US 6278837

I'll search for litigation/docket information on this patent while relying on the authoritative patent text provided.

Let me run targeted checks for litigation/docket records specific to this patent number.

Findings: US Patent 6,278,837

Bottom line up front: I located the authoritative patent document and bibliographic record, but my searches found no CAFC (Federal Circuit) 2026 docket activity and no district-court or PTAB litigation referencing this specific patent number. The litigation-oriented searches returned no 6278837 case hits at all — only false-positive collisions (an unrelated Lithuanian company-registry notice and an Illinois state court case that merely contain the digit string). I therefore cannot confirm any 2026 appellate or litigation activity, and I am not asserting any.

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Bibliographic summary

Source: https://patents.google.com/patent/US6278837/en (fetched 2026-09-30).

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Abstract (as issued)

A multichannel recording and reproducing apparatus comprising an input/output circuit; a buffer for temporarily storing multichannel video data; a disc unit; a disc interface; a user interface for receiving recording/reproducing commands and a file name; a control circuit that obtains one of N video channel circuits; a filing circuit that controls files and determines first and second disc addresses for recording and reproducing; and an access control circuit that accumulates commands and supplies them when the disc interface is idle, giving priority to either recording or reproduction per priority data. The input/output circuit may include a digital satellite broadcast receiver and a separator for demultiplexing the broadcast data into multiple video data sets.

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Plain-language overview of the independent claim (claim 1)

Only claim 1 is independent; claims 2–3 (fragment/segment file structure and endless vs. successive recording), 4 (phase-shifted vertical sync signals), 5 (multi-terminal independent channel assignment), and 6 (satellite broadcast receiver + separator) all depend from it. Claim 1 covers a system with eight cooperating elements:

1. Input/output means with N video channel circuits handling N channels of video (N any natural number).
2. N data buffers — one per channel — temporarily holding that channel's video.
3. Memory means (a disc unit) that stores the video.
4. Memory interface means (disc interface) that moves data between the buffers and the memory.
5. User interface means that receives four things from a user: request channel data (which channel to use), a recording command, a reproducing command, and a corresponding file name.
6. Control means that activates the requested channel and forwards the commands, file name, and channel data.
7. Filing means with a table that (a) maps a file name to a first address on recording to create a file, and (b) later uses the same name-to-address relation to derive a second address for playback — i.e., a file-allocation/address-translation function.
8. Access control means that is the queuing/scheduling heart of the claim: it accumulates incoming record and reproduce commands, watches whether the memory interface is busy, and when the interface is free, dispatches the queued commands in an order set by priority data — favoring either recording or reproduction. The memory interface then performs each transfer using the command, the relevant address, and the channel data.

The novelty emphasis (and the point distinguishing it from prior art such as U.S. Pat. No. 4,943,854, the cited video-surveillance system) is the combination of (i) file-name-based address mapping in the filing circuit with (ii) user-selectable record-vs-playback prioritization in the access control circuit, so that whichever operation the user deems time-critical maintains its data rate.

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Confidence / uncertainty notes

• High confidence on title, inventors, assignee, dates, abstract, and claim structure — these come directly from the patent text you supplied and the Google Patents record.
• High confidence on legal status: the record shows a lapse for failure to pay maintenance fees effective 2013-08-21 (37 CFR 1.362), so the patent is expired and cannot support a live 2026 infringement suit.
• Low confidence / no authoritative information on CAFC 2026 dockets or any litigation for this patent. My searches returned nothing tying 6278837 to a Federal Circuit appeal or to any 2026 case. If you need a definitive docket answer, that requires a direct PACER/CAFC docket query and/or a commercial service (Docket Navigator, Docket Alarm) rather than open web search, which I could not access here.
• The claim text itself contains a drafting anomaly: claim 1 recites both "reproducing command" and, later, "said reading command from said access control means" — I am reading these as referring to the same playback command, but I flag it as a literal inconsistency in the issued claim.

I'll search for litigation involving US patent 6278837 across patent litigation sources.

Let me search more targeted litigation databases.

Let me check more specific litigation databases and court records.

Litigation Search: US Patent 6,278,837

Bottom line

I found no known litigation involving US Patent 6,278,837 ("Multichannel recording and reproducing apparatus," Matsushita Electric Industrial Co., Ltd.; granted Aug. 21, 2001).

Despite multiple targeted searches across patent-litigation aggregators and open court-record collections, no district court, ITC, or Federal Circuit case asserting this specific patent surfaced.

What I searched and what returned

Notably, the only trace of "6278837" in a litigation-adjacent document was an ex parte reexamination exhibit (control no. 90/007,750 re: U.S. 6,233,389, the TiVo patent) that merely lists "6278837" among many patent numbers in a third party requester's correspondence packet. That is a passing reference in a reexam paper trail, not a lawsuit or an assertion of US 6,278,837. I mention it only so you know why the string appears.

Important limitations (stated explicitly rather than assumed)

1. Paywalled dockets not directly searched. The most reliable litigation sources — Docket Navigator, Lex Machina, RPX Insight, and PACER itself (and premium searches within Unified Patents' portal and Docket Alarm) — are behind credentials. My search was limited to what is publicly indexable. A negative result there is not conclusive proof that no case ever existed; it means no publicly indexed case surfaced.
2. The patent is expired, which sharply reduces the likelihood of any assertion activity. Per the USPTO legal-events data in the authoritative patent text: maintenance fees lapsed and the patent expired Aug. 21, 2013 for non-payment of maintenance fees (37 CFR 1.362), with status "Expired – Fee Related." An expired, non-asserted patent owned by an operating company (Panasonic/Matsushita) is consistent with a no-litigation history.
3. No auto-correction applied. I interpreted "6278837" / "6,278,837" literally and excluded results for similar but different numbers (e.g., various "'883" patents, 6,233,389, etc.).

Conclusion

Based on all publicly available sources consulted, there is no known patent litigation involving US Patent 6,278,837. Accordingly, I cannot provide plaintiff(s), defendant(s), jurisdiction, case number, filing date, or outcome — because no such case was found.

If you need a definitive negative, the confirmatory step would be a Docket Navigator or Lex Machina "patent-at-issue" search on 6,278,837 (and its EP/DE counterparts EP0884902B1 / DE69826182T2, including any European opposition proceedings, which are separate from U.S. litigation and which I also did not find indexed). I can walk through how to run that query, but I won't fabricate a case list to fill the gap.

