EMC Corp. v. Pure Storage, Inc. (154 F. Supp. 3d 81, 2016)

United States District Court for the District of Delaware 2016-02-11

Citations

Full opinion text

MEMORANDUM OPINION

ANDREWS, UNITED STATES DISTRICT JUDGE:

Before the Court are various motions filed by Defendant Pure Storage, Inc. (“Pure”) and by Plaintiffs EMC Corporation, EMC International Company, and EMC Information Systems ■ International (collectively, “EMC”). Pure brings three separate motions presently under -consideration: Motion for Summary Judgment (D.I. 198) and related briefing (D.I. 199, 258, 298); Motion to Exclude Expert Opinions and Testimony (D.I. 204) and related briefing (D.I. 205, 240, 296); and Motion to Strike Untimely Evidence and Expert Opinions (D.I. 302), related briefing (D.I. 303, 321, 324), and related letters (D.I. 345, 347). EMC brings four separate motions presently under consideration: Motion for Partial Summary Judgment, and to Exclude Expert Testimony, Regarding Pure Storage’s Hypothetical Non-Infringing Alternatives (D.I. 206) and related briefing (D.I. 207, 243, 292); Motion to Exclude Certain Opinions of Dr. James Plank (D.I. 211) and related briefing (D.I. 212, 255, 294); Motion for Summary Judgment of Direct Infringement of Claims 1, 7, and 16 of U.S. Patent No. 7,434,015 (D.I. 214) and related briefing (D.I. 215, 252, 300); and Motion for Leave .to File Sur-Reply in Opposition- to Motion for Summary Judgment of Invalidity of U.S. Patent No. 7,434,015. (D.I. 317) and Pure’s response (D.I. 326). The Court heard oral argument on Deeembér 14, 2015. (D.I. 327).

For the reasons that follow: Pure’s motion for summary judgment (D.I. 198) is GRANTED IN PART and DENIED IN PART. Summary judgment is DENIED with respect to non-infringement of the asserted claims of the ’464 and ’556 patents and invalidity of the ’015 and ’556 patents. Summary judgment is GRANTED with respect to non-infringement of the .asserted claims of the ’187 patent. Pure’s motion to exclude opinions and testimony of EMC’s ’464 patent infringement expert (D.I. 204) is DENIED. Pure’s motion to strike evidence and expert opinions regarding EMC’s attempt to swear behind the Krapp reference (D.I. 302) is DENIED. Pure’s motion to exclude opinions and testimony of EMC’s damages expert (D.I. 204) is DENIED. EMC’s motion for summary judgmént of direct infringement of claims 1, 7, and 16 of the ’015 patent (D.I. 214) is GRANTED. EMC’s motion for leave to file a sur-reply (D.I. 317) is GRANTED. EMC’s motion to exclude certain opinions of Pure’s ’556 patent expert (D.I. 211) is GRANTED IN PART and DENIED IN PART.- EMC’s motion for partial summary judgment and to exclude expert testimony regarding Pure’s non-infringing alternatives (D.I. 206) is DENIED.

I. BACKGROUND

EMC Corporation filed a complaint on November 26, 2013 alleging that Pure infringed U.S. Patent Nos. 6,904,556 (“the ’556 patent”); 7,373,464 (“the ’464 patent”); 7,434,015 (“the ’015 patent”); and 8,375,187' (“the ’187 patent”). (D.I. 1); On June 6, 2014, EMC filed an amended complaint, joining EMC International Company, and EMC Information Systems International- as plaintiffs. (D.I. 37). EMC is seeking injunctive and equitable relief and damages in the form of reasonable royalties and lost profits. (D.I. '37 at 14-15). Pure answered the aménded complaint on June 13, 2014. (D.I. 38). The Court held a Markmdn hearing on December 16, 2014 (D.I. 108) and subsequently issued a claim construction rilling (D.I. 115, 121). It became apparent at the December 14, 2015 hearing on the motions presently under consideration that the parties’ disputes with regard to certain of these motions related to their disagreement regarding the scope of several claim terms. (D.I. 327 at 125-37). The parties thereafter submitted supplemental claim construction briefing on those - terms. (D.I.332, 333, 334, 335). The Court heart oral argument on the supplemental claim construction on January 8, 2016 (D.I. 353) and issued an opinion on February 2, 2016 (D.I. 362). -

The motions under consideration-raise .infringement and validity issues with respect to the asserted ’464,’015, . ’556 and ’187 patents. The ’464 and ’015 patents disclose systems and methods for providing efficient data storage that eliminate, redundancy using deduplication techniques. (D.I. 92 at 18, 19; see ’464 patent, 1:19-21; ’015 patent, 1:18-20). Deduplication reduces the demand, for storage space in a data storage system by ensuring that only a single copy of unique data is stored. (D.I. 215 at 10). The ’556 patent discloses systems and methods of data storage involving parity-based fault tolerance techniques. (’556 patent, 1:6-8). The ’187 patent discloses apparatuses and methods related to scheduling data transfers to and from data storage devices in flash-based data storage' systems. '(’187 patent, 1:5-7).

II. LEGAL STANDARDS

A. Summary Judgment

“The court shall grant summary judgment if the movant shows that 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). The moving. party has the initial burden of proving the absence of a genuinely disputed material fact relative to the claims in question. Celotex Corp. v. Catrett, 477 U.S. 317, 330, 106 S.Ct. 2548, 91 L.Ed.2d 265 (1986). Material facts are'those “that could affect the outcome” of the proceeding, and “a dispute about a material fact is ‘genuine’ if the evidence is sufficient to permit a reasonable jury -to return a verdict for the nonmoving party.” Lamont v. New Jersey, 637 F.3d 177, 181 (3d Cir.2011) (quoting Anderson v. Liberty Lobby, Inc., 477 U.S. 242, 248, 106 S.Ct. 2505, 91 L.Ed.2d 202 (1986)). The burden .on the moving party may be discharged by pointing out to the district'court that there is an absence of evidence supporting the non-moving party’s case. Celotex, 477 U.S. at 323, 106 S.Ct. 2548.

The burden then shifts to the non-mov-ant to demonstrate the existence of a genuine issue for trial. Matsushita Elec. Indus. Co. v. Zenith Radio Corp., 475, U.S. 574, 586-437, 106 S.Ct. 1348, 89 L.Ed.2d 538 (1986); Williams v. Borough of West Chester, Pa., 891 F.2d 458, 460-61 (3d Cir.1989). . A non-moving party asserting that a fact. is genuinely dispute?} must support such an. assertion by: “(A) citing to particular parts of materials in the record, including ■ depositions, documents, electronically stored information; affidavits or declarations, stipulations ..., admissions, interrogatory answers, or other materials; or (B) showing that the materials cited [by the opposing party] do not establish the absence ... of a genuine dispute — ” Fed.R.Civ.P. 56(c)(1).

