US 5712976

I'll search for US Patent 5712976 across the USPTO database and CAFC dockets.

Initial results confirm the patent's identity. Let me search for more authoritative details, including the abstract, claims, and any CAFC litigation.

Let me search for the official abstract and claims text, and check for any USPTO/CAFC records more specifically.

Summary of U.S. Patent 5,712,976

Search note: I searched for this exact patent number (5712976 / US5712976A) in web-accessible USPTO records and CAFC-related docket searches. No CAFC case involving this patent was found in any 2026 docket search. The CAFC cases surfaced in the searches (e.g., IBM v. Zillow, Fed. Cir. Dec. 9, 2025, involving U.S. Patent 7,631,346; and Xinuos v. IBM, a Second Circuit matter) do not involve this patent. This is consistent with the patent's status: it has been expired since its anticipated expiration date of January 27, 2015, making active 2026 litigation highly unlikely.

Bibliographic Data (confirmed by Google Patents, USPTO-derived records, and secondary sources)

Classification highlights: H04N21/00 (VOD servers), H04N7/173 (two-way video systems), G06F3/06 (digital input/output to record carriers), H04N5/76 (TV signal recording).

Abstract

The fetched Google Patents record does not include a separately captioned abstract in the text I was able to retrieve, so I cannot quote the formal abstract verbatim with high confidence. Based on the specification's opening summary, the invention is directed to: a "video friendly" media streamer (video server) that delivers isochronous digital video data streams to multiple end users from a single copy of stored video data, using a low-latency switch interconnecting storage nodes, communication nodes, and control nodes, with data striped across mass storage units to enable many simultaneous streams from one copy. The stated design goals include scalability from 1 to thousands of streams, mixed output interfaces and data rates, VTR-like control, storage-hierarchy support, and low cost per delivered stream.

Plain-Language Overview of the Independent Claim(s)

Important caveat: The full claim text was not present in the fetched patent text (the provided record truncates mid-specification, before the claims section), and my searches did not return the verbatim independent claims. The following is reconstructed from the specification's detailed summary of the invention — treat the exact claim language as unverified.

Likely independent claim (system/media streamer) — drawn from the Summary of the Invention:

1. A media streamer comprising:
   • At least one storage node with mass storage (a plurality of mass storage units) storing a digital representation of at least one video presentation. The presentation takes time T to present and is stored as N data blocks, each block holding roughly T/N of the presentation.
   • A plurality of communication nodes, each having at least one input port coupled to the storage node output, and a plurality of output ports, each output port transmitting a digital representation as a data stream to a consumer.
   • The N data blocks are partitioned into X stripes (blocks 1, X+1, 2X+1, … in stripe 1; blocks 2, X+2, 2X+2, … in stripe 2; etc.), with each stripe stored on a different mass storage unit — preferably a single copy of the video presentation across the units.
   • The stripes are read out so that multiple data streams can simultaneously convey the same data block or simultaneously convey different data blocks (i.e., "single copy, multiple stream" capability).
   • X (the number of stripes) is determined by an expression involving: r = nominal stream data rate, n = maximum number of simultaneous streams at that rate, d = effective output data rate of one mass storage unit, and m = maximum number of simultaneous streams at the nominal rate from all storage units holding any part of the video.

Depending on the patent's final claim set, additional independent claims may cover the corresponding method of streaming video data and possibly the video adapter/communication-node hardware (e.g., the SCSI-based NTSC/PAL adapter with isochronous FIFO buffering described in the specification). I could not verify the number of independent claims or their exact wording from the available sources.

Uncertainties / Gaps

1. Formal abstract text — not retrievable from my searches; summarized from the specification instead.
2. Verbatim independent claims — not available in the fetched text or search results; the overview above is reconstructed from the "Definitions/Summary" section and should not be quoted as claim language.
3. CAFC 2026 dockets — no docket entries for this patent were found; the patent's expiration (2015) makes active litigation improbable, but the absence of a docket hit is not proof of no historical litigation. I found no record of district-court or CAFC litigation involving this patent in the sources searched.
4. Justia/FreePatentsOnline snippets that display "5712976" alongside other patent numbers are citations of this patent as prior art in later filings (e.g., US 8,609,085; US 8,189,819), not litigation records.

If you need the exact claim text, the authoritative sources are the USPTO Patent Center (application 08/302,624) or the USPTO Patent Full-Text database (patent 5,712,976), which were not directly accessible in my searches.

The initial searches returned no results. Let me try different search formulations.

Litigation Search Results for U.S. Patent 5,712,976

Based on the searches I was able to run, I found no known litigation involving U.S. Patent 5,712,976 (the IBM "Video data streamer" patent).

What I searched

• Unified Patents litigation portal (portal.unifiedpatents.com) — search for "5712976" returned no results.
• CourtListener / PACER-derived dockets — no docket entries referencing patent number 5712976 were found.
• CAFC docket searches — no Federal Circuit appeal involving this patent was found (consistent with the earlier analysis in this project: the patent's anticipated expiration was January 27, 2015, and it is recorded as Expired – Fee Related).
• General web searches for combinations of "5712976," "5,712,976," "video data streamer," and "IBM patent lawsuit" — no litigation hits.

Near-miss (excluded, not the same patent)

One search surfaced Broadcom Corporation v. Netflix, Inc. (N.D. Cal., Case No. 3:20-cv-04677), which references "the '976 patent." That case is not this patent: the claims at issue there are Broadcom/Avago claims directed to connecting to web services and server load balancing (see the CourtListener/Casetext excerpts), which has nothing to do with IBM's video data streamer, striping, or isochronous video delivery. That "976" patent is a different, similarly numbered patent, and per your instruction I am excluding it rather than treating it as a match.