I'll verify the ODP default against live sources before reporting.

Let me run a few more targeted checks for any post-grant activity under alternate identifiers.

Proceedings overview

Total AIA trial proceedings on U.S. Patent 6,278,837: 0. There are no IPRs, PGRs, or CBMs to break down — no active proceedings, no claims invalidated, no claims sustained, no settlements, and no institution denials, because no petition has ever been filed. The USPTO ODP structured block returns an empty proceedings list, and targeted live searching (PTAB docket/patent-number and party queries) surfaced no petition, institution decision, FWD, or Federal Circuit appeal naming this patent. Bottom line for a defendant: there is nothing at the PTAB to point to — but that matters far less than the fact that the patent itself lapsed in 2013. Your defense is expiry and the statute of limitations, not an IPR record.

Because there are no proceedings, the per-proceeding template is not populated below; instead I document the verification and then the strategic reality.

Verification performed (no proceeding numbers to report)

Misattribution warning (important if you are relying on a search hit): three same-/similar-numbered patents polluted the results and are not this patent:

• U.S. Pat. No. 5,828,837 (EIT Holdings, "Computer Network System and Method for Efficient Information Transfer") — litigated against Yelp, different patent.
• The "’627 Patent" in IPR2020-00483 — a mobile-phone camera handle, a 2015-filed patent; a different number entirely.
• U.S. Pat. No. 6,036,877 / 6,036,878 — unrelated third-party citations.

Do not let any of these be imported into a 6,278,837 invalidity narrative.

Strategic summary

Claim status: all six claims are UNTESTED. Claims 1–6 of 6,278,837 have never been before the PTAB. Nothing is canceled, nothing is confirmed. Claim 1 is the sole independent claim (a multichannel record/reproduce apparatus with N channel circuits and buffers, a memory interface, user interface, control means, filing means with an address table, and an access control means that arbitrates accumulated record/reproduce commands by priority data); claims 2–6 depend from it (fragment/segment file structure; endless vs. successive recording; phase-offset vertical sync generation; terminal-to-channel assignment; digital satellite broadcast receive + separation). There is therefore no PTAB-derived claim construction, no estoppel, and no FWD reasoning to work from.

Estoppel landscape: none exists. § 315(e)(2) estoppel only attaches to a petitioner who obtains an FWD. With no petitioner, no ground is foreclosed and every § 102/§ 103/§ 112 theory remains available to any party. That cuts both ways — it also means there is no adverse PTAB ruling to lean on.

The real posture — the patent is dead on the merits of timing, not validity. The maintenance-fee chronology in the structured data is the headline:

• 2005-01-26 — 4-year fee paid
• 2009-01-23 — 8-year fee paid
• 2013-04-01 — maintenance fee reminder mailed
• 2013-08-21 — lapse for failure to pay maintenance fees
• 2013-09-16 — information on status: patent expired due to nonpayment of maintenance fees under 37 CFR 1.362
• 2013-10-08 — "Lapsed due to failure to pay maintenance fee," effective 2013-08-21

The recorded "anticipated expiration" of 2018-06-08 (20 years from the 1998-06-08 filing) never arrived; the patent terminated roughly five years early. Under 35 U.S.C. § 286, damages reach back only six years from suit. A suit filed on or after 2019-09-16 could not reach any period of enforceable patent term — and it is now 2026. There is no live prospective infringement and no recoverable past-damages window. (Caveat: I state this from the recorded fee-lapse events and § 286 as a matter of arithmetic; confirm current bibliographic status in Patent Center before relying on it in a filing, and note that an expired patent can in principle be revived under 37 CFR 1.378 on unintentional delay if the lapse was unintentional — I found no revival record, but I did not exhaustively verify that.)

Pattern signals: absent. No serial petitioner (there is no petitioner at all), no patent-owner appeal activity, no defensive aggregator (no Unified Patents or similar filing). The patent never attracted an IPR in its ~12 years of enforceable life — consistent with a narrow, expired-in-2013 asset rather than a well-asserted campaign patent. Its own prosecution depended on a 1997 JP priority filing (JP9-151783, 1997-06-10; JP10-062787, 1998-03-13), and the family includes EP0884902B1 and DE69826182T2 — but I did not verify whether the EP counterpart drew an EPO opposition, and EPO post-grant activity is outside this task's scope regardless.

Recommended next steps

• If you received a demand letter citing 6,278,837, do not build an IPR budget. There is nothing to invalidate that time hasn't already taken care of. Lead with: (1) the recorded fee lapse and expiration effective 2013-08-21 / status entry 2013-09-16, citing the Patent Center legal-events record; and (2) § 286's six-year damages bar, which foreclosed any recovery well before today. Confirm both in Patent Center and Google Patents US6278837B1 before sending.
• No PTAB milestones to track. With zero proceedings, there is no institution-decision deadline, no oral hearing, and no statutory 1-year FWD due date in play. PTAB E2E has no case for this patent.
• If your adversary represents otherwise, demand the proceeding number. Any IPR/PGR/CBM number they cite will be for a different patent — most likely 5,828,837 or the handle '627 — and you can rebut with the ODP empty result and the searches above. If a petition somehow appears later, the PTAB decisions portal (https://www.uspto.gov/patents/ptab/decisions) and CourtListener are the places to re-check; nothing on file today suggests one is imminent given the patent's expiration.
• Residual § 112 angle, if you ever need it on the merits: claim 1 is drafted in means-plus-function form throughout ("inputting and outputting means," "memory means," "filing means," "access control means"), which invites § 112(f) definiteness scrutiny and a corresponding-structure dispute. I flag it as an untested, unpressed argument — no PTAB or court has ever construed any term of this patent.

I'll verify the assignment record and correspondent details before writing this up.

Ownership & Assignment Analysis — US 6,278,837

Scope note up front, because it changes the shape of this report: the only assignment evidence I could actually retrieve is what is embedded in the authoritative patent record you supplied (the Google Patents "Legal Events / Assignment" table). My attempts to pull the underlying Assignment Center record — including the recorded assignment PDFs (reel/frame images) and their correspondence data — did not return the documents before I exhausted my search steps. I therefore have reel/frame, conveyance type, assignor, assignee, execution and recording dates for three entries, but I do NOT have the correspondent of record for any of them. I will not invent one. Where the brief asks for a correspondent and I cannot supply it, I say so and explain how to retrieve it.

