Abstract: A storage device includes a flash memory-based cache for a hard disk-based storage device and a controller that is configured to limit the rate of cache updates through a variety of mechanisms, including determinations that the data is not likely to be read back from the storage device within a time period that justifies its storage in the cache, compressing data prior to its storage in the cache, precluding storage of sequentially-accessed data in the cache, and/or throttling storage of data to the cache within predetermined write periods and/or according to user instruction.

Abstract: Methods, systems, and computer programs are presented for allocating CPU cycles in a storage system. One method includes operations for receiving requests to be processed, and for associating each request to one task. A foreground task is for processing input/output requests, and the foreground task includes one or more flows. Each flow is associated with a queue and a flow counter value, where each queue is configured to hold requests. The method further includes an operation for selecting one task for processing by the CPU based on an examination of the number of cycles processed by the CPU for each task. When the selected task is the foreground task, the flow having the lowest flow counter is selected. The CPU processes a request from the queue of the selected flow, and the flow counter of the selected flow is increased based on the data consumption of the processed task.

Abstract: Methods and systems are presented for allocating CPU cycles among processes in a storage system. One method includes operations for maintaining segments in a first memory, each segment including blocks, and for maintaining a block temperature for each block in a second memory. The first memory is a read-cache where one segment is written at a time, and each block is readable from the first memory without reading the corresponding complete segment. The block temperature is based on the frequency of access to the respective block, and a segment temperature is based on the block temperature of its blocks. Additionally, the segment with the lowest segment temperature is selected for eviction from the second memory, and blocks in the selected segment with a block temperature greater than a threshold temperature are identified. The selected segment is evicted, and a segment with the identified blocks is written to the first memory.

Abstract: Systems and methods are disclosed for embedding information in software and/or other electronic content such that the information is difficult for an unauthorized party to detect, remove, insert, forge, and/or corrupt. The embedded information can be used to protect electronic content by identifying the content's source, thus enabling unauthorized copies or derivatives to be reliably traced, and thus facilitating effective legal recourse by the content owner. Systems and methods are also disclosed for protecting, detecting, removing, and decoding information embedded in electronic content, and for using the embedded information to protect software or other media from unauthorized analysis, attack, and/or modification.

Abstract: A storage device includes a flash memory-based cache for a hard disk-based storage device and a controller that is configured to limit the rate of cache updates through a variety of mechanisms, including determinations that the data is not likely to be read back from the storage device within a time period that justifies its storage in the cache, compressing data prior to its storage in the cache, precluding storage of sequentially-accessed data in the cache, and/or throttling storage of data to the cache within predetermined write periods and/or according to user instruction.

Abstract: A storage device made up of multiple storage media is configured such that one such media serves as a cache for data stored on another of such media. The device includes a controller configured to manage the cache by consolidating information concerning obsolete data stored in the cache with information concerning data no longer desired to be stored in the cache, and erase segments of the cache containing one or more of the blocks of obsolete data and the blocks of data that are no longer desired to be stored in the cache to produce reclaimed segments of the cache.

Abstract: A storage device made up of multiple storage media is configured such that one such media serves as a cache for data stored on another of such media. The device includes a controller configured to manage the cache by consolidating information concerning obsolete data stored in the cache with information concerning data no longer desired to be stored in the cache, and erase segments of the cache containing one or more of the blocks of obsolete data and the blocks of data that are no longer desired to be stored in the cache to produce reclaimed segments of the cache.

Abstract: Methods, systems, and computer programs are presented for creating writable snapshots of logical data units in a network storage array. One method includes operations for receiving a request to create a snapshot at a storage device, the snapshot being a point-in-time copy of a volume in the storage device, and for creating the snapshot with a first snap-point corresponding to a state of the volume when the snapshot is created. The snapshot is writeable when the snapshot is created. Further, the method includes operations for receiving one or more requests to make changes to the snapshot, for creating one or more snap-points for the snapshot after processing the one or more requests, and for closing the snapshot. The snapshot is not writeable after the snapshot is closed and access to the snapshot, after closing the snapshot, accesses data associated with a last snap-point of the snapshot.

Abstract: Methods, systems, and computer programs are presented for allocating CPU cycles in a storage system. One method includes operations for receiving requests to be processed, and for associating each request to one task. A foreground task is for processing input/output requests, and the foreground task includes one or more flows. Each flow is associated with a queue and a flow counter value, where each queue is configured to hold requests. The method further includes an operation for selecting one task for processing by the CPU based on an examination of the number of cycles processed by the CPU for each task. When the selected task is the foreground task, the flow having the lowest flow counter is selected. The CPU processes a request from the queue of the selected flow, and the flow counter of the selected flow is increased based on the data consumption of the processed task.

Abstract: Methods, systems, and computer programs are presented for storing data in a solid state drive (SSD). One method includes an operation for detecting a plurality of streams writing to the SSD, each stream writing in sectors, a page including a plurality of sectors and a block including a plurality of pages. A write operation includes writing at least one complete page, and an erase operation includes erasing at least one complete block. The method further includes operations for allocating a write buffer for each stream in RAM memory, and for storing each received sector of a stream in the corresponding write buffer. When a write buffer stores enough sectors to fill a page, content of the write buffer is written to a page in flash memory such that the page is filled. Further, the write buffer is freed after writing the content of the write buffer to the flash memory.