Conclusion

Caveat on confidence: My searches were web-based (CourtListener, Unified Patents, general web/Google Patents). I did not have direct access to the full USPTO Patent Center assignment/ litigation data or a comprehensive PACER full-text search across all district courts, so I cannot categorically prove that no historical (pre-2015) district-court case ever existed. However, all available evidence — including the patent's 2015 expiration and the absence of any docket or CAFC hits — points to no known litigation. If you need a definitive negative, the next step would be a paid PACER/USPTO litigation-search query across all district courts for the patent number 5712976.

Proceedings overview

Zero (0) AIA trial proceedings are on file for U.S. Patent 5,712,976 — no active trials, no claims invalidated, no claims sustained, no settlements, and no institution denials, because no IPR, PGR, or CBM petition was ever filed against this patent. The USPTO Open Data Portal (ODP) API returns no AIA trial proceedings for this patent as of the most recent ingest, and my web searches (PTAB decision databases, Unified Patents, CourtListener, general web) corroborated that negative — every "976 patent" hit surfaced (e.g., SAS Institute v. Iancu on the '936 patent; Broadcom v. Netflix on an unrelated Avago '976 patent; Apple v. Universal Secure Registry on the '539 patent) is a different patent. Defensive posture: neutral-to-favorable in the sense that no claim has ever been tested or narrowed before the PTAB — but the patent expired on 2015-01-27 (Expired – Fee Related), so a defendant's leverage comes from expiration, the pre-2015 damages window, and unrestricted prior-art defenses in district court, not from any IPR scalp.

Proceedings (none to report)

There are no individual proceedings to list. Per the canonical ODP block in this prompt, the USPTO Open Data Portal API returns no AIA trial proceedings for US 5712976 as of the most recent ingest. Web search confirmed the absence:

• Searches for "5712976" IPR, "5,712,976" "final written decision", "5712976" site:uspto.report, and IPR2014/2015/2016 "5712976" returned no PTAB proceeding numbers tied to this patent.
• The only 5712976-related web hits were the patent's own specification text on uspto.report and third-party patents citing the IBM media-streamer family (e.g., US 5,586,264, CA2153445C, US 8,609,085, US 8,189,819) as prior art — not PTAB activity.
• No PTAB Final Written Decision, institution decision, or Federal Circuit appeal referencing this patent was found.

Caveat on confidence: The ODP negative is the authoritative signal and my searches corroborate it. I cannot categorically prove that a pre-2015 historical proceeding never existed from web-accessible sources alone; if a definitive negative is needed, a paid PTAB E2E / Patent Center query for patent number 5712976 would close the loop. But every available indicator points to no PTAB activity, ever.

Strategic summary

Claims status — all UNTESTED. Because no AIA proceeding was ever filed, no claim of 5712976 has been canceled, sustained, or even reached an institution decision. All claims remain exactly as issued, and none carries any PTAB-derived patentability gloss. For a defendant facing assertion today, the more decisive facts are (1) the patent's anticipated expiration on 2015-01-27 and its Expired – Fee Related status — meaning damages are confined to pre-expiration conduct and no injunctive relief exists — and (2) the complete absence of any § 315(e)(2) estoppel cloud: no prior-art ground has been consumed by an IPR, so every § 102/§ 103 theory remains available to any defendant who was not itself the petitioner in a (nonexistent) proceeding. The only real procedural trap is § 315(b): any defendant who was served with a complaint more than a year ago is time-barred from filing an IPR — but with the patent expired since 2015, an IPR's practical value (and the one-year bar's sting) is largely theoretical anyway.

Estoppel landscape. Vacant. § 315(e)(2) estoppel binds only IPR petitioners and their privies as to grounds raised or reasonably available in a filed and instituted proceeding. With zero proceedings, there is no estoppel against anyone. A defendant sued today can raise any § 102/§ 103 combination, any § 112 issue, and any eligibility/indefiniteness defense in district court without PTAB-estoppel constraint. Note the corollary: the patent owner likewise holds no PTAB "wins" to brandish — no claim has been confirmed by the Board, so there is no administrative-validation argument for the patentee to lean on.

Pattern signals. None. There is no repeat petitioner, no patent-owner litigation pattern before the Board, and no defensive aggregator (e.g., Unified Patents) in the chain — because there is no chain. The absence of any IPR against a prominent IBM video-server patent is itself mildly notable: the patent issued in 1998 and was assertable for 17 years, yet no one ever challenged it at the PTAB. That is consistent with the patent being cited but rarely (if ever) asserted in litigation — the earlier litigation search in this project found no district-court or CAFC cases involving 5712976. One family-level flag worth checking: the same 1994-09-08 priority date and IBM inventorship carry over to US 5,586,264 ("Video optimized media streamer with cache management") and CA2153445C ("Video optimized media streamer user interface"). If the demand letter cites those siblings rather than 5712976 itself, run the same ODP/PTAB check against those numbers — I did not verify their PTAB status in this analysis.

Recommended next steps

1. Confirm the negative on the record. Run a PTAB E2E / Patent Center search for patent number 5712976 (and application 08/302,624) so the "no proceedings" finding is documented in the file, and pull the USPTO assignment database to identify the current owner — Google Patents lists IBM as assignee, but title may have moved, and knowing who is actually asserting matters more than the PTAB record.

2. Anchor the defense on expiration, not IPR. The patent expired 2015-01-27. Any infringement claim is limited to acts before that date (and, if no litigation was ever filed, likely faces laches/limitations issues of its own). Quote the Google Patents legal-status line — "Expired – Fee Related," anticipated expiration 2015-01-27 — and the pre-AIA damages framework. There is no FWD to link because none exists; do not represent otherwise to the court or opposing counsel.

3. Preserve all prior-art grounds. With zero IPRs, § 315(e)(2) estoppel does not apply. If the case is worth litigating, run a full § 102/§ 103 search (the specification itself concedes the field was crowded — VTR/tape systems, RAID, DVI/JPEG/MPEG, ATM — so 1990s video-server art is plentiful). Just be mindful of the § 315(b) one-year clock if a complaint has already been served: the window to file an IPR may be closed even though the patent is expired, so plan on district-court validity defenses rather than a PTAB challenge.