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Inventors

Patterns worth flagging (documentation, not fire-sale):

• Omissive-inventor correction 4.5 years late. Noriko Tanaka is a named inventor on the issued patent (she appears in the Google Patents inventor field and in the 2003-01-29 corrective assignment), yet she was omitted from the original 1998 assignment and only added in 2003 — two years after issue. This is a chain-of-title housekeeping defect, not an NPE tell, but it is the kind of gap an acquisition-side diligence reviewer would flag.
• Name mis-transliteration. "Satch" → "Satoh" correction (recorded 2001-05-16) shows the original recording was filed with a misspelled assignor name.
• No inventor-departure signal determinable. I found no evidence any inventor left Matsushita within 12 months of the 1998-06-08 filing. All four are presumed Matsushita employees (the assignments run to Matsushita as employer), and there is no post-1998 assignment activity of any kind from any inventor — consistent with steady employment rather than a pre-fire-sale exodus. Absence of contrary evidence, not proof.

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Original assignee

Matsushita Electric Industrial Co., Ltd. (1006, Oaza Kadoma, Kadoma-shi, Osaka, Japan) — the entity named on the issued patent and the assignee on all three recorded assignments.

• Primary line of business: consumer and professional electronics; this patent sits squarely in its VTR / optical-disc video recording business (apparatus for multichannel video recording/reproduction on a disc unit — a surveillance- and professional-recording-class product).
• Did it ship a product embodying the claims? The specification is written as an implementation disclosure for a multichannel disc-based video recorder, and the patent's own background cites the Chuo Electronics surveillance system (US 4,943,854) as the commercial context. Matsushita was an active vendor of video surveillance and professional VTR/disc recording equipment in this era. I can confirm the business context; I did not locate a specific commercial model number in the record, so treat "shipped an embodying product" as probable but not documented to a model level.
• Current status: operating, not acquired or dissolved. Matsushita Electric Industrial Co., Ltd. renamed itself Panasonic Corporation (effective 2008-10-01) and later reorganized as Panasonic Holdings Corporation (2022-04-01), which is why Google Patents lists the "Current Assignee" as Panasonic Holdings Corp. Note for the record: that is a change of name / corporate reorganization, not a recorded patent assignment on this patent's chain — no assignment document for it appears in this patent's legal-events record.

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Assignment timeline

Three recorded assignments, all to the same assignee (Matsushita). There is no post-issuance transfer to any third party on this chain.

• 1998-05-28 (executed) / recorded 1998-06-08 — Reel 009233 / 0746

  • Conveyance: Assignment (original inventor→employer)
  • Assignor: Ryuji Yasukohchi; Akio Uesugi; Masaki Satch (sic — later corrected to Satoh)
  • Assignee: Matsushita Electric Industrial Co., Ltd., Japan
  • Correspondent: Not exposed in the record I could retrieve. The Google Patents legal-events entry carries only the assignor/assignee/reel-frame and an effective date; the Assignment Center correspondence-data field was not surfaced, and I could not open the recorded PDF (assignment-pat-009233-0746 style) within my search budget. I cannot name the correspondent. Do not treat this as "none."
  • Context: Ordinary employee assignment to employer at filing. No fire-sale, no aggregator, no licensing entity.

• 2001-05-16 (recorded; effective date stated as 1998-05-28) — Reel 011804 / 0605

  • Conveyance: Corrective Assignment — "to correct the name of the assignor, filed on 06/08/1998, recorded on reel 9233, frame 0746"
  • Assignor: Masaki Satoh
  • Assignee: Matsushita Electric Industrial Co., Ltd., Japan
  • Correspondent: Not available in the retrieved record (same limitation as above).
  • Context: Error correction only — fixes "Satch" → "Satoh." No ownership change.

• 2003-01-29 (recorded; effective date stated as 1998-05-28) — Reel 013403 / 0804

  • Conveyance: Corrective Assignment — "to add a fourth assignor to the document previously recorded on reel 009233, frame 0605"
  • Assignors: Ryuji Yasukohchi; Akio Uesugi; Masaki Satoh; and Noriko Tanaka
  • Assignee: Matsushita Electric Industrial Co., Ltd., Japan
  • Correspondent: Not available in the retrieved record.
  • Context: Error correction only — adds the omitted fourth inventor. No ownership change.

Literal discrepancies I am flagging rather than silently reconciling (per operating rules):

1. The 2003 corrective assignment describes the document it corrects as recorded at Reel 009233, Frame 0605, but the original assignment was recorded at Reel 009233, Frame 0746, and the 2001 corrective assignment occupies Reel 011804, Frame 0605. The "frame 0605" reference in the 2003 text therefore points at the wrong frame (or conflates the 2001 corrective reel/frame with the 1998 original). I report it as written and do not auto-correct it.
2. The 2001 corrective assignment purports to correct a name "filed on 06/08/1998" while its own stated effective date is 1998-05-28 (the assignment execution date). These are consistent (executed 05-28, filed/recorded 06-08) but the mixed phrasing is worth noting.

Post-issuance events (not assignments):

• 2005-01-26 — FPAY, year-4 maintenance fee paid
• 2009-01-23 — FPAY, year-8 maintenance fee paid
• 2013-04-01 — REMI (maintenance-fee reminder mailed)
• 2013-08-21 — LAPS (lapse for failure to pay maintenance fees)
• 2013-09-16 — STCH (patent discontinued; expired under 37 CFR 1.362)
• 2018-06-08 — anticipated expiration

Foreign-family context (not US assignments, listed for completeness): EP 0884902 B1 and DE 69826182 T2 are the same family; JP H1169279 A is the JP publication. I found no European opposition or post-grant transfer records for the EP member in the sources I could reach.

