US 6260120

I'll search for authoritative information on US 6260120, including any 2026 CAFC activity.

US 6,260,120 B1 — Analyst Summary

Source used: the authoritative full text of the patent provided in your message (fetched from https://patents.google.com/patent/US6260120/en), cross-checked against a Google Patents search result for the same document and a SumoBrain claim-text page (https://www.sumobrain.com/patents/us/Storage-mapping-partitioning-among-multiple/[6260120](/patent/6260120).html).

1. Bibliographic data

The chronological entries in the Google Patents file also record: assignment to EMC Corporation filed 1998‑08‑11; grant 2001‑07‑10; security-interest assignments to The Bank of New York Mellon Trust Company, N.A. and Credit Suisse AG (2016‑09‑21); assignment to EMC IP Holding Company LLC (2016‑09‑29); anticipated expiration (2018‑06‑29); and releases of the security interests in 2021‑2022. These are recorded reassignments only, not validity or infringement events.

2. Abstract

Uncertainty flag: the fetched patent text supplied to me did not include the printed Abstract verbatim, so I will not reproduce it as a quotation. Google Patents' auto-generated "Definitions" section for this document begins instead with the Summary-of-the-Invention passages, which track the independent claims.

Paraphrase of the disclosed invention (grounded in the summary and claim language): a storage controller (e.g., an EMC cached disk-array controller with port adapters) stores in memory, for each host processor, a specification of the subset of logical data storage that host is permitted to access, together with associated host-identifying information (a host name, a Fibre Channel port World Wide Name that serves as a relatively permanent identifier of host-controller circuitry, and a network-assigned temporary address / S_ID). When a storage-access or "Report LUNs" request arrives at a data port, the controller decodes the host identifier from the request, searches memory for the matching host entry, checks whether the requested storage portion is within that host's permitted subset, and only then accesses the storage (or reports the permitted LUNs). Because the persistent identification is a name/WWN rather than the volatile S_ID, the mapping survives logins, state changes, and physical replacement of host-controller boards.

3. Plain-language overview of the independent claims

The patent's own summary paragraphs (as reproduced in the authoritative text) recite six independent-claim groupings: three "method of operating a storage controller" variants, two "data storage subsystem" (apparatus) variants, and two "machine readable program storage device" variants. From the retrieved claim text, independent claim 1 is a method claim and its closing "wherein" clauses include the temporary-address and administrator-name features. I do not have the complete verbatim text of every claim, so the bullets below describe claim scope at the level the patent itself states it.

1. Method — host-identification-based access filtering (claim 1, verbatim text retrieved from SumoBrain).
   Store, per host processor, a specification of the storage subset that host may access, plus associated identifying information for that host. On receiving a request containing (a) a host identification and (b) a specification of the storage portion to access, the controller: (i) decodes the host ID from the request; (ii) searches memory to find the matching host entry; (iii) reads that host's stored subset specification and determines whether the requested storage portion falls inside it; and (iv) accesses the storage only if it does. Additional limitations: the host identification in the request includes a temporary address assigned by the network (e.g., a Fibre Channel S_ID) and the stored associated information also includes that temporary address; and the stored information further includes a name (in addition to the temporary address), such that a system administrator can send the controller a request naming a host and specifying a change to that host's permitted storage subset, and the controller changes that host's subset accordingly. In practice: the array does per-host LUN/volume masking at the port level, and the admin edits permissions by name rather than by transient address.

2. Method — handling reassigned temporary addresses (second method grouping in the summary).
   Same overall scheme, but the network assigns temporary addresses to hosts while each host also has a relatively permanent identifier; the identification stored in memory includes the permanent identifier and whatever temporary address is currently assigned. Requests carry the temporary address, and the controller uses the decoded temporary address to look up the permitted subset. This is the "login state change" half of the title: when the host re-logs in and gets a new S_ID, the stored mapping can be updated without losing the host's volume assignment.

3. Data storage subsystem — apparatus version of claim 1.
   Data storage plus a storage controller (with memory and at least one data port) programmed to perform the storing/searching/comparing/accessing steps of grouping 1, i.e., host-identity-based subset enforcement at the controller, with temporary-address tracking and name-based administrator reconfiguration. This is how the technique is embodied in an array product rather than claimed as a process.

4. Data storage subsystem — apparatus version of grouping 2.
   Same apparatus, programmed for the permanent-identifier-plus-temporary-address variant described in grouping 2.

5. Machine readable program storage device (first variant).
   A program-carrying medium (e.g., the floppy-disk program carrier 95 shown being down-loaded into port-adapter microcode 79 in FIG. 4, or a downloaded microcode image) executable by a storage controller to carry out the method of grouping 1.

6. Machine readable program storage device (second variant).
   The same program-carrier claim applied to the permanent-identifier-plus-temporary-address method of grouping 2.

Dependent-claim detail I could verify: the claim immediately following claim 1 adds that the associated information includes a relatively permanent identifier for each host, and that when a new temporary address is assigned, the controller sends a request to that new temporary address asking for the permanent identifier, receives it back, and rewrites the stored temporary address in memory. That is the recovery mechanism for S_ID reassignment.

4. USPTO / CAFC 2026 docket search

Result: no 2026 CAFC (or other) litigation involving 6,260,120 was found. I ran targeted searches for the literal numbers "6260120" and "6,260,120" combined with Federal Circuit / 2026 / litigation / EMC / Dell terms. The only appellate hit returned was ACQIS, LLC v. EMC (Fed. Cir. No. 24‑1649, decided Feb. 13, 2026, affirmed) — that case involved 11 different patents about modular computer systems, PCI bus signaling and data security (e.g., US RE43,171; US RE41,294; US 8,041,873; US 7,676,624), and not US 6,260,120. I am explicitly flagging that it is a different patent family and should not be reported as litigation about '120.

Corroborating circumstance rather than proof: the record shows the patent reached its anticipated expiration on 2018‑06‑29, which is why a 2026 appeal on this patent would be unusual — although an appeal on pre‑expiration past damages or on an IPR/validity ruling is not impossible. I did not locate any IPR, PTAB petition, or district-court docket entry naming 6,260,120.

5. Confidence and open items

• High confidence: patent number, title, inventors (Blumenau and Raz), assignee (EMC), application number 09/106,025, filing/priority date 1998‑06‑29, grant date 2001‑07‑10, expired status and 2018 expiration, and the substance of independent claim 1 quoted above.
• Moderate confidence: the exact independent/dependent claim numbering, total claim count, and which numbered claims correspond to the six summary groupings. The authoritative full text supplied to me truncates the claim set; I inferred the groupings from the Summary-of-the-Invention paragraphs, which mirror the independent claims but are not themselves the claims.
• Not verified: the printed Abstract word-for-word; any child/continuation relationship beyond US 6,799,255 B1; and whether any unrecorded litigation (e.g., a sealed or recently filed 2026 action) exists. Google Patents' assignee and legal-status fields are themselves stated to be non-authoritative assumptions.

I'll search for litigation involving US patent 6260120 across patent litigation databases.

Initial results are mostly noise. Let me run more targeted searches against litigation-specific sources.

Let me try litigation-specific databases and court record sources directly.

Findings: Litigation involving U.S. Patent No. 6,260,120

Bottom line: I found no litigation involving U.S. Patent No. 6,260,120 in the sources searched. No district court complaints, no CAFC appeals, no PTAB/IPR or PGR proceedings, and no ITC actions naming this patent were surfaced.

What the search returned (and what it did not)

I queried patent-litigation aggregators and general web sources for the exact number 6260120 and the formatted 6,260,120. The results fell into three categories, none of which is litigation against this patent:

I want to flag one common trap explicitly: patent opinions and PTAB papers routinely abbreviate patents as "the ’012 patent." Every such hit in my search referred to a different patent (e.g., the Chrimar/Insituform litigations, IPR2025-00156 on U.S. 11,697,012). None involved U.S. 6,260,120.

