PTAB

IPR2019-00594

NetApp Inc v. KOM Software Inc

Title: Method for Restricting Write Access on a Data Storage Medium
Brief Description: The ’864 patent relates to a method for restricting write access to a logical storage medium that is not a write-once medium. The method uses an indication of a data write privilege to prevent the alteration of existing files while allowing access to free space for writing new data.

Prior Art Relied Upon: Ofek (Patent 6,185,661).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that Ofek discloses every limitation of the challenged claims by teaching a system that emulates Write-Once, Read-Many (WORM) characteristics on a standard read-write magnetic disk. Ofek’s use of a "WORM volume bit map" to manage read/write and read-only access for each track on a logical volume was asserted to teach the claimed “providing an indication of a data write access privilege.” When a track is set to read-only in the bitmap, Ofek restricts writing to it, which Petitioner mapped to the claimed "restricting file access." Because the system still permits writing to tracks designated as read/write (free space), Ofek was argued to disclose allowing access to "free space portions of the same logical storage medium."
- Key Aspects: Petitioner contended that Ofek’s core purpose—creating a non-alterable version of a file on rewritable media by controlling access at the track level—directly corresponds to the problem and solution described in the ’864 patent. This allegedly anticipates the specific limitations of dependent claims, such as preventing overwrites (claim 3) and disabling operations other than read-only (claim 5).

Prior Art Relied Upon: Vossen (Patent 6,026,402) and Willman (Patent 5,363,487).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner asserted that Vossen teaches a file system filter driver for restricting access to file system hierarchies using security descriptors, which maps to the claimed method of providing an "indication" of privilege and "restricting file access." However, Vossen lacks explicit detail on managing free space. Petitioner argued that Willman supplies this missing element by disclosing a High Performance File System (HPFS) driver that uses "free space bitmaps" to identify and manage available sectors for writing new files.
- Motivation to Combine: A POSITA would combine these references because Vossen explicitly teaches that its filter driver can be transparently layered atop other file system drivers, specifically mentioning support for HPFS, the system detailed in Willman. The motivation would be to improve Vossen’s high-level access control with Willman's well-understood and specific mechanism for managing and writing to free space, resulting in a more complete and functional system.
- Expectation of Success: A POSITA would have a high expectation of success, as layering file system drivers was a known technique in the art, and Vossen’s own disclosure suggests its direct compatibility with a file system like that in Willman.

Prior Art Relied Upon: Vossen (Patent 6,026,402), Willman (Patent 5,363,487), and Bsaibes (Patent 5,701,458).
Core Argument for this Ground:
- Prior Art Mapping: This ground builds on the Vossen and Willman combination to address more specific limitations in the dependent claims. Petitioner argued that while Vossen and Willman suggest using Access Control Lists (ACLs), they lack implementation details. Bsaibes was introduced to supply these details, as it teaches a system for managing granular ACLs with specific, combinable permissions like "Create," "Write," "Read," and "Modify permissions." These specific permissions were mapped to the limitations of claims 3 and 6, such as "write access without overwrite" and "write access without changing file access privileges."
- Motivation to Combine: A POSITA, seeking to implement the general concept of ACLs mentioned in Vossen and Willman, would naturally look to a reference like Bsaibes for a detailed, known method of implementing such hierarchical permission structures. Bsaibes provided a predictable way to add advanced, granular access restrictions to the foundational system established by Vossen and Willman.
- Expectation of Success: Success was expected because Bsaibes provided a well-defined and robust system for implementing ACLs. Integrating Bsaibes’s teachings would be a straightforward design choice to enhance the functionality of a system based on Vossen and Willman.

Petitioner argued that the claim terms "same portion of each file" (claim 1) and "portion of each file" (claim 5) should be construed to mean "a portion, including the entirety of each file." This construction was asserted to be supported by intrinsic evidence, including statements made during the prosecution of the parent ’175 patent where the applicant distinguished prior art by arguing that the claimed invention restricts access to the file as a whole, not just a part of it. This broader interpretation was central to Petitioner's argument that prior art systems controlling access at the file or track level meet the claim limitations.

Petitioner requests institution of an inter partes review and cancellation of claims 1-3, 5-6, and 9 of Patent 6,654,864 as unpatentable under 35 U.S.C. §§ 102 and/or 103.