When determining whether a genuine issue of material fact exists, the court must view the evidence in the light most favorable to the non-moving party and draw all reasonable inferences in that party’s favor. Scott v. Harris, 550 U.S. 872, 880, 127 S.Ct. 1769, 167 L.Ed.2d 686 (2007); Wishkin v. Potter, 476 F.3d 180, 184 (3d Cir.2007). A dispute is “genuine” only if the evidence is such that a reasonable jury could return a verdict for the non-moving party. Anderson, 477 U.S. at 247-49, 106 S.Ct. 2505. If the non-moving party fails to make a sufficient showing on an essential element of its case with respect to which it has the burden of proof, the moving party is entitled to judgment as a matter of law. See Celotex Corp., 477 U.S. at 322, 106 S.Ct. 2548.

B. Motions to Exclude Expert Opinions and Testimony

1. Motions to Exclude Under Federal Rule of Evidence 702 and Daubert

Federal Rule of Evidence 702 sets out the requirements for expert witness testimony and states:

A witness who is qualified as an expert by knowledge, skill, experience, training; or education may testify in the form of an opinion or otherwise if: (a) the expert’s scientific, technical, or other specialized knowledge will help the trier of fact to understand the evidence or to determine a fact in issue; (b) the testimony is based on sufficient facts or data; (c) the testimony is the product of reliable principles and methods; and (d) the expert has reliably applied the principles and methods to the facts of the case.

Fed.R.Evid. 702. The Third Circuit has explained:

Rule 702 embodies a'trilogy of restrictions on expert testimony: qualification, reliability and fit. Qualification refers to the requirement that the witness possess specialized expertise. We have interpreted this requirement liberally, holding that “a broad range of knowledge, skills, and training qualify an expert.” Secondly, the testimony must be reliable; it “must be based on'the'‘methods and procedures of science’ rather than on ‘subjective belief or unsupported speculation’; the expert must have ‘good grounds’ for his o[r] her belief. In sum, Daubert [v. Merrell Dow Pharm., Inc., 509 U.S. 579, 113 S.Ct. 2786, 125 L.Ed.2d 469 (1993) ] holds that an inquiry into the reliability of scientific evidence under Rule 702 requires á determination as to its scientific validity.” Finally, Rule 702 requires that the expert testimony must fit the issues in the case. In other words, the expert’s testimony must be relevant for the purposes of the case and must assist the trier of fact. The Supreme Court explained in Daubert that “Rulé 702’s ‘helpfulness’ standard requires a valid scientific connection to the' pertinent inquiry as a precondition to admissibility.”

By means of a so-called “Daubert hearing,” the district court acts as a gatekeeper, preventing opinion testimony that does not meet the requirements of qualification, reliability and fit from reaching the jury. ' See Daubert (“Faced with a proffer of expert scientific testimony, then, the trial judge must determine at the outset, pursuant to Rule 104(a) [of the Federal Rules of Evidence] whether the expert is proposing to testify to (1) scientific knowledge that (2) will assist the trier of fact to understand or determine a fact in issue.”).

Schneider ex rel. Estate of Schneider v. Fried, 320 F.3d 396, 404-05 (3d Cir.2003) (footnote and citations omitted).

The party offering the expert testimony bears the burden of proving admissibility. Daubert, 509 U.S. at 592 n. 10, 113 S.Ct. 2786. “The expert must explain how and why he or she has reached the conclusion being proffered and must have as a basis more than a subjective belief or speculation.” Cryovac Inc. v. Pechiney Plastic Packaging, Inc., 430 F.Supp.2d 346, 362 (D.Del.2006); see General Elec. Co. v. Joiner, 522 U.S. 136, 144, 118 S.Ct. 512, 139 L.Ed.2d 508 (1997). “A court may conclude that there is simply too great a gap between the data and the opinion proffered.” Oddi v. Ford Motor Co., 234 F.3d 136, 146 (3d Cir.2000) (citing General Elec. Co., 522 U.S. at 146, 118 S.Ct. 512). A Daubert motion should be denied where there is a logical basis for the expert’s opinion testimony. Masimo Corp. v. Philips Elec. N. Am. Corp., 62 F.Supp.3d 368, 388 (D.Del.2014). In that case, “[t]he weight and credibility of an expert’s testimony may be challenged through ‘[vigorous cross-examination, presentation of contrary evidence, and careful instruction on the burden of proof.’ ” Id. (quoting Daubert, 509 U.S. at 596, 113 S.Ct. 2786).

2. Motions to Exclude Under the Federal Rules of Civil Procedure

A party who has ... responded to an interrogatory ... must supplement or correct its disclosure or response ... in a timely manner if the party learns that in some material respect the disclosure or response is incomplete or incorrect, and if the additional or corrective information has not otherwise been made known to the other parties during the discovery process or in writing.

Fed.R.Civ.P. 26(e)(1)(A). Additionally, an expert’s report must contain “a complete statement of all opinions the witness will express and the basis and reasons for them; [and] the facts or data considered by the witness in forming them.” Fed. R.Crv.P. 26(a)(2)(B). “Expert reports must also be supplemented when required in accordance with the provisions of Rule 26(e)(1).” Alza Corp. v. Andrx Pharm., LLC, 2008 WL 1886042, at *2 (D.Del. Apr. 28, 2008). The purpose of the disclosure requirements of Rule 26 “is to prevent a party from being unfairly surprised by the presentation of new evidence.” Id.

Federal Rule of Civil Procedure 37(c)(1) provides: “If a party fails to provide information ... as required by Rule 26(a) or (e), the party is not allowed to use that information ... to supply evidence on a motion, at a hearing, or at a trial, unless the failure was substantially justified or is harmless.” In determining whether a failure to disclose is harmless, courts in the Third Circuit typically consider the following factors:

(1) the importance of the information withheld; (2) the prejudice or surprise to the party against whom the evidence is offered; (3) the likelihood of disruption of the trial; (4) the possibility of curing the prejudice; (5) the explanation for the failure to disclose; and (6) the presence of bad faith or willfulness in not disclosing the evidence (the “Penny-pack factors”).

Lab. Skin Care, Inc. v. Ltd. Brands, Inc., 661 F.Supp.2d 473, 477 (D.Del.2009) (citing Meyers v. Pennypack Woods Home Ownership Ass’n, 559 F.2d 894, 904-05 (3d Cir.1977), overruled on other grounds, Goodman v. Lukens Steel Co., 777 F.2d 113 (3d Cir.1985)). It is well established that courts must assess these factors with the understanding that “[exclusion of critical evidence, such as an expert report on infringement, is an extreme sanction, not normally to be imposed absent a showing of willful deception or flagrant disregard of a court order by the proponent of the evidence.” Power Integrations, Inc. v. Fairchild Semiconductor Int’l Inc., 763 F.Supp.2d 671, 692 (D.Del.2010) (quoting In re Paoli R.R. Yard PCB Litig., 35 F.3d 717, 791-92 (3d Cir.1994)) (internal quotation marks omitted). Courts in the Third Circuit favor resolution of .disputes on their merits, particularly with respect to patent validity issues, which raise public interest concerns extending beyond the immediate dispute between the parties. Novartis Pharm. Corp. v. Actavis, Inc., 2013 WL 7045056, at *12 (D.Del. Dec. 23, 2013).