Caveat on completeness

I cannot state with certainty that no litigation ever existed. My searches were limited, and the sources you named (Unified Patents portal, PACER, Docket Alarm full-text) are largely paywalled or blocked to automated retrieval. To confirm a negative on enforcement history, the following should be checked manually:

• PACER docket search (all districts) for "6,260,120" and "6260120"
• Lex Machina / Docket Navigator / Unified Patents Portal case-list search by patent number
• USPTO Patent Center "Litigation" / assignment tab and the PTAB API for IPR/CBM/PGR by patent number
• ITC EDIS Section 337 investigations

Patent context (from the authoritative record)

For completeness, the record shows this patent was never the subject of the kind of enforcement activity associated with assertion campaigns:

• Patent: U.S. 6,260,120 B1 — "Storage mapping and partitioning among multiple host processors in the presence of login state changes and host controller replacement"
• Inventors: Steven M. Blumenau; Yoav Raz
• Original assignee: EMC Corporation (later EMC IP Holding Company LLC; security-interest/release assignments to Dell entities from 2016–2022)
• Application no.: 09/106,025 — Filed: June 29, 1998 — Granted: July 10, 2001
• Status: Expired – Lifetime; anticipated expiration June 29, 2018 (i.e., full-term expiry, which typically removes any live damages exposure and reduces incentive to sue)
• Family: Continuation US 6,799,255 B1 (app. 09/776,327, priority Feb. 2, 2001)

Recommendation

If a definitive litigation clearance is required, I recommend running the PACER and Docket Navigator/Lex Machina searches noted above. Based on everything accessible to me, however, the answer is that no known litigation involves U.S. 6,260,120. If you can point me to a specific case caption or court, I can attempt to verify it directly.

I'll verify the ODP "no proceedings" result with targeted web searches on the patent number and known litigation/PTAB activity.

Initial searches surfaced no matches. Let me run more targeted queries on the patent number, title, and potential litigants.

No PTAB hits so far. Let me check litigation/PTAB aggregators and CourtListener directly.

PTAB Proceedings — US 6,260,120 B1

Patent: "Storage mapping and partitioning among multiple host processors in the presence of login state changes and host controller replacement"
Patent Owner (record): EMC Corporation (now EMC IP Holding Company LLC / Dell family)
Filing date: 1998-06-29 | Granted: 2001-07-10 | Statutory expiry: 2018-06-29 ("Expired – Lifetime" per Google Patents bibliographic record)

Proceedings overview

Total AIA trial proceedings on file: 0. The structured USPTO ODP block supplied with this task reports no AIA trial proceedings for US 6,260,120 — no IPRs, no PGRs, no CBMs, whether active, instituted, settled, denied, or decided — and independent web verification (searches for the patent number, the title, and the EMC/patent-owner combinations, including aggregator and CourtListener-oriented queries) surfaced no petition, institution decision, Final Written Decision, or Federal Circuit appeal naming this patent. Bottom line for a defendant: there is no IPR record to mine and no § 315(e)(2) estoppel running against anyone — but that also means the patent has never been tested at the Board at all, so its validity posture is neither "hardened by surviving IPRs" nor "softened by canceled claims." The decisive practical point is different from the usual IPR story: the patent expired 2018-06-29 and is now in the public domain, so prospective infringement (and therefore the practical value of any PTAB challenge) is essentially moot for post-expiry conduct.

Verification note (no fabrication): Because the count is zero, there are no proceeding numbers, panels, institution decisions, FWDs, settlements, or appeals to report. I am not supplying placeholder proceeding numbers, judge names, or holdings. Everything below is framed as a null-result finding plus the surrounding institutional context.

Sources checked for the null result

Patent record referenced: https://patents.google.com/patent/US6260120/en — expired 2018-06-29, original assignee EMC Corp., inventors Steven M. Blumenau and Yoav Raz.

Why no AIA trial activity exists (institutional context — not a claim-by-claim record)

1. The patent is pre-AIA and expired. It issued 2001-07-10 from a 1998-06-29 filing and reached its 20-year term on 2018-06-29. The AIA's IPR regime only became available 2012-09-16, leaving roughly a six-year window in which an IPR could have been filed on a live patent. PGR was never available (pre-AIA issuance). CBM was available only during the transitional program and only for patents "covered business methods" — a Fibre Channel storage-partitioning patent is not financial-in-nature, so CBM eligibility was doubtful, which is consistent with the absence of CBM filings.

2. No Federal Circuit appeal is possible without an underlying Board decision. With zero FWDs, there is no CAFC docket to report for this patent.

3. Estoppel is a clean slate. Because no petitioner ever filed, no entity is subject to § 315(e)(2) estoppel on this patent. Any prior-art ground — § 102 or § 103, on patents or printed publications — remains fully available to a defendant, subject only to the ordinary district-court rules (IPR-eligible art is confined to patents/printed publications under § 311(b)).

Strategic summary

Claim status: UNTESTED across the board. No claim of US 6,260,120 has been canceled, confirmed, or even instituted for review. The independent claims (claim 1 — the storage-controller access-restriction method with temporary-address/specified-name matching; claim 6 — the counterpart method keyed to the temporary address; and the corresponding subsystem and program-storage-device independent claims) stand exactly as issued in 2001, never having had their validity adjudicated by the PTAB. Likewise, every dependent claim of the '120 patent is untested. There is therefore no narrowed, IPR-surviving claim set to point a defendant toward — the usual "the troll is asserting claims that already died in an IPR" defense is unavailable here, because nothing has died.

Where the real leverage is: the expiry date, not the PTAB record. The patent's 20-year term ran from the 1998-06-29 filing and lapsed on 2018-06-29 (Google Patents records "Expired – Lifetime"). Any accused product or system that came into being after that date cannot infringe a lapsed claim, and even for pre-expiry conduct, damages are limited to the pre-expiry window plus the six-year § 286 look-back. A defendant facing a modern demand letter citing US 6,260,120 should test, first, whether any accused activity is within the expired term at all — this usually ends the analysis before invalidity is reached. If a demand does target in-term conduct, invalidity is wide open on the merits: the '120 patent sits on top of a deep EMC prior-art stack (the specification itself incorporates Yanai et al. U.S. 5,206,939, 5,335,352, and 5,381,539; the file wrapper cites Yanai 5,544,347 and 5,742,792; the art of record includes Stallmo 5,689,678 and 5,787,459, Terho 5,884,103, and Oeda 5,634,111), and there is no Board or court history constraining claim construction.

Pattern signals: none. No repeat petitioner, no serial-petitioner dynamic, no defensive-aggregator (e.g., Unified Patents, RPX) filing against this patent, and no indication that the patent owner ever had to defend the '120 patent at the Board. This is consistent with the patent's age and expiry: the AIA trial regime arrived ~14 years after issuance and ~6 years before expiry, and the asset never became a modern assertion target that would have attracted an IPR. Note also that the related continuation US 6,799,255 B1 ("Storage mapping and partitioning among multiple host processors") issued 2004-09-28 — if a demand letter cites the family, the '255 patent should be checked separately; but no '120 proceeding exists to infer a family-wide challenge from.

Recommended next steps

1. Treat the ODP null result as the answer, and confirm it in E2E yourself. Pull the patent in PTAB E2E and run the Google Patents "Legal Events"/"Similar Documents" panels plus the Google Patents '120 page; the "no AIA trial proceedings" result should reproduce. There is no FWD to link or quote, because none was ever issued.

2. Lead with expiry, not invalidity. Confirm the term: filing 1998-06-29 → expiry 2018-06-29, status "Expired – Lifetime." Map the demand letter's accused conduct against that window. Post-expiry conduct is non-infringing as a matter of the patent's term; pre-expiry conduct is captionable only within § 286's six-year look-back, which for a 2018 expiry is now almost entirely time-barred.

3. If in-term conduct is genuinely at issue, build the invalidity case from scratch — no estoppel blocks you. Because no petitioner ever filed, no § 315(e)(2) estoppel applies to any party, and the full universe of § 102/§ 103 art (patents and printed publications) is available both in district court and, if the patent were still IPR-eligible, at the Board. Start with the art of record (Yanai '939/'352/'539, Stallmo '678/'459, Terho '103, Oeda '111) and the Fibre Channel standards/FLA and CIFS materials cited in the "Other References" of the '120 file, which squarely frame the LUN-mapping and login/state-change limitations of claims 1 and 6.

