuit Judges.
2   PAPST LICENSING GMBH & CO. KG v. SAMSUNG ELECTRONICS
                                                 AMERICA


TARANTO, Circuit Judge.

    Papst Licensing GMBH & Co. KG owns U.S. Patent No.
9,189,437. Samsung Electronics America, Inc. and Sam-
sung Electronics Co., Ltd. (collectively, Samsung) success-
fully petitioned the Patent Trial and Appeal Board of the
U.S. Patent and Trademark Office to institute an inter
partes review (IPR) of all claims of the ’437 patent. In its
final written decision, the Board determined that claims 1–
38 and 43–45 are unpatentable for obviousness based on a
combination of U.S. Patent No. 5,758,081 (Aytac), a publi-
cation setting forth standards for the Small Computer Sys-
tem Interface-2 (SCSI), and “admitted prior art” (what the
’437 patent specification describes as prior art). Samsung
Electronics Co., Ltd. v. Papst Licensing GmbH & Co. KG,
No. IPR2016-01733, 2018 WL 813014 (P.T.A.B. Feb. 2,
2018) (’437 Patent Decision). Papst appeals. We affirm,
relying in the alternative on issue preclusion and our re-
view of the merits of Papst’s challenges.

                             I

                             A
    The ’437 patent is entitled “Analog Data Generating
and Processing Device Having a Multi-Use Automatic Pro-
cessor” and names Michael Tasler as the sole inventor. Is-
sued in 2015, it claims priority to a 1999 application
through continuations of applications that issued as U.S.
Patent Nos. 6,470,399 and 6,895,449, which are owned by
Papst and were before this court in Papst Licensing GmBH
& Co. v. Fujifilm Corp., 778 F.3d 1255 (Fed. Cir. 2015). Of
significance here, that same specification also gave rise to
Papst’s U.S. Patent Nos. 8,966,144 and 8,504,746.
    The specification describes an interface device for com-
munication between a data device (on one side of the inter-
face) and a host computer (on the other). The interface
device achieves high data transfer rates, without the need
PAPST LICENSING GMBH & CO. KG v. SAMSUNG ELECTRONICS         3
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for a user-installed driver specific to the interface device,
by using fast drivers that are already standard on the host
computer for data transfer, such as a hard-drive driver.
’437 patent, col. 2, lines 4–29; id., col. 3, lines 10–40. The
interface device signals to the host device that the interface
device is an input/output device for which the host already
has such a driver. Id., Abstract.
    Claim 1 is illustrative for present purposes. It recites:
    1. An analog data generating and processing de-
    vice (ADGPD), comprising:
    an input/output (i/o) port;
    a program memory;
    a data storage memory;
    a processor operatively interfaced with the i/o port,
    the program memory and the data storage
    memory;
    wherein the processor is adapted to implement a
    data generation process by which analog data is ac-
    quired from each respective analog acquisition
    channel of a plurality of independent analog acqui-
    sition channels, the analog data from each respec-
    tive channel is digitized, coupled into the processor,
    and is processed by the processor, and the pro-
    cessed and digitized analog data is stored in the
    data storage memory as at least one file of digitized
    analog data;
    wherein the processor also is adapted to be in-
    volved in an automatic recognition process of a
    host computer in which, when the i/o port is opera-
    tively interfaced with a multi-purpose interface of
    the host computer, the processor executes at least
    one instruction set stored in the program memory
    and thereby causes at least one parameter identi-
    fying the analog data generating and processing
4   PAPST LICENSING GMBH & CO. KG v. SAMSUNG ELECTRONICS
                                                 AMERICA