III. ANALYSIS

A. ’464 Patent

The ’464 patent discloses systems and methods for providing efficient data storage that eliminate redundancy using dedu-plication techniques. (’464 patent, 1:19-21). EMC asserts that Pure’s FlashArray infringes claims 2, 3,14, 19, 20, 21, and 32 of the ’464 patent. (D.I. 199 at 6). Claim 32 of the ’464 patent is representative and states:

32. A computer program product for storing data, the computer program product being embodied in a computer readable medium and comprising computer instructions for:

receiving a data stream comprising a plurality of data segments wherein each data segment is associated with an identifier;

determining using a subset of identifiers that are, stored in a low latency whether a data segments has been previously stored; and

returning the identifier for the data segment in the event the data segment is determined to have been stored previously.

(’464 patent, 12:35-47).

1. Pure’s Motion to Exclude Opinions and Testimony of EMC’s Patent Infringement Expert

Pure moves to exclude the opinions and testimony of Mr. Ian Jestice, EMC’s expert on-the ’464 and ’015 patents, regarding infringement of the ’464 patent under the doctrine of equivalents. (D.I. 205 at 22). The doctrine of equivalents function-way-result test “requires the evidence to establish what the function,- way, and result of both the claimed device and the accused device are, and why those functions, ways;' and results are substantially the same.” Malta v. Schulmerich Carillons, Inc., 952 F.2d 1320, 1327 n. 5 (Fed.Cir.1991) (emphasis omitted).

Pure objects that Mr. Jestice “offered nothing but his own say-so to support his opinions that: 1) a person of ordinary skill would understand returning to also include, using, indexes to accessible arrays or .structures [ (D.I. 217-1 at 183, ¶ 48) ], and 2) the described return of an array index meets the same function, way, and result test for equivalence [ (D.I. 217-1 at 184) ].” (D.I. 205 at 23 (citations and internal quotation marks omitted)). Pure argues, that Mr. .Jestice’s statement that a person of ordinary skill in the art would understand returning an identifier to include returning an index is a bare assertion, without support. (Id. at 24). Pure contends that Mr. Jestice’s report fails to present the particularized testimony required to sustain a doctrine of equivalents claim because it “does not explain the purpose for which the supposedly equivalent index is returned, how that index fits into the accused process, or even how the index is used after it is returned.” (Id.).

Mr. Jestice opined that a person of ordinary skill would understand “ ‘deliver back to a calling routine’ to include not only returning the actual identifier, but also returning pointers and indexes to accessible arrays or- structures (this is because pointers and indexes are used to reference other data).” (D.I. 217-1 at. 183, ¶48). Although, he did not specifically cite evidence in support of this opinion, Mr. Jes-tice adequately explained his reasoning by reference to the function/way/result test. (See id. at 183-84, ¶¶ 48-49). Mr. Jestice explained that delivering an index in an array to an identifier yields the same result (“has the same effect”) as returning an identifier itself. (Id. at 183). Mr., Jestice explained that returning an index accomplishes the same function as returning the identifier in the claim because “[u]pon such returnj the system is able to keep track of, and perform additional steps relating to, that potentially duplicate segment.” (Id. at 184). Finally, Mr. Jestice explained that the accused’ product’s returning an index functions in the same way as the claimed returning an identifier because the accused product “returns a representation of an identifier after a preliminary determination has been made that the identifier is associated with a duplicate data segment.” (Id.).

' Mr. Jestice thus offered an explanation of how and why he concluded that “deliver back to a calling routine” includes not only returning an actual identifier, but also returning pointers and indexes to accessible arrays or structures. Cf. Magnetar Techs. Corp. v. Six Flags Theme Parks Inc., 2014 WL 529983, at *8 (D.Del. Feb. 7, 2014) (excluding opinion and testimony where the expert merely “state[d] the' claim limitations followed by general references to several documents and [deposition testimony]”); MKS Instruments Inc. v. Advanced Energy Indus., Inc., 325 F.Supp.2d 471, 473 (D.Del.2004) (excluding opinion and testimony where expert “only pointed to evidence of literal infringement and argued that, by inference, this evidence also demonstrates infringement by equivalence”). Mr. Jestice based his opinion, not on speculation, but on analysis of Pure’s source code and his experience in the field. (See D.I. 217-1 at 7, 147-48, 183-84). Pure’s criticisms therefore go to the weight and credibility of Mr. Jestice’s DOE opinion and the appropriate vehicle for Pure’s challenges is cross examination and the presentation of contrary evidence. See Inline Connection Corp. v. AOL Time Warner Inc., 470 F.Supp.2d 435, 439 (D.Del.2007). Pure’s motion to exclude Mr, Jes-tice’s opinions and testimony regarding infringement-of'the ’464 patent under the doctrine of equivalents is therefore DENIED.

2. Pure’s Motion for Summary Judgment of Non-Infringement of the %6Jp . ■ Patent Asserted Claims

Pure seeks summary judgment of non-infringement of the asserted claims of the ’464 patent. (D.I. 199 at 10). A patent is directly infringed when a person “without authority makes, uses, offers to sell, or sells any patented invention, within the United States ... during the term of the patent.” 35 U.S.C. § 271(a). A two-step analysis is employed in making an infringement determination. See Markman v. Westview Instruments, Inc., 52 F.3d 967, 976 (Fed.Cir.1995) (en banc), aff'd, 517 U.S. 370, 116 S.Ct.1384, 134 L.Ed.2d 577 (1996). First, the court must construe the asserted claims to ascertain their meaning and scope. See id. The trier of fact must then compare the properly construed claims with the accused infringing product. See id. at 976. This second step is a question of fact. See Bai v. L & L Wings, Inc., 160 F.3d 1350, 1353 (Fed.Cir.1998).

“Literal infringement of a claim exists when every limitation recited in the claim is found in the accused device.” Kahn v. Gen. Motors Corp., 135 F.3d 1472, 1477 (Fed.Cir.1998). “If any claim limitation is absent from the accused device, there is no literal infringement as a matter of law.” Bayer AG v. Elan Pharm. Research Corp., 212 F.3d 1241, 1247 (Fed.Cir.2000). If an accused product does hot infringe an independent claim, it also does not infringe any claim depending thereon. See Wahpeton Canvas Co. v. Frontier, Inc., 870 F.2d 1546, 1553 (Fed.Cir.1989). However, “[o]ne may infringe an independent claim and not infringe a claim dependent on that claim.” Monsanto Co. v. Syngenta Seeds, Inc., 503 F.3d 1352, 1359 (Fed.Cir.2007) (internal quotation marks omitted). A product that does not literally infringe a patent claim may still infringe under the doctrine of equivalents if the differences between an individual limitation of the claimed invention and an element of the accused product are insubstantial. See Warner-Jenkinson Co. v. Hilton Davis Chem. Co., 520 U.S. 17, 24, 117 S.Ct. 1040, 137 L.Ed.2d 146 (1997). The patent owner has the burden of proving infringement and must meet its burden by a preponderance of the evidence. See Smith-Kline Diagnostics, Inc. v. Helena Labs. Corp., 859 F.2d 878, 889 (Fed.Cir.1988).