4. If the demand letter cites a family member, repeat the ODP/PTAB check for US 5,586,264 and CA2153445C before assuming the same clean record — and confirm whether the asserted claims are method claims, system claims, or the video-adapter claims, since the truncated fetched text did not include the full claim set. The claims of 5712976 have never been PTAB-tested; treat them as "untested, expired, and assertable only for pre-2015 conduct" — which is the accurate, and for a defendant a fairly comfortable, posture.

Inventors

Pattern note: No unusual pattern. Both inventors assigned their interest to IBM at filing in the normal course. I found no evidence (and no basis in the record) that either inventor departed IBM within 12 months of filing, and there is no portfolio fire-sale signature — the assignment record is a routine employer assignment.

Original assignee

• Entity: International Business Machines Corporation (Armonk, NY) — the entity named on the issued patent and the assignee of the only recorded assignment.
• Line of business: Operating company — diversified computer hardware, software, and services.
• Product embodiment: The patent's specification describes the "media streamer" / video-optimized stream server, and it is one of a same-day IBM family (US 5,586,264; US 5,603,058; US 5,668,948) covering the same architecture. IBM did market video-server products in this era (the IBM media streamer / VideoCharger line grew out of this architecture), but I could not verify from my web-accessible sources that a specific shipped product embodied these exact claims. Treat "product shipped" as probable but unverified.
• Current status of the company: Operating (one of the world's largest technology companies). Current status of the patent: Expired – Fee Related, anticipated expiration January 27, 2015, per Google Patents legal-status data.

Assignment timeline

I was unable to run a direct query of the USPTO Assignment Center (assignmentcenter.uspto.gov) from this environment, and no web-accessible source surfaced the reel/frame or correspondent for this patent's assignment. I will not fabricate those fields. What follows is what the record affirmatively shows.

• ~1994-09 (executed, with filing 1994-09-08) / recorded 1994-11-09 — Reel/frame not retrievable from sources searched (do not treat as absent — treat as unverified)
  • Conveyance: Assignment of Assignors' Interest
  • Assignor: Falcon, Lorenzo, Jr.; Saxena, Ashok Raj
  • Assignee: International Business Machines Corporation
  • Correspondent: not retrievable from sources searched
  • Context: Routine employer assignment from the two inventors to IBM at filing (this is the only legal event of record per Google Patents' legal-event feed for this patent).

No post-issuance assignments, security agreements, mergers, name changes, or licenses were found. Google Patents' legal-event feed for US5712976A shows only the 1994-11-09 assignment to IBM; the patent then remained in IBM's hands until its fee-related expiration on 2015-01-27. If the USPTO Assignment Center confirms this, it means IBM — an operating company — owned the patent for its entire life and no NPE ever entered the chain.

Caveat: Because I could not pull the Assignment Center abstract of title directly, I cannot categorically rule out a later recorded conveyance that Google Patents' feed does not surface. The affirmative evidence, however, points entirely to continuous IBM ownership.

Timeline diagram

timeline
    title Ownership of US 5712976
    1994 : Filed by IBM inventors
         : Assigned to IBM
    1998 : Patent issued
    2015 : Expired fee related

NPE / troll-pattern signals

1. Shell-entity transfer — not present. No transfer from IBM to any LLC / IP / Licensing / Holdings entity appears anywhere in the record. The patent never left IBM.
2. Known asserter in the chain — not present. No Acacia, Marathon, Intellectual Ventures, Wi-LAN, Conversant, or any Unified Patents / RPX-listed asserter appears as assignee or assignor. The only assignee of record is IBM.
3. Repeat correspondent across the chain — not present / not assessable. There is only one recorded assignment, and its correspondent could not be retrieved from my sources. Recurrence is impossible with a single link, so this signal cannot be scored.
4. Cascading transfers — not present. No chained LLC transfers exist in any time window.
5. Pre-litigation transfer — not present. No infringement suit naming this patent was found (see prior litigation summary), and no transfer exists to be timed against one.
6. Bankruptcy fire-sale — not present. IBM has not been in Chapter 7/11, and no bankruptcy-proceeding sale of this patent appears.
7. Privateering — not present. No operating-company-to-NPE transfer exists, and no SEC-filing or EFF/Patent Progress coverage of such an arrangement for this patent was found.
8. Defensive aggregator (anti-NPE) — not present. The chain does not terminate at RPX, AST, LOT Network, Unified Patents, or OIN. It terminates at IBM / natural expiration. (This is the inverse of an NPE signal, but it is not a defensive-aggregation outcome either.)

Verdict

Insufficient data — the record contains only the original inventors-to-IBM assignment (recorded 1994-11-09), and I could not retrieve the reel/frame or correspondent from web-accessible sources to complete the abstract of title.

That said, the available evidence is affirmatively clean: every source (Google Patents legal events, legal-status "Expired – Fee Related" as of 2015-01-27, and the absence of any litigation) indicates IBM, a large operating company, owned this patent for its entire life and never transferred it to any NPE. No shell LLC, no known asserter, no cascading transfers, and no privateering appear anywhere in the record. The "insufficient data" verdict is driven strictly by the definition (only the original assignment is on record) and by my inability to run a direct Assignment Center query — not by any affirmative NPE signal, of which there are none.

For verification, query the USPTO Assignment Center by patent number 5712976: https://assignmentcenter.uspto.gov/ (search "Patent Number" = 5712976); the legacy mirror is https://assignment.uspto.gov/patent/index.html.

I'll search for the specific patent US 5712976 and its cited prior art references.

I found the authoritative record. The USPTO-derived record (uspto.report) confirms the full "References Cited" list for US 5712976, and also confirms the actual claim set (4 claims; claim 1 is the sole independent claim). Now let me verify details and filing dates for the most relevant cited references so I can assess § 102 status accurately.

I now have solid data on the two most relevant Microsoft/IBM references. Let me verify filing dates for the remaining key cited patents to correctly determine § 102(e) status relative to the September 8, 1994 filing date.

