US 6006227

I'll search for the specific patent number first, then summarize.

Let me verify the independent claims and any 2026 CAFC activity.

Search scope and method

I searched for the literal identifier 6006227 and its formatted equivalents (US 6,006,227 / US6006227A / application 08/673,255). I did not pad the result set with look-alike numbers. I also searched for CAFC/PTAB activity tied to this number.

Important caveat up front: I did not find any 2026 Court of Appeals for the Federal Circuit docket entry naming US 6,006,227. The Federal Circuit activity I could document for this patent is from 2011–2012 and later case numbers that I cannot verify as 2026 activity. I therefore cannot confirm any 2026 CAFC activity for this patent, and I am not going to imply otherwise. My search of "USPTO database" is likewise indirect — it is search-engine mediated, not a direct USPTO API query — so treat the bibliographic data below as reliable-where-cross-checked but not as an official USPTO extract.

Bibliographic summary — US 6,006,227

Assignment chain (as recorded): Freeman → LIFESTREAMS, INC. (1996-09-03); LIFESTREAMS → Yale University (1997-07-14); Gelernter → Yale University (1998-03-24); Yale → MIRROR WORLDS TECHNOLOGIES, INC. (2000-01-19); → RECOGNITION INTERFACE, INC. (2005-02-22); nunc pro tunc assignments through Recognition Interface, LLC / Plainfield Specialty Holdings I Inc. / Mirror Worlds, LLC (2008); → MIRROR WORLDS TECHNOLOGIES, LLC (2013-06-21).

Abstract (verbatim)

"A document stream operating system and method is disclosed in which: (1) documents are stored in one or more chronologically ordered streams; (2) the location and nature of file storage is transparent to the user; (3) information is organized as needed instead of at the time the document is created; (4) sophisticated logic is provided for summarizing a large group of related documents at the time a user wants a concise overview; and (5) archiving is automatic. The documents can include text, pictures, animations, software programs or any other type of data."

Independent claims in plain language

The patent has 33 claims. The independent claims I can verify are claim 1, claim 13, and claim 23.

Claim 1 — a computer system that organizes every data unit it receives or generates.
Plain language: the system creates a main stream holding every data unit the computer receives or generates, plus one or more substreams that can only draw from the main stream. It receives data units from other computers, generates its own data units, picks a timestamp for each unit, tags each unit with a chronological indicator carrying that timestamp, files each unit into the main stream in timestamp order, and keeps the main stream and substreams as persistent streams. (This is drafted in means-plus-function form — "means for…" — so its scope is tied to the corresponding structure in the specification and equivalents under 35 U.S.C. §112(f).)

Claim 13 — the method counterpart.
Plain language: same concept recited as steps — generate a main stream plus at least one substream (substreams only drawing from the main stream); receive data units from other computers; generate data units locally; select a timestamp for each; associate each with a chronological indicator bearing that timestamp; place each in the stream per its timestamp; and maintain the main stream and substreams as persistent streams.

Claim 23 — a second computer-system claim.
Plain language: "A computer system for organizing each data unit received by or generated by the computer system…" (the claim text I retrieved is truncated at this point; see uncertainty note below). Structurally it re-recites the main-stream/substream/timestamp/persistence architecture of claim 1 in system form, and — based on a district-court claim chart for this patent — a system claim in this family also recites display limitations: representing data units of a selected stream as document representations each including its timestamp, with on-screen order determined by timestamp; selecting which units are shown by picking a representation to display units within a range of a timepoint; and selecting representations with a pointing device so that a second document representation comprising an alternative version of the content is displayed (i.e., the spec's "browse card"/micro-browse-card concept).

Representative dependent claims (for context, not independent scope): timestamp selectable from past/present/future (claims 2, 14); text/video/audio/multimedia data (claims 3, 17); receiving data units from the World Wide Web or a client computer (claims 4, 5); displaying alternative versions of content (claim 6); summarizing/"squish" with continuously updated live overview documents (claims 7, 8); automatic archiving of units older than a time point while retaining the chronological indicator and/or an alternative-version data unit (claim 9); substreams generated from existing substreams (claim 11); access privileges and inter-stream access via a data unit indicating another stream (claims 18, 19); abbreviated-form display (claim 20); displaying selected time segments (claim 16).

Post-grant and litigation posture (cross-checked)

• Ex parte reexamination 90/010,506, filed 2009-04-23, was granted; the decision identified a substantial new question of patentability affecting claims 1–6, 9–17, 20, 22, and 25–29.
• PTAB CBM2016-00019, Apple Inc. et al. v. Mirror World Technologies LLC et al. (petition filed 2015-11-19; institution date 2016-05-26) — status "Not Instituted – Merits."
• District court: Mirror Worlds, LLC v. Apple, Inc., E.D. Tex. 6:08-cv-00088; also E.D. Tex. 6:13-cv-00419 and 6:13-cv-00941; S.D.N.Y. 1:17-cv-03473.
• CAFC: 11-1392 and 11-1393 (the Mirror Worlds v. Apple appeals; the Federal Circuit reversed the ~$625M jury verdict — judgment of non-infringement affirmed, with a partial dissent by Judge Prost). Later Federal Circuit case numbers listed for this family: 18-2276, 22-1600, 22-1709.
• Supreme Court: 12-1158 (Mirror Worlds v. Apple).
• Claim construction (Markman): the court construed "stream" as "a time-ordered sequence of documents that functions as a diary of a person or an entity's electronic life and that is designed to have three main portions: past, present, and future"; "main stream" as "a stream that is inclusive of every data unit, or document, received by or generated by the computer system"; "substream" as "a stream that is a subset of data units, or documents, yielded by a filter on a stream, the filter identifying certain documents within the stream"; "timestamp to identify" as "a date and time value that uniquely identifies each document."
• Commercial outcome: Network-1 Technologies acquired the Mirror Worlds portfolio in 2013; Apple settled for a reported $25 million non-exclusive license in 2016, following a reported $4.65M Microsoft settlement.

Uncertainty / limits of what I verified

1. Independent-claim count. The authoritative claim text supplied to me is truncated after claim 15, and my retrievals of the patent's claim set are also truncated. I verified claims 1, 13, and 23 as independent. I could not verify whether additional independent claims exist (e.g., a further system claim with the display-representation limitations, which one secondary district-court document labels as claim 25). Treat "independent claims are 1, 13, and 23" as high-confidence-but-not-exhaustive.
2. Claim 23's full text is not in my authoritative excerpt; my plain-language rendering of it is partly inferred from the claim-1 structure and a district-court claim chart, and I have flagged that.
3. Assignee. The patent face lists Yale University. Google Patents' "current assignee" field (Recognition Interface Inc / Mirror Worlds Technologies LLC) carries its own disclaimer that it "may be inaccurate," and I have not independently verified the current record owner.
4. 2026 CAFC dockets. I found no 2026 Federal Circuit activity for 6006227. Absence of evidence in my searches is not proof of absence — a PACER/CourtListener docket query would be needed to confirm the current state.
5. Date discrepancy in my instructions. My session metadata says 2026-09-30; your prompt says April 26, 2026. I flag this only because it affects the freshness boundaries of any "current litigation" statement; I did not reconcile it.
6. One related-number caution: the OCR in one litigation exhibit renders the continuation patent as "U.S. Pat. No. 6,638,318," whereas other sources give 6,638,313 for the '227 continuation. Per the strict no-auto-correct rule I am reporting both as-seen and adopting neither.

I'll research litigation involving US patent 6006227 specifically. Let me run several searches.

Let me dig deeper into each specific case.

Let me verify additional details — the Facebook case docket, the Federal Circuit appeals, and any other suits.

Scope and method

I searched for litigation and post-grant proceedings specifically involving U.S. Patent No. 6,006,227 ("Document Stream Operating System," filed June 28, 1996, issued Dec. 21, 1999, inventors Eric Freeman and David H. Gelernter, original assignee Yale University, later assigned through Lifestreams → Mirror Worlds Technologies → Recognition Interface → Plainfield/Mirror Worlds, LLC → Network-1's subsidiary Mirror Worlds Technologies, LLC). I did not include results for other patents in the same family (e.g., 6,638,313; 6,725,427; 6,768,999; 7,865,538; 8,255,439; 8,285,093) except where they were asserted alongside the '227 in the same case, which I flag.

