Prosecution Insights
Last updated: April 19, 2026
Application No. 18/599,898

METHOD OF RAID IMPLEMENTATION ON FLEXIBLE DATA PLACEMENT DRIVES

Final Rejection §103§112
Filed
Mar 08, 2024
Examiner
GOLDSCHMIDT, CRAIG S
Art Unit
2132
Tech Center
2100 — Computer Architecture & Software
Assignee
Sandisk Technologies LLC
OA Round
2 (Final)
73%
Grant Probability
Favorable
3-4
OA Rounds
2y 10m
To Grant
99%
With Interview

Examiner Intelligence

Grants 73% — above average
73%
Career Allow Rate
293 granted / 401 resolved
+18.1% vs TC avg
Strong +32% interview lift
Without
With
+32.1%
Interview Lift
resolved cases with interview
Typical timeline
2y 10m
Avg Prosecution
21 currently pending
Career history
422
Total Applications
across all art units

Statute-Specific Performance

§101
6.9%
-33.1% vs TC avg
§103
46.4%
+6.4% vs TC avg
§102
9.4%
-30.6% vs TC avg
§112
29.4%
-10.6% vs TC avg
Black line = Tech Center average estimate • Based on career data from 401 resolved cases

Office Action

§103 §112
DETAILED ACTION Re Application No. 18/599898, this action responds to the amended claims dated 02/20/2026. At this point, claims 1, 6, 10, 12, and 16 are currently amended. Claims 1-20 are pending. The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA . Claim Rejections - 35 USC § 112 Examiner notes Applicant’s amended claims dated 02/20/2026; in view of the amended claims, Examiner’s prior rejections under 35 USC § 112(b) have been rendered moot, and are accordingly withdrawn. Claim Rejections - 35 USC § 103 In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status. The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action: A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made. Claims 1, 4-5, 7, 9-10, 13, 15-16, 18, and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Karamcheti et al (US 2014/0281138 A1). Re claim 1, Karamcheti discloses the following: A storage device to carve out redundant array of independent disks (RAID) […] the storage device comprises (¶ 151). The memory card (storage device) carves out a RAID from a plurality of flash memory dice; multiple flexible data placement drives that are configured to execute RAID techniques; and (¶ 151). The flash memory dice (multiple flexible data placement drives) are carved into a RAID (execute RAID techniques); a controller to receive data from a host (¶ 103-104). The embedded processors, controlling master and slave controllers (a controller), receive data read and write operation requests from a host; obtain reclaim unit handles from the data to determine locations in reclaim units where the data is to be stored on flexible data drives (¶ 57, 66, and 72). The write I/O updates data (the data) and is associated with a particular logical block address (reclaim unit handle). It is noted that Applicant has not explicitly defined “reclaim unit handle”; Applicant’s specification discloses that it is “a logical representation of non-volatile storage within a reclaim group that is able to be physically erased by controller 108 without disturbing other reclaim units” (¶ 21). Accordingly, Examiner interprets a LBA to be a “reclaim unit handle” (¶ 57). It corresponds to a physical block number (¶ 72), and the physical erase blocks are the smallest units which can be erased without disturbing other erase blocks (¶ 66); and stripe the data across the reclaim units within different reclaim groups on the flexible data placement drives in parallel (¶ 49 and 67-68). The data is striped across erase blocks (reclaim units) within different segments (reclaim groups) on the flexible data placement drives (¶ 67-68). Data are broken up into pieces that are sequentially stored to location in parallel different devices, i.e. ‘in parallel” (¶ 49); wherein the storage device reduces a write amplification factor on the RAID by using the reclaim unit handles to stripe data across the rAID in parallel (¶ 197-198). It is noted that Applicant has not explicitly claimed what the write amplification factor is reduced relative to. Accordingly, Examiner interprets it to mean that the storage device, through its operation (which includes using the reclaim handles to stripe data across the RAID in parallel), write amplification is reduced relative to some other way of operating (which does not necessarily need to involve not using the reclaim handles to stripe data across the RAID in parallel). The storage device of Karamcheti discloses operating the RAID system by using synchronous mirroring, which avoids the additional writes due to the disaster recovery log (another way of operating the RAID system), thus reducing write amplification relative to using the disaster recovery log. Karamcheti discloses the limitations noted above; however, it appears to disclose multiple embodiments, and it is unclear whether each limitation appears in a single embodiment. Nevertheless, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention (AIA ) to combine the various embodiments of Karamcheti to yield the claimed invention, because it would be merely making the various elements integral (MPEP § 2144.04(V)(C)). Re claim 4, Karamcheti discloses the device of claim 1, and further discloses that a reclaim unit handle points to one of an empty and unused reclaim unit (¶ 11 and 70). A request to write to a new segment may be received (¶ 11); new segments may be erased during garbage collection so that they are ready for these writes (¶ 70); accordingly, the address (reclaim unit handle) points to an (initially) empty/unuse