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Timeline diagram

timeline
    title Ownership of US 6278837
    1997 : JP priority application filed
    1998 : US application filed 08 Jun
         : Inventors assign to Matsushita
    2001 : Corrective assignment Satoh name
         : Patent issued 21 Aug
    2003 : Corrective assignment adds Tanaka
    2008 : Matsushita renamed Panasonic
    2013 : Maintenance fee lapse 21 Aug
    2018 : Anticipated expiration 08 Jun

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NPE / troll-pattern signals

1. Shell-entity transfer — NOT PRESENT. The chain has exactly three recorded conveyances, all running to Matsushita Electric Industrial Co., Ltd. (Reels 009233/0746, 011804/0605, 013403/0804). No "IP / Licensing / Holdings / Ventures" LLC ever appears as assignee. No single-purpose Delaware or Texas entity. Nothing to cite beyond the three Matsushita-to-Matsushita entries.

2. Known asserter in the chain — NOT PRESENT. No assignee on this chain matches Acacia, Marathon, IV, IPNav, Wi-LAN/Conversant, Mosaid, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Document Generation Corp, Spangenberg entities, or any RPX/Unified high-frequency-plaintiff list. Current assignee is Panasonic Holdings Corp, an operating manufacturer, and it is a name-change successor, not a purchaser.

3. Repeat correspondent across the chain — UNCLEAR / NOT ASSESSABLE. I could not obtain the correspondent of record for any of the three entries (see retrieval limitation above). Because the signal is defined by recurrence, and I have zero correspondent data points, this is not assessable — not "not present." How to close it: run the patent number at the USPTO Assignment Center (or the legacy index at assignment.uspto.gov), open each of Reels 009233/0746, 011804/0605, and 013403/0804, and read the "Correspondence Data / Correspondent Name" field plus the recorded PDF's signature block. Given that all three are Matsushita-internal documents handled by Matsushita's own IP operation (Panasonic's US filings of this era commonly route through its Panasonic Patent Center in Washington, DC, e.g., the Kenji Kamata / ppc@us.panasonic.com correspondent seen on later Panasonic recordings), I would expect the same or an affiliated in-house/outside firm on all three — but I will not assert that as a finding without the actual field.

4. Cascading transfers — NOT PRESENT. No chained LLCs, and the three entries span 1998→2003, with two of the three being same-day-effective corrections, not transfers. No clustering of transfers in any 24-month window.

5. Pre-litigation transfer — NOT PRESENT. There is no transfer at all, and (consistent with the previously generated litigation section) no infringement suit naming this patent was found. A within-6-months pre-suit assignment cannot exist because it cannot be tied to a suit.

6. Bankruptcy fire-sale — NOT PRESENT. Neither Matsushita Electric Industrial Co., Ltd. nor Panasonic Corporation entered Chapter 7/11 in connection with this patent. No trustee, no Sherwood Partners-type assignment, no sale in bankruptcy appears anywhere on the chain.

7. Privateering — NOT PRESENT. No transfer to an NPE asserting on Matsushita/Panasonic's behalf. The patent remained with the operating manufacturer through expiration.

8. Defensive aggregator (anti-NPE) — NOT PRESENT. The chain does not terminate at RPX, AST, LOT Network, Unified Patents, or OIN. It terminates at the original operating company.

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Verdict

Insufficient data — with the important qualification that the insufficiency is confined to correspondent data, not to the ownership chain.

Justification: The only recorded conveyances on this patent are the original inventor→employer assignment (Reel 009233/0746, executed 1998-05-28, recorded 1998-06-08) and two Matsushita-internal corrective assignments (Reels 011804/0605 and 013403/0804). All three name Matsushita Electric Industrial Co., Ltd. as assignee; there is no post-issuance transfer to any third party, no NPE, and no litigation. The one field I could not populate — the correspondent of record, which is the field this analysis is built to exploit — is the reason for the "insufficient data" call rather than a clean "no NPE" finding: without it I cannot test signal #3 (repeat correspondent), the single most diagnostic tell in an NPE chain. Substantively, though, the affirmative evidence is benign: a single-assignee, no-transfer chain ending in an operating manufacturer, on a patent that expired 2013-08-21 for non-payment of maintenance fees.

Verify at: https://assignmentcenter.uspto.gov/ (patent number search: 6278837), mirrored at https://assignment.uspto.gov/patent/index.html — open each of the three reels/frames above and read the "Correspondent Name" field to close signal #3.

Confidence: High on the three reel/frame entries, dates, conveyance types, and the absence of any third-party transfer (these come directly from the authoritative patent record). Low/none on correspondents. If you have authenticated Assignment Center access, the correspondent fields on Reels 009233/0746, 011804/0605, and 013403/0804 are the exact items to pull and paste back to me — I'll then finalize signal #3 and re-run the verdict.

I'll analyze the prior art cited against US 6,278,837. Let me verify the cited references and their details.

Let me verify the remaining cited references.

Prior-Art Analysis — US 6,278,837 B1

Scope note. I could not issue a live USPTO PatentCenter/Open-Data API query from this environment (no authenticated USPTO endpoint access), so I grounded the citation set in the authoritative patent record you supplied (which mirrors the USPTO file wrapper) and cross-checked individual references against Google Patents / Espacenet / USPTO.report. Where a reference's full text was not retrievable, I say so and rely on the bibliographic data recorded in the '837 front page. I interpreted the numbers literally and did not substitute similar numbers (e.g., I did not fold in US 6,233,389 or other "'837/'883" collisions).

Governing law. US 6,278,837 has an effective filing date of 1998-06-08 with a foreign priority of 1997-06-10 (JP 9-151783; later JP 10-062787, 1998-03-13). It is therefore a pre-AIA patent (filed before 2013-03-16), so pre-AIA 35 U.S.C. §§ 102(a), 102(b), 102(e) and § 103 apply. For § 102(b) the critical date is 1996-06-10 (one year before the earliest priority date). Only claim 1 is independent; claims 2–6 all depend from it, so any § 102 hit must first clear claim 1's eight elements.

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1. The nine cited references (the § 102/§ 103 art of record)

The '837 front page lists nine patent citations relevant to this analysis:

Note the secondary "Patent Citations (9)" and primary "Citations (8)" lists in the record are the same nine documents (US 6,091,883 is the ninth). US 4,943,854 is the sole reference the applicant itself discusses as the background art in the "Description of the Prior Art."

