Abstract: A system for low density parity code decoding according to one embodiment includes a plurality of variable node (vnode) logic modules for sequentially processing groups of vnode values associated with a codeword and outputting updated vnode values; a vnode memory for storing the vnode values and updated vnode values; a plurality of check node (cnode) logic modules for sequentially processing groups of cnode values and outputting updated vnode values; a cnode memory for storing the cnode values and updated cnode values; and logic for checking the codeword using the updated vnode values and the updated cnode values. Additional systems and methods are also presented.

Abstract: A method for monitoring a plurality of servo channels, providing a finite state machine (“FSM”) comprising a single servo channel mode and a combined servo channel mode, and moving a sequential information storage medium comprising a plurality of servo bands across a read/write head comprising a corresponding plurality of servo sensors. The method further asserts an acquisition flag by a servo channel if that servo channel is tracking a servo pattern, and asserts a bit flag by a servo channel if a new LPOS bit is decoded. If at least one acquisition flag is asserted, the method determines if a bit flag is asserted by a servo channel associated with said asserted acquisition flag, and if an acquisition flag and a bit flag are asserted by a servo channel, the method determines a relative positioning of each servo sensor with respect to an associated servo pattern.

Abstract: Provided are a method, system, and article of manufacture that maintains, at a decryption unit, and expected key identifier and an expected initialization vector. A key identifier and an initialization vector are received at the decryption unit, wherein a plurality of encrypted data records are preceded by the key identifier and the initialization vector in a data stream, and wherein the plurality of encrypted data records have been encrypted with a cryptographic key that is recoverable by the decryption unit from the key identifier. An initiation is made of the reading of the plurality of encrypted data records of the data stream, in response to determining at the decryption unit that the received key identifier matches the expected key identifier. Certain embodiments are implemented in a storage library, comprising at least one storage drive, and at least one decryption unit included in the at least one storage drive, wherein in certain embodiments the storage library is a tape library.

Abstract: A method for monitoring a plurality of servo channels, providing a finite state machine (“FSM”) comprising a single servo channel mode and a combined servo channel mode, and moving a sequential information storage medium comprising a plurality of servo bands across a read/write head comprising a corresponding plurality of servo sensors. The method further asserts an acquisition flag by a servo channel if that servo channel is tracking a servo pattern, and asserts a bit flag by a servo channel if a new LPOS bit is decoded. If at least one acquisition flag is asserted, the method determines if a bit flag is asserted by a servo channel associated with said asserted acquisition flag, and if an acquisition flag and a bit flag are asserted by a servo channel, the method determines a relative positioning of each servo sensor with respect to an associated servo pattern.

Abstract: Provided are a method, system, and article of manufacture, wherein a first write only register is maintained in an encryption engine of a cryptographic unit. A second write only register is maintained in a decryption engine of the cryptographic unit. A cryptographic key is written in the first write only register and the second write only register, wherein the cryptographic key is inaccessible for reading from any entity that is external to the cryptographic unit.

Abstract: A system for low density parity code decoding according to one embodiment includes a plurality of variable node (vnode) logic modules for sequentially processing groups of vnode values associated with a codeword and outputting updated vnode values; a vnode memory for storing the vnode values and updated vnode values; a plurality of check node (cnode) logic modules for sequentially processing groups of cnode values and outputting updated vnode values; a cnode memory for storing the cnode values and updated cnode values; and logic for checking the codeword using the updated vnode values and the updated cnode values. Additional systems and methods are also presented.

Abstract: Provided are a method, system and article of manufacture, wherein a cryptographic key generator generates a cryptographic key. The cryptographic key generator encrypts the cryptographic key with a session key that is available to both the cryptographic key generator and a cryptographic unit. The encrypted cryptographic key is transmitted across a link from the cryptographic key generator to the cryptographic unit.

Abstract: A tape drive system which includes the ability to reliably reproduce LPOS information even if both of the servo channels of the tape drive system could not detect the LPOS information due to defects. The system recognizes that an LPOS sequence is sequentially incremented by one if a tape is moving in a forward direction and decremented by one if the tape is moving in a backward direction. This sequential property of the LPOS information lends itself to LPOS prediction, where the LPOS prediction is the previous LPOS value plus one if the tape is moving forward and the previous LPOS value minus one if the tape is moving backward. Even if the LPOS words from the two servo channels are both bad, but not all of the bits in the LPOS word are bad. The system uses the remaining good bits from the two servo channels to verify all of the bits of the LPOS prediction word.

Abstract: A tape drive system which includes the ability to reliably reproduce LPOS information even if both of the servo channels of the tape drive system could not detect the LPOS information due to defects. The system recognizes that an LPOS sequence is sequentially incremented by one if a tape is moving in a forward direction and decremented by one if the tape is moving in a backward direction. This sequential property of the LPOS information lends itself to LPOS prediction, where the LPOS prediction is the previous LPOS value plus one if the tape is moving forward and the previous LPOS value minus one if the tape is moving backward. Even if the LPOS words from the two servo channels are both bad, but not all of the bits in the LPOS word are bad. The system uses the remaining good bits from the two servo channels to verify all of the bits of the LPOS prediction word.

Abstract: An apparatus, system, and method are disclosed for testing data compression and data encryption circuitry. A pattern configuration module generates initial pattern parameters. Holding registers store the initial pattern parameters. A pattern generation module generates patterns for compression/encryption logic. A detection module detects a failure of the compression/encryption logic. The failure of the compression/encryption logic may be a cyclic redundancy check failure of a decompression module and/or a message authentication code failure of a decryption module.

Abstract: Provided are a method, system and article of manufacture, wherein a cryptographic key generator generates a cryptographic key. The cryptographic key generator encrypts the cryptographic key with a session key that is available to both the cryptographic key generator and a cryptographic unit. The encrypted cryptographic key is transmitted across a link from the cryptographic key generator to the cryptographic unit.

Abstract: Provided are a method, system, and article of manufacture that maintains, at a decryption unit, and expected key identifier and an expected initialization vector. A key identifier and an initialization vector are received at the decryption unit, wherein a plurality of encrypted data records are preceded by the key identifier and the initialization vector in a data stream, and wherein the plurality of encrypted data records have been encrypted with a cryptographic key that is recoverable by the decryption unit from the key identifier. An initiation is made of the reading of the plurality of encrypted data records of the data stream, in response to determining at the decryption unit that the received key identifier matches the expected key identifier. Certain embodiments are implemented in a storage library, comprising at least one storage drive, and at least one decryption unit included in the at least one storage drive, wherein in certain embodiments the storage library is a tape library.

Abstract: Provided are a method, system, and article of manufacture, wherein a first write only register is maintained in an encryption engine of a cryptographic unit. A second write only register is maintained in a decryption engine of the cryptographic unit. A cryptographic key is written in the first write only register and the second write only register, wherein the cryptographic key is inaccessible for reading from any entity that is external to the cryptographic unit.