I have reached the tool-call limit, but I have enough verified data to answer: the authoritative USPTO-derived record for US 5,712,976 (uspto.report/patent/grant/5,712,976) contains the complete "References Cited" list and the full claim set, and I verified key details (titles, filing dates, disclosures) for the most important references. Below is the complete analysis. I am treating the uspto.report record (USPTO-derived) and Google Patents/FreePatentsOnline citation lists as ground truth; the patent was filed September 8, 1994, so the pre-AIA § 102 framework applies, with § 102(b) cutting off at September 8, 1993 and § 102(e) turning on whether a cited U.S. patent's own effective filing date precedes September 8, 1994.

1. Confirmation of the target patent and its claim set

I searched only for 5712976 (U.S. Patent 5,712,976, application 08/302,624). Excluded as "similar numbers" per your instruction: the unrelated Broadcom/Avago "'976 patent" in Broadcom v. Netflix, the neighboring 5712975–5712999 patents, and the Canadian family member CA2154511A1.

Claim set (verified from uspto.report/patent/grant/5,712,976): The patent has 4 claims; claim 1 is the sole independent claim.

• Claim 1 – A media streamer comprising: (a) at least one storage node with mass storage made of a plurality of mass storage units, storing a video presentation that takes time T and is stored as N data blocks each ≈ T/N of the presentation; (b) switch means coupled to the storage node; (c) a plurality of communication nodes, each having an input port coupled via the switch to the storage node output, receiving and buffering data blocks, and each having a plurality of output ports transmitting an isochronous digital representation as a data stream to a consumer; (d) the N data blocks partitioned into X stripes (blocks 1, X+1, 2X+1 … in stripe 1; blocks 2, X+2 … in stripe 2; etc.), each stripe stored on a different mass storage unit; and (e) control means operating the switch in accord with consumer inputs so the stripes are read out to enable a plurality of streams to simultaneously convey the same or different data blocks to a plurality of communication nodes.
• Claim 2 – T/N period in the range of ~0.2 s to ~2 s.
• Claim 3 – X (number of stripes) determined by the expression involving r (nominal stream data rate), n (max simultaneous streams at that rate), d (effective output rate of one mass storage unit), and m (max simultaneous streams from all units storing the video).
• Claim 4 – Claim 3 + the 0.2–2 s range.

Because claims 2–4 add only narrow numerical/expression limitations, the § 102 anticipation analysis centers on claim 1.

2. Most relevant prior art — ranked

(A) US 5,473,362 — Fitzgerald et al. (Microsoft) — strongest § 102 candidate for claim 1

• Full citation: U.S. Patent 5,473,362, "Video on demand system comprising stripped data across plural storable devices with time multiplex scheduling," inventors R. P. Fitzgerald et al., assignee Microsoft Corporation, filed Nov. 30, 1993, issued Dec. 5, 1995 (verified via Google Patents and the patent PDF).
• Description: A video-on-demand server in which video image sequences are stored as blocks striped across a sequence of storage devices (consecutive blocks on consecutive devices, wrapping around), with a time-multiplexed scheduler dividing each device's bandwidth into columns of time slots; a "bandwidth unit" (one like-positioned slot per device column) is allocated per subscriber so that consecutive blocks are read from consecutive devices in consecutive time slots. The interconnection network "acts like a crosspoint switch" (ATM is expressly named). Multiple subscribers can concurrently view different portions of the same or different sequences.
• § 102 analysis: Filed before 9/8/1994, so it is prior art under § 102(e) (and § 102(a)/(g) on the presumed invention date). It appears to disclose nearly every element of claim 1: mass storage comprising a plurality of storage units (the striped drives); a data sequence stored as blocks (each block ≈ a time quantum of the presentation); switch-like interconnection (network functioning as a crosspoint switch); multiple subscriber outputs receiving streams; round-robin X-stripe partitioning (blocks 1, X+1, 2X+1… on device 1, etc., matching the claim's striping arithmetic); and scheduling/control so multiple streams simultaneously convey the same or different blocks. Potential anticipation of claim 1 is plausible; the main gap is whether its "subsystems" map cleanly onto claim 1's "communication nodes each having a plurality of output ports" and whether it expressly teaches isochronous delivery and consumer-input-driven switch control. Claims 2 and 3 are weaker (no express 0.2–2 s window or the r/n/d/m formula). This is the reference an infringer would lead with.

(B) US 5,442,390 — Hooper et al. (Digital Equipment Corp.) — strong § 102 candidate for claim 1

• Full citation: U.S. Patent 5,442,390, "Video on demand with memory accessing and or like functions," inventors D. F. Hooper, M. S. Goldman, P. C. Bixby, S. Krishnamoorthy, assignee Digital Equipment Corporation, filed July 7, 1993, issued Aug. 15, 1995 (verified via Google Patents/uspto.report/Espacenet).
• Description: A centralized VOD system with a gateway server, a video server (disks, expressly including RAID arrays), FIFO buffers partitioned into chunks, packet controllers, and communications ports; multiple customers share a single broadcast stream and read different portions of the same video from a FIFO/segment cache; video is divided into packets/time-stamped segments; a segment cache uses fill/play pointers with a moving viewing window; VCR-like commands (reverse, forward, pause, jump) come from a remote controller over a bidirectional control channel.
• § 102 analysis: Filed before 9/8/1994, so prior art under § 102(e)/(a). It discloses: mass storage with a plurality of disk units (RAID), video stored as segments/blocks each representing a time interval, buffering of data blocks, multiple output ports/customers, control responsive to consumer commands, and multiple customers sharing the same data — i.e., "same data block to multiple streams." Its principal gap versus claim 1 is the explicit X-stripe round-robin partitioning with each stripe on a different mass storage unit (RAID striping is referenced, which supports an inference) and the "switch means coupled between storage node and communication nodes." Moderate-to-strong candidate for claim 1; good § 103 anchor.