    device, independent of analog data source, as a dig-
    ital storage device instead of an analog data gener-
    ating and processing device to be automatically
    sent through the i/o port and to the multi-purpose
    interface of the computer (a) without requiring
    any end user to load any software onto the
    computer at any time and (b) without requiring
    any end user to interact with the computer to set
    up a file system in the ADGPD at any time,
    wherein the at least one parameter is consistent
    with the ADGPD being responsive to commands is-
    sued from a customary device driver;
    wherein the at least one parameter provides infor-
    mation to the computer about file transfer charac-
    teristics of the ADGPD; and
    wherein the processor is further adapted to be in-
    volved in an automatic file transfer process in
    which, when the i/o port is operatively interfaced
    with the multi-purpose interface of the computer,
    and after the at least one parameter has been sent
    from the i/o port to the multi-purpose interface of
    the computer, the processor executes at least one
    other instruction set stored in the program memory
    to thereby cause the at least one file of digitized an-
    alog data acquired from at least one of the plurality
    of analog acquisition channels to be transferred to
    the computer using the customary device driver for
    the digital storage device while causing the analog
    data generating and processing device to appear to
    the computer as if it were the digital storage device
    without requiring any user-loaded file trans-
    fer enabling software to be loaded on or in-
    stalled in the computer at any time.
Id., col. 11, line 56 through col. 12, line 42 (emphases
added).
PAPST LICENSING GMBH & CO. KG v. SAMSUNG ELECTRONICS            5
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                                B
     After Papst sued several companies for infringement of
various patents in the Tasler family, including the ’437 pa-
tent, various combinations of companies filed numerous pe-
titions for IPRs to review many claims of the patents.
Samsung requested the present IPR, which the Board in-
stituted on February 8, 2017.
     The key piece of prior art of relevance is the Aytac pa-
tent. Aytac describes connecting a personal computer to an
interface device that would in turn connect to (and switch
between) various other devices, such as a scanner, fax ma-
chine, or telephone. The interface device includes the
“CaTbox,” which is “connected to a PC via SCSI cable, and
to a telecommunications switch.” Aytac, Abstract. CaTbox
“runs an operating system, CaTOS, and contains a hard
disk” accessible “as a SCSI disk” known as “CaTdisc.” Id.;
id., col. 8, line 63 through col. 9, line 4; Figure 1. While the
main PC is off, CaTbox, which uses less energy, “receives
faxes, voicemail, email and stores them on CaTdisc.” Id.,
Abstract. Aytac points to SCSI as performing some of the
functions involving the CaTdisc in the overall CaTbox sys-
tem. See, e.g., id.; id., col. 8, lines 1−14, col. 10, lines 8−12,
36−37, 52−58; Figure 1. Papst explains in this court that
“[t]he ’437 Patent indicates that SCSI interfaces and SCSI
drivers were known in the art at the time of the invention.
SCSI interfaces were present on most host devices or lap-
tops, and SCSI drivers were ‘normally included by the
manufacturer of the multi-purpose interface.’” Papst Br.
at 13 (citations omitted).
    In its determination of obviousness, the Board adopted
a claim construction that is central to Papst’s appeal.
Claim 1 requires an automatic recognition process to occur
“without requiring any end user to load any software onto
the computer at any time” and an automatic file transfer
process to occur “without requiring any user-loaded file
transfer enabling software to be loaded on or installed in
6    PAPST LICENSING GMBH & CO. KG v. SAMSUNG ELECTRONICS
                                                  AMERICA


the computer at any time.” See also ’437 patent, col. 17,
lines 9–10 (“without requiring the user to load the device
driver”). The Board interpreted the “without requiring”
limitations to mean “without requiring the end user to in-
stall or load specific drivers or software for the ADGPD be-
yond that included in the operating system, BIOS, or
drivers for a multi-purpose interface or SCSI interface.”
’437 Patent Decision at *6. In adopting that construction,
the Board made clear that SCSI interface drivers are
among those that can be required to be installed for the
processes to occur, relying on the specification and claims
as making clear that the invention contemplates use of
SCSI drivers to carry out the processes. See id. at *5−*6.
The Board also rejected Papst’s contention that “the ‘with-
out requiring’ limitations prohibit an end user from in-
stalling or loading other drivers.” Id. at *6. Relying on
Celsis In Vitro, Inc. v. CellzDirect, Inc., 664 F.3d 922,
926−27 (Fed. Cir. 2012), the Board concluded that “[t]he
claim language, under a plain reading, means that the end
user is ‘not required’ to load or install the recited software
for transferring a file or recognizing a device,” but the lan-
guage “does not prohibit the end user” from doing so. Id.
“[I]f the software is not required [for the claimed function],
then it does not matter whether the end user loaded or in-
stalled the software.” Id. 1



