Abstract:
Methods, logic, apparatus and computer program product write data, comprising less than a full Data Set, to magnetic tape. Data is received from a host, a do-not-interleave command is issued and C1 and C2 ECC are computed. Codeword Quad (CQ) sets are then formed. At least one CQ set of the Data Set is written to a magnetic tape in a non-interleaved manner and a Data Set Information Table (DSIT) is written to the magnetic tape immediately following the at least one written CQ set. An address transformation may be used to cancel interleaving. Writing a CQ set may include writing a plurality of contiguous instances of the CQ set to the magnetic tape to maintain the effectiveness of ECC capability.
Abstract:
A system in one embodiment includes multiple analog inputs for receiving readback signals, an analog to digital converter coupled to each of the analog inputs for converting the readback signals to digital signals, a buffer coupled to outputs of the analog to digital converters for at least temporarily storing the digital signals, and a digital processing section also coupled to outputs of the analog to digital converters for processing the digital signals for reconstructing data therefrom. A method in one embodiment includes receiving multiple channels of analog readback signals from a magnetic head, converting the analog signals in each channel to digital signals, buffering the digital signals, and outputting the buffered digital signals. A method in another embodiment includes receiving a readback waveform from a magnetic storage device, reducing a frequency offset of the readback waveform, and generating a synchronized, oversampled waveform from the readback waveform.
Abstract:
Provided is a technology capable of managing the processing status of hardware blocks by a less number of registers. A processing system includes a buffer composed of a plurality of segments which store data, which is to be input to the processing system, in transactions in the order of inputting, respectively; a plurality of processing units which perform a series of processes in a given order for the data; a plurality of first tables corresponding to the plurality of processing units, respectively, the first tables each storing beginning information which indicates a beginning segment among a plurality of segments at continuous addresses completed in the process by the corresponding processing unit, end information which indicates an end segment among them, and existence information which indicates the presence or absence of segments completed in the process by the corresponding processing unit; and a management unit which manages a data transfer between the buffer and the plurality of processing units so that the series of processes are performed in a given order on the basis of the processing status of the series of processes retained in the plurality of first tables.
Abstract:
Memory access arbitration allowing a shared memory to be used both as a memory for a processor and as a buffer for data flows, including an arbiter unit that makes assignment for access requests to the memory sequentially and transfers blocks of data in one round-robin cycle according to bandwidths required for the data transfers, sets priorities for the transfer blocks so that the bandwidths required for the data transfers are met by alternate transfer of the transfer blocks, and executes an access from the processor with an upper limit set for the number of access times from the processor to the memory in one round-robin cycle so that the access from the processor with the highest priority and with a predetermined transfer length exerts less effect on bandwidths for data flow transfers in predetermined intervals between the transfer blocks.
Abstract:
A magnetic tape drive having a tape drive system for moving magnetic tape, tape read/write and servo system, tape cartridge load/unload systems, I/O communications, memory; and a control system, operates in three modes to conserve energy consumption. A first low power mode powers the I/O communications, the memory, and the control system. If a magnetic tape cartridge is in loaded position in the magnetic tape drive, the second low power mode powers the same as the first low power mode, and additionally powers the tape drive system to apply tension to a magnetic tape of the magnetic tape cartridge. In the first and the second low power modes, the control system operates the I/O communications, the memory and the control system to respond to and execute commands received at the I/O communications if the commands are executable without magnetic tape access. The third, full power mode, is entered if a command received at the I/O communications requires magnetic tape access.
Abstract:
A method for transferring corrected data to an external buffer within a tape drive is disclosed. After the receipt of data from a data recording medium, the data are stored in an external buffer. The data are then transferred from the external buffer to an error correction code (ECC) device. Any error in the data within the ECC device are corrected. The corrected data are subsequently divided into multiple sub-units, and a transfer flag is added to each of the sub-units having corrected data. Only the sub-units having corrected data are transferred from the ECC device back to the external buffer.
Abstract:
A backup power-source module that controls a backup power source for supplying power from a battery charged by an AC input to an electronic device when the AC input is cut off. The backup power-source module includes a selection which generates a selection signal for selecting power supplied by a battery when the electronic device is kept in an electrified state until the electronic device is shifted to a power cutoff state and there is no AC input. I.E., the selection signal causes the power supplied by the battery to be selected only when the electronic device is kept in a power cutoff state and there is no AC input.
Abstract:
Provided is a memory access device for a shared memory mechanism of main memory for a plurality of CPUs. The present invention includes a plurality of CPUs using memory as main memory, another function block using memory as a buffer, a CPU interface which controls access transfer from the plurality of CPUs to memory, and a DRAM controller for performing arbitration of the access transfer to the memory. Therein, the CPU interface causes access requests from the plurality of CPUs to wait, and receives and stores the address, data transfer mode and data size of each access, notifies the DRAM controller of the access requests, and then, upon receiving grant signals for the access requests, sends information to the DRAM controller according to the grant signals, whereupon the DRAM controller receives the grant signals, and on the basis of the access arbitration, specifies CPUs for which transfers have been granted so as to send the grant signals to the CPU interface.
Abstract:
A method for integrating data and header protection in tape drives includes receiving an array of data organized into rows and columns. The array is extended to include one or more headers for each row of data in the array. The method provides two dimensions of error correction code (ECC) protection for the data in the array and a single dimension of ECC protection for the headers in the array. A corresponding apparatus is also disclosed herein.
Abstract:
Conventional C2 coding and interleaving for multi-track data tape in LTO-¾ do not support recording data onto a number of concurrent tracks which is not a power of two. Higher-rate longer C2 codes, which do not degrade error rate performance, are provided. An adjustable format and interleaving scheme accommodates future tape drives in which the number of concurrent tracks is not necessarily a power of two. A data set is segmented into a plurality of unencoded subdata sets and parity bytes are generated for each row and column. The parameters of the C2 code include N2 as the least common multiple of the number of possible tracks to which codeword objects are to be written. COs are formed from N2 C1 codewords, mapped onto a logical data track according to information within headers of the CO and modulation encoded into synchronized COs which are written to the tape.