(C) US 5,461,415 — Wolf & Yu (IBM) — relevant, but not an anticipation candidate

• Full citation: U.S. Patent 5,461,415, "Look-ahead scheduling to support video-on-demand applications," inventors J. L. Wolf and P. S. Yu, assignee IBM, filed Mar. 15, 1994, issued Oct. 24, 1995 (verified).
• Description: A VOD server supporting pause/resume where multiple viewers share a common data stream, backed by "look-ahead" streams and look-aside buffering; the server has disks, memory buffers, a scheduler, and set-top-box clients.
• § 102 analysis: Prior art under § 102(e)/(a) (filed 3/15/1994), and it is an IBM sibling — but common ownership does not defeat § 102 anticipation (only § 103(c) shields commonly owned art from obviousness). It teaches multiple viewers sharing one stream (relevant to "same data block to multiple streams") but lacks the storage-node/communication-node/switch architecture and the X-stripe partitioning. Does not anticipate claim 1; useful in § 103 combinations on scheduling.

(D) Older, clearly prior art (§ 102(b)) video-distribution systems — relevant but each missing claim-1 elements

• US 4,949,187 (Cohen, Aug. 14, 1990) – "Video communications system having a remotely controlled central source of video and audio data": home viewers download a movie in digital format from a central archive library for local storage/playback. § 102(b) art. Discloses central storage + remote consumer control but no striped multi-unit storage, no switch-interconnected communication nodes; does not anticipate claim 1.
• US 5,133,079 (Ballantyne et al., July 21, 1992) – "Method and apparatus for distribution of movies": central digital movie distribution to customers' TV sets. § 102(b) art; same gaps as Cohen; no striping/switch architecture.
• US 5,200,989 (Milone, Apr. 6, 1993) – "Wide band communication system transmitting video and audio signals among a plurality of users." § 102(b) art; central-source multi-user video system without the claim-1 node/switch/striping structure.
• US 5,089,885 (Clark, Feb. 18, 1992) – "Telephone access display system with remote monitoring." § 102(b) art; remote display/monitoring over telephone lines; not a video server per claim 1.
• US 5,283,639 (Esch et al., Feb. 1, 1994) – "Multiple media delivery network method and apparatus." Issued after 9/8/1993, so not § 102(b); § 102(e) depends on its filing date (unverified). Describes a multimedia delivery network, relevant to the network/switch side of claim 1 but not the striping/storage-node side.
• US 5,289,461 (de Nijs, Feb. 22, 1994) – "Interconnection method for digital multimedia communications." Same timing caveat as Esch; relevant to "switch means" but not the storage striping.

(E) Disk-array / scheduling / server patents (mid-1990s issue dates) — § 102(e) candidates if filed before 9/8/1994 (filing dates not all verified)

• US 5,471,640 (McBride, Nov. 28, 1995) – "Programmable disk array controller having n counters for n disk drives for stripping data…": expressly teaches data striping across n disk drives. If filed before 9/8/1994, § 102(e) art. Strong for the stripe-partitioning limitation of claim 1, but it is a disk-controller patent, not a video streamer — does not disclose the communication nodes/switch/iso-stream elements.
• US 5,530,830 (Iwasaki et al., June 25, 1996) – "Disk array system": striped disk array. Same § 102(e) caveat; teaches striping, not the full streamer.
• US 5,528,513 (Vaitzblit et al., June 18, 1996) – "Scheduling and admission control policy for a continuous media server": continuous-media server scheduling/admission control; relevant to control/scheduling but not the full claim-1 architecture.
• US 5,544,327 (Dan et al., Aug. 6, 1996) – "Load balancing in video-on-demand servers…": buffer allocation across streams; § 103 material.
• US 5,550,982 (Long et al., Aug. 27, 1996) – "Video application server": general video server; relevant background.
• US 5,510,905 (Birk, Apr. 23, 1996) – "Video storage server using track-pairing": storage-server track-pairing scheme; relevant to storage-node read strategy.
• US 5,513,011 (Matsumoto et al., Apr. 30, 1996) – "Method and apparatus for recording or reproducing video data on or from storage media": video data storage/retrieval; background.
• US 5,487,167 (Dinallo et al., Jan. 23, 1996) – "Personal computer with generalized data streaming apparatus for multimedia devices": streaming apparatus; relevant to communication-node output, not the full system.
• US 5,522,054 (Gunlock et al., May 28, 1996) – "Dynamic control of outstanding hard disk read requests for sequential and random operations": disk read-request control; relevant to storage-node scheduling only.
• US 5,526,507 (Hill, June 11, 1996) – "Computer memory array control for accessing different memory banks simultaneously": memory-bank parallelism; tangential.
• US 5,606,359 (Youden et al., Feb. 25, 1997) – "Video on demand system with multiple data sources configured to provide vcr-like services": VOD with multiple data sources; § 102(e) only if filed before 9/8/1994 (unverified; likely filed in 1994–1995 — verify before relying on it).
• US 5,421,031 (De Bey, May 30, 1995) – "Program transmission optimisation": CATV program transmission optimization; tangential.

(F) Same-day sibling — NOT prior art

• US 5,586,264 (Belknap et al., Dec. 17, 1996) – "Video optimized media streamer with cache management": filed Sept. 8, 1994 — the same day as 5,712,976 (application 08/302,619; cross-referenced on the face of 5,712,976). It is not § 102(e) prior art (not an earlier filing) and is commonly owned. It describes the same "media streamer" family, so it is excellent intrinsic evidence of the scope of the disclosure, but it cannot be used to anticipate claim 1.

(G) Four oldest citations — prior art under § 102(b), descriptions not verified

• US 4,355,324 (Reitmeier, Oct. 1982); US 4,604,687 (Abbott, Aug. 1986); US 4,616,263 (Eichelberger, Oct. 1986); US 4,679,191 (Nelson et al., July 1987). These are all § 102(b) prior art by issue date (well before Sept. 8, 1993). I could not verify their titles/disclosures from the sources I accessed, so I will not describe them substantively rather than risk fabrication. Given their 1980s vintage and the class context (interactive video distribution, 348/7 et seq.), they are unlikely to be anticipation candidates for claim 1's 1990s-vintage distributed-server architecture; treat them as background.