reclaim unit. Re claim 5, Karamcheti discloses the device of claim 1, and further discloses that a reclaim unit is one of reset and erased during a rewrite (¶ 70). The blocks (reclaim units) are erased during garbage collection, as part of the rewriting process. Re claim 7, Karamcheti discloses the device of claim 1, and further discloses that the controller performs striping and parity in any direction on the flexible data placement drives (¶ 125). The controller performs parity and striping across the memory dice. Across the memory dice is a direction, therefore it is any direction. Re claim 9, Karamcheti discloses the device of claim 1, and further discloses that the controller performs parity calculations at a reclaim unit level (¶ 135-137). The parity may be calculated at a chunk level, and the chunk size may be an erase block (reclaim unit) size. Re claims 10, 13, and 15, Karamcheti discloses the devices of claims 1, 7, and 9, respectively; accordingly, it also discloses methods implemented by those devices, as in claims 10, 13, and 15, respectively (see Karacheti, ¶ 3). Re claim 16, Karamcheti discloses the following: A storage device to carve out redundant array of independent disks (RAID) […] the storage device comprises (Fig. 2A; ¶ 151). See claim 1 above; a flexible data placement drive that is configured to execute RAID techniques, the flexible data placement drive includes multiple reclaim groups and multiple reclaim unit handles that reference reclaim units in a reclaim group; and (Fig. 5; ¶ 145 and 151). See claim 1 above (¶ 151). The flash dice 504, 506, 50J, and 50K each contain a plurality of segments 522, 524, 52M (reclaim groups), each segment containing a plurality of erase blocks, e.g. 504z and 504c (reclaim units) (Fig. 5; ¶ 145); a controller to receive data from a host (¶ 103-104). See claim 1 above; obtain reclaim unit handles from the data to determine locations in the reclaim units where the data is to be stored on the flexible data drive (¶ 57, 66, and 72). See claim 1 above; and stripe the data across the reclaim units within different reclaim groups on the flexible data placement drive in parallel (¶ 49, 67-68, and 86). The data is striped across erase blocks (reclaim units) within different segments (reclaim groups) (¶ 67-68). Data are broken up into pieces that are sequentially stored to location in parallel different devices, i.e. ‘in parallel” (¶ 49). The data may be striped across a plurality of flash memory chips packaged on a flash memory card (flexible placement drive) (¶ 86); wherein the storage device reduces a write amplification factor on the RAID by using the reclaim unit handles to stripe the data across the RAID in parallel (¶ 197-198). See claim 1 above. Karamcheti discloses the limitations noted above; however, it appears to disclose multiple embodiments, and it is unclear whether each limitation appears in a single embodiment. Nevertheless, it would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention (AIA ) to combine the various embodiments of Karamcheti to yield the claimed invention, because it would be merely making the various elements integral (MPEP § 2144.04(V)(C)). Re claims 18 and 20, Karamcheti discloses the devices of claims 7 and 9, respectively; accordingly, they also disclose the same limitations as applied to the device of claim 16, as in claims 18 and 20, respectively. Claims 2 and 11 are rejected under 35 U.S.C. 103 as being unpatentable over Karamcheti in view of Handy, Understand NVMe 2.0 specification and its related features, 01/04/2022, available at https://www.techtarget.com/searchstorage/feature/Understand-NVMe-20-specification-and-its-related-features (last accessed 10/16/2025) [hereinafter “Handy”]. Re claim 2, Karamcheti discloses the device of claim 1, and further discloses that a flexible placement drive includes different reclaim groups in at least one […] group and a reclaim group includes multiple reclaim units (Fig. 5; ¶ 145). The flash dice 504, 506, 50J, and 50K each contain a plurality of segments 522, 524, 52M (reclaim groups), each segment containing a plurality of erase blocks, e.g. 504z and 504c (reclaim units). The plurality of segments on each die is arranged in at least 1 group (i.e. the group of all segments on the die). It is noted that Applicant does not explicitly define the term “endurance group”; accordingly, each dice can broadly be interpreted as “at least one endurance group”. Nonetheless, in the interest of furthering compact prosecution, Examiner has provided Handy, which more explicitly discloses endurance groups. Handy discloses at least one endurance group (p. 6, § Endurance Group Management). The NVM SSD dice utilize endurance groups (at least one endurance group). It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention (AIA ) to modify the flash memory system of Karamcheti to utilize endurance groups, as in Handy, because Handy suggests that utilizing endurance groups and NVM sets gives the host a better understanding of the SSD’s access granularity and gives the host more control of the SSD to improve their combined performance (p. 6, ¶ Endurance Group Management). Re claim 11, Karamcheti and Handy disclose the device of claim 2; accordingly, they also disclose a method implemented by that device, as in claim 11 (see Karacheti, ¶ 3). Claims 3 and 17 are rejected under 35 U.S.C. 103 as being unpatentable over Karamcheti in view of Doerner et al (US 2020/0333983 A1). Re claim 3, Karamcheti discloses