    1   Papst mentions one other claim-construction issue
in this court—whether “end user” encompasses a system
administrator. The Board, having addressed the issue in
instituting the IPR, declined to resolve it in its final written
decision, explaining that the patentability issue “turns on
the question of whether software need be installed at all,
not on whether the installation is done by an end user or
not.” ’437 Patent Decision at *6−*7. Papst has identified
no way in which the dispute over the “end user” construc-
tion affects the unpatentability ruling of the Board, but it
PAPST LICENSING GMBH & CO. KG v. SAMSUNG ELECTRONICS         7
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    Regarding the application of the construed claim lan-
guage to the prior art, there is no material issue before us
about the motivation to combine the three prior-art
sources—Aytac, SCSI, and admitted prior art. As already
noted, Aytac expressly refers to SCSI. The sole issue on
which this appeal turns concerns what Aytac teaches about
the host computer’s ability to use the SCSI driver, even
without additional CaTbox software, to accomplish an au-
tomatic file transfer.
    The Board found that Aytac does teach that the auto-
matic file transfer can take place using only the PC-
resident SCSI drivers. Id. at *13−*16. The Board noted
that Papst’s argument relied on the presence of CATSYNC
software in the CaTbox system together with the conten-
tion that the claim language prohibits user loading of any
other software. Id. at *14. The Board, having already re-
jected the “prohibits” claim construction, found that, alt-
hough CATSYNC is used for some purposes (such as
synchronizing different demands for access to the CaTdisc),
Aytac teaches that an automatic file transfer can indeed
occur using only the SCSI drivers, without use of
CATSYNC. The Board recited supporting material from
Aytac as well as supporting testimony, from Samsung’s ex-
pert and from Papst’s own expert. Id. at *13−*15.
    The Board also agreed with Samsung’s showing that
Aytac teaches a process of automatic recognition that could
occur using only the SCSI drivers, without additional user-
installed CaTbox software. Id. at *13−*14. The Board’s
discussion of that issue is abbreviated; specifically, there is
no counterpart for the recognition-process issue to the
Board’s extended discussion of the arguments Papst made


asks this court to rule on the proper construction anyway.
Papst Br. at 30. We decline to do so, seeing no impact on
the correctness of the Board’s unpatentability determina-
tion.
8   PAPST LICENSING GMBH & CO. KG v. SAMSUNG ELECTRONICS
                                                 AMERICA


regarding the file transfer process. Id. at *14−*16. Papst
made few arguments to the Board concerning the recogni-
tion process. Of particular importance, Papst did not make
the argument that it makes to this court on that issue.
    For those reasons, the Board found that Aytac in fact
teaches the claim elements in dispute. Upon completion of
additional claim and prior-art analysis not at issue in this
appeal, the Board ultimately determined that claims 1–38
and 43–45 (but not 39–42) of the ’437 patent are unpatent-
able for obviousness in view of Aytac, SCSI, and the admit-
ted prior art. Id. at *22. Papst appealed.
                              C

      Several other inter partes reviews and corresponding
appeals are relevant to this proceeding. In particular, six
weeks before the Board rendered its ’437 Patent Decision,
the Board rendered final written decisions in two other
IPRs (requested by Samsung among other petitioners) in-
volving two other Papst-owned patents mentioned above,
i.e., the ’144 patent and the ’746 patent, which share a spec-
ification with the ’437 patent and contain claim terms re-
lated to those involved in the disputes before us. In the two
Board decisions of importance regarding those patents, as
in the ’437 Patent Decision here on appeal, the Board found
unpatentability based on Aytac, SCSI, and the admitted
prior art. Canon Inc. v. Papst Licensing GmbH & Co. KG,
No. IPR2016-01199, 2017 WL 6345414 (P.T.A.B. Dec. 11,
1017) (’144 Patent Aytac Decision); Canon Inc. v. Papst Li-
censing GmbH & Co. KG, No. IPR2016-01200, 2017 WL
6343591 (P.T.A.B. Dec. 11, 2017) (’746 Patent Aytac Deci-
sion).