Caveat: I have list-level information, not live PACER images for every docket. Statuses below reflect what the sources state; docket entries can change. This is not legal advice.

1. District court litigation asserting the '227 patent

(a) Mirror Worlds, LLC v. Apple Inc. — E.D. Tex.

Sources: UniCourt docket summary; Judge Nixes $625M Patent Ruling Against Apple (Courthouse News); Federal Circuit Says No To $626M Patent Verdict Against Apple.

(b) Mirror Worlds Technologies, LLC v. Apple Inc. et al. — E.D. Tex.

Sources: Network-1 Form 10-Q excerpt; Apple Pays $25 Million in Settlement Over Cover Flow, Time Machine Patents (MacRumors); 7/7/2015 opinion in 6:13-cv-00419-RWS; KIIP summary (Korean IP office).

(c) Mirror Worlds Technologies, LLC v. Dell Inc. et al. — E.D. Tex. (Microsoft/customer action, severed from (b))

Sources: Justia docket 6:2013cv00941; Plainsite docket; In re Dell Inc., 600 F. App'x 728; MacRumors.

(d) Mirror Worlds Technologies, LLC v. Facebook, Inc. / Meta Platforms, Inc. — S.D.N.Y.

Sources: Fed. Cir. opinion, 22-1600/22-1709, Dec. 4, 2024; Lexology case note; Schwabe, Latest Federal Court Cases 12/9/2024; Network-1 disclosure of the 2017 filing and 2020 reversal; S.D.N.Y. venue opinion, 17-cv-3473 (JGK).

2. Post-grant / PTO proceedings on the '227 patent (not litigation, but litigation-adjacent)

• Apple Inc. et al. v. Mirror Worlds Technologies LLC, PTAB CBM2016-00019 (Covered Business Method review of U.S. 6,006,227; App. No. 08/673,255). Filed Nov. 19, 2015; petitioner's counsel Gibson, Dunn & Crutcher LLP; patent owner's counsel Buchanan, Ingersoll & Rooney PC. Not instituted on the merits (institution decision May 26, 2016; status shown as "Not Instituted – Merits"). Network-1's filings note the Board found the challenged '227 claims "do not recite an abstract idea." Unified Patents PTAB page.
• Ex parte reexaminations of the '227. Apple-initiated reexaminations produced two reexamination certificates (including "Reexamination Certificate 6,006,227 C2," dated Dec. 20, 2011), which were cited as further validating the '227. One control number referenced is 90/010,506 (Notice of Intent to Issue dated Jan. 28, 2011). Network-1 10-Q; 6:13-cv-00419-RWS opinion.

3. Appellate and Supreme Court proceedings tied to the '227 (per the Google Patents litigation family links)

Sources: Google Patents US6006227A litigation links.

Additionally, a February 2025 Supreme Court filing (application for extension of time, docket 24A821) appears in the appendix to the Federal Circuit's Dec. 4, 2024 opinion, indicating further Supreme Court certiorari activity after the Meta affirmance. I could not confirm whether a cert petition was actually filed or its disposition. Supreme Court filing.

4. Bottom line

Yes — the '227 patent has a substantial litigation history. Four district court actions asserted it: 6:08-cv-00088 (E.D. Tex., Mirror Worlds v. Apple — $625.5M verdict vacated, affirmance on appeal); 6:13-cv-00419 (E.D. Tex., Mirror Worlds v. Apple et al. — settled, ~$25M Apple license); 6:13-cv-00941 (E.D. Tex., Mirror Worlds v. Dell/Microsoft et al. — dismissed Nov. 9, 2015; Microsoft license ~$4.65M); and 1:17-cv-03473 (S.D.N.Y., Mirror Worlds v. Facebook/Meta — final judgment of non-infringement affirmed by the Federal Circuit Dec. 4, 2024). Ancillary proceedings include PTAB CBM2016-00019 (not instituted), two ex parte reexaminations, the Federal Circuit appeals 11-1392 / 11-1393 / 18-2276 / 22-1600 / 22-1709, the mandamus decision In re Dell Inc., 600 F. App'x 728 (Fed. Cir. 2015), and a listed Supreme Court case 12-1158 (disposition unverified). The '227 patent itself expired June 28, 2016, and the patent family is now expired.

Items I could not confirm and would verify against PACER/the Unified Patents litigation portal before relying on them: the outcome of Supreme Court No. 12-1158; whether any cert petition was actually filed after the Dec. 4, 2024 Federal Circuit affirmance; and whether there are any additional license-only settlements (e.g., other Mirror Worlds portfolio licensees) not reflected in dockets.

I'll start by verifying the one PTAB reference in the family data (CBM2016-00019) and checking for any other AIA trials on this patent.

Found the CBM. Let me confirm its details and search for any additional AIA trials (including on sibling patents in the family).

Let me check for any other AIA trials — including on sibling patents and by Facebook/Meta.

Proceedings overview

One AIA trial proceeding on file for US 6,006,227 — CBM2016-00019 — and it never got past the threshold: 0 active, 0 claims invalidated, 0 claims sustained on the merits, 0 settlements, and 1 institution denial. Bottom line for a defendant: no claim of the '227 patent has ever been canceled or even reviewed on the merits by the PTAB. The petitioner (Apple/Best Buy) lost at institution on § 101 and § 112 ¶ 2, the rehearing request was denied, and no Final Written Decision ever issued. The patent's real losses came in district court and the Federal Circuit (summary judgment of non-infringement, affirmed 2024-12-04), not at the Board. Note the discrepancy you should carry forward: the structured "PTAB proceedings on file" block reports no ODP-indexed AIA trials, but the patent's own family record lists PTAB case CBM2016-00019 filed (Not Instituted - Merits). That CBM is real and is described below.

CBM2016-00019 — Apple Inc. et al. v. Mirror Worlds Technologies LLC

• Type: Covered Business Method review (AIA § 18; 37 C.F.R. § 42.301). Not an IPR or PGR.
• Filed: 2015-11-19 (petition; petitioner exhibits submitted 2015-11-20). Status verbatim: "Not Instituted - Merits." Termination/institution date listed as 2016-05-26, with the rehearing decision 2016-07-06.
• Real parties-in-interest: Apple, Inc.; Best Buy Stores, LP; BestBuy.com, LLC. Petitioner counsel: Gibson, Dunn & Crutcher LLP. Patent owner counsel: Buchanan, Ingersoll & Rooney PC. (Note: "Unified Patents PTAB Data" appearing in the family record is the data source attribution for the docket, not a petitioner — Unified Patents did not file this CBM.)
• Judge panel: APJs Thomas Giannetti (author), David McKone, and Barbara Parvis. McKone filed an opinion concurring in the result.
• Petition grounds: Challenged claims 13, 14, 17, 20, 22, 42, 44, and 55 on two bases only — (1) 35 U.S.C. § 101 ineligibility (claims directed to the abstract idea of "organizing items of information, i.e., 'data units,' in chronological order"); and (2) 35 U.S.C. § 112 ¶ 2 indefiniteness of "data unit." Notably, no prior-art § 102/§ 103 grounds were asserted.
• Institution decision: Denied, 2016-05-26 (Paper 12). The Board split the decision in two:
  • CBM eligibility (petitioner won): The majority held the '227 patent is CBM-eligible because the specification describes financial-service embodiments (checking accounts, securities, budgets), reasoning that the claims need only be broad enough to cover a financial product or service even without financial terms in the claim language. APJ McKone disagreed in the concurrence, reading Blue Calypso to require the financial nature to appear in the claims.
  • Merits (petitioner lost): The Board construed "data unit" as "document" (broadest reasonable interpretation, rejecting the district court's narrower "item of information that is of direct user interest in the user's timeline") and held the claims not indefinite. On § 101, the Board found claim 13 and its dependents were not directed to an abstract idea, quoting Enfish v. Microsoft (Fed. Cir. 2016-05-12) for the proposition that "some improvements in computer-related technology when appropriately claimed are undoubtedly not abstract" and holding the claims "are directed to improving computer functionality by improving the functionality of computer operating systems." It also found step two of Alice unmet, citing DDR Holdings, and rejected petitioner's analogy to In re TLI Communications. The Board authorized and received supplemental submissions on Enfish (Papers 9 and 11) before ruling. Order: "the Petition is denied and no covered business method patent review is instituted."
• Final Written Decision: None issued. No claim-level invalidity or patentability holding exists. Do not treat this proceeding as having sustained any claim on the merits — it was a threshold denial only.
• Settlement / termination: No settlement. Petitioner filed a Request for Rehearing on 2016-06-13, which the Board denied on 2016-07-06. Petitioner later sought a refund of post-institution fees (2017-05-16), and the Board issued a Notice of Refund (2017-05-25) — confirming nothing was instituted.
• Appeal: None from this proceeding. An institution denial is not appealable (§ 324(e)), and the hearing request was denied. The CAFC dockets in the family record (11-1392, 11-1393, 18-2276, 22-1600, 22-1709) arise from the district court cases, not from CBM2016-00019.
• Defensive value: Low direct value, high caution. Because there was no FWD, no § 325(e)(1) estoppel attached — Apple/Best Buy are free to raise § 101 and § 112 in district court, and any defendant today could file a fresh IPR on prior art without CBM-related estoppel. But the decision is also a negative precedent: the Board's reasoning that the '227 claims improve computer functionality (and its construction of "data unit" as "document") was later echoed by the CAFC in 2024 in construing "data unit" broadly as "an item of information." An eligibility attack on these claims is uphill; a prior-art attack was never tested at the PTAB.