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2. Reference-by-reference analysis

① US 4,943,854 — Shiota & Takeuchi, "Video surveillance system for selectively selecting processing and displaying the outputs of a plurality of TV cameras" (Chuo Electronics) — granted 1990-07-24

• Cited for: the entire concept of a multichannel video recorder.
• Disclosure (verified): multiple TV cameras; means to time-division multiplex the camera signals onto a single VTR; ID control signals inserted in vertical blanking to identify camera/event/time; selection and reproduction of still or sequential still pictures from the multiplexed recording; event-driven weighting of frame counts. Source: https://patents.justia.com/patent/[4943854](/patent/4943854) ; https://uspto.report/patent/grant/4943854.
• § 102 assessment: This is the closest single reference to the general environment of claim 1 (multichannel acquisition, shared recorder, selective playback). However it lacks several claim-1 elements: no file-name-based address table (filing means), no distinct reproducing command queued against recording command, and no user-selectable priority data for record-vs-playback arbitration. It cannot anticipate claim 1 in full. It is most relevant as a § 103 base, and it is the art the applicant conceded.
• Claims it could arguably touch: claim 1 only obliquely (multichannel + shared recorder + selective reproduction); claims 2–6 not disclosed (no fragment/segment file, no endless mode, no phase-shifted syncs, no multi-terminal channel assignment, no satellite demultiplexing).

② US 5,371,602 — Tsuboi, Yasuoka & Okamoto, "Picture data recording/reproducing system … with plural reproduction modes" (Hitachi) — granted 1994-12-06

• Disclosure (verified): intra-frame + inter-frame coding of moving picture data, interleaved/multiplexed onto a recording medium; on reproduction, either the full moving-picture signal or only the intra-frame row is read out to yield different reproduction modes. Source: https://worldwide.espacenet.com/publicationDetails/biblio?CC=US&NR=[5371602A](/patent/5371602A) ; https://uspto.report/patent/grant/[5371602](/patent/5371602).
• § 102 assessment: Relevant to the compression / selective read aspects of the "video channel circuits" and to the reproduction-mode capability. It says nothing about N independent channels with per-channel buffers, a file-name→address table, or priority-based command queuing. No § 102 anticipation of any claim.
• Claims it could touch: marginally relevant background to claim 1 (compression) and, very loosely, the round/endless replay idea of claim 3 — but nothing more.

③ US 5,355,353 — "Data recording system of magneto-optic type" (Binet Co., Ltd.) — granted 1994-10-11

• Disclosure: a magneto-optic data recording system (disc-type random-access recording). Full text not retrieved during this run; description based on the title of record.
• § 102 assessment: Relevant only to the generic "memory means" / disc-unit element of claim 1. It addresses data recording on a magneto-optic medium, not multichannel video, buffers, filing tables, or command priority. No § 102 anticipation.

④ US 5,371,551 — Logan & Goessling, "Time delayed digital video system using concurrent recording and playback" — granted 1994-12-06

• Disclosure (verified, extensive): a circular buffer combining a semiconductor RAM and a magnetic disk; the system constantly records incoming signals while concurrently reading delayed playback from a different address; a microprocessor selects read/write addresses to give user-selected delay, pause, fast-forward, reverse; plural input signal processors; compressed digital storage; direct recording of already-compressed digital HDTV signals. Sources: https://patents.google.com/patent/[US5371551A](/patent/US5371551A)/en ; https://lexdana.ai/patent/[5371551](/patent/5371551).
• § 102 assessment: This is one of the two strongest single-reference candidates. It discloses concurrent record/playback to a disk-based memory with user-controlled read addressing — i.e., much of the "simultaneous record and reproduce from one disc unit" functionality. But it is single-program/single-output, has no N-channel architecture with N buffers/channel circuits, no file-name→address allocation table, no reproducing command accumulated against recording command, and no priority data governing dispatch order. It therefore does not anticipate claim 1 as a whole, nor any dependent claim.
• Claims it could touch: claim 1 (memory + concurrent record/playback + user commands) as a § 103 base; claim 3's "endless/overwrite" concept is conceptually analogous to Logan's circular buffer (writing over the oldest data), but claim 3 requires the fragment/segment structure of claim 2, which Logan lacks.
• Prosecution note (useful context): the Logan family (Re. 36,801) was itself used by examiners as primary art against later DVR patents, and '837 was cited in those office actions as a secondary reference for "recording/reproducing a multichannel video signal." That is a citation of '837, not against it, and is outside the § 102 analysis of '837.

⑤ US 5,625,846 — Kobayakawa et al., "Transfer request queue control system using flags … round-robin system for dequeuing" (Fujitsu) — granted 1997-04-29

• Disclosure (verified): a transfer request queue structure with a queue-valid flag, a priority-specifying flag per queue, and a priority selection circuit that selects the highest-priority queue when multiple requests are pending, using round-robin among equal-priority queues; transfers start only when the target is ready. Source: https://patents.google.com/patent/US5625846.
• § 102 assessment: This is the closest art for the "access control means" element of claim 1 — accumulating requests, detecting readiness, and dispatching according to priority flags, including round-robin. But it is a parallel-computer/packet-transfer invention: it has no video channels, buffers, disc, file table, or record/reproduce commands. It cannot anticipate claim 1 (which requires the video apparatus as a whole) and is not directed to any dependent claim. Under § 103 it is the natural secondary reference to combine with a video-recorder primary reference. No § 102 anticipation.

⑥ US 5,719,985 — "Apparatus for simultaneously recording and reproducing data to and from a recording medium" (Sony) — granted 1998-02-17

• Disclosure (verified): input means continuously receiving data; compression; input buffer storing compressed data; recording/reproducing means that records to and reproduces from a recording medium in a time-divisional manner; output buffer; expansion means; and control means governing read-out timing and record/reproduce so that plural channels are time-division recorded/reproduced. Mentions satellite-antenna-sourced video. Source: https://patents.google.com/patent/[US5719985A](/patent/US5719985A)/en ; https://uspto.report/patent/grant/[5719985](/patent/5719985).
• § 102 assessment: This is the other strongest single-reference candidate and arguably the closest overall of the nine. It discloses the time-division multichannel record/reproduce architecture, per-channel input/output buffers, compression/expansion, and a control means — mapping well onto claim 1's elements (1)–(4), (6), and the memory-interface storage/read behavior. What it does not disclose: a user interface receiving a file name; a filing means with a name→first/second-address table; accumulation of a reproducing command vs. recording command with user-selectable priority data. Because claim 1 requires those elements, it does not fully anticipate claim 1, and it discloses nothing of independent-claim-1-plus-dependent-claim features (fragments/segments, endless mode, phase-shifted syncs, multi-terminal assignment, satellite demultiplexing). Best characterized as a § 103 primary reference, not a § 102 anticipation.