When an accused infringer moves for summary judgment of non-infringement, such relief may be granted only if at least one limitation of the claim in question does not read on an-element of the accused product, either literally or under the doctrine of equivalents. See Chimie v. PPG Indus., Inc., 402 F.3d 1371, 1376 (Fed.Cir.2005); see also TechSearch, L.L.C. v. Intel Corp., 286 F.3d 1360, 1369 (Fed.Cir.2002) (“Summary judgment of noninfringement is ... appropriate where the patent owner’s proof is deficient in meeting an essential part of the legal standard for infringement, because such failure will render all other facts immaterial.”). “Thus, summary judgment of non-infringement can only be granted if, after viewing the alleged facts in the light most favorable to the non-movant, there is no genuine issue whether the accused device is encompassed- by the claims [as construed by the court].” Pitney Bowes, Inc. v. Hewlett-Packard Co., 182 F.3d 1298, 1304 (Fed.Cir.1999).

Pure seeks summary judgment of non-infringement of the asserted claims of the ’464 patent on the ground that the FlashArray does not “return[ ] the identifier.” (D.1.199 at 10). The asserted claims of the ’464 patent all require “returning the identifier” (or' “to return the identifier”) after a data segment is determined to be a duplicate. (’464 patent, 10:14-21; 10:53-57; 11:17-26; 11:32-33; 12:35-47). The. Court construed “return” to mean “deliver back.” (D.1.115 at 8).

EMC asserts two theories in support of its argument that Pure’s FlashArray “return[s] the identifier.” (D.I. 258 at 12-17). First, EMC argues that the FlashArray returns the identifier because it takes the identifier as input and returns an index representing the identifier to the calling routine that requested it. (Id. at 14-16). Second, EMC argues that the FlashArray delivers the identifier back to the first step in the deduplication process, the SD Table step. (Id. at .16-17). Pure argues that both infringement theories fail as a matter of law. (D.I. 199 at 11, 13-14). Pure maintains that the FlashArray does not “return" the identifier,” either literally or under the doctrine of equivalents, by returning an index because an index is .not an identifier. (Id.). Pure maintains that the FlashArray does not “deliver back” an identifier to the SD Table because the SD table did not previously contain the identifier. (Id. at 11).

The parties’ experts agree regarding the relevant operations of the FlashArray de-duplication source, code. (See D.I. 200-2 at 28-29).

[Djuring normal operation, the Accused Products first perform a lookup in the SD Table. This means that the hash signature of the newly written data is checked against the contents of the SD Table. If no match is found in the SD Table, the Accused Products then perform a lookup in the Recent Table. If a match is found in the Recent Table, and the segment is confirmed to be a duplicate through a byte by-byte comparison, the hash signature of the confirmed duplicate is delivered back to the SD Table to record the hash signature as a successful duplicate.

(D.I. 217-1 at 86 (citations omitted); see also D.I. 199 at 11-12). The parties’ experts disagree, however, regarding whether the operation of the FlashArray falls within the plain and ordinary meaning of “returning the identifier.” (D.I. 199 at 10; D.I. 258 at 13).

There is a genuine dispute of material fact regarding whether the FlashAr-ray “return[s] the identifier,” either literally or under the doctrine of equivalents, by-returning an index representing the identifier to a calling routine that requested it. Mr. Jestice acknowledges that no FlashAr-ray routines return the value of the identifier to the calling routine. (D.I. 200-2 at 28- 30). Mr. Jestice opines, however, that FlashArray meets the “returning the identifier” claim limitation by returning an index representing the identifier to a calling ■routine.' (D.I. 217-1 at 183-84). Mr; Jes-tice testified that returning an index is the same as returning an identifier to a person of skill in the art because indexes are often used to refer to data in a computer system. (Id.). Mr. Jestice also opines that returning an index is at least equivalent to returning an identifier. (Id.). Dr. Erez Zadok, Pure’s expert on the ’464 and ’015 patents, testified that an index representing an identifier is not the same as the identifier itself because it is a different piece of data altogether. (D.I. 201-3 at 42^43). Relying on Mr. Jestice’s testimony, a jury could reasonably conclude that returning an index representing the identifier either literally satisfies the claim language “returning the identifier” or satisfies it under the doctrine of equivalents.

There is also a genuine dispute of material fact regarding whether the FlashArray “return[s] the identifier” to the SD Table. The parties’ experts agree that, if an identifier is not located in the SD Table but is subsequently located in the Recent Table, the FlashArray updates the SD Table to add the identifier to the SD Table for the first time. (D.I. 200-2 at 11-14, 17-19; see also D.I. 199 at 11-12). Dr.- Zadok opines that, because the last step of Flash-Array deduplication is adding the identifier to a data structure that did not already contain it, the FlashArray does not “return” the identifier to the SD Table. (D.I. 201-3 at 41). Mr. Jestice opines that, because the SD Table is compared with the identifier at the first deduplication step, the FlashArray “return[s] the identifier” to the SD Table by delivering it back to the SD Table as the last step of the deduplication process. (D.I. 217-1 at 86; see D.I. 258 at 13-14). A reasonable jury could conclude, based on the evidence, that an identifier is delivered “back” to the SD Table, even though the identifier had not previously been stored in the SD Table, because the identifier is returned to the table against which it had previously been compared.

For the reasons stated above, Pure’s motion for summary judgment of non-infringement of the ’464 patent is DENIED.

B. ’015 Patent

Like the ’464 patent, the ’015 patent discloses systems and methods for providing efficient data storage that eliminate redundancy using deduplication techniques. (’015 patent, 1:18-20; see ’464 patent, 1:19-21). For purposes of this motion, claim 1 is representative. Claim 1 of the ’015 patent states:

1. A method for storing data comprising:

receiving a data stream comprising a plurality of data segments;

assigning an identifier to one of the plurality of data segments; and

determining whether one of the plurality of 'data segments has been stored previously using a summary, wherein the summary is a space efficient, probabilistic summary of segment information.

(’015 patent, 9:53-61).

1. EMC’s Motion for Summary Judgment of Direct Infringement of ’015 Patent Claims 1,7, and 16

EMC seeks summary judgment of direct infringement of claims 1, 7, and 16 of the ’015 patent. (D.I. 215 at 8). EMC argues that its expert, ■ Mr. Jestice, has shown how the FlashArray meets every element of claims 1, 7, and 16 of the ’015 patent. (Id. at 13). Dr. Zadok opines that the FlashArray does not “receiv[e] a data stream” or use a “summary,” as required by the claims. (D.I. 216-1 at 86-91). EMC contends that Dr. Zadok’s opinions with respect to the receiving a data stream and using a summary elements are based on incorrect claim constructions and that there is no genuine dispute that the Flash-Array infringes claims 1, 7, and 16 under the proper constructions. (D.I. 215 at 13). EMC also seeks partial summary judgment that Pure uses, sells, or offers to sell the accused FlashArray and that Pure’s customers use the accused FlashArray. (Id. at 26-28).

The Court construed “receiving a data stream” to have its plain and ordinary meaning. (D.I. 121 at 2). Pure initially argued that the FlashArray does not receive a data stream because a person of ordinary skill in the art would understand “data stream” to be a series of data segments related to each other by some characteristic, and EMC’s expert agrees that the data segments received by the Flash-Array are not necessarily related. (D.I. 252 at 10 & n.7). In conducting supplemental claim construction, however, the Court held that the term does not require “receiving a series of segments that are related to each other by some characteristic that distinguishes them from other received data streams.” (D.I. 362 at 8).