Strategic summary

Claim status — CANCELED: none. SUSTAINED: none. UNTESTED: all of them. No AIA trial on US 6,006,227 ever reached a Final Written Decision, so every claim of the '227 patent — 1 through 33 as issued, plus the claims added by reexamination (including the challenged claims 42, 44, and 55) — remains formally intact at the PTAB. The claims that have actually been adjudicated are claims 13, 14, and 17 of the '227 patent, and only in the infringement context: the CAFC affirmed summary judgment of non-infringement on the "main stream" limitation on 2024-12-04, while holding "data unit" means "an item of information" (not merely information of "direct user interest"). Separately, the '227 patent was the subject of ex parte reexamination control no. 90/010,506, filed 2009-04-23, request granted, which produced reexamination certificates US 6,006,227 C1 and C2 (cited as Ex. 1001 at 17–23 in the CBM petition). That is a non-AIA USPTO proceeding, not a PTAB trial — but a defendant should pull the C1/C2 certificates before asserting anything about claim scope, since the challenged claims 42/44/55 in the CBM only exist because of that reexamination. I have not independently verified what the reexamination certificates confirmed or canceled; do not rely on this paragraph for claim-level reexam outcomes.

Estoppel landscape. This is the good news for a defendant. Because CBM2016-00019 was denied institution and no FWD issued, no § 315(e)(2) or § 325(e)(2) estoppel was triggered — not for Apple/Best Buy, and not for anyone else. There is no estoppel fence around prior art on this patent. Two additional points of leverage: (1) the CBM program sunset on 2020-09-16 under AIA § 18(a)(3), so a covered-business-method theory is no longer available to any new petitioner, and (2) the '227 patent has expired — the family record lists an anticipated expiration of 2016-06-28, and the CAFC noted that all three patents in the family "expired by the end of April 2018." An expired patent can still be IPR'd, and IPRs on expired patents are conducted under Phillips claim construction, which is generally petitioner-friendlier than the BRI the Board applied in 2016. Meanwhile, the Board's own 2016 construction of "data unit" (= "document") was narrowed in the patent owner's favor by the CAFC's 2024 broad construction ("an item of information") — a reminder that the intrinsic record here cuts toward breadth, which helps non-infringement and hurts validity-backed § 112 theories.

Pattern signals. The patent owner is a serial enforcer, not a passive holder: the family record shows district court actions in the Eastern District of Texas (6:08-cv-00088, 6:13-cv-00419, 6:13-cv-00941) and the Southern District of New York (1:17-cv-03473), plus CAFC appeals 11-1392/11-1393, 18-2276, and 22-1600/22-1709, a cert petition docket (Supreme Court No. 12-1158), and a 2025 cert-stage extension application (24A821, seeking to extend the cert deadline in No. 22-1600 from 2025-03-04 to 2025-05-02). Only one petitioner group ever filed at the PTAB, and it filed only one petition — no follow-on IPRs, no joinders, no second petitioner. Unified Patents is not in the chain despite appearing in the family record's data-source byline; the chain is Yale University → Mirror Worlds Technologies, Inc. → Recognition Interface, Inc./LLC and Plainfield Specialty Holdings I → Mirror Worlds, LLC → Mirror Worlds Technologies, LLC, with the portfolio later monetized through Network-1 Technologies (which publicly disclosed license agreements with Microsoft in November 2015 ($4.65M reported) and Apple in July 2016 ($25M reported)). The practical read: this is a well-asserted, well-lawyered, expired patent whose PTAB history is a single, failed eligibility challenge.

Recommended next steps

1. You have no FWD to hang your hat on. There is no PTAB holding to cite for invalidity — institution was denied on 2016-05-26. The decision denying institution is public and citable on the claim construction and § 101 reasoning: see the Board's decision (Paper 12) at https://www.ipwatchdog.com/wp-content/uploads/2016/05/CBM2016-00019-denying-institution.pdf and the docket at https://portal.unifiedpatents.com/ptab/case/CBM2016-00019. Secondary coverage: https://ipwatchdog.com/2016/05/26/ptab-cafc-enfish-covered-business-method-mirror-world-patent/ and https://natlawreview.com/article/ptab-relies-federal-circuit-s-recent-section-101-decision-to-deny-cbm-institution.
2. Lead with the CAFC non-infringement affirmance, not the PTAB. The dispositive win against the '227 patent is Mirror Worlds Technologies, LLC v. Meta Platforms, Inc., Nos. 2022-1600, 2022-1709 (Fed. Cir. 2024-12-04) (precedential), affirming SJ of non-infringement and construing "data unit" as "an item of information": https://caselaw.findlaw.com/court/us-federal-circuit/116739925.html. If the patent owner's demand letter rests on the old, narrower "direct user interest" reading of "data unit" — the one the district court adopted and the CBM panel refused to apply — that theory is inconsistent with the CAFC's construction.
3. Confirm the reexamination posture before you rely on claim numbering. Claims 42, 44, and 55 (challenged in the CBM) are not in the 33 claims printed in the patent; they are consistent with claims added via reexamination certificates C1 and C2. Order both certificates from the USPTO (PatentCenter, control no. 90/010,506) and confirm which claims are confirmed, which are canceled, and whether any new claims are enforceable — this is the only place where claim-level attrition on this patent is likely hiding.
4. If you want a PTAB vehicle, an IPR on prior art is the open lane. CBM is sunset; no estoppel attaches; no prior-art ground was ever presented to the Board; and the patent is expired, so Phillips construction applies. Note the statutory clock: institution decision within 6 months of a complete petition, FWD within 12 months of institution (35 U.S.C. § 314(b), § 316(a)(11)).
5. For damages exposure, mark the expiration date. The family record shows an anticipated expiration of 2016-06-28 (the CAFC opinion states all three family patents expired by the end of April 2018). Either way, § 286's six-year damages lookback from any current complaint likely reaches back only to a period when the patent may already have lapsed — plead expiration and get it stipulated early.
6. Do not overstate what the PTAB did. If you are drafting a defense or a licensing-position memo, say plainly: CBM2016-00019 was denied institution on 2016-05-26; no Final Written Decision issued; no claim was canceled; no claim was sustained on the merits. Any statement to the contrary is fabricated.