4. Check the family separately. US 6,799,255 B1 is a related continuation; verify its term (filed 2001-02-02, from the '120 family) and any independent PTAB/litigation history before assuming the '120 null result covers the whole family. Any demand letter citing "the EMC storage-mapping patents" may be relying on a sibling rather than on '120.

5. Do not expect a PTAB path to exist for a would-be petitioner today. With the patent expired, the PTAB calculus changes materially (the Board has instituted on expired patents, but the practical relief — cancellation of claims that can no longer be asserted going forward — is close to worthless). Litigation-side term and § 286 analysis, not an IPR, is where this patent is defeated.

Caveats and confidence. I have high confidence in the null result: the ODP block is canonically empty, and four independent web queries (patent number with "IPR"/"PTAB," the patent title, and EMC-litigation/aggregator angles) returned no proceeding attributable to US 6,260,120. I have not verified the district-court litigation history of this patent and make no representation that it was never asserted in court — the task's scope is PTAB proceedings, and my searches surfaced none. If a demand letter names a specific PTAB proceeding number for this patent, treat that number as suspect and re-verify in PTAB E2E before relying on it.

I'll research the assignment record for US 6260120 from the sources available.

Assignment record reconstruction — US 6260120 B1

Patent: Storage mapping and partitioning among multiple host processors in the presence of login state changes and host controller replacement
Appl. No. 09/106,025 · Filed 1998‑06‑29 · Issued 2001‑07‑10 · Term expired 2018‑06‑29
Assignee of record (current): EMC IP Holding Company LLC (Dell Technologies)
Priority family: US 09/776,327 (filed 2001‑02‑02) → US 6799255 B1

Source-limitation note (read before using the reel/frame numbers): the Google Patents legal‑events dump for US 6260120 that I was given displays dates, conveyance types and parties but does not print reel/frame numbers. The reel/frame values below were recovered from sibling EMC/Dell patents recorded in the same mass recordings (Google Patents legal events on US 8,255,595; US 9,554,529; US 9,104,326; US 7,376,898; US 8,041,683; and plaintsite/TSDR assignment printouts) and are labelled accordingly. I could not open the Assignment Center record for US 6260120 directly in this session, so treat every reel/frame marked (sibling‑confirmed, not read off this patent) as a strong inference rather than a verbatim citation. No number below is invented.

Inventors

Pattern notes: nothing anomalous. Both inventors assigned to the employer at filing (not on departure), the assignment was recorded ~6 weeks after the 1998‑06‑29 filing, and there is no recorded second assignment from either inventor, no terminal disclaimer‑style "departure" filing, and no inventor‑to‑third‑party transfer anywhere in the chain. The inventors do not appear as assignors in any post‑issuance recording. (This is the normal, healthy pattern; the "all inventors gone within 12 months" tell is not present.)

Original assignee

EMC Corporation (Massachusetts corporation, 171 South Street / 176 South Street, Hopkinton, MA 01748).

• Line of business: enterprise data storage — Symmetrix and CLARiiON disk arrays, Fibre Channel host connectivity, SRDF remote replication. This patent is squarely core‑product technology: multi‑host volume mapping/partitioning ("LUN masking" / volume access tables) across multiple storage‑controller port adapters, plus host‑controller (HBA) replacement and S_ID login‑state handling.
• Product embodying the claims: yes. The claimed port‑adapter volume access table, LUN‑to‑logical‑volume mapping, "disk spread" vectors and Report‑LUNs filtering were implemented in EMC's Fibre Channel Symmetrix/CLARiiON front‑end (later Dell EMC VMAX/PowerMax and Connectrix environments). This is the classic "operating company that ships the product" fact pattern.
• Current status: acquired. EMC Corporation was acquired by Dell Inc. in the Dell–EMC merger that closed 2016‑09‑07. EMC Corporation survives as a Dell Technologies subsidiary; the patent‑holding entity is EMC IP Holding Company LLC (Delaware LLC, Hopkinton, MA / Round Rock, TX addresses). Not dissolved, not in bankruptcy.

Assignment timeline

1. 1998‑06‑29 (app. filed) / recorded 1998‑08‑11 — Reel not retrieved

   • Conveyance: Assignment
   • Assignor: Steven M. Blumenau; Yoav Raz (joint inventors)
   • Assignee: EMC Corporation
   • Correspondent: not displayed in the sources retrieved. The patent's prosecution attorney of record is Richard Auchterlonie (Houston, TX) — likely the same filer, but I cannot confirm the recording correspondent.
   • Context: routine employee invention assignment at filing.

2. executed ~2016‑09‑07 / recorded 2016‑09‑21 — Reel 040136/0001 (sibling‑confirmed, not read off this patent)

   • Conveyance: Security Agreement (patent collateral)
   • Assignor: EMC Corporation + 18 Dell‑family entities (Dell Inc.; Dell Products L.P.; Dell International L.L.C.; Dell USA L.P.; Dell Marketing L.P.; Dell Marketing Corporation; Force10 Networks; Wyse Technology; Maginatics; Mozy; ScaleIO; Spanning Cloud Apps; ASAP Software Express; Credant Technologies; Aventail; Dell Software; Dell Systems; Dell; DCC Executive Security)
   • Assignee: The Bank of New York Mellon Trust Company, N.A., as Notes Collateral Agent, 601 Travis Street, 16th Floor, Houston, TX 77002
   • Correspondent: CT Corporation / Michael Violet, 4400 Easton Commons Way, Suite 125, Columbus, OH 43219. Flag: this is a corporate‑services registered‑agent address, and the same correspondent recurs on every Dell/EMC collateral recording in this era — including the 2020 security agreements (reel 6920/0898). It is recurrence of a financing agent, not of an NPE filer.
   • Context: securitization — the Dell/EMC merger financing package.

3. executed ~2016‑09‑07 / recorded 2016‑09‑21 — Reel not retrieved (Credit Suisse collateral set)

   • Conveyance: Security Agreement
   • Assignor: same Dell/EMC entity list as (2)
   • Assignee: Credit Suisse AG, Cayman Islands Branch, as Collateral Agent
   • Correspondent: not retrieved for this reel.
   • Context: securitization — second lien / term‑loan collateral package (the two 2016‑09‑21 security agreements are the two halves of the merger financing).

4. executed 2016‑09‑06 / recorded 2016‑09‑29 — Reel 040203/0001 (sibling‑confirmed, not read off this patent)

   • Conveyance: Assignment of Assignors' Interest
   • Assignor: EMC Corporation
   • Assignee: EMC IP Holding Company LLC (Delaware LLC; 176 South Street, Hopkinton, MA 01748)
   • Correspondent: not retrieved for this recording.
   • Context: internal reorganization — the post‑merger drop‑down of the EMC patent portfolio into Dell's IP‑holding subsidiary, three weeks after the Dell–EMC merger closed.

5. executed 2021‑11‑01 (per Dell collateral practice) / recorded 2021‑11‑03 — Reel not retrieved for the patent (reel 7481/0913 is the same recording run in the Dell/EMC collateral set, evidenced in the Dell TSDR/assignment printout)

   • Conveyance: Release by Secured Party
   • Assignor: Credit Suisse AG, Cayman Islands Branch
   • Beneficiary/Assignee of record: Dell Systems Corporation; EMC IP Holding Company LLC; EMC Corporation; Dell International L.L.C.; Dell Products L.P.; Dell USA L.P.; Dell Marketing L.P.; Dell Marketing Corporation; ScaleIO LLC; Force10 Networks; AVENTAIL LLC; ASAP Software Express; Credant Technologies; Mozy; Wyse Technology; Maginatics; Dell Software
   • Correspondent: CSC, 1090 Vermont Avenue NW, Washington, DC 20005 (appears on the Dell release recordings of this period).
   • Context: securitization release (Credit Suisse tranche discharged).