Pure argues that there is still a genuine factual dispute regarding whether the FlashArray receives a “data stream” as that term is understood by a person of skill in the art. (D.I. 252 at 16-17; D.I. 358 at 5-6). Pure contends that, even under the meaning of “data stream” proposed by EMC’s expert, • Mr. Jestice, the FlashArray does not receive a “data stream.” (See D.I. 252 at 12-13; D.I.'327 at 42; D.I. 353 at 5-6). Mr. Jestice opined that the plain and ordinary meaning, of “data stream comprising a plurality of data segments” is “a flow of data that consists of a plurality of segments.” (D.I.; 253-5 at 4; see also D.I. 253-4 at 4-5). Mr. Jestice explained that “random piecemeal transmissions” would not be a. “flow” of data. (D.I. 253-5 at 5). Extrinsic 'evidence supports Mr. Jestice’s view that data’stream means a continuous flow of data. (See, e.g., D.I. 254-2 at 31-32).

There is no genuine dispute regarding whether the FlashArray .“receives] a data stream comprising a plurality of segments.”. ■ Mr. Jestice and Dr. Zadok agree that the FlashArray receives 512-byte data sectors from a host. (See D.I. 217-1 at 42; D.I.-253-8 at 8; D.I. 254-2 at 67). Mr. Jestice opined that receiving the 512-byte data sectors const!, tutes ‘“receiving .a data, stream.” (D.I. 217-1 at 29, 185). Dr. Zadok did .not rebut Mr. Jestice’s opinion that the Flash-Array receives a continuous flow of data. Even so, Pure argues that -there is no evidence, in the record that, “a host sends a data, stream to the FlashArray such that the FlashArray could receive a data stream.” (D.I. 327 at 41-43). How data segments are sent to the FlashArray is irrelevant, however, beeau'se the claim does not impose any requirements on' how data segments are sent, only on the manner in which they are received. A reasonable jury thus could not conclude that the FlashArray does' not satisfy the '“receiving a data stream” element of the ’015 patent claims 1, 7, and 16.

There is no also genuine dispute that the FlashArray “determin[es] whether one of the plurality of data segments has been stored previously using á summary, wherein the summary is a- space efficient, probabilistic summary of segment information.” (D.I. 215, at 18). Dr. Zadok opined that the FlashArray does not. infringe the asserted claims of the ’015 patent because the FlashArray does not use a “summary” to determine whether one of 'the plurality of data segments has been stored previously. (D.I. 216-1 at 86). Dr. Zadok stated that “[t]he additional context of the claims of the ’015 patent demonstrate to one of ordinary skill. ... that the ‘summary5 cannot be the same structure as the ‘subset of identifiers.’ ” (D.I. 216-1 at 87; see D.I. 216-1 at 43-44). Additionally, Dr. Zadok stated that “summary” refers to “a structure that summarizes the entire segment database, not just a portion of it.” (D.I. 216-1 at 47 (emphasis omitted)).

Claim construction is a legal question within the province of the court. Markman v. Westview Instruments, Inc., 517 U.S. 370, 372, 116 S.Ct. 1384, 134 L.Ed.2d 577 (1996). “No party may contradict the court’s construction to a jury.” Exergen Corp. v. Wal-Mart Stores, Inc., 575 F.3d 1312, 1321 (Fed.Cir.2009). In construing “summary,” I rejected Pure’s proposals to limit “summary” to a data structure that (1) is different from a subset of - identifiers and (2) determines that a segment is not in the entire segment database. (D.I. 362 at 5-8). Thus, Dr. Za-dok’s opinions regarding the additional limitations are irrelevant. See Liquid Dynamics Corp. v. Vaughan Co., 449 F.3d 1209, 1224 n. 2 (Fed.Cir.2006) (affirming exclusion of expert testimony as irrelevant where it was based on an impermissible claim construction).

EMC presents undisputed evidence that, under the Court’s construction of “probabilistic summary,” the FlashArray’s SD Table and Recent Table are each a “data structure that indicates with possible uncertainty whether a data segment has already been stored.” (See D.I. 215 at 21-23 and documents cited therein). Indeed, Dr. Zadok explicitly acknowledged that, unless “summary” means a data structure that is different from a subset of identifiers and that can determine that a segment is not in the entire segment. database, “a cached data structure such as the accused ‘successful dedupe’ table ... fall[s] within the Court’s construction of a ‘probabilistic summary.’” (D.I. 216-1 at 48). Thus, there is no genuine dispute that, under the Court’s constructions of “summary” and “probabilistic summary,” the FlashArray “determin[es] whether one of the plurality of data segments, has been stored'previously using a summary wherein the summary is a space efficient, probabilistic summary of segment information.” (E.g., ■ ’015 patent, 9:58-61).

For the reasons stated above, there is no genuine dispute of fact regarding whether the FlashArray “receiv[es] a data stream” or uses a “summary” as required by claims 1, 7, and 16 of the ’015 patent. Additionally, there is no dispute that the FlashArray meets all other’ claim limitations of claims 1, 7, and 16 of the ’015 patent. In particular, there is no dispute that the FlashArray:- (1) “assign[s] an identifier to one of. the plurality of data segments”- as-required by claims 1, 7, and 16; (2) embodies “[a] computer program product for storing data, the computer program product being embodied in a computer readable storage medium and comprising computer instructions” as recited in the preamble to claim 16; or (3) “confirm[s] whether the one of the plurality of data segments has been stored previously using a relatively high latency memory” as required by claim 7. (See D.I. 216-1 at 86-93; D.I. 217-1 at 43-45, 55-57, 65; see also D.T. 215 at 23-25). There are also no genuine disputes that Pure has sold the FlashArray and offered it for sale (see, e.g., D.I: 216-1 at 291-92) or that Pure used it in testing (see, e.g., D.I. 216-1 at 192-94, 248, 250-51, 298, 300-01); see Waymark Corp. v. Porta Sys. Corp., 245 F.3d 1364, 1366 (Fed.Cir.2001) (“This court has established that testing is a use of the invention that may infringe under § 271(a).”). Finally, there is no genuine dispute that Pure’s customers use the FlashArray. (See D.I. 216-1 at 100-01 (Pure’s expert, Dr. Zadok, discussing analyzing customer log data “from [a] Pure Storage engineer .. that represents many typical customers and their use of multiple FlashArrays”)).

EMC’s motion for summary judgment of direct infringement of claims 1,‘7, and 16 of the ’015 patent is therefore GRANTED. EMC’s request for partial summary judgment that Pure uses, sells, or offers to sell the accused FlashArray and that Pure’s customers use the FlashArray is also GRANTED.

2. Pure’s Motion to Strike Evidence and Expert Opinions Regarding EMC’s Attempt to Swear Behind the Krapp , Reference

Pure moved for summary judgment of invalidity of the ’015 patent, arguing, among other things, that the asserted claims of the ’015 patent are anticipated by U.S. Patent No. 6,889,297 (the “Krapp patent.”). (D.I. 199 at 16, 28). In its opposition to Pure’s motion for summary judgment of invalidity of the ’015 patent, EMC asserted that the Krapp patent is not prior art because the ’015 patent was invented no later than March 16, 2002 — six days before the application resulting in the Krapp patent was filed. (D.I. 258 at 17-18). In support of its prior conception and diligent reduction to practice contentions, EMC filed a declaration by ’015 patent co-inventor Dr. Kai Li. and a declaration by Mr. Jestice, EMC’s expert on the ’015 and ’464 patents. (D.I. 260; D.I. 260-1; D.I. 263; D.I. 263-1; D.I. 263-2). Pure moves to strike the declarations and the documents attached thereto under Federal Rule of Civil Procedure 37(c)(1) on the ground that EMC violated Rules 26(e)(1)(A) and 26(a)(2)(B). (D.I. 303 at 8).