⑦ US 5,870,497 — "Decoder for compressed video signals" (C-Cube Microsystems) — granted 1999-02-09 (filed 1991-03-15)

• Disclosure: a video decoder for compressed video; prior-art date is its 1991-03-15 filing, making it available only under § 102(e) as of that filing. Full text not retrieved in this run; characterization based on the title of record.
• § 102 assessment: Relevant only to the decompression performed by the "video channel circuits / inputting and outputting means." It discloses no channel architecture, buffers, disc, filing table, or priority arbitration. No § 102 anticipation of any claim.

⑧ EP 0 753 964 A1 — "Procedure and device for recording and reproducing, comprising a high capacity recording carrier" (THOMSON multimedia) — published 1997-01-15

• Disclosure: recording/reproducing methods and apparatus built around a high-capacity recording carrier (the family of the "large-capacity medium" recording/reading method). Full text not retrieved in this run.
• § 102 assessment: Published 1997-01-15, which is before the 1997-06-10 priority date but less than one year before it, so it is § 102(a) art (before the applicant's invention), not § 102(b). It speaks to disc-based recording/reproduction and file/data organization generally, but does not disclose the multichannel-buffer architecture, file-name→address table, or priority-data command arbitration of claim 1. No § 102 anticipation of any claim.

⑨ US 6,091,883 — "Method and device for recording and reading on a large-capacity medium" (Thomson Multimedia S.A.) — granted 2000-07-18

• Disclosure: the US counterpart of EP 0 753 964 A1 (same 1995-07-13 priority). Available as prior art only under § 102(e) (US patent granted on an application filed before the applicant's invention date). Full text not retrieved in this run.
• § 102 assessment: Same substance as ⑧ and same conclusion — relevant to disc-based record/read and medium management, but silent on the combination that defines claim 1. No § 102 anticipation of any claim.

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3. Bottom line on § 102 versus § 103

• No single cited reference anticipates claim 1, and therefore none anticipates dependent claims 2–6 (all of which incorporate claim 1's limitations). Each of the nine misses at least one essential claim-1 element; the two most complete single references — US 5,719,985 (Sony) and US 5,371,551 (Logan) — still lack the file-name→address filing table and the priority-data-driven queuing of record vs. reproduce commands.
• The distinguishing combination that appears to have carried patentability is (i) the filing means' name-to-address mapping (claim 1 / claims 2–3) plus (ii) the access-control means' user-selectable record-vs-playback prioritization (claim 1), in an N-channel time-division apparatus. The art of record supplies these pieces only in separate, non-analogous contexts:
  • US 5,625,846 (Fujitsu) → the priority/queue-dispatch concept (claim 1's access-control element);
  • US 5,719,985 (Sony) and US 5,371,551 (Logan) → time-division concurrent record/reproduce with buffers;
  • US 4,943,854 (Chuo) → multichannel acquisition on a shared recorder;
  • US 5,371,602 (Hitachi) and US 5,870,497 (C-Cube) → compression/decompression.
• Accordingly, the realistic challenge vector against '837 is a § 103 combination (e.g., Sony '985 or Logan '551 as primary, with Fujitsu '846 for the priority-queue feature, and a file-management reference such as EP '964/US '883 for address mapping) — not a clean § 102 anticipation.

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4. Confidence and limitations

• High confidence: the list of nine citations, their titles, assignees, and the record's dates — taken from the authoritative patent text/front page and corroborated for references ①②④⑤⑥ via the sources cited above.
• Medium confidence: the substantive characterization of ③ US 5,355,353, ⑦ US 5,870,497, ⑧ EP 0 753 964 A1, and ⑨ US 6,091,883 — I relied on bibliographic data and titles because full texts were not retrievable in this session. If you need element-by-element § 102 charts for those four, I can pull their full claim sets next.
• Explicitly not claimed: I did not find, and do not assert, any § 102 anticipation by these references. Any statement here that the claims issued over this art is based on the fact that the patent granted with 6 claims; I did not retrieve the examiner's written reasons of allowance and do not attribute specific reasoning to the examiner.
• No auto-correction applied: all patent numbers were read literally.

Sources: https://patents.google.com/patent/US6278837/en ; https://patents.google.com/patent/US5719985A/en ; https://patents.google.com/patent/US5625846 ; https://patents.google.com/patent/US5371551A/en ; https://patents.justia.com/patent/4943854 ; https://uspto.report/patent/grant/4943854 ; https://worldwide.espacenet.com/publicationDetails/biblio?CC=US&NR=5371602A ; https://uspto.report/patent/grant/5371602 ; https://uspto.report/patent/grant/5719985 ; https://lexdana.ai/patent/5371551.

I'll research the cited prior-art references to ground the obviousness analysis accurately.

Let me research the remaining key cited references.

Obviousness Analysis — U.S. Patent 6,278,837 under 35 U.S.C. § 103

Building on the prior "Patent summary" and "Litigation summary" sections. I do not repeat the bibliographic table or the (negative) litigation findings here. This is a technical analyst's hypothetical § 103 assessment, not a legal opinion; the patent is expired, so this is an academic/reconstruction exercise rather than a live validity contest.

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1. Analytical framework

Pre-AIA § 103 (the application was filed 1998-06-08, so pre-AIA governs). The controlling inquiry is the Graham v. John Deere framework as refined by KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007):

1. Scope and content of the prior art;
2. Differences between the prior art and the claims at issue;
3. Level of ordinary skill in the pertinent art; and
4. Secondary considerations (nexus-bearing objective evidence).

Under KSR, a claim is obvious not only where the references contain an explicit "teaching, suggestion, or motivation" to combine, but also where the combination is "the product of ordinary creativity, not of genius" — e.g., combining familiar elements according to known methods to yield predictable results, or applying a known technique to a known device ready for improvement.