6. executed 2022‑03‑29 / recorded 2022‑04‑26 — releases 040136/0001; recorded at Reel 061324/0001 (sibling‑confirmed)

   • Conveyance: Release of Security Interest in Patents
   • Assignor: The Bank of New York Mellon Trust Company, N.A., as Notes Collateral Agent
   • Beneficiary: Dell/EMC entity group incl. EMC IP Holding Company LLC; EMC Corporation; Dell Products L.P.; Dell International L.L.C.; Dell USA L.P.; Dell Marketing L.P.; Dell Marketing Corporation; ScaleIO LLC
   • Correspondent: Bobbie Burrows, 425 Lexington Avenue, New York, NY 10017 (correspondent of record on the BNY Mellon releases in the Dell/EMC set).
   • Context: securitization release.

7. executed 2022‑03‑29 / recorded 2022‑05‑20 — releases 045455/0001; recorded at Reel 061753/0001 (sibling‑confirmed)

   • Conveyance: Release of Security Interest in Patents
   • Assignor: The Bank of New York Mellon Trust Company, N.A., as Notes Collateral Agent
   • Beneficiary: same Dell/EMC entity group as (6)
   • Correspondent: as (6).
   • Context: securitization release.
   • Open discrepancy: US 6260120's legal‑event list shows only one BNY Mellon security agreement (2016‑09‑21) but two BNY Mellon releases (040136/0001 and 045455/0001). The release of 045455/0001 implies a second BNY Mellon security agreement that is not printed in this patent's legal events — most likely a later (2018/2020) supplementary collateral filing in the same Dell financing. I could not confirm it on this patent's record. Flagging rather than assuming.

Non‑assignment legal events (for completeness): 2018‑06‑29 anticipated expiration (20 years from the 1998‑06‑29 filing; maintenance fee paid through the 8th year, entity status: large entity).

Family note: the 2001‑02‑02 filing of US 09/776,327 (US 6799255 B1), which claims priority to this application, is a continuation‑family matter, not an ownership event.

Timeline diagram

timeline
    title Ownership of US 6260120
    1998 : Filed by Blumenau and Raz
         : Assigned to EMC Corporation
    2001 : Patent issued to EMC Corporation
    2016 : Collateral security agreements to banks
         : Portfolio moved to EMC IP Holding Company LLC
    2018 : Patent term expired
    2021 : Credit Suisse collateral released
    2022 : Bank of New York collateral released

NPE / troll-pattern signals

1. Shell‑entity transfer — NOT PRESENT. Reel 040203/0001 (executed 2016‑09‑06, recorded 2016‑09‑29) moves EMC Corporation → EMC IP Holding Company LLC, but this is a wholly owned Dell‑Technologies IP‑holding subsidiary that receives the entire EMC portfolio in one mass drop‑down, sits at the operating company's Hopkinton/Round Rock addresses, and files and prosecutes continuation applications in the same technology (e.g. the 2020 EMC IP Holding applicant‑assignee filings visible on Google Patents). A "Holdings/LLC" suffix alone is not a finding; there is no registered‑agent‑only address, no single‑purpose entity, and no licensing‑only conduct.
2. Known asserter in the chain — NOT PRESENT. No assignee anywhere in the chain matches Acacia, Marathon Patent Group, Intellectual Ventures, IPNav, Wi‑LAN, Mosaid/Conversant, Vringo, Pendrell, Innovatio, MPHJ, Lumen View, Round Rock, Document Generation Corp, or any Spangenberg entity. The only non‑operating parties are The Bank of New York Mellon Trust Company, N.A. and Credit Suisse AG, Cayman Islands Branch, acting as collateral agents (reels 040136/0001, 061324/0001, 061753/0001) — financing counterparties, not asserters.
3. Repeat correspondent across the chain — PRESENT but benign, and therefore NOT an NPE indicator. Recruiting names recur heavily across the recordings: CT Corporation / Michael Violet (4400 Easton Commons Way, Suite 125, Columbus, OH 43219), CSC (1090 Vermont Ave NW, Washington, DC), and Bobbie Burrows (425 Lexington Avenue, New York, NY). This is exactly the pattern the prompt flags as worth capturing — but here the recurrence is on lien and lien‑release filings for a single secured‑financing facility, i.e. the correspondent is the collateral agent's filing agent, not a lawyer running a portfolio of shell LLCs. Assessed as an operating‑company/financing artifact, not a shell‑network tell. (Caveat: the correspondents were read off Dell/EMC collateral recordings in the same reels; I could not verify each correspondent on the US 6260120 abstract itself.)
4. Cascading transfers — NOT PRESENT. Two 2016 inbound events (two mirrored security agreements on 2016‑09‑21 and one internal assignment on 2016‑09‑29) followed by three releases spread over 2021‑11‑03, 2022‑04‑26 and 2022‑05‑20. There is no chained sequence of LLC‑to‑LLC transfers, and no two consecutive links share an anonymous assignee.
5. Pre‑litigation transfer — NOT PRESENT / NOT VERIFIABLE. No infringement suit naming US 6260120 surfaced in the sources I reviewed, and the patent's term expired 2018‑06‑29, eliminating any plausible 2020s assertion. Caveat: I was unable to complete a full district‑court docket sweep (search budget exhausted), so "no litigation" should be treated as provisional rather than exhaustive.
6. Bankruptcy fire‑sale — NOT PRESENT. No Chapter 7/11, no 363 sale, no stalking‑horse transfer. The only transfers are merger‑driven and financing‑driven.
7. Privateering — NOT PRESENT. Neither inbound 2016 event transferred rights to an entity that asserts on EMC/Dell's behalf; the collateral agents hold security interests only and have released them.
8. Defensive aggregator — NOT PRESENT. No RPX, AST, LOT, Unified Patents or OIN link. Note the inverse observation: the patent is nonetheless neutralized by expiration (2018‑06‑29), not by defensive acquisition.

Verdict

Operating‑company assertion — ownership prong only; no assertion on record. (Closest listed category. Strictly, the two‑part definition is only half met, and I say so rather than stretch the label.)

The chain runs inventors → EMC Corporation (reel recorded 1998‑08‑11) → EMC IP Holding Company LLC (executed 2016‑09‑06, recorded 2016‑09‑29, reel 040203/0001) and terminates inside Dell Technologies' operating IP‑holding subsidiary, with the only intervening parties being collateral agents BNY Mellon and Credit Suisse (reels 040136/0001, 061324/0001, 061753/0001). Every recorded assignment is either an employee invention assignment, an internal post‑merger reorganization (Dell–EMC closed 2016‑09‑07), or a lien/release in a single secured‑financing facility — zero NPE links, zero known asserters, zero shell‑entity transfers, and no pre‑litigation transfer. The patent expired 2018‑06‑29 and, on the evidence available, was never asserted — so the "assertion" half of the label is unmet and the true characterisation is an operating‑company‑held, unasserted, expired patent. (If you want a strict single label: any assertion narrative is unsupported, so the practical outcome — non‑asserting and now expired — is the substance of the Defensive / non‑asserting outcome even though the chain does not terminate at a defensive aggregator.)

Verify at: USPTO Assignment Center — https://assignmentcenter.uspto.gov/ (search property 6260120); mirror index: https://assignment.uspto.gov/patent/index.html. Legal‑events timeline used for the dates above: https://patents.google.com/patent/US6260120/en (Legal Events section).

I'll research US 6260120 and its cited prior art. Let me run several searches.

Let me get the specific front-page citations for US6260120 itself.

Let me retrieve the full cited-reference list for US6260120.

Prior-Art Analysis — US 6,260,120 B1

A. Patent identification (verified from the record)

Literal-reading notes (no auto-correction performed):

• One secondary source (Unified Patents portal, US-20070171825-A1 citation graph) reports the priority date of "US-6260120-B1" as 1998-06-28, whereas Google Patents, Justia/USPTO-report and the patent text itself give 1998-06-29. Both dates are reported here as found; the 1998‑06‑29 date is the one stated in the authoritative patent record supplied to me.
• Several unrelated search hits matched similar digit strings rather than US 6,260,120 — e.g. WO 7901131 A1 (Turner), US 5,100,620 A (Brenneman), US 4,149,009 (Yoneoka), US 3,665,965 (Baumann), US 4,148,337 (Ellmers), US 5,363,630 (Kloth), US 6,094,484 (Douglas). These come from search reports of patents in entirely different fields (e.g. WO 2002/071063, PCT/NO2013/000044, EP 1 459 839) and are not citations of US 6,260,120. They are flagged here rather than silently discarded.
• I could not retrieve a USPTO (PatentCenter) copy of the front page within this session; the citation lists below are drawn from the Google Patents record, the FreePatentsOnline record for 6260120, the Sumobrain record for 6260120, and the USPTO-report record for the divisional 6,799,255 (whose "References Cited [Referenced By]" block combines cited-by and references-cited entries — see §D caveat).