Caveats on confidence: I verified the proceeding number, petitioner/RPIs, filing date, panel, grounds, denial date, rehearing denial, and refund events from the Unified Patents case docket and the Board's own denial decision as surfaced by search. I did not personally open the PTAB E2E docket, and I did not verify the claim-level outcomes of ex parte reexamination 90/010,506 — treat that as an open item.

I'll start by pulling what I can verify about this patent's assignment chain and litigation history.

Let me dig into the Network-1 acquisition and try to find reel/frame and correspondent details.

Let me try to locate the actual reel/frame records and the recording correspondent for these assignments.

Ownership & Assignment Analysis — US 6006227 ("Document Stream Operating System")

Verification sources used: Google Patents legal-events reassignment table for US6006227A; PlainSite entity profile for Mirror Worlds, LLC; Network‑1 Security Solutions / Network‑1 Technologies SEC Form 8‑K (2013‑05‑28) and press releases at ir.network‑1.com; PTAB/Unified Patents docket CBM2016‑00019.

Data limitation, stated up front (read before the timeline). This analysis was assembled from the public sources above. I was unable to retrieve two of the fields you asked for — the USPTO reel/frame numbers and the correspondent of record (the attorney/firm that filed each recording) — because Google Patents' legal-events table does not expose them and I did not have live access to Assignment Center search results in this session. Every reel/frame and correspondent field below is marked "not retrieved" rather than guessed. Any section that would depend on a repeat-correspondent analysis is therefore returned as unclear, not as a finding. You should re-run this against https://assignmentcenter.uspto.gov/ (patent‑number search "6006227") to populate those columns before relying on the report for a litigation or diligence purpose.

Inventors

Pattern note (unusual but not a fire-sale tell): the two inventors' rights traveled by different routes to the same destination — Freeman → Lifestreams, Inc. (≈2 months post‑filing) → Yale (≈13 months post‑filing); Gelernter → Yale directly (≈21 months post‑filing). Both are back‑dated/curative‑flavored conveyances to the university, which is typical of a university spin‑out being papered up after the fact, not of inventors bailing out. There is no evidence of inventors departing the assignee within 12 months on adverse terms — the same two inventors later founded Mirror Worlds Technologies, Inc., which took the patent back from Yale in 2000. Both inventors were later disclosed as consultants to Network‑1 and associated with Lifestreams Technologies Corporation (Network‑1 press release, 2013‑07‑19) — i.e., they stayed attached to the family across the whole chain.

Original assignee

Yale University (New Haven, Connecticut) — listed as original assignee on the face of the issued patent per Google Patents, and the record owner at issue (1999‑12‑21).

• Primary line of business: higher education and university research. Yale is an operating institution; it does not manufacture products.
• Did it ship a product embodying the claims? No. The claims were commercialized (imperfectly) by a later assignee/licensee: Mirror Worlds Technologies, Inc. shipped Scopeware (released March 2001), described by Network‑1 as the product embodying aspects of the portfolio. Scopeware sold poorly and the company announced it would "cease operations effective May 15, 2004."
• Current status: operating (university). Its interest in this patent was conveyed out in 2000 (see below), so Yale has no current stake.

Note on the record chain that follows: Yale → Mirror Worlds Technologies, Inc. (2000) is a university spin‑out / commercialization transfer, not a sale to a stranger. Everything after that is where the NPE character accumulates.

Assignment timeline

Reel/frame not retrieved for any entry (see data limitation above). Dates below are the recording dates shown in Google Patents' legal‑events table, which mirrors the USPTO reassignment records; execution dates are shown in parentheses only where a source other than the record itself supplies them.

• 1996‑09‑03 (executed) / recorded 1996 — Reel not retrieved

  • Conveyance: Assignment
  • Assignor: FREEMAN, ERIC
  • Assignee: LIFESTREAMS, INC.
  • Correspondent: not retrieved
  • Context: founder's assignment of inventor rights into his own startup, executed ~2 months after filing.

• (executed n/d) / recorded 1997‑07‑14 — Reel not retrieved

  • Conveyance: Assignment
  • Assignor: LIFESTREAMS, INC.
  • Assignee: YALE UNIVERSITY, a corporation by charter granted by the General Assembly of the Colony and State of Connecticut
  • Correspondent: not retrieved
  • Context: consolidation of rights at the university (startup → university).

• (executed n/d) / recorded 1998‑03‑24 — Reel not retrieved

  • Conveyance: Assignment
  • Assignor: GELERNTER, DAVID H.
  • Assignee: YALE UNIVERSITY
  • Correspondent: not retrieved
  • Context: inventor → university; completes Yale's record title on the eve of prosecution/issuance.

• (executed n/d) / recorded 2000‑01‑19 — Reel not retrieved

  • Conveyance: Assignment
  • Assignor: YALE UNIVERSITY
  • Assignee: MIRROR WORLDS TECHNOLOGIES, INC.
  • Correspondent: not retrieved
  • Context: university spin‑out — the patent moves to the founders' commercial vehicle (Scopeware).

• (executed n/d) / recorded 2005‑02‑22 — Reel not retrieved

  • Conveyance: Assignment
  • Assignor: MIRROR WORLDS TECHNOLOGIES, INC.
  • Assignee: RECOGNITION INTERFACE, INC.
  • Correspondent: not retrieved
  • Context: distressed transfer — happens ~9 months after the operating company ceased operations (May 15, 2004). Per Network‑1's 8‑K, Recognition Interface is "a New York based investment partnership that financed the commercialization of the Patent Portfolio prior to its sale to Mirror Worlds, LLC and also retained an interest in the licensing proceeds." This is a litigation‑financing / proceeds‑participation arrangement, not an operating acquisition.

• (executed n/d) / recorded 2007‑11‑28 — Reel not retrieved

  • Conveyance: Assignment (entity conversion / change of form)
  • Assignor: RECOGNITION INTERFACE, INC.
  • Assignee: RECOGNITION INTERFACE, LLC
  • Correspondent: not retrieved
  • Context: internal reorg — corporate form change only.

• (executed n/d, retroactive) / recorded 2008‑03‑12 — Reel not retrieved

  • Conveyance: Nunc pro tunc assignment (curative)
  • Assignor: MIRROR WORLDS TECHNOLOGIES, INC.
  • Assignee: RECOGNITION INTERFACE, INC.
  • Correspondent: not retrieved
  • Context: curative re‑papering — the record designates this nunc pro tunc, i.e., filed to fix/back‑date the 2005 link.

• (executed n/d, retroactive) / recorded 2008‑03‑13 — Reel not retrieved

  • Conveyance: Nunc pro tunc assignment
  • Assignor: RECOGNITION INTERFACE, INC.
  • Assignee: RECOGNITION INTERFACE, LLC
  • Correspondent: not retrieved
  • Context: curative confirmation of the 2007 conversion.

• (executed n/d, retroactive) / recorded 2008‑03‑13 — Reel not retrieved

  • Conveyance: Nunc pro tunc assignment
  • Assignor: RECOGNITION INTERFACE, LLC
  • Assignee: PLAINFIELD SPECIALTY HOLDINGS I INC.
  • Correspondent: not retrieved
  • Context: transfer into the holding vehicle on the eve of litigation.

• (executed n/d, retroactive) / recorded 2008‑03‑13 — Reel not retrieved

  • Conveyance: Nunc pro tunc assignment
  • Assignor: PLAINFIELD SPECIALTY HOLDINGS I INC.
  • Assignee: MIRROR WORLDS, LLC (Tyler, Texas; per PlainSite, a subsidiary of Plainfield Specialty Holdings I, Inc.)
  • Correspondent: not retrieved
  • Context: pre‑litigation standing transfer — this is the assignee that sued Apple the next day (Mirror Worlds, LLC v. Apple, Inc., No. 6:08‑cv‑00088, E.D. Tex., filed 2008‑03‑14).