Level of ordinary skill (my proposed definition): a bachelor's degree in electrical engineering or computer science (or equivalent), plus roughly 2–4 years of experience in digital video recording/storage systems, including knowledge of disc-drive control, file-system address mapping, data buffering, and data compression. This is a modest skill level; all the asserted combinations are within the ordinary creativity of such a person.

Prior art status of the references relied on. All nine references listed on the patent's own face were available before the 1997-06-10 priority date (or, for US 6,091,883, qualify as pre-AIA § 102(e) art by virtue of its 1995-07-13 priority). They are thus § 102-qualifying art usable in a § 103 combination. Notably, every reference I rely on below was of record and considered by the examiner, which means the references themselves are not "new art"; the question is whether a proper combination of them, with articulated reasoning, would have rendered the claims obvious. The examiner allowed the claims, so the record reflects that this particular combination was not found — a fact I flag for balance, not as a legal conclusion.

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2. Claim 1 — element-by-element mapping

Claim 1 is the only independent claim. Its eight elements map onto the cited references as follows.

The two elements that carry the novelty emphasis (per the "plain-language overview" in the prior section) are G (filing/address-mapping table) and H (priority-based command arbitration). Both have direct, closely analogous counterparts in the cited art, as shown.

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3. Primary combination: Chuo + Sony + Fujitsu

3.1 What each reference contributes

Chuo (US 4,943,854) — multichannel time-division video recording.

• Plural TV cameras → multiplexing means → time-division multiplexed signal → single VTR (time-shared recording), with ID/control signals identifying each camera and enabling selective reproduction of desired scenes by comparing a selection signal against the control signals. This supplies elements A (multichannel input), E (operator selection input), and the general architecture of selecting one channel for record/reproduce on shared media.

Sony (US 5,719,985) — simultaneous recording and reproduction on a shared recorder.

• Expressly addresses "time-division recording/reproduction of plural channels," a plurality of interface circuits, compressing circuits, input buffers, output buffers, and recording/reproducing circuits, plus control means that controls read-out timing so that recording and reproduction are carried out in a time-divisional manner while data is continuously output — and that reproduces an earlier-recorded portion of the same file without interrupting recording. This supplies elements A, B, C, D, and F essentially completely. Its stated problem (avoiding multiple dedicated VTRs for plural viewers; supplying a data file to plural viewers time-shifted) is the same problem space as the '837 patent.

Fujitsu (US 5,625,846) — priority-ordered queue arbitration for a shared transfer resource.

• Discloses transfer-request queues that accumulate transfer requests; a transfer queue valid flag; per-queue priority-specifying flags set by program/user; and a priority selection circuit that selects the highest-priority queue when the transfer controller is in the state waiting for enqueuing (i.e., when the resource is not busy), with round-robin among equal priorities. This is a near text-book mapping to element H: accumulate commands → detect resource busy → dispatch on idle → ordered by priority data.

3.2 Differences between the combination and claim 1

Even taking all three together, the combination does not expressly recite:

• (i) the file-name-based address table of element G in a video-recorder context — though this is standard file-allocation functionality and is squarely disclosed in analogous form by Thomson/Hitachi (see § 4); and
• (ii) the user-selectable record-vs-playback binary priority of element H — Fujitsu teaches user/priority-flag ordering of queues generally, and the '837 patent itself concedes (col. description, steps 301–316) that the priority bit merely chooses which of two queues is drained first.

These are the only meaningful differences, and both are addressed by additional references in the same field.

3.3 Motivation to combine (articulated reasoning)

1. Common field of endeavor and common problem. All three are data-recording/reproducing systems confronting how to share one recorder or storage device among multiple competing video streams and/or between recording and playback, while keeping each stream's data rate up. Combining them involves no change in the principle of operation of any one of them.

2. Chuo → Sony. Chuo's time-division multiplexing of plural cameras into a single VTR is precisely the architecture Sony improves upon; Sony's motivation statement — replacing multiple dedicated VTRs, enabling time-division plural-channel record/reproduction, and serving plural viewers time-shifted — is a direct reason a PHOSITA would look to Sony's buffered, time-division, single-medium design to implement Chuo's multichannel selection more flexibly on a disc. KSR's "improvement of one device in the same way" rationale applies.

3. Sony → Fujitsu. Once record and playback commands from multiple channels queue up against a single disc interface, the need to arbitrate and to preserve a chosen data rate is exactly the problem Fujitsu solves for a shared transfer resource. A PHOSITA regularly looks to known bus/DMA arbitration and queue-scheduling techniques when adding a second class of traffic to a shared I/O channel; applying Fujitsu's priority-flag/priority-selection queue mechanism to the recorder's disc interface is the predictable application of a known technique to a known device (KSR).

4. Reasonable expectation of success. Every element is a known, self-contained functional block (buffers, disk controller, queue, priority flag). No new chemistry/physics is required; the combination merely wires known blocks together. There is no teaching away in any reference.

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4. Secondary combinations addressing the "differences"

4.1 Filing/address-mapping element (G)

Thomson (EP0753964A1 / US 6,091,883) — recording and playback of broadcast programs onto a high-capacity recording carrier using logical blocks and management of those blocks. This supplies the notion of managing stored content by address on the medium and reproducing selected programs — the functional equivalent of the '837 filing table.

Hitachi (US 5,371,602) — a picture-data recording/reproducing system that records compressed picture data and reproduces it under plural reproduction modes, with corresponding address/unit management. This supplies both the compression context and the record-address→reproduce-address relationship.

Binet (US 5,355,353) — a magneto-optic data recording system with address management of blocks.

A PHOSITA implementing Chuo/Sony would implement file-name→address translation as an ordinary file-system function (linked allocation, FAT-style tables). This is routine engineering; the '837 specification's own FIG. 5A–5E tables (block, fragment, file management, bit maps) are conventional file-system data structures. KSR treats such "design incentives and other market forces" implementations as obvious.

4.2 Combination for claim 1 (strongest form)

Chuo (US 4,943,854) + Sony (US 5,719,985) + Fujitsu (US 5,625,846) + Thomson (EP0753964A1 / US 6,091,883).

• Chuo + Sony provide the multichannel buffered time-division record/reproduce architecture (elements A–F).
• Thomson provides the file/address management (element G).
• Fujitsu provides the priority-ordered command arbitration (element H).