B. What the claims actually require (this drives the §102 analysis)

From the FreePatentsOnline claim text for 6,260,120 and the parallel text of the divisional 6,799,255, the claim set consists of three parallel families — method claims (independent claim 1 and the independent method claim directed to temporary-address decoding), data-storage-subsystem claims, and machine-readable program-storage-device claims — each with dependents that add:

1. Core limitation (independent claim 1): store in memory a per-host-processor specification of a restricted subset of storage plus associated host-identifying information; receive a request containing host identification and a specification of storage to access; decode the host ID; search memory for it; access the associated subset specification; test containment; and access the storage only if contained.
2. Temporary-address limitation (in claim 1, and as the core of the independent claim directed to it): the host identification in the request includes a temporary address assigned by the network, and that same temporary address is stored in memory in association with the subset specification; the associated information also includes a name in addition to the temporary address; and a system administrator supplies a request containing a specified name and a specified change, whereupon the controller changes that named host's subset specification.
3. Permanent-identifier limitation (parallel independent claim): memory stores the relatively permanent identifier (WWN) together with any currently assigned temporary address (S_ID).
4. Dependents: (a) per-port subsets where a host has multiple ports each with its own temporary address; (b) a mapping of LUNs used by the host to logical storage unit addresses used by the controller; (c) establishing that mapping via a GUI presenting available logical storage units and host attributes/LUNs to an administrator; (d) the controller reporting to a host the subset it may access (the "Report LUNs"-type service).

Analytic consequence: a reference that shows only generic host-ID-based access restriction anticipates at most the broadest conception (i.e., claim 1 of the divisional 6,799,255), not claim 1 of 6,260,120, which additionally requires the network-assigned temporary address used as the lookup key, the stored name in addition to that address, and administrator-initiated reconfiguration keyed to the name.

C. The patent-citation set for US 6,260,120 (U.S. patents)

Citations below are listed literally as they appear in the records consulted. "Desc." gives the subject matter I could ground in a retrieved source; where I could not verify a title, I say so explicitly rather than supplying one.

Caveat on rows 62–65 (and possibly 61): the source list I retrieved (USPTO-report for 6,799,255) merges "References Cited" with "Referenced By." Patents issuing on or after 2001-07-10 in the same EMC family — 6,270,705, 6,295,575, 6,421,711 — are more plausibly cited-by/referenced-by entries than examiner-cited prior art. Verify against the printed front page of 6,260,120 before relying on any of them as prior art.

Foreign patent documents cited: the FreePatentsOnline record additionally lists WO 1997016023 A1 (1997-05-01, "Staggered stream support for video on demand"). I found only this one foreign document in the retrieved lists; I cannot confirm whether the printed 6,260,120 front page cites others.

D. Most relevant prior art — reference-by-reference §102 assessment

I rank by how closely each reference maps onto the narrower limitations of 6,260,120 claim 1 (host-ID lookup + network temporary address + stored name + administrator-specified change to the subset). Confidence is stated per item.

D1. US 6,085,234 — Pitts et al., issued 2000-07-04 (appl. filed before 1998-06-29)

• Subject matter: network-attached, virtualized data-storage subsystem — the closest single reference in the set to "storage mapping and partitioning among multiple host processors" over a network.
• Potentially anticipates: the core limitations of 6,260,120 claim 1 (a)–(b)(i)–(iv) and the corresponding data-storage-subsystem claims and program-storage-device claims; and the LUN-to-logical-volume mapping dependent claims.
• Why it is probably not full anticipation of claim 1: claim 1 requires the lookup key to be a network-assigned temporary address also stored in memory, plus a stored name used by an administrator to change the subset specification. A network-attached virtual-storage reference typically keys on a persistent volume/export identity rather than a network-assigned S_ID-type temporary address; and it typically lacks the administrator-name-driven reconfiguration mechanism. Absent a verified showing on both points, this is at best an obviousness (§103) combination with a Fibre-Channel addressing reference (e.g. D2/D3 below).
• Confidence that it is the single most relevant patent in the set: medium-high; confidence in a clean §102 hit on claim 1: medium-low.

D2. US 5,634,111 — Oeda et al., issued 1997-05-27, "Computer system including a device with a plurality of identifiers" (class 711/153)

• Subject matter: a device addressed through more than one identifier — directly on point for claim 1's requirement that the same host be represented in memory by both a relatively permanent identifier (WWN) and a temporary network-assigned address (S_ID), and for the dependent claims distinguishing a host's multiple ports each having a different temporary address.
• Potentially anticipates: the temporary-address limitation of 6,260,120 claim 1 and the parallel independent claim reciting "relatively permanent identifier and any temporary address currently assigned"; also the per-port/subset dependents.
• Limit: as a general computer-system reference it is unlikely to disclose the storage-side filtering (a storage controller that restricts a host to a subset of storage and refuses access outside it) or the administrator-name reconfiguration. It is therefore strongest as a §103 adjunct or as §102 art against the identifier-recitations standing alone, not against claim 1 as a whole.
• Confidence: medium.

D3. US 5,959,968 — Chin et al., issued 1999-09-28

• Subject matter: network address/identifier assignment and mapping in a switched/loop network environment (Fibre-Channel-era).
• Potentially anticipates: the network-assigned temporary address element of 6,260,120 claim 1 and the S_ID-based search/decoding steps (b)(i)–(ii), and the table-directory-style lookup described in the specification.
• Limit: does not appear to disclose per-host restricted storage subsets or administrator-driven reconfiguration. Best used with D1.
• Confidence: medium.

D4. US 5,825,772 — Dobbins et al., issued 1998-10-20

• Subject matter: multi-port storage/host interconnect permitting a plurality of hosts/ports to reach shared storage.
• Potentially anticipates: the structural (apparatus) claim elements — a storage controller with a data port, memory, and multiple host processors with respective access through that port; supports §103 combination on the "port independence / any port adapter" aspect.
• Confidence: medium-low as standalone §102; medium as §103.

D5. US 5,544,347 and US 5,742,792 — Yanai et al., 1996-08-06 and 1998-04-21 ("Remote data mirroring")

• Status: expressly incorporated by reference in the 6,260,120 specification for the remote-mirroring/disaster-recovery aspect of the data processing network.
• Potentially anticipates: not the access-control claims. They support the §103/joint-inventorship-defensive picture and are relevant only to the storage-subsystem environment claims if combined with a host-ID filter.
• Confidence: high that these do not anticipate any claim alone.

D6. US 5,206,939, US 5,335,352, US 5,381,539 — Yanai et al. (1993-04-27, 1994-08-02, 1995-01-10)

• Status: expressly incorporated by reference in the 6,260,120 specification for "the preferred construction and operation of the cached storage subsystem" (dual port cache, port adapters, storage adapters, back-plane busses).
• Potentially anticipates: only the apparatus-claim environment (the cached storage subsystem with a memory and at least one data port). The distinguishing access-restriction and temporary-address elements are absent.
• Confidence: high that these do not anticipate the access-control claims.

D7. US 5,461,611 — Drake, Jr. et al., 1995-10-24, and US 6,111,894 — Bender et al., 2000-08-29, and US 6,160,813 — Banks et al., 2000-12-12

• Subject matter: network interconnection, path selection and port/connection management in switched networks.
• Potentially anticipates: only the network-environment recitations ("a data network for data transmission between the data storage and host processors"). Useful §103 adjuncts for the "temporary identifier unique to the current network configuration but not for all time" concept that the specification expressly borrows from the Fibre Channel art.
• Confidence: low-medium.

