Abstract: A disc cassette includes a curved portion configured to hold multiple discs and a platform portion abuts the curved portion. The platform portion and the curved portion each include multiple rib pairs configured to separate adjacent discs from touching one another, and to form a disc slot between each rib pair. Disc slots of the platform portion of the disc cassette are configured to provide a guide for disc removal from the disc cassette.

Abstract: Embodiments relate to correcting erasures in a storage array. An aspect includes dividing data into a plurality of stripes for storage in a storage array comprising a plurality of storage locations, each stripe comprising M rows and N columns, each of the M rows including a number r of row parities, wherein r is greater than zero. Another aspect includes dividing each stripe into two or more column sets, each column set comprising a respective set of one or more columns of the stripe. Another aspect includes adding a respective first responder parity to each column set, wherein each first responder parity gives parity information for only the two or more columns in the first responder parity's respective column set. Yet another aspect includes, based on an isolated erasure in a column set, correcting the isolated erasure by reading data from only storage locations corresponding to the column set in which the isolated erasure occurred using the first responder parity of the column set.

Abstract: Embodiments relate to a computer system for storing data on a time multiplexed redundant array of independent tapes. An aspect includes a memory device that buffers data received by the computer system to be written to a set of tape data storage devices. The data is written to the set of tape data storage devices in blocks that form parity stripes across the set of tape data storage device. Aspects further includes a tape drive that writes data to one of the set of tape data storage devices at a time in a tape-sequential manner and a processor that computes a parity value for each of the parity stripes. The tape drive writes the parity values for each of the parity stripes to a last subset of tapes of the set of tape data storage devices.

Abstract: Embodiments relate a universal serial bus (USB) filter hub. An aspect includes receiving, by the USB filter hub that is in communication with a host computer system, a connection from a USB device at a USB port of the USB filter hub. Another aspect includes determining, by the USB filter hub, a type of the USB device. Another aspect includes determining whether the type of the USB device is valid. Yet another aspect includes, based on determining that the type of the USB device is valid, filtering commands that are communicated between the USB device and the host computer system via the USB filter hub based on a predetermined command set corresponding to the determined type of the USB device.

Abstract: Embodiments include generating an error correction code by identifying two error-correcting codes of length n with minimum distances d and 2d, such that the second code is contained into the first code. Data is then encoded into t?1 blocks using the first code, and into the t-th block using the second block. The first t?1 encoded blocks are stored into t?1 blocks of memory locations, while the exclusive-OR (XOR) of such t?1 encoded blocks and the t-th encoded block is stored into a t-th block of memory location. The final encoded vector of length to is identified as belonging in a code with minimum distance 2d. Rotations of an encoded vector jn times are identified as belonging to the same equivalence class. A received vector or its rotations jn times can be successfully identified in the presence of up to d?1 errors, while d errors are identified as uncorrectable errors.

Abstract: Embodiments of the invention provide parity logs for raid systems with variable-capacity media. In one embodiment, a system includes a first set of data storage media devices having variable capacity. The storage devices include a data portion of a parity data set for storing write data being striped to the first. The system further includes a second set of data storage media devices having variable capacity. The second set includes a linear address space of blocks for storing a parity portion of the parity data set. The linear address space is written in a log form. The first and second sets comprise at least one array in a RAID configuration. The system writes the parity portion of the parity data set to the second set, which enables each storage device among the first set to be written to full capacity.

Abstract: A technique for storage and retrieval of objects is provided. A holding structure is configured to hold the objects, and the objects are stored in the holding structure such that the objects can slide in and out of the holding structure. An elastic mechanism is at the back of the holding structure, and the elastic mechanism pushes the objects toward the front of the holding structure such that the objects are accessible at the front of the holding structure. A selector mechanism is positionable to push the objects that are adjacent to a selected object to be retrieved toward the back of the holding structure, and the selector mechanism exposes a portion of the selected object so that the selected object can be engaged at the exposed portion. A gripper is configured to engage the exposed portion of the selected object and pull the selected object from the holding structure.

Abstract: Aspects of the present invention include a system, method, and computer program product for skewing expected wearout times of memory devices in an array are provided according to some embodiments of the present invention. In general, the method includes determining or receiving an amount of spare space to provide in an array of memory devices, allocating the spare space non-uniformly to the memory devices in the array, and skewing expected wearout times of the memory devices by controlling writing of data to the array according to the allocation of the spare space.

Abstract: Embodiments of the invention provide parity logs for raid systems with variable-capacity media. In one embodiment, a system includes a first set of data storage media devices having variable capacity. The storage devices include a data portion of a parity data set for storing write data being striped to the first. The system further includes a second set of data storage media devices having variable capacity. The second set includes a linear address space of blocks for storing a parity portion of the parity data set. The linear address space is written in a log form. The first and second sets comprise at least one array in a RAID configuration. The system writes the parity portion of the parity data set to the second set, which enables each storage device among the first set to be written to full capacity.

Abstract: Embodiments relate to a computer system for storing data on a time multiplexed redundant array of independent tapes. An aspect includes a memory device that buffers data received by the computer system to be written to a set of tape data storage devices. The data is written to the set of tape data storage devices in blocks that form parity stripes across the set of tape data storage device. Aspects further includes a tape drive that writes data to one of the set of tape data storage devices at a time in a tape-sequential manner and a processor that computes a parity value for each of the parity stripes. The tape drive writes the parity values for each of the parity stripes to a last subset of tapes of the set of tape data storage devices.