The facts are undisputed. On March 21, 2014, Pure served EMC with its first set of interrogatories and requests for production of documents. (D.I. 27 at 1). Pure’s Interrogatory No. 1 asked EMC to describe in detail all facts relating to the conception and reduction to practice of each asserted claim of the patents in suit, including but not limited to the conception date and the date of reduction to practice of the subject matter of each patent in suit, and all documents relating to conception and reduction to practice. (D.I. 304-1 at 3). Pure’s Request No. 4 asked EMC to produce all documents “relating to the conception, reduction to practice, research, design, development, or testing of the inventions or subject matters disclosed, described, or claimed in any of the Patents-in-Suit or any related patent or related application, including, but not limited to, the first written description or disclosure (including drawings) ■ and the first prototype of such subject matter.” (D.I. 304-2 at 3). EMC responded to Pure’s discovery requests on April 24, 2014. (D.I. 32 at 1). EMC responded to interrogatory No. 1 by stating that the inventors conceived of the ideas claimed in the ’015 and ’464 patents “at least as early as June 4, 2002.” (D.I. 304-3 at 4). EMC responded to Pure’s request for production No. 4 by agreeing to “produce all non-privileged, responsive documents in its possession, custody, or control that relate to the inventions claimed in any of the Patents-in-Suit and that predate the effective filing date of the Patents-in-Suit, to the extent such documents exist and have been uncovered after a diligent search of a reasonable number of custodians most likely to possess relevant information.” (D.I. 304-4 at 3).

In its initial infringement contentions served on May 2, 2014, EMC asserted that the ’015 and ’464-patents are entitled to a priority date of December 20, 2002. (D.I. 33 at 1; D.I. 304-5 at 3). “EMC further contended] that each asserted claim -of each of the Asserted Patents is entitled to a priority date corresponding to its date of conception.” (D.I. 304-5 at 3). On June 6, 2014, Pure served its initial invalidity contentions, in which‘it asserted the Krapp patent as an obviousness reference. (D.I. 304-6 at 3, 7). Pure’s initial invalidity contentions listed the filing date of the Krapp patent as March 22, 2002, as indicated on the face of the patent. (D.I. 200-8 at 3; D.I. 304-6 at 3). Pure did not identify Krapp as an anticipation reference in its invalidity contentions. (See D.I. 192-I at 126-29; D.I. 193 at 3).

On February 11, 2015, EMC suppler mented its response to Interrogatory No. 1, identifying multiple documents that further reflected evidence of the conception, diligence, .and reduction to practice of the ’015 and ’464 patents. (D.I. 304-8 at 5). None of the documents EMC identified in its February 11 supplemental response were dated earlier than May 30, 2002. (D.I. 304 at 4). EMC’s' February II supplemental response did not identify a date of alleged, conception earlier than June 4, 2002. (D.I. 304-8 at .5). On March 26, 2015, Pure deposed EMC’s Rule 30(b)(6) designee on the.topics of conception and reduction to practice of the inventions of the ’015 and ’464. patents. • (D.I. 304-11 at 4-7). EMC’s Rule 30(b)(6) des-ignee testified that documents that would impact the areas of conception and reduction to practice of the ’015 patent were produced and covered in an answer to an interrogatory and that “any proof [EMC] would have would be dependent on those documents.” (Id.).

On May 15, 2015, Dr. Zadok identified-Krapp as anticipatory prior art to the ’015 patent and opined that Krapp discloses the elements of the asserted claims. (D.I. 201-2 at 1, 43-49; see also D.I. 196 at 28-29). In his reply report -served on August 6, 2015, Dr.. Zadok offered an expanded explanation of his opinion that the Krapp patent discloses the “summary” limitation of the ’015 patent asserted claims. (D.I. 201-4 at 40-43). Although Mr. Jestice opined that Krapp does not anticipate the ’015 and ’464 patents, he did not challenge-the prior art status of Krapp either in his rebuttal expert report or at deposition. (D.I. 200-2 at 43-44; see D.I. 260-1 at 122-26). Mr. Jestice also offered no opinions'regarding the timing of conception or reduction to practice of the inventions claimed in the ’015 patent. (See D.I. 260-1 at 3-4).

On September 30, 2015, EMC moved to strike the Krapp patent and Dr. Zadok’s related anticipation opinion as untimely disclosed. - (D.I. 192 at 3). At the hearing on October 2, 2015, the Court denied EMC’s motion to strike, thus permitting Pure to rely on Krapp as an anticipation reference. (D.I. 196 at 32). Four days later, on October 6, 2015, the parties filed their summary judgment motions. (D.I. 198, 206, 214). On October 28, 2015, EMC served its opposition to Pure’s motion for summary judgment. EMC argued in its opposition to Pure’s motion for summary judgment- that Krapp is not prior art to the ’015 patent because the inventions of the ’015 patent were conceived no later than March 16, -2002. (D.I. 258 at 8-12). Also on October 28, 2015, EMC: served a supplemental response to Pure’s Interrogatory No, l.that: (1) disclosed the March 16, 2002 date of conception; . (2) identified, for the first time, technical specifications pre-dating May 30, 2002; and (3) incorporated by reference the declarations of Dr. Li and Mr. Jestice that EMC served with its opposition to Pure’s motion for summary judgment. (D.I. 304-17 at 6).

The Pennypack factors militate against striking the Li and Jestice declarations and exhibits thereto. 'First, the Li and Jestice declarations are of critical importance'to the issue of invalidity of the-’015 patent because Pure has moved for summary judgment of invalidity of all asserted claims of the ’015 patent on the ground that they are anticipated by the Krapp patent. Second, there is no reason to believe, at this point, that the trial will be disrupted if the declarations are not struck.

Third, Pure will not suffer incurable prejudice if the Court, does not strike the Li and Jestice declarations. Pure has not demonstrated that it will suffer prejudice on the ground that, had it known earlier that EMC would assert a March 2002 conception date, it would have searched for prior art dated before March 2002 because, aside from the Krapp patent, all but one of Pure’s invalidity references predate March 2002. (See D.I. 192-1 at 128). I am also unpersuaded that Puré will suffer prejudice because, had it known earlier ,that EMC would assert a March 2002 conception date, it would have moved for summary judgment of invalidity on the ground that a different prior art. reference anticipates the asserted ’015 patent claims. (See D.I. 303 at 21). Pure could have included such other anticipatory references in its summary judgment motion and yet chose not to mention them. Pure .will still be able to assert them at trial. Finally, Pure will not suffer prejudice due to an inability to meaningfully cross examine Dr. Li and Mr. Jestice regarding the prior conception and diligent reduction to practice evidence. Pure has had adequate time and an opportunity to conduct discovery to develop its response to EMC’s assertion that the invention of the ’015 patent predates the Krapp patent filing date. (See D.I. 327 at 122-23; D.I. 355 at 1).