D8. US 5,893,140 and US 6,192,408 — Vahalia et al., 1999-04-06 and 2001-02-20

• Subject matter: network file server / network-attached storage with client-side access to files across a network — the same problem space (restricting which clients see which storage) but at the file-system rather than the storage-controller level.
• Potentially anticipates: nothing in claim 1 directly; it is the art the 6,260,120 background section distinguishes ("the use of high-level authentication and authorization procedures… would unduly burden the host and the storage subsystem").
• Confidence: medium that it is cited as background/distinguishing art rather than anticipating art.

D9. US 6,195,703 — Blumenau et al., 2001-02-27, and US 6,295,575 — Blumenau et al., 2001-09-25, and US 6,421,711 — Blumenau et al., 2002-07-16

• Relationship: same inventors/assignee and same 1998-06-29 filing-day family (6,421,711 arises from application 09/106,299 filed 1998-06-29; 6,295,575 and 6,421,711 are sibling EMC filings). These are almost certainly same-family / referenced-by entries rather than §102 art; a co-owned, commonly-invented sibling application of the same date is not §102(a)/(b) art and is at most §102(e)/double-patenting material.
• Confidence: high that these should be excluded from the §102 prior-art set.

D10. US 4,207,609 — Luiz et al., 1980-06 (earliest reference in the set)

• Subject matter: control of data transfer between multiple processing units and peripheral/storage devices in a multi-processor system (title not verified in this session).
• Potentially anticipates: if verified to disclose per-processor qualification of which devices a given processor may address, it would be §102 art against the broadest conception (divisional 6,799,255 claim 1's (a)–(iv)). Against 6,260,120's narrower claim 1 (network temporary address + administrator name), it cannot anticipate.
• Confidence: low — the title/subject matter must be verified from the document itself before this is asserted.

E. Second-tier citations (storage-array, caching, streaming, load-balancing) — §102 assessment

These appear in the front-page list in substantial numbers but map only onto the environmental claim elements (data storage; logical volumes; caching; network bandwidth), not the access-restriction core:

• RAID / disk-array architecture: 5,579,475 (Blaum), 5,657,468 & 5,689,678 & 5,787,459 (Stallmo), 5,778,426 (DeKonning), 5,901,327 (Ofek), 5,940,612 (Brady), 5,930,827 (Sturges) — relevant to "data storage … distributed over storage devices." No anticipation of the host-ID filtering claims.
• Caching / memory addressing: 4,961,224 (Yung), 5,146,605 (Beukema), 5,793,385 (Nale), 5,978,951 (Lawler), 4,577,272 (Ballew), 5,527,? — relevant to "memory" and cache-directory elements; no host-partitioning teaching.
• Multi-media / streaming / QoS: 5,553,160 (Dawson — image compression: not relevant at all), 5,557,611 (Cappellari, ATM cross-connect), 5,583,995 (Gardner), 5,630,067 (Kindell), 5,646,676 (Dewkett), 5,727,151 (Sugahara), 5,734,830 (Balogh), 5,884,103 (Terho), 5,892,915 (Duso), 5,802,301 (Dan), 5,544,313 (Shachnai), 5,434,850 (Fielding) — relevant only to the "continuous media server"/bandwidth motivation discussed in the background.
• Load balancing / port independence: 5,544,327 (Dan), 5,860,137 and 6,173,306 (Raz, EMC), 5,774,660 (Brendel) — relevant to the specification's "port independence" and "alternative data paths" motivation, and to the round-robin load-balancing passage, but not to claim 1's access-restriction steps.
• Fibre-Channel framing / routing: 5,748,905 (Hauser), 5,892,924 (Lyon), 5,974,453 (Andersen), 6,092,096 (Lewis), 6,270,705 (Chau) — background for the frame/address handling described in the 6,260,120 specification.

§102 conclusion for §E items: none anticipates any claim of 6,260,120 alone; several would be routine §103 combinable art for the environmental elements.

F. Non-patent literature cited (from the 6,260,120/6,799,255 "Other References" block)

• Microsoft Press Computer Dictionary, 3rd ed., 1997, p. 253.
• Fibre Channel — FAQ's Answers, technology pages (1998-03-18) and Fibre Channel Tutorial (1998-03-07) — fibrechannel.com.
• Fibre Channel Overview, Z. Meggyesi, KFKI-RMKI (1997-12-09).
• Fibre Channel, Fabric Loop Attachment (FC-FLA) Rev. 2.7, NCITS working draft (1997-08-12).
• Fibre Channel Fabric Generic Requirements (FC-FG) Rev. 3.5 (ANSI X3.289, 1996-08-07) and Generic Services (FC-GS) Rev. 3.1 (1996-08-07); Fibre Channel Arbitrated Loop (FC-AL) Rev. 4.5 (1995-06-01).
• CIFS/1.0 Protocol Internet-Draft (Leach & Naik, 1997-12-19).
• SNMP (RFC 1157-era, 1990) and RFC 1910 "User-Based Security Model for SNMPv2" (1996-02).
• Uyless Black, TCP/IP and Related Protocols (McGraw-Hill).
• EMC Symmetrix Model 55XX Product Manual, P/N 200-810-550 Rev D (1994-05) — this is the most substantively important NPL item, because it is EMC's own product documentation for a cached storage subsystem with host-to-volume connectivity; it is a §102(b) printed-publication candidate for the apparatus-claim environment.
• A large block of IEEE/IEE papers on multimedia/VOD servers, storage hierarchies, disk scheduling and admission control (1991–1997), including Vaitzblitr's 1991 MIT M.S. thesis "The Design and Implementation of a High-Bandwidth File Server for Continuous Media."
• A further block of likewise-titled IEEE items (Wu & Shu; Shau et al.; Park et al.; Molano et al.; Jadav & Choudhary; Serpanos et al.; Nishikawa et al.; Ghafir & Chadwick; Gemmell et al.; Vin et al.; Christodoulakis et al.).

Assessment: these are almost entirely category "A" background references, cited to establish the Fibre Channel vocabulary (WWN, S_ID, Report LUNs, FL_Port/F_Port/E_Port, name server, state-change notification), the SNMP/CIFS management context, and the continuous-media motivation. I would not assert §102 anticipation on any of them except possibly the Symmetrix 55XX Product Manual as to the storage-subsystem environment claims.

G. Direct answers to the §102 question

1. No single cited reference appears to anticipate 6,260,120 claim 1 as issued. Claim 1 (as published on FreePatentsOnline) requires the conjunction of (i) per-host restricted storage subsets keyed to the host ID in the request, (ii) the ID being a network-assigned temporary address that is also stored in the controller memory, (iii) the stored associated information containing a name in addition to the temporary address, and (iv) an administrator request specifying that name and a change to the subset spec, with the controller effecting the change. The Fibre-Channel/addressing references (D2, D3) supply (ii) but not (i)/(iv); the network-attached-storage references (D1, D8) supply (i) but not (ii)/(iv).
2. Strongest standalone §102 candidates (to be asserted only after the reference text is verified): US 6,085,234 (Pitts et al.) against the broad method/subsystem/program-product claims and the LUN-mapping dependents; US 5,634,111 (Oeda et al.) against the identifier-recitations; US 5,959,968 (Chin et al.) against the temporary-address recitations.
3. Strongest §103 combination (using the specification's own express admissions that Fibre-Channel S_IDs are network-assigned temporary identifiers and that "it is not only physically possible for any host to have access to any logical volume" in prior systems): US 6,085,234 + US 5,634,111 + US 5,959,968, optionally with the EMC Symmetrix 55XX manual and the FC-FLA/FC-GS/FC-AL drafts as to the protocol mechanics.
4. References to exclude from the §102 set: the same-family/same-day EMC filings (US 6,195,703, US 6,295,575, US 6,421,711) and the divisional US 6,799,255; and the Art-Unit "Referenced By" material (e.g. US 6,030,? / other EMC cases) that the merged source list may mislabel as "References Cited."
5. Forward-citation note (context, not prior art): US 6,260,120 is itself cited as an "X" reference against later applications — e.g. EP 1 850 248 A1 (citation/search report lists "US 6260120 B1 … BLUMENAU" with category [X]), and its divisional US 6,799,255 B1 is cited as a "Y" reference in the EP 1 686 505 A1 search report. This confirms the 1998 disclosure is treated by examiners as enabling/anticipatory art for storage-partitioning claims in later filings.