    Papst appealed those decisions, along with the ’437 Pa-
tent Decision, and those appeals (together with still others)
were fully briefed and set to be orally argued before this
panel on the same day. Shortly before the argument, Papst
voluntarily dismissed its appeals from the ’144 Patent
PAPST LICENSING GMBH & CO. KG v. SAMSUNG ELECTRONICS        9
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Aytac Decision and the ’746 Patent Aytac Decision. Those
decisions therefore became final. See Martin v. Dep’t of
Justice, 488 F.3d 446, 451–52, 454–55 (D.C. Cir. 2007) (vol-
untary dismissal of appeal creates preclusion based on the
predicate opinion); 18A Charles A. Wright., et al., Federal
Practice and Procedure § 4433 (2d ed. 2002).

                              II
     Papst makes three arguments on appeal. See also su-
pra note 1 (noting the “end user” claim-construction argu-
ment we do not address). First, it challenges the Board’s
construction of the “without requiring” claim limitations as
meaning that the claimed processes can take place with
only SCSI software (or other multi-purpose interface soft-
ware or software included in the operating system or
BIOS), without other user-added software. Second, Papst
challenges, as not supported by substantial evidence, the
Board’s finding that Aytac teaches an automatic file trans-
fer that can take place with only the SCSI drivers, without
the assistance of the user-added CATSYNC software.
Third, Papst challenges the Board’s finding that Aytac like-
wise teaches an automatic recognition process that uses
only SCSI rather than requiring additional software.
    As an initial matter, we hold that the third challenge
has not been preserved. The argument Papst now makes
on this point is that SCSI itself does not allow the CaTbox
to send a signal that it is a hard disk because, under the
SCSI standard, the CaTbox would send an “unknown”
(“1Fh”) identifier rather than a hard drive (“00h”) identifier
in response to an INQUIRY signal. But this factual con-
tention did not appear until the appeal, and such a conten-
tion is forfeited if not fairly presented to the Board. See In
re NuVasive, Inc., 842 F.3d 1376, 1380 (Fed. Cir. 2016).
    Papst has not shown where it presented this contention
to the Board. It cites a portion of the SCSI specification,
see Papst Reply Br. at 16 (citing J.A. 532–36), but it does
not cite any place in its Board filings or arguments where
10   PAPST LICENSING GMBH & CO. KG v. SAMSUNG ELECTRONICS
                                                  AMERICA