• 2013‑05‑21 (executed, per Asset Purchase Agreement) / recorded 2013‑06‑21 — Reel not retrieved

  • Conveyance: Assignment (asset purchase)
  • Assignor: MIRROR WORLDS, LLC (elsewhere in Network‑1's S‑1 referred to as "Looking Glass LLC (formerly Mirror Worlds, LLC)")
  • Assignee: MIRROR WORLDS TECHNOLOGIES, LLC — a newly formed, wholly owned subsidiary of Network‑1 Security Solutions, Inc. (now Network‑1 Technologies, Inc., NYSE American: NTIP)
  • Correspondent: not retrieved
  • Context: transfer‑to‑asserter / portfolio monetization sale. Consideration per the 8‑K: $3,000,000 cash + 875,000 warrants at $1.40 + 875,000 warrants at $2.10. Recognition Interface, LLC signed a consent to the assignment and retained a proceeds interest. The very next day (2013‑05‑22) the new owner filed infringement suits on the '227 against Apple, Microsoft, HP, Lenovo, Lenovo (US), Dell, Best Buy, [Samsung Electronics America](/litigations/by-defendant/Samsung%20Electronics%20America), and Samsung Telecommunications America in E.D. Tex., Tyler Division.
  • Record discrepancy worth noting: Google Patents lists the 2013‑06‑21 event twice (identical entries, assignor "MIRROR WORLDS, LLC"), while PlainSite's table for the 2013 transfer shows Plainfield Specialty Holdings I Inc. as assignor with a 2013‑05‑22 record date. The chain‑of‑title substance (Mirror Worlds, LLC → Network‑1's Mirror Worlds Technologies, LLC) is confirmed by the APA and 8‑K; the duplicate/assignor discrepancy should be resolved against the actual reel images.

Latest recorded owner of record: MIRROR WORLDS TECHNOLOGIES, LLC (Network‑1 subsidiary). Google Patents lists current assignees as RECOGNITION INTERFACE INC and MIRROR WORLDS TECHNOLOGIES LLC — this dual listing appears to be an artifact of Google's assignee extraction across the chain; the operative record transfer is the 2013 asset purchase.

Timeline diagram

timeline
    title Ownership of US 6006227
    1996 : Filed by Gelernter and Freeman
         : Freeman assigns to Lifestreams Inc
    1997 : Lifestreams assigns to Yale University
    1998 : Gelernter assigns to Yale University
    1999 : Patent issued
    2000 : Yale assigns to Mirror Worlds Technologies Inc
    2004 : Operating company ceases operations
    2005 : Assigned to Recognition Interface Inc
    2007 : Recognition Interface converts to LLC
    2008 : Curative assignments recorded
         : Plainfield to Mirror Worlds LLC
         : Suit filed against Apple
    2010 : Jury awards 625.5 million
    2011 : Verdict vacated on JMOL
    2013 : Portfolio sold to Network-1 subsidiary
         : Suit filed against nine vendors
    2016 : Patent expires
         : Apple settles for 25 million
    2017 : Suit filed against Facebook
    2022 : Federal Circuit affirms non infringement

NPE / troll-pattern signals

1. Shell‑entity transfer — PRESENT. The chain leaves any operating entity at the 2005‑02‑22 recording (Mirror Worlds Technologies, Inc. → Recognition Interface, Inc.), a "New York based investment partnership" that financed the portfolio and retained a share of licensing proceeds (Network‑1 8‑K, 2013‑05‑28). It then passes through Recognition Interface, LLC (2007‑11‑28), Plainfield Specialty Holdings I Inc. and Mirror Worlds, LLC (both 2008‑03‑13 nunc pro tunc) to Mirror Worlds Technologies, LLC, a newly formed wholly owned subsidiary of the public patent‑monetization company Network‑1 (2013). Concrete corroboration beyond naming: Mirror Worlds, LLC's recorded address is 4540 Kinsey Dr, Tyler, TX 75703 (PlainSite), and Network‑1's 10‑K/10‑Q confirm Mirror Worlds Technologies, LLC leased a ~420 sq ft office in Tyler, Texas — a litigation venue address, not a product‑development site.

2. Known asserter in the chain — PRESENT. Current recorded owner Mirror Worlds Technologies, LLC is the assertion vehicle of Network‑1 Technologies, Inc. (NTIP), whose stated business is "the acquisition, development, licensing, and monetization of intellectual property." Network‑1's own 10‑K reports $47,150,000 of revenue generated from the Mirror Worlds Patent Portfolio as of FY2023. Assertion activity on the '227 specifically: E.D. Tex. 6:08‑cv‑00088 (Apple, 2008); E.D. Tex. 6:13‑cv‑00419 and 6:13‑cv‑00941 (nine vendors, 2013); S.D.N.Y. 1:17‑cv‑03473 (Facebook/Meta, 2017); plus PTAB CBM2016‑00019 (Apple et al. v. Mirror Worlds Technologies LLC, filed 2015‑11‑19, not instituted on the merits).

3. Repeat correspondent across the chain — UNCLEAR / NOT VERIFIABLE. I could not retrieve the correspondent of record for any recording (see data limitation). Note for the follow‑up run: PTAB counsel of record (Gibson, Dunn & Crutcher for the CBM petitioner; Buchanan, Ingersoll & Rooney PC as patent‑owner representative) is litigation counsel and must not be conflated with the assignment correspondent. Populate this field from the reel images before treating it as a signal.

4. Cascading transfers — PRESENT. Six recorded reassignments in roughly 37 months: 2005‑02‑22 → 2007‑11‑28 → 2008‑03‑12 → 2008‑03‑13 (×3). Three of those are nunc pro tunc curative assignments all recorded on a single day, 2008‑03‑13, and the 2007 conversion, the 2008 curative set, and the 2013 sale all run through the same Recognition Interface / Plainfield / Mirror Worlds orbit. The clustering of paper on one date, plus the fact that the successor entity took the same "Mirror Worlds" name under different corporate parents, is the concrete evidence — not the names alone.

5. Pre‑litigation transfer — PRESENT (twice, textbook).

   • The nunc pro tunc chain executed/recorded 2008‑03‑12 to 2008‑03‑13 placed title in Mirror Worlds, LLC, which filed against Apple on 2008‑03‑14 — 1 day later.
   • The 2013‑05‑21 Asset Purchase Agreement placed title in Network‑1's Mirror Worlds Technologies, LLC, which filed against nine vendors on 2013‑05‑22 — 1 day later. This is the strongest signal in the file: the acquisition and the assertion were simultaneous by design.

6. Bankruptcy fire‑sale — UNCLEAR. There is a distressed transfer (operating company ceased operations 2004‑05‑15; rights conveyed to the financing entity on 2005‑02‑22), but I found no Chapter 7/11 filing, no docketed bankruptcy sale, and no confirmed receivership for Mirror Worlds Technologies, Inc. Treat the 2005 transfer as a distressed/financing‑driven conveyance that I cannot characterize as a bankruptcy sale on this record.

7. Privateering — NOT PRESENT (as classically defined). Nobody in the chain is an operating company asserting the patent against its own competitors. The operating entity (Mirror Worlds Technologies, Inc.) was defunct a decade before the monetization campaign. The closest analogue is the Recognition Interface proceeds‑participation/financing arrangement disclosed in the Network‑1 8‑K — a third‑party financing interest in licensing outcomes — which is NPE‑adjacent rather than operating‑company privateering.

8. Defensive aggregator — NOT PRESENT. The chain terminates at an active asserter (Mirror Worlds Technologies, LLC / Network‑1), not at RPX, AST, LOT, Unified Patents, or OIN. The third‑party licenses taken (Microsoft ≈$4.65M in 2015; Apple $25,000,000 in July 2016, non‑exclusive) are settlement licenses to the asserter, not defensive aggregation. Inverse check: the patent expired 2016‑06‑28 (20 years from filing), and the last Federal Circuit appeal (22‑1709, affirmed per PACER) ended in non‑infringement for the '227, '538 and '439 — so the asset is now both expired and claim‑scope‑neutralized.

Verdict

NPE — high confidence.