the device of claim 1, and further discloses that RAID volumes are carved out of the reclaim groups (¶ 67-68), but does not specifically disclose namespaces. Doerner discloses that a namespace is carved out of a flexible placement drive for a reclaim group, wherein RAID volumes are carved out of the reclaim groups (¶ 18). Namespaces are carved out of portions (reclaim groups) of each disk (flexible placement drive), and RAID volumes are carved out of the namespaces, and thus their respective reclaim groups. It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention (AIA ) to modify the RAID of Karamcheti to utilize namespaces, as in Doerner, because it would be applying a similar technique to improve a similar device in the same way. Karamcheti discloses carving out a RAID. Doerner also discloses carving out a RAID, which has been improved in a similar way to the claimed invention, to utilize namespaces. It would have been obvious to modify the RAID of Karamcheti to utilize namespaces, as in Doerner, because it would yield the obvious improvement of granting increased granularity over control of the disks. Re claim 17, Karamcheti discloses the device of claim 16, but does not specifically disclose namespaces. Doerner discloses that a namespace is carved out of the flexible placement drive, wherein RAID volumes are carved out of the reclaim groups (¶ 18). Namespaces are carved out of portions (reclaim groups) of each disk (flexible placement drive), and RAID volumes are carved out of the namespaces, and thus their respective reclaim groups. It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention (AIA ) to modify the RAID of Karamcheti to utilize namespaces, as in Doerner, because it would be applying a similar technique to improve a similar device in the same way. Karamcheti discloses carving out a RAID. Doerner also discloses carving out a RAID, which has been improved in a similar way to the claimed invention, to utilize namespaces. It would have been obvious to modify the RAID of Karamcheti to utilize namespaces, as in Doerner, because it would yield the predictable improvement of granting increased granularity over control of the disks. Claims 6 and 12 are rejected under 35 U.S.C. 103 as being unpatentable over Karamcheti in view of Kunimatsu et al (US 2013/0191609 A1). Re claim 6, Karamcheti discloses the device of claim 1, but does not explicitly disclose reading out the entire reclaim unit, updating it, and writing it back to a reclaim unit. Kunimatsu discloses that during a block update, the controller copies an entire data from a reclaim unit to the host, wherein the host updates the data and sends updated data with a reclaim unit handle to the storage device, the controller uses the reclaim unit handle to locate an associated reclaim unit and writes the updated data to the associated reclaim unit (Fig. 9; ¶ 115 and 118). The NAND flash, which includes a controller, reads out a block (entire reclaim unit) of data, updates the data, and sends it to a new block (associated reclaim unit/the reclaim unit) (¶ 118). When a new block is selected, it is associated with the previous address (reclaim unit handle) (¶ 115). The host and memory are part of an information processing device; since the information processing device includes a host, it is a host, and so is the memory device, even if it is not explicitly referred to as such (Fig. 9). It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention (AIA ) to modify the RAID of Karamcheti to utilize a read-modify-write technique for updating data, as in Kunimatsu, because it would be applying a known technique to a known device ready for improvement to yield predictable results. Karamcheti discloses updating data in memory blocks, which is ready for the improvement of utilizing read-modify-write. Kunimatsu discloses a read-modify-write update process, which is applicable to the memory block updating of Karamcheti. It would have been obvious to modify the block updating of Karamcheti to utilize read-modify-write operations, as in Kunimatsu, because it would have the predictable result of wear-leveling writes to data, by ensuring that updated data would be written to a fresh block. Re claim 12, Karamcheti and Kunimatsu disclose the device of claim 6; accordingly, they also disclose a method implemented by that device, as in claim 12 (see Karacheti, ¶ 3). Claims 8, 14, and 19 are rejected under 35 U.S.C. 103 as being unpatentable over Karamcheti in view over Venkatesh et al (US 5974503 A). Re claim 8, Karamcheti discloses the device of claim 1, but does not disclose a multi-dimensional matrix. Venkatesh discloses that the controller receives a multi-dimensional matrix forming any number of combinations with parallelism for striping data and parity on the flexbile data placement drives (Fig. 2, controllers 28-29; abstract). The m x n matrix (multidimensional matrix) is used by the controller for striping data (using n columns) and parity (using m rows). It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention (AIA ) to modify the RAID device of Karamcheti to use a matrix for the RAID, as in Venkatesh, because it would be applying a known technique to a known device ready for improvement to yield predictable results. Karamcheti discloses carving out a RAID, which is ready for the improvement of organizing the RAID using a matrix. Venkatesh discloses using a matrix to organize a RAID, which is applicable to the RAID of Karamcheti. It would have been obvious to