it mentioned a 1Fh signal or made its current point about
the cited SCSI specification passage. In the portion of the
Patent Owner Response addressing the “automatic recog-
nition process” limitation, Papst focused on its “end user”
argument, see J.A. 2234–35, which is a different point (and
not material to the outcome here, see supra note 1). Nei-
ther the petitioners nor the Board had fair notice of a con-
tention that SCSI would not permit the CaTbox to identify
itself as a hard drive. Accordingly, Papst failed to preserve
this argument for appeal. See NuVasive, 842 F.3d at 1380–
81.
    We therefore have before us only two arguments for up-
setting the ’437 Patent Decision. We reject those argu-
ments for two reasons: they are barred by issue preclusion,
and they fail on their merits.
                              A
    The Supreme Court has made clear that, under speci-
fied conditions, a tribunal’s resolution of an issue that is
only one part of an ultimate legal claim can preclude the
loser on that issue from later contesting, or continuing to
contest, the same issue in a separate case. Thus:
     subject to certain well-known exceptions, the gen-
     eral rule is that “[w]hen an issue of fact or law is
     actually litigated and determined by a valid and fi-
     nal judgment, and the determination is essential to
     the judgment, the determination is conclusive in a
     subsequent action between the parties, whether on
     the same or a different claim.”
B & B Hardware, Inc. v. Hargis Indus., Inc., 135 S. Ct.
1293, 1303 (2015) (quoting Restatement (Second) of Judg-
ments § 27, then referring to exceptions stated in § 28); see,
e.g., Ohio Willow Wood Co. v. Alps S., LLC, 735 F.3d 1333,
1342 (Fed. Cir. 2013); Levi Strauss & Co. v. Abercrombie &
Fitch Trading Co., 719 F.3d 1367, 1371 (Fed. Cir. 2013);
PAPST LICENSING GMBH & CO. KG v. SAMSUNG ELECTRONICS      11
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Stephen Slesinger, Inc. v. Disney Enters., Inc., 702 F.3d
640, 644 (Fed. Cir. 2012).
    The Supreme Court also has made clear that issue-pre-
clusion principles apply in a court case even when the first
“action” was before an agency if the agency proceeding
meets certain standards. B & B Hardware, 135 S. Ct. at
1303. Following the Supreme Court’s conclusion in B & B
Hardware that those standards are met by certain adver-
sary proceedings before the Trademark Trial and Appeal
Board, we have held that the same is true of an IPR pro-
ceeding before the Patent Trial and Appeal Board, so that
the issue preclusion doctrine can apply in this court to the
Patent Trial and Appeal Board’s decision in an IPR once it
becomes final. MaxLinear, Inc. v. CF CRESPE LLC, 880
F.3d 1373, 1376 (Fed. Cir. 2018); see XY, LLC v. Trans Ova
Genetics, 890 F.3d 1282, 1294 (Fed. Cir. 2018); Nestle USA,
Inc. v. Steuben Foods, Inc., 884 F.3d 1350, 1351 (Fed. Cir.
2018). 2
    We first indicate why Papst has not justified denying
issue preclusion in this case if the above-quoted standards
are met. We then find those standards met here, so issue
preclusion applies.




    2    The Supreme Court and this court have approved
“non-mutual” issue preclusion—the label assigned when
the loser in the first case is precluded from relitigating an
issue even in a later action that does not involve its first-
case adversary. See Blonder-Tongue Labs., Inc. v. Univer-
sity of Illinois Foundation, 402 U.S. 313, 349–50 (1971);
XY, 890 F.3d at 1295. The present case involves “mutual”
issue preclusion because Samsung and Papst were adverse
not only in this case but in the IPRs decided in the ’144
Patent Aytac Decision and the ’746 Patent Aytac Decision.
12   PAPST LICENSING GMBH & CO. KG v. SAMSUNG ELECTRONICS
                                                  AMERICA