Two strong, independently documented signals drive this: (i) pre‑litigation standing transfers timed to the day — the nunc pro tunc chain recorded 2008‑03‑12/13 handed the patent to Mirror Worlds, LLC, which sued Apple on 2008‑03‑14 (No. 6:08‑cv‑00088), and the 2013‑05‑21 Asset Purchase Agreement handed it to Network‑1's newly formed Mirror Worlds Technologies, LLC, which sued nine vendors on 2013‑05‑22 (E.D. Tex. 6:13‑cv‑00419 / 6:13‑cv‑00941); and (ii) transfer‑to‑asserter — the current recorded owner is the wholly owned monetization subsidiary of public PAE Network‑1 Technologies, Inc., which reports $47.15M of Mirror Worlds portfolio revenue, with consideration of $3M cash plus 1,750,000 warrants and a retained proceeds interest held by Recognition Interface, LLC. The cascading 2005→2007→2008→2013 chain through Recognition Interface / Plainfield Specialty Holdings I / Mirror Worlds, LLC supplies an independent third strong signal. Reel/frame citations and a repeat‑correspondent analysis are outstanding — I could not retrieve them in this session and have not substituted guesses; verify at https://assignmentcenter.uspto.gov/ (patent number 6006227) or https://assignment.uspto.gov/patent/index.html before filing.

I'll search for the patent's front-page citations and prior art references, since the full text provided does not include the "References Cited" section.

I have candidate citation lists, but I need to verify which belong to US6006227 specifically (the list I found came from a continuation, US6725427). Let me verify.

I found a key reexamination document with the Examiner's actual rejections. Let me pull the full reference lists for US6006227 from the reexamination record and the patent's own front page.

1. Patent identification (interpreted literally)

US 6,006,227 A — "Document stream operating system"

• Application No. 08/673,255; filed 1996‑06‑28; issued 1999‑12‑21
• Inventors: Eric Freeman; David H. Gelernter
• Original assignee: Yale University; later Mirror Worlds / Recognition Interface; current listed assignees include Recognition Interface Inc. and Mirror Worlds Technologies LLC
• Prior art date: 1996‑06‑28 | Status: Expired – Lifetime (anticipated expiration 2016‑06‑28)
• Classifications: G06F16/93 (document management), G06F16/168, G06F16/188, G06F16/192, G06F16/30; Y10S707/912–917
• Litigation/administrative history: CBM2016‑00019 (Apple v. Mirror Worlds; not instituted), CAFC 11‑1392, 11‑1393, 18‑2276, 22‑1600, 22‑1709; district cases including 6:08‑cv‑00088 (E.D. Tex., which also produced the ex parte reexamination of the '227 patent); an ex parte reexamination request filed 23 April 2009.

⚠️ Literal‑ID caution. A search for "6006227" also returns (a) JP 6006227 B2 — a 2016 Thomson Licensing patent on distinguishing cold boot from warm boot — which is unrelated to US 6,006,227; and (b) non-patent uses of "6006227" (a City of Detroit contract number; a laboratory product code LLG‑6006227). These are different identifiers and were excluded.

2. Sources used and their limits

I was not able to reach USPTO PatentCenter/Global Dossier directly in this session, so I relied on: the authoritative full text of the patent supplied in the prompt (Google Patents), the Espacenet bibliographic/claims record for US6006227(A), the ex parte reexamination determination reproduced in the E.D. Tex. docket (cases.justia.com, 6:08‑cv‑00088), the Unified Patents/PTAB portal, and a Google Patents citation table retrieved via a family member (see §5 caveat).

The full text supplied in the prompt includes the specification's numeric literature citations [1]–[4] but not the front‑page "References Cited" block. Everything below is labeled by source and confidence.

3. Prior art actually applied by the Examiner during original prosecution

From the reexamination determination quoting the non‑final Office action of 15 September 1997 on App. 08/673,255:

Notes on §102 theory for these:

• The Gelernter 1994 Washington Post article is by a co‑inventor and was published more than one year before the 1996‑06‑28 filing — hence the §102(b) statutory bar. It is the single most damaging reference in the file: it is cited in the specification itself as reference [4] ("One such system is outlined in a 1994 article [4]. However, this article fails to address many of the disadvantages…"). Its disclosure overlaps claim 1's core concept (a chronologically ordered document stream) and claims 2–4 (past/present/future timestamps; heterogeneous media content), which is why the Examiner mapped it to 1–4 and 8–11.
• US 5,530,859 (Tobias II) was applied to essentially the same independent claims 1–5 and 8–12 plus dependent claims 6–7 by §103. Because it issued in June 1996 — just before the '227 filing — its applicability rests on §102(a)/(e) timing rather than §102(b); a §102(b) analysis would fail, which is worth checking against the actual issue date printed on that patent.
• The Microsoft Outlook 1995–96 manual was applied to claims 1, 3, 6–8, 10 (§102(a)) — i.e., the Examiner treated a commercial product manual (Outlook's chronological inbox / journaling / time‑ordered messaging) as anticipating the stream‑based organizing claims.

The '227 patent nevertheless issued 1999‑12‑21, meaning these rejections were overcome (amendment/argument or a showing that the references lacked the "substream from main stream," "persistent streams," and "chronological indicator" limitations of claim 1).

4. Prior art in the 2009 ex parte reexamination (SNQ found)

Requester alleged claims 1–6, 9–17, 20, 22, 25–29 unpatentable over:

The determination states these were not of record in the original '227 file and not cumulative to the art of record, and that a substantial new question of patentability was raised for claims 1–6, 9–17, 20, 22, 25–29. The Board/Examiner further mapped:

• claims 1–6, 10–17, 20, 25–29 → Mander (§102(e), since US 6,243,724 post‑dates the '227 filing but claims earlier priority);
• claims 9 and 22 → Mander + Retrospect (the archiving/backup aspect — claim 9 in '227 recites "means for archiving a data unit associated with a timestamp older than a specified time point…" and claim 22 is a comparable dependent claim in the issued claim set);
• claims 15, 16, 26–28 → the snippet is truncated at this point, so I cannot confirm the reference(s) asserted for those claims.

I could not confirm the final reexamination certificate outcome from the retrieved sources; the patent nonetheless ran to statutory expiration in 2016, which suggests the claims survived (possibly amended).

5. Face‑of‑patent US patent citations (⚠️ family‑level list — read the caveat)

The Google Patents "Patent Citations" table I could retrieve was rendered on the page for US 6,725,427 B2 ("Document stream operating system with document organizing and display facilities"), which is a divisional/continuation in the same family (US 6,725,427 ← 10/013,150 ← 09/398,611 ← 08/673,255 = the '227 application). I could not independently verify in this session which of these appear on the face of the '227 patent itself.

Caveats on this table:

1. US 6,243,724 (issued 2001) cannot have appeared on the face of US 6,006,227, which issued in 1999 — it is a citation from the later family members (and from the 2009 reexamination). Do not attribute it to the '227 front page.
2. US 5,890,177 and US 5,912,668 post‑date the '227 filing (1996) and could only have been of record as §102(e) art, if at all.
3. The "Examiner" vs. "Applicant" column tells you who cited the reference (Examiner‑cited art carries more weight as prior art of record).
4. This table gives no claim‑by‑claim §102 mapping; Google Patents citation tables never do. Only the Office actions (§3) and the reexamination (§4) provide claim mappings.
5. Most relevant substantively: US 5,159,669 (Trigg et al.) and US 5,535,063 (Lamming) (time‑ordered information streams), US 5,283,864 (Knowlton) and US 5,287,448 (Nicol et al.) (stacked/overlapping document representations and glance views), and US 5,530,859 (Tobias) — which the Examiner actually used.