modify the RAID of Karamcheti to utilize a matrix, as in Venkatesh, because it would yield the predictable result of allowing the RAID data and parity portions to be organized as specified in the matrix. Re claim 14, Karamcheti and Venkatesh disclose the device of claim 8; accordingly, they also disclose a method implemented by that device, as in claim 14 (see Karacheti, ¶ 3). Re claim 19, Karamcheti and Venkatesh disclose the device of claim 8; accordingly, they also disclose the same limitations as applied to the device of claim 16, as in claim 19. ACKNOWLEDGEMENT OF ISSUES RAISED BY THE APPLICANT Response to Amendment Applicant’s arguments with respect to claims 1-20 filed on 02/20/2026 have been fully considered. As required by M.P.E.P. § 707.07(f), a response to these arguments appears below. ARGUMENTS CONCERNING 35 USC § 112(b) REJECTIONS Re claims 1-20, Examiner notes Applicant’s amended claims dated 02/20/2026. In view of the amended claims, Examiner’s prior rejections under 35 USC § 112(b) have been rendered moot, and are accordingly withdrawn. ARGUMENTS CONCERNING PRIOR ART REJECTIONS Claims must be given the broadest reasonable interpretation during examination and limitations appearing in the specification but not recited in the claim are not read into the claim (See M.P.E.P. 2111 [R-1]). Re claims 1, 10, and 16, Applicant argues that Karamcheti do not disclose the claimed invention, for 2 reasons. First, Applicant argues that the drives of Karamcheti do not disclose “flexible data placement drives”, because the Karamcheti allegedly teaches that storage is “broken into discrete units at a granularity of erase blocks that are physically organized in a RAID group into sequential segments. In response, Applicant’s first argument has been fully considered, but is not deemed persuasive. Applicant has not actually claimed any specifics about what “flexible” means, other than that data is striped across reclaim units within different reclaim groups on the drives in parallel. Karamcheti discloses striping data across blocks (reclaim units) in different segments (reclaim groups), and the drives operate in parallel. Furthermore, while the claims are read in light of the specification, limitations from the specification are not read into the claims (MPEP § 2145(VI)). Accordingly, Examiner declines to read any further requirements for what constitutes “flexible placement” into the claims beyond what is actually claimed. Second, Applicant argues that the reclaim units in the instant claims refer to physical locations, and not logical block addresses. In response, Applicant’s second argument has been fully considered, but is not deemed persuasive. In the interview dated 01/27/2026, Examiner clarified his position that the claim language makes no mention to the distinction between physical and logical addressing. The logical block addresses of Karamcheti correspond to specific physical erase blocks; they need not be limited to physical addressing, as opposed to logical addressing that is mapped to physical locations. The addition of the words “determine locations in reclaim units” does not meaningfully limit the unit handles to physical addressing either; a logical block address indicates an entire block, and thus all the locations within that block. Furthermore, while the claims are read in light of the specification, limitations from the specification are not read into the claims (MPEP § 2145(VI)). Accordingly, Examiner declines to read a physical addressing requirement into the “reclaim units” limitation of the claims. Re claims 2-9, 11-15, and 17-20, Applicant argues that the claims are allowable by virtue of their dependence upon one of claims 1, 10, and 16 above, respectively. Accordingly, Applicant is directed to Examiner’s comments regarding claims 1, 10, and 16 above, respectively. All arguments by the Applicant are believed to be covered in the body of the office action; thus, this action constitutes a complete response to the issues raised in the remarks dated 02/20/2026. Conclusion THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a). A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action. The prior art made of record and not relied upon is considered pertinent to applicant's disclosure. Jung et al (US 2013/0262920 A1). Discloses modifying RAID striping in order to reduce write amplification. Per the instant office action, claims 1-20 have received an action on the merits and are subject to a final rejection. Any inquiry concerning this communication or earlier communications from the examiner should be directed to CRAIG S GOLDSCHMIDT whose telephone number is (571)270-3489. The examiner can normally be reached M-F 10-6. Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Hosain Alam can be reached on 571-272-3978. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000. /CRAIG S GOLDSCHMIDT/Primary Examiner, Art Unit 2132
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Prosecution Timeline

Mar 08, 2024
Application Filed
Oct 17, 2025
Non-Final Rejection — §103, §112
Jan 14, 2026
Interview Requested
Jan 27, 2026
Applicant Interview (Telephonic)
Feb 07, 2026
Examiner Interview Summary
Feb 20, 2026
Response Filed
Mar 09, 2026
Final Rejection — §103, §112 (current)

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Prosecution Projections

3-4
Expected OA Rounds
73%
Grant Probability
99%
With Interview (+32.1%)
2y 10m
Median Time to Grant
Moderate
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