                              1
    Papst has advanced no persuasive reason for an excep-
tion to applying the above-quoted conditions for issue pre-
clusion in this case. Papst cites Worlds Inc. v. Bungie, Inc.,
903 F.3d 1237 (Fed. Cir. 2018), but all we did there was
remand on issue preclusion because the record before the
court was too scant for the panel to decide if issue preclu-
sion existed. Id. at 1247. Here, as we will discuss, we can
decide that issue preclusion exists. Papst also cites In re
Cygnus Telecommunications Technology, LLC, Patent Liti-
gation, 536 F.3d 1343 (Fed. Cir. 2008), but there we held
only that an accepted rule—that issue preclusion does not
apply within the confines of the single case formed when
multiple cases are formally consolidated—also applies in
the context of cases formally consolidated for pre-trial pur-
poses through the multi-district-litigation process. See id.
at 1349–50. Here, there was no comparable consolidation;
these were distinct “cases” separately resolved.
    The Supreme Court in B & B Hardware noted as a gen-
eral matter that the Restatement standards allow for some
exceptions to issue preclusion even when the above-quoted
conditions are met. 135 S. Ct. at 1303, 1309−10. The Court
specifically recognized that “[i]ssue preclusion may be in-
apt if ‘the amount in controversy in the first action [was] so
small in relation to the amount in controversy in the second
that preclusion would be plainly unfair.” Id. at 1309 (quot-
ing Restatement (Second) of Judgments § 28, cmt. j). The
Court added: “After all, ‘[f]ew . . . litigants would spend
$50,000 to defend a $5,000 claim.” Id. (quoting Wright &
Miller § 4423, at 612); see Kroeger v. U.S. Postal Service,
865 F.2d 235, 239−40 (Fed. Cir. 1988); Marciel v. Comm’r,
489 F.3d 1018, 1023 (9th Cir. 2007); United States v. Ber-
man, 884 F.2d 916, 922 (6th Cir. 1989); Ferrell v. Pierce,
785 F.2d 1372, 1385 (7th Cir. 1986).
    But Papst has not justified denying issue preclusion
here if the basic conditions set out in the above block quote
PAPST LICENSING GMBH & CO. KG v. SAMSUNG ELECTRONICS        13
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from B & B Hardware are met. Papst has not asserted in-
adequate representation or an impaired opportunity to lit-
igate in the IPRs involving the ’144 patent and the ’746
patent. See Soverain Software LLC v. Victoria’s Secret Di-
rect Brand Mgt., LLC, 778 F.3d 1311, 1315−16 (Fed. Cir.
2015) (discussing such grounds for denying preclusive ef-
fect). Nor has Papst presented, let alone supported, any
allegation of a legally significant disparity in incentives be-
tween the present IPR and the two other Aytac-based IPRs
at issue. Papst is in no position now to say that the litiga-
tion costs in those other two IPRs were not worth incurring.
After all, Papst litigated all the way through to final writ-
ten decisions—rather than, for example, disclaim the chal-
lenged patent claims in the ’144 patent and the ’746 patent
IPRs before the Board reached final written decisions.
Papst then litigated all the way up to the eve of oral argu-
ment in this court. Such pursuit through nearly all of the
available process undermines any assertion of relevantly
low incentives in the IPRs involving Aytac and the ’144 pa-
tent and ’746 patent.
    More generally, given the heavy burdens that Papst
placed on its adversaries, the Board, and this court by wait-
ing so long to abandon defense of the ’144 patent and ’746
patent claims, Papst’s course of action leaves it without a
meaningful basis to argue for systemic efficiencies as a pos-
sible reason for an exception to issue preclusion. Papst also
has no basis to argue that it tried unsuccessfully to secure
an agreement, from Samsung or other petitioners (in this
IPR or others), for efficiency-enhancing multi-case-man-
agement steps: it did not even ask its adversaries to waive
reliance on preclusion. In noting these circumstances, we
do not address what if any ultimate legal relevance differ-
ent circumstances might have in justifying an exception to
the important policy of issue preclusion.
14   PAPST LICENSING GMBH & CO. KG v. SAMSUNG ELECTRONICS
                                                  AMERICA