Abstract: Methods and systems are presented for allocating CPU cycles among processes in a storage system. One method includes operations for maintaining segments in a first memory, each segment including blocks, and for maintaining a block temperature for each block in a second memory. The first memory is a read-cache where one segment is written at a time, and each block is readable from the first memory without reading the corresponding complete segment. The block temperature is based on the frequency of access to the respective block, and a segment temperature is based on the block temperature of its blocks. Additionally, the segment with the lowest segment temperature is selected for eviction from the second memory, and blocks in the selected segment with a block temperature greater than a threshold temperature are identified. The selected segment is evicted, and a segment with the identified blocks is written to the first memory.

Abstract: A storage device made up of multiple storage media is configured such that one such media serves as a cache for data stored on another of such media. The device includes a controller configured to manage the cache by consolidating information concerning obsolete data stored in the cache with information concerning data no longer desired to be stored in the cache, and erase segments of the cache containing one or more of the blocks of obsolete data and the blocks of data that are no longer desired to be stored in the cache to produce reclaimed segments of the cache.

Abstract: Methods and systems are presented for allocating CPU cycles among processes in a storage system. One method includes operations for maintaining segments in a first memory, each segment including blocks, and for maintaining a block temperature for each block in a second memory. The first memory is a read-cache where one segment is written at a time, and each block is readable from the first memory without reading the corresponding complete segment. The block temperature is based on the frequency of access to the respective block, and a segment temperature is based on the block temperature of its blocks. Additionally, the segment with the lowest segment temperature is selected for eviction from the second memory, and blocks in the selected segment with a block temperature greater than a threshold temperature are identified. The selected segment is evicted, and a segment with the identified blocks is written to the first memory.

Abstract: Systems and methods are disclosed for providing a trusted database system that leverages a small amount of trusted storage to secure a larger amount of untrusted storage. Data are encrypted and validated to prevent unauthorized modification or access. Encryption and hashing are integrated with a low-level data model in which data and meta-data are secured uniformly. Synergies between data validation and log-structured storage are exploited.

Abstract: A system includes a computing device that includes a memory configured to store instructions. The system also includes a processor to execute the instructions to perform operations that include receiving, at an imaging device, one or more files representing a network asset that is presentable on a display of the imaging device. At least one of the files includes data for presenting textual content of the network asset. Operations also include presenting on the display of the imaging device a portion of the network asset and textual content that corresponds to the portion of the network asset. Operations also include, as the portion of the network asset and corresponding textual content is being presented, executing operations at the imaging device to determine if textual content of at least one other portion of the network asset can be presented on the display using font characters residing at the imaging device.

Abstract: A storage device made up of multiple storage media is configured such that one such media serves as a cache for data stored on another of such media. The device includes a controller configured to manage the cache by consolidating information concerning obsolete data stored in the cache with information concerning data no longer desired to be stored in the cache, and erase segments of the cache containing one or more of the blocks of obsolete data and the blocks of data that are no longer desired to be stored in the cache to produce reclaimed segments of the cache.

Abstract: Systems and methods are disclosed for embedding information in software and/or other electronic content such that the information is difficult for an unauthorized party to detect, remove, insert, forge, and/or corrupt. The embedded information can be used to protect electronic content by identifying the content's source, thus enabling unauthorized copies or derivatives to be reliably traced, and thus facilitating effective legal recourse by the content owner. Systems and methods are also disclosed for protecting, detecting, removing, and decoding information embedded in electronic content, and for using the embedded information to protect software or other media from unauthorized analysis, attack, and/or modification.

Abstract: Described herein are methods, systems and machine-readable media for simulating a FIFO cache using a Bloom filter ring, which includes a plurality of Bloom filters arranged in a circular log. New elements are registered in the Bloom filter at the head of the circular log. When the Bloom filter at the head of the circular log is filled to its capacity, membership information associated with old elements in the Bloom filter at the tail of the circular log is evicted (simulating FIFO cache behavior), and the head and tail of the log are advanced. The Bloom filter ring is used to determine cache statistics (e.g., cache hit, cache miss) of a FIFO cache of various sizes. In response to simulation output specifying cache statistics for FIFO cache of various sizes, a FIFO cache is optimally sized.

Abstract: Described herein are methods, systems and machine-readable media for simulating a FIFO cache using a Bloom filter ring, which includes a plurality of Bloom filters arranged in a circular log. New elements are registered in the Bloom filter at the head of the circular log. When the Bloom filter at the head of the circular log is filled to its capacity, membership information associated with old elements in the Bloom filter at the tail of the circular log is evicted (simulating FIFO cache behavior), and the head and tail of the log are advanced. The Bloom filter ring is used to determine cache statistics (e.g., cache hit, cache miss) of a FIFO cache of various sizes. In response to simulation output specifying cache statistics for FIFO cache of various sizes, a FIFO cache is optimally sized.

Abstract: A storage device made up of multiple storage media is configured such that one such media serves as a cache for data stored on another of such media. The device includes a controller configured to manage the cache by consolidating information concerning obsolete data stored in the cache with information concerning data no longer desired to be stored in the cache, and erase segments of the cache containing one or more of the blocks of obsolete data and the blocks of data that are no longer desired to be stored in the cache to produce reclaimed segments of the cache.