Fourth, with-respect to EMC’s explanation for the failure to disclose and the presence of bad faith or willfulness, EMC argues that it did not - have a reason, to seek to antedate the-Krapp patent until Pure served its reply expert report fully articulating its Krapp anticipation theory. (D.I. 321 at 17). Until Dr. Zadok fully articulated his anticipation theory, Pure described Krapp as disclosing techniques that the ’015 patent itself identified' as being used in the prior art. (Id. - at 20). EMC contends that it -promptly obtained and served the Li and Jestice declarations after Pure served Dr. Zadok’s reply report. (Id. at 17). EMC maintains that the whiteboard photos were not in EMC’s possession, custody, or control during fact discovery and that Dr. Li, a professor at Princeton University, is not an EMC employee. (Id. at 14, 19). 'The whiteboard photos attached as exhibits to Dr. Li’s declaration were in his personal files until he located them while preparing the declaration. (D.I. 263 at 5). Pure argues, on the other hand, that EMC had a duty to seek relevant evidence from Dr. Li prior to Pure’s deposition of EMC’s Rule 30(b)(6) designee because Dr. Li was a member of EMC’s Technical Advisory' Board during the discovery period. (D.I. 324 at 8). As á member of the Technical Advisory Board, Dr. Li agreed to assist in litigation related to his'Services. (D.I. 345-1 at 5).

EMC’s explanation for the failure to disclose is reasonable and Pure has not established the presence of bad faith. EMC’s belated disclosure of evidence of prior invention was a consequence of Pure’s belated disclosure of Krapp as an anticipatory reference. Further, EMC sought evidence of conception and reduction to practice from Dr. Li within a reasonable time after learning of Pure’s intention to assert the Krapp patent as an anticipatory reference. As an external technical advisor to EMC, Dr. Li had an obligation to cooperate in litigation related to his services as an ad-visor. • (Id,.). Dr. Li was not, however, under any contractual obligation to EMC with respect to the present litigation until after Pure filed its motion for summary judgment. (See id.; D.I. 347 at 2 & n.2; D.I. 347-1 at 5-6). Thus, EMC’s failure to produce the whiteboard photos that had been stored in Dr. Li’s flies does- not suggest bad faith. Further, the fact that Pure stated in its reply briéf to this motion, filed December 10, 2015, that Dr. Li served on EMC’s Technical Advisory Board during the discovery period undermines Pure’s suggestion that it was unaware of that fact until January 5, 2016. (See D.I. 324 at 8; D.I. 345 at 2).

For the reasons stated above, Pure’s motion to strike the declarations of Dr. Li and Mr. Jestice and the exhibits attached thereto is DENIED.

3. EMC’s Motion for Leave to File a Sur-Reply to Pure’s Motion for Summary Judgment of Invalidity of the ’015 Patent

EMC seeks leave to file a short ¡sur-reply regarding corroboration of conception in response , to new legal issues Pure raised for the first time in its reply brief in support of its motion for summary judgment of invalidity of the ’015 patent. (D.I. 317 at 3). Courts in this district disfavor sur-replies. D. Del. Loe. R. 7.1.2(b). Thus, generally, leave to file a sur-reply is granted only where the proposed brief responds to new evidence, facts, or arguments raised for the first time in the moving party’s reply brief. St. Clair Intellectual Prop. Consultants, Inc. v. Samsung Elecs. Co., 291 F.R.D. 75, 80 (D.Del.2013). But see S3 Graphics Co. v. ATI Techs., ULC, 2015 WL 7307241, at *11 n. 7 (Oct. 21, 2015) (granting leave to defendants to file surreply where plaintiffs inclusion of argument in its-reply brief was not procedurally improper).

As discussed above, EMC asserted that the ’015 patent is entitled to a priority date of March 16, 2002 for the first time in its opposition to Pure’s motion for summary judgment of invalidity. (See D.I. 321 at 13-14). In its reply, Pure maintained that Dr. Li’s declaration was legally insufficient evidence of conception and reduction to practice because it was not corroborated. (D.I. 298 at 13-14). Pure’s reply did not contain “new” argument to the extent it responded to the new argument EMC raised in its opposition to Pure’s motion for summary judgment. See Siemens Med. Solutions USA Inc. v. Humedica, Inc., 2015 WL 1738186, at *1 n. 1 (D.Del. Apr. 8, 2015). Still, Pure’s reply undoubtedly raised, legal arguments that EMC did not have an opportunity to rebut and relied on case law not cited in Pure’s opening brief. Further, EMC’s belated disclosure of evidence was a result of Pure’s belated disclosure of Krapp as an anticipatory reference. EMC’s proposed sur-reply is short'and directed.specifically to the 'question of prior invention. (See D.I. 317-1). The Court will therefore GRANT EMC’s motion for leave to file a sur-reply and consider the arguments therein. Pure’s request for leave to file a sur-sur reply is denied. (Seé D.I. 326 at 6).

A Pure’s Motion for Summary Judgment of Invalidity of the ’015 Patent

Pure seeks summary judgment .of invalidity of all asserted, claims of the ’015 patent on the grounds that they are anticipated by the. Krapp patent and are not enabled. (D.I. 199 at 16, 28). First, Pure seeks summary judgment of invalidity of the asserted claims of the ’015 patent on the ground that they are anticipated by the Krapp patent. (Id.). A patent claim is invalid as anticipated under 35 U.S.C. § 102 if “within ‘the four corners of a single, prior art document ... every element of the claimed invention [is described], either expressly or inherently, such that a person of ordinary skill in the art could practice the invention without undue experimentation.’” Callaway Golf Co. v. Acushnet Co., 576 F.3d 1331, 1346 (Fed.Cir.2009) (alterations in original) (quoting Advanced Display Sys., Inc. v. Kent State Univ., 212 F.3d 1272, 1283 (Fed.Cir.2000)). As with infringement, the court construes the claims and compares them against the prior art. See Enzo Biochem, Inc. v. Applera Corp., 599 F.3d 1325, 1332 (Fed.Cir.2010). Anticipation “may be decided on summary judgment if the record reveals no genuine dispute of material fact.” Encyclopaedia Britannica, Inc. v. Alpine Elecs. of Am., Inc., 609 F.3d 1345, 1349 (Fed.Cir.2010).

The parties dispute whether the Krapp patent is prior art to the ’015 patent and whether the Krapp patent discloses each element of the asserted claims. (D.I. 199 at 17; D.I. 258 at 18, 22; D.I. 298 at 12-14, 15; D.I. 317-1 at 7). A patent is prior art if it is filed before the date of invention of the asserted patent. 35 U.S.C. § 102(e). A patentee can swear behind an alleged prior art reference by providing evidence of prior invention. Mahurkar v. C.R. Bard, Inc., 79 F.3d 1572, 1576 (Fed.Cir.1996). Prior invention can be established by a showing that the inventor “was the first to conceive the invention and that it exercised reasonable diligence in later reducing that invention to practice.” Id. at 1577. “Conception is the formation in the mind of the inventor, of a definite and permanent idea of the complete and operative invention, as it is hereafter to be applied in practice.” Hybritech, Inc. v. Monoclonal Antibodies, Inc., 802 F.2d 1367, 1376 (Fed.Cir.1986) (internal quotation marks omitted). Every limitation- must be shown to have been known to the inventor at the time the invention is alleged to have been conceived. Davis v. Reddy, 620 F.2d 885, 889 (C.C.P.A.1980). Reasonable diligence is established by evidence that there was “reasonably continuing activity to reduce the invention to practice.” Mahurkar, 79 F.3d at 1577.