                             2
    We now apply to this case the basic conditions for issue
preclusion quoted above. To avoid redundancy, we discuss
only the ’144 Patent Aytac Decision. We readily conclude
that the conditions for issue preclusion are met. The ’144
Patent Aytac Decision resolved against Papst the claim-
construction and Aytac-teaching issues now before us, and
those resolutions were essential to the Board’s decision.
    The ’437 patent claims at issue recite a processor
adapted for an “automatic file transfer process . . . without
requiring any user-loaded file transfer enabling software to
be loaded on or installed in the computer.” ’437 patent, col.
12, lines 28–42. The core claim-construction issue is
whether the “without requiring” language prohibits end-
user-loaded software from ever playing a role in the process
or whether it simply means that no such software is needed
for the process to occur, so that it can occur without such
software. A secondary claim-construction issue is whether
SCSI software was properly included in the list of software
(along with operating system, BIOS, and other multi-pur-
pose interface software) whose use can be required. The
prior-art issue is whether Aytac teaches that performance
of the process is possible without the CaTbox software,
through SCSI software (or other software already on the
computer) alone.
    The ’144 patent recites a materially identical “without
requiring” limitation. ’144 patent, col. 12, lines 25–35 (“an
automatic file transfer process . . . without requiring any
user-loaded file transfer enabling software to be loaded on
or installed in the computer at any time”). The Board in
the ’144 Patent Aytac Decision resolved the same claim-con-
struction issue in the same way as the Board in the present
IPR. It characterized “the issue in dispute” as “center[ing]
on whether the ‘without requiring’ limitations prohibit an
end user from installing or loading other drivers.” ’144 Pa-
tent Aytac Decision at *7. “The claim language,” the Board
PAPST LICENSING GMBH & CO. KG v. SAMSUNG ELECTRONICS      15
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held, “does not prohibit the end user from ever installing or
loading the recited software.” Id. (emphasis in original).
The Board also ruled that use of SCSI software does not
violate the “without requiring” limitations, because the pa-
tent clearly shows that such software may be used. See id.
at *6−*7. That ruling was not just materially identical to
the Board’s claim-construction ruling in this case; it also
was essential to the Board’s ultimate determination, which
depended on finding that the installation of CATSYNC, as
disclosed in Aytac, was not prohibited by the ’144 patent’s
“without requiring” limitation and that Aytac taught that
the transfer process could be performed with SCSI soft-
ware. See id. at *16–*18.
    The Board in the ’144 Patent Aytac Decision also made
the same finding about Aytac’s teaching that the Board
made in the present matter. It found that, in Aytac, “the
ASPI drivers are the only file transfer enabling software
needed for transferring a file to the host computer.” Id. at
*17 (emphasis added). The other elements of the CaTbox
software, such as CATSYNC, “merely provide additional
functionalities,” which Papst’s expert “confirms in his
cross-examination testimony that the claims at issue do not
require.” Id. at *16. On that basis the Board found that
Aytac, in combination with the SCSI Specification and ad-
mitted prior art, “teaches or suggests transferring a file
from the storage memory of the interface device to the com-
puter without requiring any user-loaded file transfer ena-
bling software.” Id. at *18. This finding was essential to
the Board’s decision.
   Issue preclusion therefore applies to the only two is-
sues properly preserved for and presented on appeal. The
Board’s decision is affirmed on that basis.
                             B
    We think that the conclusion of issue preclusion here is
clear, based on application of general doctrinal principles
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to the facts. We also confirm that Papst’s challenges fail
on the merits, even apart from issue preclusion.
    We review the Board’s factual findings in an inter
partes review for substantial evidence and its legal conclu-
sions de novo. See Arendi S.A.R.L. v. Apple, Inc., 832 F.3d
1355, 1360 (Fed. Cir. 2016). Substantial evidence means
“such relevant evidence as a reasonable mind might accept
as adequate to support a conclusion.” In re Mouttet, 686
F.3d 1322, 1331 (Fed. Cir. 2012). As to claim construction,
the Board saw no difference relevant to the issues here be-
tween identifying the best construction and identifying the
broadest reasonable construction, and the parties have
identified no difference either. See 37 C.F.R. § 42.100(b).
    The Board’s conclusion regarding the construction of
the “without requiring” limitations of the ’437 patent
claims is correct. To state that a process can take place
“without requiring” a particular action or component is, by
the words’ ordinary meaning as confirmed in Celsis In
Vitro, to state simply that the process can occur even