3. Foreign patent documents

• EP 0 529 864 A1 (published Mar. 1993) – Cited on the face of 5,712,976. Published before the invention date (and within one year of filing, so § 102(a) candidate, not § 102(b)). I could not verify its title/assignee from my searches; do not rely on it without retrieving the document.
• WO 93/16557 (published Aug. 1993) – Cited on the face of 5,712,976. Published about one month before the § 102(b) bar date, so it is a § 102(a) candidate (assuming the invention was not complete before Aug. 1993), not § 102(b). Content unverified in my searches.

4. Non-patent literature (all cited on the face of 5,712,976)

1. "Intel Scalable Multi-server Technology for Interactive Multimedia Applications," Intel Corporation, May 1994, pp. 3–15 — § 102(a) (published ~4 months before filing; not § 102(b)). Describes scalable multi-server interactive multimedia architecture; § 103/§ 102(a) evidence for distributed-server architecture.
2. Thapar & Koerner, "Architectures for Video Servers," Hewlett-Packard, 1994 NCTA Technical Papers, pp. 141–148 — § 102(a). Survey of video-server architectures (storage, striping, delivery); good § 103 anchor for claim 1's combination.
3. IBM, "ALLICAT (0664) S10 SCSI Direct Access Storage Device Functional Specification, Release 4.50," Doc. No. AS01-0003-00, May 6, 1993, pp. 1–291 — § 102(b) (published >1 year before filing). SCSI disk-drive specification relevant to the "disk drive optimized for video" disclosure, not claim 1's system.
4. Hosekote et al., "Scheduling continuous media in a video-on-demand server," IEEE, 1994, pp. 19–28 — § 102(a). Continuous-media scheduling; § 103 material.
5. Kim, "Synchronized Disk Interleaving," IEEE, Nov. 1986, pp. 978–988 — § 102(b). Classic disk-interleaving/striping paper; supports the striping limitation as known art.
6. Rangan et al., "Designing File Systems for Digital Video and Audio," ACM Press, Oct. 13, 1991, pp. 91–104 — § 102(b). File-system design for digital video/audio; background for segmented storage of video.

5. Bottom line

• No cited reference is a guaranteed single-reference § 102 anticipation of claim 1 as a matter of law — every candidate is missing at least one element (most commonly the combination of (i) X-stripe round-robin partitioning with each stripe on a distinct mass-storage unit, (ii) switch means coupling the storage node to a plurality of communication nodes having plural output ports, and (iii) consumer-input-driven switch control enabling simultaneous same/different block delivery).
• The two strongest § 102 anticipation candidates are US 5,473,362 (Fitzgerald, filed 11/30/1993) — which most fully discloses striped block storage, time-multiplexed multi-stream scheduling, and a crosspoint-switch-like network — and US 5,442,390 (Hooper, filed 7/7/1993) — which discloses a multi-customer VOD server with buffered segment delivery and RAID storage.
• US 5,461,415 (Wolf, filed 3/15/1994) is the best same-assignee scheduling art but does not anticipate; US 5,471,640 (McBride) and US 5,530,830 (Iwasaki) supply the striping element alone; the 1980s/early-1990s distribution patents (Cohen, Ballantyne, Milone, Esch, de Nijs) supply the "central source + remote consumer control" element alone. Realistically, any validity challenge will be a § 103 combination anchored by Fitzgerald or Hooper, with the § 102(e) filing dates of the mid-1990s patents (McBride, Vaitzblit, Dan, Long, Birk, Youden, etc.) needing verification before reliance.
• US 5,586,264 is not prior art (same-day sibling filing).
• Claims 2–4 are unlikely to be anticipated by any single citation: no cited reference expressly discloses the 0.2–2 s T/N window (claim 2) or the r/n/d/m stripe-count expression (claim 3).

Confidence caveats: (1) I verified the § 102(e) filing dates only for 5,442,390 (7/7/93), 5,461,415 (3/15/94), and 5,473,362 (11/30/93); the other mid-1990s patents' filing dates and the content of EP 0 529 864 A1, WO 93/16557, and the four oldest U.S. citations were not independently verified and should be confirmed in Patent Center before they are used in an anticipation or obviousness argument. (2) The claim text and reference list were taken from uspto.report's USPTO-derived record, which matched the FreePatentsOnline citation list; treat that as reliable. (3) All § 102 analysis here is pre-AIA because the application was filed September 8, 1994 — before the effective date of the AIA's first-inventor-to-file provisions.

I need the complete list of prior art references cited on the face of US 5,712,976. Let me pull the full "References Cited" section from the patent record.

I have the key cited references. Let me try to get the complete citation list including foreign references and non-patent literature, and check the filing dates of the most relevant references for prior-art status.

Obviousness Analysis Under 35 U.S.C. § 103 — U.S. Patent 5,712,976

0. Preliminary caveats (read first)

Claim text. As documented in the prior sections of this file, the verbatim claims of US 5,712,976 were not retrievable from the fetched record (the Google Patents text truncates before the claims). This analysis therefore proceeds on the reconstructed independent claim derived from the specification's Summary of the Invention. Every element mapping below should be re-verified against the actual claim language (available from USPTO Patent Center, application 08/302,624) before being used in litigation.

Statutory framework. The application was filed September 8, 1994 — before the March 16, 2013 AIA transition — so pre-AIA 35 U.S.C. § 103 governs, applying the Graham v. John Deere, 383 U.S. 1 (1966) factors as refined by KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007).

Prior-art status of cited references. The references on the face of the patent were "considered" by the examiner; that does not by itself make each one § 102 prior art. Under pre-AIA § 102(e), a U.S. patent is prior art as of its earliest effective U.S. filing date. I verified the key dates where noted; several cited references have unknown filing dates and should be confirmed before reliance. The primary combination below rests on verified prior art.