6. Non‑patent literature cited of record (11 items, per the family citation table)

1. Gelernter, David, The Cyber‑Road Not Taken, The Washington Post, Apr. 3, 1994 (Applicant) — also applied by the Examiner under §102(b)/§102(f).
2. Nelson, Theodor H., The Right Way To Think About Software Design, in The Art of Human‑Computer Interface Design, Brenda Laurel (Ed.), 1990, pp. 235–243 (Applicant).
3. Lansdale, M., The Psychology of Personal Information Management, Applied Ergonomics, Mar. 1988, pp. 55–66 (Applicant).
4. Malone, Thomas W., How Do People Organize Their Desks? Implications for the Design of Office Information Systems, ACM Transactions on Office Systems, Vol. 1, No. 1, Jan. 1983, pp. 99–112 (Applicant).
5. Gelernter, The Cyber‑Road Not Taken, The Washington Post, Apr. 3, 1994, 9 pgs (Applicant) — duplicate citation.
6. Freeman, Lifestreams Project Home Page, 1994–1996, 3 pgs (Applicant).
7. Freeman, Lifestreams for the Newton, Steve Mann's Developer Corner, Oct. 1995, 5 pgs (Applicant).
8. Steinberg, Lifestreams, WIRED 5.02, Feb. 1997, 11 pgs (Applicant).
9. Freeman et al., Lifestreams: Organizing your Electronic Life, AAAI Fall Symposium, AI Applications in Knowledge Navigation and Retrieval, Nov. 1995, Cambridge MA, 6 pgs (Applicant).
10. Getting Results with Microsoft Outlook, Microsoft Corp., 1995–1996, pp. 28–29 (Applicant) — also applied by the Examiner under §102(a)/§103(a).
11. Cowart, Mastering Windows 3.1, 1992, ch. 12, pp. 396–417 (Applicant).

The specification's own reference list [1]–[4] corresponds to items 2, 4, 3 and 1 above (Nelson; Malone; Lansdale; Gelernter) — Google's transcription renders "Lansdale" as "Landsdale" and Nelson's title as "Sesign" for "Design"; these are transcription typos, not different documents. Items 6–9 (the inventors' own Lifestreams publications, 1994–1997) are self‑citations and would be §102(b) bars against the 1996 priority date only for those published more than a year before filing (i.e., the 1994–1995 ones).

7. Consolidated §102 picture

The only references with a documented, claim‑specific §102 theory are:

Note that these are the Examiner's and the Requester's stated positions, not judicial findings: the '227 patent issued over the §3 rejections, and I could not verify from the retrieved sources whether the reexamended claims were cancelled, confirmed, or amended.

8. What I could not verify (stated explicitly)

• The exact front‑page "References Cited" block of US 6,006,227 itself (the table in §5 was retrieved from a family member's page and includes at least one impossible entry, US 6,243,724).
• Whether US 5,890,177, US 5,912,668 and US 6,243,724 appear on the '227 face (they cannot have appeared at issue in 1999 and, for the latter, for a further two years).
• The precise per‑claim mappings for Lucas, Thompson‑Rohrlich, Magellan and Inside Macintosh (the docket snippet truncated the Requester's claim‑by‑claim list at "Claims 15, 16, and 26–28…").
• The final outcome of the 2009 ex parte reexamination (certificate text).
• Direct USPTO PatentCenter/Global Dossier confirmation; no USPTO API/database access was available in this session, so the above rests on the patent full text plus public reproductions of the file record.

I'll ground this in the prior-art record available for this patent — the four references cited in the specification itself, plus the prior art that surfaced in the reexamination and CBM proceedings. Let me search for those.

Good — I found the reexamination prior-art list and the CBM grounds. Let me pull more detail on the reexam office actions (including any §103 rejections) and the CBM petition's art.

Strong prior-art record emerging. Let me pin down the full claim set (claims 23–33) and the reexamination outcome, since §103 must be assessed claim-by-claim.

Obviousness Analysis — US 6,006,227 under 35 U.S.C. § 103

Scope note. The instruction was to work from the prior-art material on the patent's page. That material comprises the four references cited in the specification's own reference list — [1] Nelson (1990), [2] Malone (Jan. 1983), [3] Lansdale (Mar. 1988), [4] Gelernter, The Washington Post (Apr. 1994) — plus the examiner's/court's prior-art sets. Because a § 103 analysis requires the references actually applied, I supplement the page's list with the prior art the USPTO and Apple put on the record in ex parte reexam 90/010,506 and in Mirror Worlds, LLC v. Apple, Inc., No. 6:08-cv-00088 (E.D. Tex.). I flag explicitly which tier each reference comes from.

1. Governing law and framing

• Pre-AIA § 103(a) applies. The application was filed 1996-06-28, before the AIA's effective date. So the analysis is: scope and content of the prior art, differences from the claims, level of ordinary skill, and secondary considerations (Graham v. John Deere), with the KSR gloss that a motivation to combine may come from the design incentive, market forces, the nature of the problem, or "common sense," and that a predictable combination of known elements is obvious.
• Claims 1, 6, 9–12 and 25 are means-plus-function claims. The Markman order held the § 112 ¶ 6 presumption was not rebutted for all eighteen "means for …" terms, and that Mirror Worlds' reliance on function-as-structure failed. A § 103 rejection must therefore map each "means" to disclosed structure or its equivalents — which narrows these claims but also makes them easier to read on the prior art than pure functional claiming would. (Markman order)
• Claim-set caveat (important). The 33 claims given to me are the issued set. The PTAB's CBM decision refers to reexamination certificates US 6,006,227 C1 and C2 and to challenged claims 13, 14, 17, 20, 22, 42, 44, and 55 — i.e., the enforceable claim set now extends at least to claim 55, with text I do not have. My claim-by-claim conclusions below cover only the original 33 claims. Any conclusion about the certificate claims is necessarily provisional. (CBM2016-00019 institution decision)
• ID discipline. The reexamination request lists the Lucas reference as U.S. Patent No. 5,449,330; other documents in the same record render the Lucas reference as 5,499,330. Both appear in the source material; I report them as found and adopt neither. (reexam request)

2. Tier 1 — the prior art printed on/derived from the patent page itself

3. Tier 2 — the references actually applied (the real § 103 record)

Sources: reexam request (PA-A…PA-G, claim charts); reexam Office action; Feiner invalidity report; Keller rebuttal.

4. Ground-by-ground analysis

Ground 1 — Mander alone (§ 102(e)); i.e., Mander as the primary § 103 reference

The examiner mapped, element by element: "main stream" ← Mander's pile (col. 3, ll. 5–20); "substream" ← Mander's subpile (col. 3, ll. 60–64; Figs. 18a–18b); "data unit" ← Mander's documents; receiving data units ← Mander's e-mail network (col. 8, ll. 20–23); generating data units ← word-processing documents (col. 24, ll. 8–18). Mander's subpiles are formed by automatic content matching, so each subpile contains items drawn from the parent pile. This reads directly on claim 1's "each substream for containing data units only from the main stream."

Strength: high for the structural core. Mander's own disclosure supplies the motivation for auto-subpiling.
Weakness: Mander's piles are user-created desktop artifacts of modest size — expert testimony in the case put typical piles at "not … more than about 50 documents" because of screen space. Mander does not disclose a single universal stream that receives every document received or generated. That is the lynchpin limitation, and Mirror Worlds later prevailed on exactly this at summary judgment (construction of "data unit" and "main collection"). (Mirror Worlds Techs. v. Facebook construction, CAFC affirmance)

Ground 2 — Mander + Retrospect (+ Kuzma for claim 4)

Claims reached: 1–6, 9, 10–17, 20, 22, 25–29 (the examiner's § 103 grounds for claims 9/22 and claim 4; the rest rode on the § 102(e) Mander finding).

Motivation (from the record, not hindsight): Automatic backup/archiving (i) frees local disk space, (ii) protects against accidental deletion, (iii) removes reliance on user memory, and (iv) both Mander and Retrospect target the same platform (Macintosh). Backing up "seldom-used or old files" to archival media is the ordinary reason a file-system designer adds archiving, and the result is entirely predictable. Dr. Feiner's report develops this explicitly and the examiner adopted it. This defeats the "no motivation" attack on claim 9's "archiving a data unit … older than a specified time point while retaining the respective chronological indicator."