though the action or component is not present; it is not to
forbid the presence of the particular action or component.
664 F.3d at 926−27 (“‘without requiring’ means simply that
the claim does not require the [recited] step”; “performance
of that step does not preclude a finding of infringement”).
We therefore agree with the Board on the claim-construc-
tion issue the Board identified as the key one.
    We also agree with the Board’s inclusion of SCSI inter-
face software in the claim construction as a form of permit-
ted software. The specification is decisive. Reflecting the
recognition that SCSI interfaces were “present on most
host devices or laptops” at the time, ’437 patent, col. 8, lines
45−46—which the experts agreed was so, see J.A. 281,
2675, 2402—the specification explains that the invention
contemplates use of SCSI software, see ’437 patent, col. 3,
lines 53−55, 59−64 (Summary of the Invention notes that
SCSI interface is one implementation of a multi-purpose
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interface and states: “Communication between the host de-
vice and the devices attached to the multi-purpose inter-
face then essentially takes place by means of the specific
driver software for the multi-purpose interface and no
longer primarily by means of BIOS routines of the host de-
vice.”); id., col. 10, lines 23−29 (“As described above, com-
munications between the host device and the multi-
purpose interface can take place . . . via specific interface
drivers which, in the case of SCSI interfaces, are known as
multi-purpose interface ASPI (advanced SCSI program-
ming interface) drivers.”); see id., col. 11, lines 14−37. And
claim 21, depending on claim 1, requires a SCSI driver to
issue a SCSI INQUIRY command. Id., col. 13, lines 64−67.
     Finally, we see no reversible error in the Board’s reso-
lution of the crucial factual issue of what Aytac teaches. In
particular, we conclude that substantial evidence supports
the Board’s finding that a relevant skilled artisan would
understand that Aytac’s CaTbox can perform an automatic
file transfer using SCSI without the CATSYNC software
that Papst says is required.
    Aytac teaches that CaTbox is seen by the linked com-
puter as “a SCSI disk, a print server, a remote mo-
dem . . . and a remote fax device.” Aytac, col. 10, lines 27–
32. CaTbox provides “a SCSI hard disk (CaTdisc),” along
with other functions, to the host PC. Id. col. 10, lines 36–
40. Aytac describes CaTbox’s operation using ASPI (ad-
vanced SCSI programming interface) software as follows:
    On the PC 101 side, Windows 95 520 provides the
    operating system. An ASPI driver such as
    ASPI2DOS.SYS 521 from Adaptec corporation pro-
    vides the SCSI interface layer to all LUNs [logical
    unit numbers] on CaTbox 102 SCSI node, as well
    as other SCSI nodes. Another driver from Adaptec
    Corporation, such as ASPIDISK.SYS 522 provides
    the disk driver. This driver utilizes the logical con-
    nection 550. In tandem with this driver, a virtual
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     device driver called CATSYNC.VXD 523 imple-
     ments the synchronization between the operating
     system of PC 101 and that of CaTbox 102 that ac-
     cess the same CaTdisc 301. The virtual device
     driver    utilizes   logical    connection      554.
     CATSYNC.VXD 523 hooks the File I/O calls from
     the PC operating system (in this case Windows 95
     520) and replaces the original call with the follow-
     ing:
        if File I/O for CaTdisc
        notify CaTdisc of beginning of File I/O re-
        ceive acknowledgement
        flush File I/O caches for CaTdisc
        make the intended File I/O call (LUN=0)
        notify CaTdisc of end of File I/O
Id. col. 10, line 53 through col. 11, line 5.
    The Board had substantial evidence on which to find
that Aytac’s description would be understood by a skilled
artisan to teach that CATSYNC and its call-hooking func-
tionality are not necessary to a file transfer process. Sam-
sung’s expert Dr. Reynolds testified that only the SCSI
protocol and the ASPI drivers are needed to transfer a file
in Aytac, similar to the function of the ’437 patent. ’437
Patent Decision at *15. Dr. Reynolds also testified that
CATSYNC is ‘“intended only to provide synchronization
and coordination among multiple on-going activities be-
tween the host computer and the CaTbox/CaTdisk,’ and
this driver is not required for reading data files from the
CaTdisc because, if it were not installed, the host com-
puter’s requests to READ files would default to LUN 0, the
logical unit number for the CaTdisc.” Id. (emphasis in orig-
inal); see J.A. 2406−10. And Mr. Gafford, Papst’s expert,
wrote that ‘“CaTbox would reliably transfer good data’
when acting as ‘a remote hard disc for the PC.’” ’437 Patent
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Decision at *14 (quoting J.A. 2283−84). On this record, we
cannot find a lack of substantial-evidence support for the
Board’s finding that Aytac teaches the claim limitations at
issue.
                            IV
   The final written decision of the Board is affirmed.
                      AFFIRMED