“Because conception is a mental act, it must be proven by evidence showing what the inventor has disclosed to others and what that disclosure means to one of ordinary skill in the art.” In re Jolley, 308 F.3d 1317, 1321 (Fed.Cir.2002) (internal quotation marks omitted). Documentary evidence of conception need not be corroborated. Mahurkar, 79 F.3d at 1577-78. But see Procter & Gamble Co. v. Teva Pharm. USA, Inc., 566 F.3d 989, 999 (Fed.Cir.2009) (“The inventor must provide independent corroborating evidence in addition to his own statements and documents.” (citations and internal quotation marks omitted)). The testimony of an alleged prior inventor, however, must be corroborated. Mahurkar, 79 F.3d at 1577-78. The “testimony of one co-inventor cannot be used to help corroborate the testimony of another.” Medichem, S.A v. Rolabo, S.L., 437 F.3d 1157, 1171 (Fed.Cir.2006). “[T]he sufficiency of corroborative evidence is determined by the ‘rule of reason.’” Kridl v. McCormick, 105 F.3d 1446, 1450 (Fed.Cir.1997). Accordingly, a court must examine all pertinent- evidence when weighing the credibility of an inventor’s story. Id. “Though the patentee has the burden of production in antedating a reference, the burden of persuasion, by clear and convincing evidence, remains with the party that challenges an issued patent’s validity.” Stamps.com Inc. v. Endicia, Inc., 437 Fed.Appx. 897, 907-08 (Fed.Cir.2011) (citing Mahurkar, 79 F.3d at 1576).

EMC argues that the evidence shows that the date of invention of the ’015 patent predates the filing of the Krapp patent. (D.I. 258 at 18-21). Dr. Li, co-inventor of the ’015 patent, stated in a sworn declaration that he and his co-inventors conceived of the core deduplication concepts of the ’015 patent invention no later than March 16, 2002. (D.I. 263 at 5). In particular, Dr. Li describes a meeting with co-inventor Benjamin Zhu in February 2002 during which they prepared figures and notes on a whiteboard that explain the ’015 patent deduplication process. (Id.). Photos of the whiteboard notes are in the record. (D.I. 263-1 at 27-31). EMC also produced an Architecture Specification, the first version of which was dated March 16, 2002, that details a system containing the ’015 patent deduplication invention. (D.I. 263 at 4-5; D.I. 263-1 at 2-13). Mr. Jestice stated that all limitations of the ’015 patent’s asserted claims are disclosed in the Architecture Specification. (D.I. 260-1 at 9-11). Additionally, Hugo Patterson, another co-inventor of the ’015 patent, testified at deposition that Dr. Li and Mr. Zhu developed the core deduplication concepts of the ’015 patent before March 2002. (D.I. 259-1 at 93). EMC also argues that there is ample evidence of diligent reduction to practice. (D.I. 258 at 21). Dr. Li and Dr. Patterson stated that the co-inventors of the ’015 patent dedicated significant time and resources to implementing the ’015 patent invention. (D.I. 259-1 at 90; D.I. 263 at 6-7). A series of technical specifications from 2002 support EMC’s claim to continuous effort to reduce the invention to practice. (D.I. 263-1 at 33-150; D.I. 263-2 at 1-108; see also D.I. 260 at 11-17; D.I. 263 at 6-7).'

Pure argues that the evidence of prior conception and reduction to. practice that EMC offers is insufficient as a matter of law to antedate the Krapp patent because it consists only in the uncorroborated testimony of co-inventors and the documents created and dated by the co-inyentors. (D.I. 298 at 13), Additionally, Pure argues that the Architecture Specification, whiteboard . photos, and technical specifications demonstrate at most that the inventors were in possession, of “key concepts and claim limitations,” not all limitations of the asserted claims. (Id. at 14).

In Procter & Gamble Co., a party sought to prove conception via the oral testimony of the inventor. 566 F.3d at 998. The court held that an unwitnessed entry in an inventor’s laboratory notebook was insufficient, without more, to corroborate the inventor’s testimony that he had conceived of the invention. Id. at 999. • Dr. Li’s whiteboard photos are analogous to the unwitnessed pages of a laboratory notebook and would therefore likely be insufficient on their own to corroborate Dr. Li’s testimony of prior conception. Similarly, as testimony of a co-inventor, Dr. Patterson’s testimony on its own would be insufficient to corroborate Dr. Li’s testimony as to the date of conception. See Medichem, S.A., 437 F.3d at 1170. In addition to the whiteboard photos and Dr. Patterson’s testimony, however, EMC has also offered the Architecture Specification and a series of technical specifications to corroborate the testimony of the ’015 patent inventors with respect to conception and diligence with respect to reduction to practice. The documentary evidence and Mr. Jestice’s expert opinions are consistent with Dr; Li’s and Dr. Patterson’s testimony. Thus, analyzing all of the pertinent evidence of prior conception, I conclude that EMC has satisfied its burden' of production. See Kridl, 105 F.3d at 1450; Price v. Symsek, 988 F.2d 1187, 1195 (Fed.Cir.1993). Pure does not offer evidence inconsistent with EMC’s claim to the earlier date of conception such that no reasonable jury could conclude that the inventors were in possession of the claimed invention prior to the' filing daté of the Krapp patent. Thus, Pure’s challenges with respect to conception and reduction to practice are subject to resolution by the jury.

There is likewise a genuine dispute of fact regarding whether the Krapp patent discloses each element of the asserted claims. (D.I. 199 at 17; D.I. 258 at 22; D.I. 298 at 15). Dr. Zadok opined that the Krapp patent discloses-each element of the asserted ’015 patent claims. (D.I.201-2 at 43-47). EMC’s, expert Mr. Jestice opined that the Krapp patent does not disclose “determining] whether one of the plurality of- data segments has been stored previously using a summary, wherein the summary is a space efficient, probabilistic summary of segment information,” as required by all of the asserted ’015 patent claims. (See D.I. 260-1 at 123). Mr. Jestice acknowledged that the list of non-unique identifiers disclosed in Krapp is a “probabilistic summary” as that term has been construed by the Court in the context of the ’015 patent. (D.I. 200-2 at 51-52). Still, Mr. Jestice explained that the Krapp patent does not disclose the probabilistic summary limitation of the asserted claims because the Krapp patent is directed toward improving the allocation of memory during runtime, which is' different than deduplicating data during storage as is claimed in the ’015 patent. (D.I. 260-1 at 19-20, 66-67,122). Mr. Jestice also opines that the Krapp patent does not disclose the dependent claim 7 step of “confirming whether the one of the plurality of data segments has been stored previously using a relatively high latency memory.” (D.I. 260-1 at 125). There is a thus a genuine dispute of fact, with res