1. The prior art record (from the patent's citation records)

The patent's own "References Cited" (FreePatentsOnline / Google Patents) and the specification cite the following, which constitute the available prior-art pool:

U.S. patents cited on the face of '976:

• US 5,473,362 (Fitzgerald et al., Microsoft) — Video on demand system comprising stripped data across plural storable devices with time multiplex scheduling — filed Nov. 30, 1993 (verified); § 102(e) prior art against the Sept. 8, 1994 filing.
• US 5,606,359 (Youden) — VOD with multiple data sources providing VCR-like services
• US 5,550,982 (Long) — Video application server
• US 5,544,327 (Dan) — Load balancing in VOD servers by buffer allocation
• US 5,528,513 (Vaitzblit) — Scheduling and admission control policy for a continuous media server
• US 5,530,830 (Iwasaki) — Disk array system
• US 5,522,054 (Gunlock) — Dynamic control of outstanding disk read requests
• US 5,510,905 (Birk) — Video storage server using track-pairing
• US 5,487,167 (Dinallo) — PC with generalized data streaming apparatus
• US 5,471,640 (McBride) — Programmable disk array controller with counters for striping data
• US 5,461,415 (Wolf) — Look-ahead scheduling for VOD
• US 5,442,390 (Hooper) — VOD with memory accessing
• US 5,421,031 (De Bey), US 5,289,461 (de Nijs), US 5,283,639 (Esch), US 5,200,989 (Milone), US 5,133,079 (Ballantyne), US 5,089,885 (Clark), US 4,949,187 (Cohen) — distributed/multimedia distribution systems
• US 5,586,264 (Belknap) — Video optimized media streamer with cache management — sibling application, same filing date (Sept. 8, 1994), commonly owned; excluded as § 103 prior art under pre-AIA § 103(c) (same-day, common-assignee; I do not rely on it).

Non-patent literature cited in the specification:

• Patterson, Gibson & Katz, "A Case for Redundant Arrays of Inexpensive Disks (RAID)," ACM SIGMOD, Chicago, June 1–3, 1988, pp. 109–116 (verified) — the foundational RAID striping paper, expressly incorporated into the '976 specification's own discussion of disk storage.

Uncertain dates to verify before reliance: Vaitzblit '513, Dan '327, Wolf '415, Long '982, Youden '359, Hooper '390, McBride '640 all issued after Sept. 8, 1994; each is usable only if its underlying application was filed before the invention date (likely for several, since the VOD art of 1993–1994 was active, but unverified here).

2. The reconstructed independent claim — element breakdown

Based on the specification's Summary, the principal system claim requires:

3. Person of ordinary skill in the art (POSITA)

A POSITA circa 1993–1994 would be an engineer with a B.S./M.S. in computer science or electrical engineering and roughly 2–5 years' experience in digital video-on-demand server design, disk-array/RAID storage systems, continuous-media I/O scheduling, and multimedia networking (SCSI, ATM, MPEG), familiar with the contemporaneous literature (RAID/SIGMOD, IEEE COMPCON multimedia sessions, the Microsoft/Bellcore/Oracle VOD server efforts). Such a person would routinely perform bandwidth engineering — computing how many disks are required to sustain N isochronous streams at a given bit rate.

4. Primary obviousness combinations

Combination A (strongest): Fitzgerald '362 + RAID (Patterson 1988) — striped single-copy VOD server

Fitzgerald '362 (verified § 102(e) prior art) discloses nearly the entire claimed system:

• Element (a) — plurality of storage units storing a video as blocks: Fitzgerald's VOD system has "a plurality of storage devices" (explicitly including magnetic disk drives) storing "data sequences" (video image sequences) as "blocks of data." ✓
• Element (c) — round-robin striping, each stripe on a different device: Fitzgerald: "each consecutive block of data for the video image sequence is stored on a next storage device in the predetermined sequence… The predetermined sequence wraps around to the beginning." This is exactly the claim's "blocks 1, X+1, 2X+1…" round-robin partition. Each block of a sequence resides on a different device (the default is one copy, with multiple copies optional). ✓
• Element (d) — simultaneous conveyance of different blocks: Fitzgerald's "bandwidth unit" model schedules each subscriber to a like-positioned time slot across the devices; during each consecutive slot a consecutive block is read from the appropriate device, so different subscribers simultaneously receive different blocks from the same single copy. ✓
• Element (d) — simultaneous conveyance of the same block: In Fitzgerald's model, subscribers assigned to the same bandwidth unit receive the same block stream; a block read once from a device during its slot can be delivered to all subscribers sharing that unit. The "same block to multiple streams" is thus inherent in (or trivially derived from) the time-multiplexed schedule. ✓
• Element (e) — stripe count as a function of bandwidth: Fitzgerald's entire scheduling architecture treats device I/O bandwidth as the limiting resource, allocated in bandwidth units sized to the stream data rate. The notion that the number of devices (stripes) must satisfy aggregate device bandwidth ≥ (number of streams) × (stream rate) is inherent in the model; the '976 formula (≈ n·r/d) is simply that constraint written down. ✓

RAID (Patterson 1988) supplies the general motivation and mechanism for striping data across "a plurality of disks" specifically "to improve bandwidth" and "scalability" — precisely the reason '976 gives for striping ("concurrency or bandwidth reasons," not parity). The '976 specification itself cites RAID as background, conceding the concept's presence in the art. McBride '640 (programmable disk array controller with counters feeding "every nth data segment" to each disk) supplies the round-robin controller implementation if a hardware limitation were argued.

Motivation to combine: RAID and Fitzgerald are in the same field (high-bandwidth disk storage; VOD servers). A POSITA implementing Fitzgerald's striped VOD storage would use the standard disk-array striping techniques of RAID/McBride to realize the striping hardware. This is a textbook combination of known elements with predictable results (KSR).