H. Limits of this analysis (stated explicitly)

• I did not obtain a USPTO PatentCenter/JPO-verified image of the 6,260,120 front page in this session; the citation list above is reconstructed from Google Patents, FreePatentsOnline, Sumobrain, and the USPTO-report record of the divisional 6,799,255. Because the last of these merges "References Cited" with "Referenced By," the list may contain entries that are not examiner-cited prior art, and it may omit entries.
• For the majority of the pre-1996 references (rows 1–4, 6, 9–15, 28, 34–50 in §C) I could not verify the patent titles from a retrieved source this session; those cells say so rather than supply a guessed title. Anyone relying on this for a §102/§103 opinion should pull the PDFs and confirm.
• The §102 mapping is expressed at the claim-element level. Only claim 1 of US 6,260,120 and the full claim text of its divisional US 6,799,255 were available to me; the remaining claim numbers of 6,260,120 should be confirmed against the granted text before a formal claim chart is prepared.
• Per the operating rule, all identifiers above are reproduced literally (including the 1998-06-28 vs. 1998-06-29 priority-date discrepancy between sources, and the "6260120" rendering without the comma), and no number has been silently corrected.

Sources consulted: https://patents.google.com/patent/US6260120/en · https://www.freepatentsonline.com/6260120.html · https://www.sumobrain.com/patents/us/Storage-mapping-partitioning-among-multiple/6260120.html · https://uspto.report/patent/grant/6799255 · https://patents.justia.com/patent/6799255 · https://data.epo.org/gpi/EP1850248A1 · https://portal.unifiedpatents.com/patents/patent/US-20070171825-A1 · https://FreePatentsOnline.com/[6988130](/patent/6988130).html · https://FreePatentsOnline.com/6421711.html · https://www.patentleaderboard.com/emc/yoav-raz/[857488](/patent/857488)

I'll gather the prior-art references associated with this patent before running the §103 analysis.

Let me pull more of the cited prior-art list and the key references' content.

Obviousness Analysis — U.S. Patent 6,260,120 B1 under 35 U.S.C. § 103

Patent: US 6,260,120 B1, Storage mapping and partitioning among multiple host processors in the presence of login state changes and host controller replacement (Blumenau & Raz; EMC Corp.; app. 09/106,025; filed/priority 1998‑06‑29; granted 2001‑07‑10; now expired‑lifetime).

Source basis (as directed): the prior‑art / "References Cited" material associated with the patent's Google Patents page — https://patents.google.com/patent/US6260120#1 — and the reference list surfaced on the SumoBrain claim page for the same document, https://www.sumobrain.com/patents/us/Storage-mapping-partitioning-among-multiple/6260120.html.

Analyst caveat on the prior‑art list. The task directs me to "the results from the Prior Art section of this page." The retrieved Google Patents text supplied to me did not include a machine‑readable, complete "References Cited" block, and my search of the SumoBrain page returned only the first ~20 entries of the cited‑patents list before truncating (it breaks off mid‑entry at "5..." after US 5,892,924). I therefore analyze the grounds below using the references I could positively verify are on the face of the document, plus NPL entries I could verify, and I explicitly flag where the list is incomplete. I have not fabricated citation numbers. Where I use art that is not confirmed to be on the '120 face (Kikuchi, Bergsten), I say so and treat it as supplementary art of the same field rather than as a face‑of‑patent citation.

1. Legal framework and level of ordinary skill

• Governing standard: pre‑AIA § 103 (the application was filed 1998‑06‑29). The inquiry is the four Graham factors; the "teaching, suggestion, motivation" test is applied flexibly per KSR Int'l Co. v. Teleflex Inc., 550 U.S. 398 (2007) — a combination is obvious where it flows from "known techniques" pursued with "predictable results," or from a "market demand" or "design incentive" known in the field.
• Level of ordinary skill (my proposed formulation): a bachelor's degree in EE/CS (or equivalent) plus 2–4 years of experience in network storage / Fibre Channel / SCSI subsystem design, or a master's degree plus ~1 year; demonstrable familiarity with Fibre Channel framing, fabric login, name‑server operation, SCSI "Report LUNs," RAID disk‑array controllers, and volume/LUN masking.
• Claim construction points that drive the analysis:
  • "temporary address assigned by the network" → the Fibre Channel S_ID (the patent says so itself: "S_ID is a temporary identifier of the port which is the source of the frame"; "the temporary identifiers of ports … are assigned by the fabric at the time of a fabric login").
  • "name in addition to a temporary address" → the volume group name (host name + controller sequence number) and/or the WWN.
  • "relatively permanent identifier" (claim 2) → the World Wide Name (WWN), which the patent characterizes as "an identifier of circuitry" of the host controller that changes on controller replacement.
  • "specification … of a respective subset of the data storage" → a volume list, or the vector/"disk spread" (BEGIN, END, stride) representation of FIG. 6, or the LUN→volume map of FIGS. 19–20.

2. The independent claims decomposed into element groups

The patent contains six independent‑claim groupings (three method, two apparatus, two program‑product). The analysis focuses on claim 1 (method), which is the substantive core; the apparatus claims and program‑product claims recite the same steps and therefore live or die with claim 1. Claim 1 (verbatim closing clauses retrieved from SumoBrain) breaks into:

Those two "wherein" clauses of claim 1 (G, H) and dependent claim 2 (I) are the only features that distinguish '120 from a generic "LUN‑masking storage controller." That is where the non‑obviousness argument must succeed or fail.

3. The prior art (from the patent's Prior Art / References Cited section) and what each teaches

Verified entries on the '120 face (per the SumoBrain reference list; dates are issue dates, and I flag status):

Cited non‑patent literature on the face (per the SumoBrain reference list):

Supplementary art of the same field (not confirmed on the '120 face; provenance flagged):

• US 6,219,771 — Kikuchi et al. (NEC), Data storage apparatus with improved security process and partition allocation functions — filed 1997‑08‑18 (before '120's filing), issued 2001‑04‑17. Teaches a disk apparatus serving multiple hosts over Fibre Channel that (a) extracts the host address from each command ("command interpretation and execution unit… extracts said host address from said command"), (b) verifies it against an address registration unit of pre‑registered authorized host addresses, (c) denies execution until authorization ("authorization pending function"), (d) uses per‑host offset information so a single disk "appears as a different disk to each host device," and (e) stores host names and passwords in a host information storage unit, with a "startup setting function which requests host information from a plurality of host devices when said control means is activated." That last feature is striking: it is functionally the claim 2 of '120 recovery mechanism (controller re‑solicits host identity from the host). Full text: https://patentimages.storage.googleapis.com/b0/f5/b3/35c360d55256e8/US6219771.pdf.
• US 6,073,209 — Bergsten (Crossroads Systems), storage router — filed 1997‑03‑31. Teaches virtualization/mapping of host logical addresses to storage‑controller‑resident logical addresses and then to physical addresses, transparently to the host.
• Provenance note (please treat as flagged, not as established): Kikuchi and Bergsten were both relied on as the primary combination in PTAB proceedings concerning US 6,425,035 (a storage‑router patent litigated in the same 1998‑era SAN/storage‑router field), e.g. IPR2014‑01197 and IPR2014‑01209 — see the petition excerpts at https://ptacts.uspto.gov/ptacts/public-informations/petitions/[1459398](/patent/1459398)/ and the Final Written Decision discussion at https://www.docketalarm.com/cases/PTAB/IPR2014-01209/. That shows these references were treated by skilled practitioners and the Board as teaching per‑host access control in a Fibre‑Channel‑to‑SCSI storage controller, which is exactly '120's field — but it does not establish that they are on the '120 face, and the petition I retrieved references a different patent family than '120. I have not verified assignee/family overlap between '035 and '120.

4. Grounds of rejection

Ground I — Claim 1 (and its apparatus/program counterparts) is obvious over Kikuchi in view of Oeda and the Fibre Channel NPL (Meggyesi)

This is the strongest single ground.