Abstract: A technique for storage and retrieval of objects is provided. A holding structure is configured to hold the objects, and the objects are stored in the holding structure such that the objects can slide in and out of the holding structure. An elastic mechanism is at the back of the holding structure, and the elastic mechanism pushes the objects toward the front of the holding structure such that the objects are accessible at the front of the holding structure. A selector mechanism is positionable to push the objects that are adjacent to a selected object to be retrieved toward the back of the holding structure, and the selector mechanism exposes a portion of the selected object so that the selected object can be engaged at the exposed portion. A gripper is configured to engage the exposed portion of the selected object and pull the selected object from the holding structure.

Abstract: Aspects of the present invention include a system, method, and computer program product for skewing expected wearout times of memory devices in an array are provided according to some embodiments of the present invention. In general, the method includes determining or receiving an amount of spare space to provide in an array of memory devices, allocating the spare space non-uniformly to the memory devices in the array, and skewing expected wearout times of the memory devices by controlling writing of data to the array according to the allocation of the spare space.

Abstract: A system includes a linear storage media tier; a second storage tier having higher performance than the linear storage media tier; a data controller for moving data between the tiers; and a host interface responsive to disk and/or network storage commands. The linear storage media tier includes: a rest area for storing reels having linear media thereon, at least one linear media drive configured for reading and/or writing the linear media, and at least one robot for transporting the linear storage media between the rest area and the at least one linear media drive. The robot moves along a first surface via contact with the surface. A system according to another embodiment includes a linear storage media tier characterized by having a read access time to any block of data stored on any reel in the rest area in less than 10 seconds.

Abstract: An aspect is a method that includes receiving (k0?1)k1+k2 write data symbols, where k2<k1. The write data symbols are arranged in an array that includes k0?1 rows of length k1 followed by a row of length k2. The first k2 columns are encoded to form a partially encoded array using a vertical error correcting code of length m, m>k0, resulting in k2 columns of length m including the write data symbols and vertical parity values. The k0?1 rows of the write data symbols of length k1 and the m?k0+1 rows from the partially encoded array are encoded into an encoded array of m rows of length n columns, n>k1 including at least one parity value in each of the m rows, thereby enabling correction of up to (n?k1)/2 errors in any row and up to (n?k2)/2 errors in up to m?k0+1 rows of the encoded array.

Abstract: A computer-implemented method includes receiving a request for data; determining whether the data is stored in a linear storage media tier and/or in a second storage tier having higher performance than the linear storage media tier. The linear storage media tier includes: reels having linear media thereon, a rest area for storing the reels when not in use, linear media drive(s) configured for reading and/or writing the linear media, and mobile robot(s) for transporting the linear storage media between the rest area and the linear media drive(s). The method also includes instructing the mobile robot to transport one of the reels having the data thereon to one of the linear media drives in the linear storage media tier when the data is stored in the linear storage media tier; receiving the data from the one of the linear media drives; and sending the data.

Abstract: Embodiments include generating an error correction code by identifying two error-correcting codes of length n with minimum distances d and 2d, such that the second code is contained into the first code. Data is then encoded into t?1 blocks using the first code, and into the t-th block using the second block. The first t?1 encoded blocks are stored into t?1 blocks of memory locations, while the exclusive-OR (XOR) of such t?1 encoded blocks and the t-th encoded block is stored into a t-th block of memory location. The final encoded vector of length to is identified as belonging in a code with minimum distance 2d. Rotations of an encoded vector jn times are identified as belonging to the same equivalence class. A received vector or its rotations jn times can be successfully identified in the presence of up to d?1 errors, while d errors are identified as uncorrectable errors.

Abstract: Embodiments of the invention relate to tape drive systems having overlapped operations. In one aspect, a system includes a head for performing read and/or write operations, a first set of motors for performing positioning operations on a first tape, a second set of motors for performing positioning operations on a second tape, and a processor and logic integrated with and/or executable by the processor. The logic is configured to cause the first set of motors to pass the first tape over the head while causing the second set of motors to perform at least one of a coarse locate and a rewind operation on the second tape. Additional systems and methods are also disclosed.

Abstract: An aspect is a method that includes receiving (k0?1)k1+k2 write data symbols, where k2<k1. The write data symbols are arranged in an array that includes k0?1 rows of length k1 followed by a row of length k2. The first k2 columns are encoded to form a partially encoded array using a vertical error correcting code of length m, m>k0, resulting in k2 columns of length m including the write data symbols and vertical parity values. The k0?1 rows of the write data symbols of length k1 and the m?k0+1 rows from the partially encoded array are encoded into an encoded array of m rows of length n columns, n>k1 including at least one parity value in each of the m rows, thereby enabling correction of up to (n?k1)/2 errors in any row and up to (n?k2)/2 errors in up to m?k0+1 rows of the encoded array.

Abstract: Embodiments of the invention relate to erasure correcting codes for storage arrays. An aspect of the invention includes receiving a read stripe from a plurality of storage devices. The read stripe includes a block of pages arranged in rows and columns, with each column corresponding to one of the storage devices. The pages include data pages and parity pages, with the number of parity pages at least one more than the number of rows and not a multiple of the number of rows. The method further includes reconstructing at least one erased page in response to determining that the read stripe includes the at least one erased page and that the number of erased pages is less than or equal to the number of parity pages. The reconstructing is responsive to a multiple erasure correcting code and to the block of pages. The reconstructing results in a recovered read stripe.

Abstract: Bitmap compression for fast searches and updates is provided. Compressing a bitmap includes receiving a bitmap to compress, and reading the bitmap to determine a value of a bit location for all bits in the bitmap. In one embodiment, a compressed bitmap is created by encoding a variable number of bytes to represent a distance between adjacent 1s in the uncompressed bitmap. In another embodiment, a compressed bitmap is created by representing a distance between adjacent 1s in the uncompressed bitmap using a plurality of bits, and encoding a marker word to indicate the number of bits used to represent the distance.