Combination B: Fitzgerald '362 + continuous-media admission-control art (Vaitzblit '513, Dan '327, Wolf '415) — the stripe-count formula and scheduling

If the examiner/patentee points to element (e) (the X-formula) as the point of novelty, the continuous-media server literature fills it:

• Vaitzblit '513 teaches "scheduling and admission control policy for a continuous media server": before admitting a stream, the server verifies sufficient disk bandwidth and buffer capacity; the sustainable number of concurrent streams at a given data rate is a function of disk count and per-disk effective throughput — the exact parameters (r, n, d, m) of the '976 expression.
• Dan '327 teaches allocating buffers to streams based on stream requirements — resource provisioning per stream at connect time, the same operation '976 performs ("calculations of sfc and dfc are made at connect time").
• Wolf '415 teaches look-ahead scheduling of disk reads to meet isochronous output deadlines — the "just-in-time" read scheduling of the '976 storage/communication nodes.

Motivation to combine: The problem the '976 formula solves — how many disks do I need to support n simultaneous streams at rate r? — is the central capacity-planning question of every continuous-media server. Vaitzblit/Dan/Wolf all address it from the admission-control/scheduling side. Writing the constraint as a simple expression of r, n, d, m is an "obvious to try" algebraic exercise with a predictable result (KSR; see also the '976 spec's own admission that the stripe count is "calculated from the formula m·r/d"). A POSITA combining Fitzgerald's striped layout with Vaitzblit's admission control would necessarily arrive at the claimed stripe-count determination.

Combination C: Fitzgerald '362 + distributed-server architecture art (Youden '359, Long '982, Hooper '390, de Nijs '461, Esch '363, Ballantyne '079) — the multi-node communication architecture

Element (b) — "communication nodes each having an input port coupled to the storage node output and plural output ports transmitting data streams" — is the conventional distributed-server decomposition, taught by:

• Youden '359 — VOD system with multiple data sources configured to provide VCR-like services to multiple outputs;
• Long '982 — a video application server with storage feeding networked video outputs;
• Hooper '390 — VOD with memory accessing, i.e., shared memory so multiple users access the same video data (also supporting element (d)'s same-block-to-many-streams);
• de Nijs '461 / Esch '363 — interconnection/switching methods for digital multimedia communications, i.e., a switch fabric between multimedia nodes;
• Ballantyne '079 — central movie-distribution source serving many user terminals.

Motivation to combine: Scaling a VOD server beyond one machine's bandwidth by separating storage nodes from communication/output nodes over a switch is the standard distributed-server design of the era (the '976 spec concedes the field was crowded with VOD, ATM, and multimedia-server work). A POSITA would combine Fitzgerald's striped storage with a switch-based node architecture to achieve the claimed scalability — again a predictable aggregation of known components.

5. Graham-factor and KSR analysis

1. Scope and content of the prior art. The prior art (Fitzgerald, RAID, Vaitzblit, Dan, Wolf, Youden, Long, Hooper, de Nijs) collectively teaches every element of the reconstructed independent claim: striped single-copy storage of video blocks across multiple disks (Fitzgerald + RAID), time-scheduled simultaneous delivery of different blocks to different streams and the same block to multiple streams (Fitzgerald + Hooper), multi-node server architecture with a switch (Youden/de Nijs/Esch), and admission-control/bandwidth-based stripe-count calculation (Vaitzblit/Dan/Wolf).

2. Differences between the claim and the prior art. The principal arguable differences are (i) the express multi-node "storage node/communication node" partitioning and (ii) the closed-form X-expression. Both are (i) a standard design decomposition and (ii) a routine algebraic restatement of the known bandwidth constraint — not structural or functional surprises.

3. Level of ordinary skill. High — VOD server design was an active, crowded field in 1993–1994 (Microsoft's Tiger, Bellcore, Oracle, IBM's own media-streamer family all being contemporaneous).

4. Secondary considerations. None found. The patent expired (Jan. 27, 2015) with no known litigation, no PTAB challenge, and no evidence of commercial success, long-felt need, or copying (see the litigation/PTAB sections of this file). The absence of any assertion history cuts against a non-obviousness showing.

KSR points: This is the paradigmatic KSR case — a combination of known prior-art elements (disk striping, time-slot scheduling, admission control, node-based server architecture), each performing its known function, with a predictable result (more concurrent streams by adding disks), and no teaching away in any reference. The "single copy, multiple stream" goal is expressly the design objective of Fitzgerald's bandwidth-unit scheduling, not a novel insight of '976.

6. Anticipated patentee counterarguments and rebuttals

7. Bottom line

The reconstructed independent claim of US 5,712,976 is highly likely obvious under pre-AIA § 103. The strongest combination is Fitzgerald '362 (verified Nov. 30, 1993 filing; striped single-copy VOD storage with time-multiplexed simultaneous stream delivery) + RAID/Patterson 1988 and McBride '640 (stripe implementation) + Vaitzblit '513 / Dan '327 / Wolf '415 (admission-control-based stripe-count determination and isochronous scheduling) + Youden '359 / de Nijs '461 (multi-node switch architecture). A POSITA had every motivation to combine these — the same field, complementary teachings, a known scaling problem, and predictable results — and no secondary considerations offset that conclusion.

Two cautions before reliance in any proceeding: (1) verify the verbatim claims (the analysis is keyed to the reconstructed summary-based claim); (2) confirm the § 102(e) filing dates of Vaitzblit '513, Dan '327, Wolf '415, Long '982, Youden '359, Hooper '390, and McBride '640 — if any filed after Sept. 8, 1994, drop it from the combination and rely on Fitzgerald '362 + RAID (verified) plus the verified pre-filing art (Ballantyne '079, Milone '989, Esch '363, de Nijs '461, Clark '885, Cohen '187), which is still a strong case for elements (a)–(d), with element (e) supported by the inherent bandwidth-constraint reasoning.