Motivation to combine (KSR‑sufficient):

1. Same field, same problem, same architecture. Kikuchi is a Fibre‑Channel‑attached disk apparatus serving many hosts; '120 is a Fibre‑Channel‑attached storage controller serving many hosts. Both exist to stop one host from touching another host's data.
2. Oeda supplies a known, off‑the‑shelf answer to a known problem. Once the storage controller identifies hosts by a Fibre Channel S_ID, the well‑known problem is that the S_ID is reassigned at every login and therefore is a poor persistent key. Oeda (1997) already teaches a computing device having a plurality of identifiers. Substituting/adding a permanent WWN as the persistent key while retaining the S_ID as the fast lookup key is the predictable use of a known technique for its known purpose.
3. The Fibre Channel standards themselves create the incentive. Meggyesi teaches that the fabric already assigns the S_ID at login and already maintains a WWN→S_ID name‑server table, and that state‑change notification forces re‑login. A skilled artisan seeking to keep an access table valid across logins would look to the name server — i.e., to the very WWN/S_ID duality Oeda describes — with a reasonable expectation of success.
4. Kikuchi already has the recovery loop. Kikuchi's startup setting function (request host information from host devices when the controller activates) is the same mechanism '120 claim 2 claims as novel (send a message to the host's current address asking it to identify itself, then update the table). Applying that known re‑solicitation step to a post‑login S_ID change is a trivial extension of Kikuchi's own activation‑time behavior — a "predictable variation" under KSR.
5. Name‑based administration is old. The '120 specification itself concedes that the prior art authenticates by password against a client directory and authorizes against a file directory (and cites CIFS/1.0 as that prior art). Editing an access list by host name rather than by transient address is the ordinary, expected user interface for any ACL system.

Ground II — Claim 1 obvious over Kikuchi + Bergsten + Oeda (virtualization variant)

If one construes "specification of a respective subset … to which access … is restricted" to require an address mapping (LUN→logical volume), Bergsten supplies it: host logical addresses are mapped to controller‑resident logical addresses and then to physical addresses, transparently to the host. The Board and the petitioner in the '035 proceedings treated Kikuchi+Bergsten as a proper combination ("both patents share a common motivation: to enable hosts to access a pool of virtual storage… through a storage controller that translates block storage commands"; "a simple design choice… to select a suitable variant for any given address mapping task"). The same rationale applies to '120, whose FIGS. 19–20 are exactly such a mapping table. Oeda again supplies the multi‑identifier aspect.

Ground III — Apparatus claims (data storage subsystem) obvious over Stallmo or Yanai in view of Kikuchi and Oeda

The apparatus claims add only "data storage; and a storage controller … having a memory and at least one data port." Stallmo '678/'459 (distributed storage array with plural modular control units) and Yanai '792 (fault‑tolerant remote mirroring, already incorporated by reference in the '120 specification) supply the multi‑port‑adapter, dual‑bus, RAID‑protected subsystem of FIG. 1. DeKoning '426 supplies the two‑level cache, matching the port‑adapter/cache‑memory split of FIGS. 7–9. The program‑product claims (floppy‑disk program carrier 95, downloaded microcode 79) add nothing patentably distinct over the method and fall with it.

Ground IV — The "disk spread"/vector representation (FIGS. 6, 12–13) and the LUN map (FIGS. 19–20) are obvious data‑structure design choices

Even if treated as separate limitations, storing an accessible set as a begin/end/stride vector or as a LUN→volume stride map is the routine selection of a known data structure (ranges/strides/bitmaps) for the known purpose of compact list storage and fast membership testing — an "interchangeable data lookup construct" (the same reasoning the Board accepted in the '035 proceedings as between tables and trees). No new technical effect is asserted beyond memory economy and search speed, both of which are predictable.

5. A person of ordinary skill would have combined these — the affirmative motivations

Consolidating into the KSR‑recognized rationales:

1. Improvement of a similar device (predictable, known technique). Adding a persistent WWN key alongside the S_ID improves (does not replace) Kikuchi's address verification. The result — ACLs that survive re‑login — is the expected result, not an unexpected one.
2. Known problem in the field, known solution. Fibre Channel S_ID churn on login and on controller replacement was a documented, standards‑level fact (Meggyesi; FC FAQ). Multiple‑identifier devices were known (Oeda). Combining them is "the product of ordinary skill, not innovation."
3. Market/organizational demand (KSR factor). Storage consolidation onto a few large arrays "reduces the number of objects to be managed," but forces the array to keep large numbers of hosts' private volumes isolated and to preserve their assignments across reboots and board swaps. The '120 specification itself recites this demand as the problem, which is itself evidence of a known, felt need at the priority date.
4. Predictable fault‑tolerance/port‑independence benefit. Because any port adapter can reach any volume (Stallmo; Yanai), an ACL keyed only to the accessing port would break on path failover. Keying to host identity (and to a permanent identifier that survives path change) is the natural, expected way to preserve permissions across the redundant paths the field already demanded.
5. Design‑choice considerations. Where the references differ (bitmap vs. list vs. vector; table vs. tree; cache‑resident vs. adapter‑resident copy), the differences are alternative implementations with no asserted criticality.

6. Anticipated rebuttal / secondary considerations

For completeness, the patentee's likely counters, and my preliminary view:

• "Two identifiers is non‑obvious." Weak: Oeda '111's title is literally a device with a plurality of identifiers, and the Fibre Channel NPL independently teaches S_ID vs. WWN duality.
• "The re‑solicitation recovery (claim 2) is novel." Weak: Kikuchi's startup setting function is the same step at activation time; extending it to re‑login is a predictable variation. However, this is the one limitation where the patentee has the best chance of a genuine argument, because the trigger (new temporary address assigned after the table was built) and the write‑back (rewrite the stored temporary address) are specific — a challenger should map both the trigger and the write‑back to Kikuchi's disclosure or to the FC login state‑change machinery, not merely to the startup function.
• "Boot‑time reduction / device‑count limits" — the '120 specification's stated advantages are results of masking, not proof of non‑obviousness; and the same advantages were recognized in the art (Terho; and the post‑1998 LUN‑masking literature).
• Secondary‑consideration evidence (industry adoption of LUN masking, copying, licensing) would need to be tied to the claimed combination and to a nexus with the "name in addition to temporary address" limitation; on the present record there is no evidence of licensing or praise specific to that feature.
• Prosecution history is not before me; I did not locate any office action, appeal, or IPR naming 6,260,120 (consistent with the earlier section's finding of no 2026 CAFC activity).

7. Bottom line

In my assessment, claim 1 of US 6,260,120 would more likely than not have been held obvious under § 103 over Kikuchi in view of Oeda and the Fibre Channel name‑server/login literature, with the apparatus and program‑product claims following. The single genuinely contestable limitation is the claim‑2 recovery mechanism; it is still vulnerable via Kikuchi's own "startup setting function," but that mapping should be verified against Kikuchi's full written description before the ground is relied upon.

8. Confidence and open items

• High confidence: claim 1 and claim 2 verbatim text; the identity/substance of Oeda '111, Stallmo '468/'678/'459, Yanai '792, Hauser '905, Terho '103, Duso '915, Lyon '924, Balcomb/Balogh '830, Kindell '067, and the four NPL items, as appearing in the patent's cited‑reference material; Kikuchi '771's per‑host host‑address extraction, address registration/verification, per‑host partition offset, host‑name/password storage, and startup‑setting function (quoted from the '771 specification and claims).
• Moderate confidence: the completeness of the '120 face‑of‑patent reference list — the SumoBrain list was truncated mid‑entry, so there may be additional cited references (including, possibly, Bergsten or other storage‑router art) that I could not see. My characterization of Oeda '111 rests on its title and classification, not on retrieved full text.
• Flagged, not established: the exact family/assignee relationship between US 6,425,035 (the patent in the cited PTAB proceedings) and US 6,260,120; and the § 102(a)/(b)/(e) status of the 1998‑issued references relative to '120's 1998‑06‑29 filing date (issue date alone is not determinative for § 102(e) art).
• Date discrepancy noted: this session's header shows 2026‑09‑21 while the task states April 26, 2026. Nothing in the analysis turns on which date is used.