I assess claim 1 as likely obvious over this four-reference combination, with the strongest single teaching being Fujitsu for element H and Sony for elements A–F.

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5. Dependent claims 2–6

Claim 2 (fragments → segments → one frame per segment; table of first addresses + link relation).

• Files stored as composed fragments/successive segments, each segment holding a fixed unit (one frame), is standard file-allocation on block devices. Thomson (EP0753964 / US 6,091,883) manages logical blocks on a high-capacity carrier; Hitachi (US 5,371,602) stores compressed picture data in units with plural reproduction modes; Logan (US 5,371,551) and C-Cube (US 5,870,497) confirm frame/segment-oriented compressed storage. A linked-fragment file structure is a design choice within the ordinary skill level. Likely obvious over Chuo + Sony + Thomson/Hitachi.

Claim 3 (endless recording = recurrent overwrite of a predetermined number of fragments; successive recording).

• This is the classic circular-buffer / overwrite-oldest recording. Logan (US 5,371,551) expressly discloses the memory subsystem "continually stores the incoming data, writing over the oldest data stored on the hard disk … so that a fixed duration or 'time window' of prior recorded signals are recorded" — i.e., endless recording over a bounded set of storage units — and it is a surveillance/time-shifting system, the same use context as Chuo. Adding a user-selectable "endless vs. successive" mode is the predictable application of Logan's ring-buffer teaching to Chuo/Sony's system. Likely obvious.

Claim 4 (plural vertical synchronizing signals with different phases).

• This is the weakest element for a pure § 103 attack, because none of the cited references expressly discloses deliberately phase-offsetting multiple vertical-sync signals. But the reasoning is straightforward: Chuo time-division-multiplexes on a frame/field basis and associates control signals with the vertical blanking interval; when independent channels share a common capture/storage resource, a PHOSITA routinely staggers capture timing to avoid contention — a mere design choice / optimization (consistent with KSR's "predictable variation"). I would expect a rejection premised on "routine engineering to avoid simultaneous input collisions," but I flag this element as the one most susceptible to a patentee's rebuttal absent a specific secondary reference on staggered sync generation.

Claim 5 (user interface with plural terminals; control means assigns a channel independently per terminal).

• Sony (US 5,719,985) expressly contemplates serving plural viewers and supplying the same recorded data file to them shifted in time, and discloses plural interface circuits; Chuo discloses operator input/selection. Providing multiple independent control terminals each assigned a channel is a natural extension of a multi-channel, multi-user recorder and is within ordinary skill (and is essentially the architecture the '837 patent itself describes). Likely obvious.

Claim 6 (digital satellite broadcast receiver + separator storing demultiplexed channels in different buffer areas).

• Thomson (EP0753964A1) is directed to recording/playing programs broadcast via radio, satellite or cable; Sony (US 5,719,985) references a satellite antenna and compressed digital input; C-Cube (US 5,870,497) provides the compressed-video decoder for such digital streams. Demultiplexing a multiplexed digital satellite stream (e.g., an MPEG transport stream carrying multiple channels) into separate channel buffers is well-known in the art. Combining a satellite front end with the multichannel buffer architecture of Chuo/Sony is the predictable substitution of one video source for another. Likely obvious.

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6. Motivation-to-combine summary (the § 103 "why")

A single, cohesive motivation runs through the whole set: how to record, manage, and reproduce multiple video channels on one storage device while allowing simultaneous recording and playback and preserving the data rate of the operation the user deems most important. Every cited reference addresses some facet of that same problem in the same field:

• Chuo — multiple channels on one recorder (surveillance).
• Sony '985 — simultaneous, time-division record/reproduce and multi-viewer service on one medium.
• Logan — bounded "time-window" (circular) recording with concurrent record/playback.
• Fujitsu — arbitrating competing transfer requests by user-specified priority.
• Thomson / Hitachi / Binet — file/address management and compressed-picture storage on a random-access medium.
• C-Cube — compressed-video codec.
• EP0753964 — broadcast (including satellite) program recording.

Because these are familiar elements combined according to their known functions, with no change in their respective principles of operation and no teaching away, the combination satisfies KSR's "predictable results" rationale. The only element lacking an explicit, pinpoint disclosure is claim 4's phase-offset sync generation, and even that is a routine optimization rather than an inventive step.

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7. Secondary considerations and rebuttal considerations

• No known objective evidence. The prior "Litigation summary" found no litigation, and no license/industry-praise record is known. There is therefore no nexus-bearing secondary-consideration evidence to weigh against the obviousness case. (I state this as absence of evidence, not evidence of absence.)
• Prosecution history cuts both ways. All relied-upon references were cited/of record and the examiner still allowed the claims. A challenger would need to articulate the specific combination and reasoning above — which is essentially the point of this analysis — rather than merely re-cite the references. This is a meaningful practical hurdle even though my technical assessment leans "obvious."
• Claim-drafting anomaly (carried forward from the prior section). Claim 1 recites both a "reproducing command" and, later, a "reading command from said access control means." For this analysis I treated them as the same playback command, as the specification uses "reading/reproducing" interchangeably; the literal inconsistency remains.

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8. Confidence and caveats

• High confidence on the substance and teachings of the four references I lean on most heavily (Chuo US 4,943,854; Sony US 5,719,985; Fujitsu US 5,625,846; Logan US 5,371,551) — grounded in the sources retrieved and, for Chuo, the patent's own specification.
• Moderate confidence on Thomson EP0753964A1 / US 6,091,883 (US 6,091,883 is the US family member of the EP 1995-priority application; I could not retrieve the US 6,091,883 abstract directly in the steps available, so I rely on the family relationship and the EP title/abstract). I flag this rather than assert chapter-and-verse.
• Lower confidence on Hitachi US 5,371,602 and C-Cube US 5,870,497 details; I used them as supporting references for compressed-picture storage/addressing, which is consistent with their titles and the patent's own citation of them.
• No auto-correction of identifiers: US 6,278,837, US 09/092,972, and the cited numbers are interpreted literally as they appear on the Google Patents record at https://patents.google.com/patent/US6278837/en (fetched 2026-09-30).
• This is a technical § 103 reconstruction, not a validity opinion, and it has no live effect because the patent expired for non-payment of maintenance fees effective 2013-08-21.