Kuzma (US 5,771,355) for claim 4 supplies WWW/HTTP delivery of e-mail and attachments; motivation = network bandwidth efficiency (don't transmit an attachment unless the recipient wants it). That is the classic KSR-sanctioned efficiency rationale.

Ground 3 — Lucas + Lotus Magellan

Claims reached (per the request's claim chart CC-B): 1–6, 9–17, 20, 22, 25–29, § 103.

Lucas discloses "screen objects organized along strand paths" — a spatial, path-ordered document display, which supplies the receding/foreshortened stack and the display-by-segment limitations (claims 15, 16, 20, 26–28). Lotus Magellan supplies full-text indexing and result sets drawn from an underlying corpus — the substream/"find" concept and the "subset" relationship. Together they give a time/position-ordered document display plus filtered subsets.

Motivation: Both address the same problem — retrieving a handful of relevant documents out of a large corpus without a folder hierarchy — and Magellan's index is a natural, predictable addition to Lucas's path-organized display to let the user define what subset is shown.

Ground 4 — Thompson-Rohrlich + Inside Macintosh

Claims reached: 1–6, 10–17, 20.

Thompson-Rohrlich ("Smart Folders") teaches dynamic, content-filtered folders. Inside Macintosh: Files teaches per-file creation/modification timestamps in the catalog B-tree, plus aliases (reference documents pointing to other files) and the desktop database. Combining gives: content-filtered collections (substreams) over a store in which every file already carries a chronological indicator, plus a reference-document mechanism mapping onto the calling card feature.

Motivation: Sorting/ordering a file list by its existing creation-date field is a routine, well-known use of an existing data field — the KSR "known technique, known field" rationale. No new structure is required; the Mac OS catalog already stored the timestamp.

Ground 5 — Mander + Lucas

Claims reached: 15, 16, 26, 27, 28 — i.e., the display-of-selected-time-segments claims. Mander supplies the pile/subpile ordering; Lucas supplies the path-organized, foreshortened display with the ability to traverse. Motivation: give the pile a workable visual presentation when the collection is large.

Ground 6 — MEMOIRS (+ Retrospect / Lucas / Thompson-Rohrlich / Lotus Magellan / SDM / On Location / Mander)

Claims reached (Feiner): '227 claims 13, 14, 15, 16, 17, 20, 22 — i.e., the independent method claim 13 itself.

This is the ground with the highest payoff and the highest risk. MEMOIRS (Lansdale, Young & Bass, 1989) is a personal information system with time-ordered/context-based retrieval from a single personal collection. If it discloses a universal personal store with context-filtered subsets, claim 13 falls. But Mirror Worlds fought this hard: Dr. Keller's rebuttal opined that MEMOIRS does not anticipate or render the claims obvious, and — critically — asserted teaching away: combining Thompson-Rohrlich/Inside Macintosh with Mander, Piles and Lucas "would make the desk top metaphor more complicated — it would not improve the '852 patent but would make it worse." (Keller rebuttal, ¶¶ 240–248)

Ground 7 (synthesis) — Gelernter '94 + Mander + Retrospect + Inside Macintosh

This is the KSR "common sense / design incentive" combination and, in my view, the strongest prima facie case against the broad original claims:

• Gelernter '94 supplies the admitted core: a chronologically ordered stream of a person's documents as the storage model, including the future/present/past orientation.
• Mander supplies piles/subpiles with automatic content-based division → main stream / substream.
• Inside Macintosh supplies timestamps stored on every file → "chronological indicator having the respective timestamp."
• Retrospect supplies automatic archiving of old items while retaining an index → claim 9 / claim 22.

Motivation, stated without hindsight: (a) the patent itself concedes the stream model was already published by its own co-inventor in 1994; (b) Malone's pile findings and Nelson's and Lansdale's critiques established, years earlier, a known problem (hierarchy + naming is a poor fit for personal information) with known solutions (piles, virtual collections, retrieval-time organization); (c) the ordinary designer adding the known elements (timestamped files, automatic backup, content filters) to the admitted stream model would expect predictable results — chronological ordering without user naming, which is precisely the patent's stated objective list.

5. Where the § 103 case is genuinely weak

A candid analyst must flag these, because they are the reasons the claims survived:

1. The "universal main stream" limitation. Claim 1 requires the main stream to receive "each data unit received by or generated by the computer system." No Tier-1 or Tier-2 reference is shown to disclose an exhaustive, universal store. Mander's piles are selective; Magellan indexes a directory tree; MEMOIRS is a bounded personal database. Mirror Worlds won non-infringement on exactly this construction twice (district court and CAFC 2024). A § 103 challenger must therefore supply an explicit rationale for making the store all-inclusive, not merely assert it.
2. "Substreams containing data units only from the main stream." The filtering relationship — as opposed to a folder that merely happens to contain copies — is the architectural core. Mander's subpiles and Smart Folders are close, but the invariant (everything in a substream is necessarily in the main stream, and the main stream is unaffected by substream creation/destruction) needs a clean mapping.
3. "Persistent streams" with the block-at-the-end/simultaneous-access semantics described in the spec. The reexam record does not show a reference teaching the concurrency semantics; Retrospect's persistence is backup persistence, not a live persistent data structure.
4. Means-plus-function exposure cuts both ways. Under the Markman order, the eighteen "means for …" terms are governed by § 112 ¶ 6. The challenger must identify corresponding structure for each; conversely, Mirror Worlds will argue the narrow disclosed structures are not met. This makes a system claim (1, 25) harder to invalidate than the method claim 13.
5. Teaching away. The Keller declaration articulates a "combination makes the desktop metaphor worse" argument. Whether that rises to teaching away or merely less preferred is a factual question; if accepted, it defeats the motivation prong for Grounds 4 and 6.
6. Secondary considerations are real here. The record shows the patentee obtained a reported $25M Apple license and $4.65M Microsoft settlement, that Apple's CEO circulated the Scopeware material in 2002, and that Apple marketed Spotlight as reducing "the 20-year-old Mac/Windows system of nested folders to irrelevance." That is evidence both of commercial success and of copying/industry recognition, which a patentee can array against any prima facie case.
7. Prosecution/reexam survival. Claims 7, 8, 18, 19, 21, 23, 24, 30–33 were never even subjected to the reexamination, and the C1/C2 certificates confirm/amend and add claims. Separately, the PTAB declined to institute CBM2016-00019 — but note carefully: the CBM was a § 101 and § 112 challenge only; there was no § 103 ground in that petition, so the non-institution decision says nothing about obviousness. (PTAB decision; IPWatchdog; Unified Patents docket)

6. Bottom line

Overall: There is a substantial, record-grounded prima facie § 103 case, strongest against the broad original claims 1 and 13 and weakest against claims 7–8 (live summarization) and the "persistent, universal main stream" limitation. The critical vulnerabilities are (i) the absence of art disclosing an all-inclusive master stream, (ii) the § 112 ¶ 6 narrowing of the system claims, (iii) the patentee's teaching-away evidence, and (iv) significant secondary considerations in the form of industry licensing and copying.

7. Confidence and limits

• High confidence: the identity and dates of the Tier-2 references (Mander, Retrospect, Lucas, Magellan, Thompson-Rohrlich, Inside Macintosh, Kuzma) and the examiner's/Feiner's mapping, because these come from the reexam Office action and the litigation expert reports themselves.
• High confidence: the four Tier-1 references and the patent's admission about Gelernter [4].
• Moderate confidence, flagged: independent-claim identity for 23 and 25 (text not in my authoritative excerpt; inferred from the Markman "means for" listing and the reexam's subject-claim list).
• Low confidence / cannot assess: the C1/C2 reexamination certificate claim text (claims to at least 55) and the final disposition of reexam 90/010,506. I have the initiation documents and the rejection, not the certificate.
• Explicit non-finding: The PTAB's CBM non-institution is not evidence of non-obviousness — no § 103 ground was raised there.
• Date note: My session metadata says 2026-09-30 while the task header says April 26, 2026; nothing in this analysis turns on the difference, but any "currently pending" statement about the family would.