摘要:
In one embodiment, a system includes a processor, logic in the processor and/or memory configured to determine a physical position on a magnetic medium that corresponds to an end of encrypted data written over residual unencrypted data, and logic configured to store an indicator of the physical position on at least one of the magnetic medium and a memory coupled thereto. In another embodiment, a method includes determining a physical position on a magnetic medium that corresponds to an end of encrypted data written over residual unencrypted data, storing an indicator of the physical position on at least one of the magnetic medium and a memory coupled thereto.
摘要:
In one embodiment, a system includes a processor, logic in the processor and/or memory configured to determine a physical position on a magnetic medium that corresponds to an end of encrypted data written over residual unencrypted data, and logic configured to store an indicator of the physical position on at least one of the magnetic medium and a memory coupled thereto. In another embodiment, a method includes determining a physical position on a magnetic medium that corresponds to an end of encrypted data written over residual unencrypted data, storing an indicator of the physical position on at least one of the magnetic medium and a memory coupled thereto.
摘要:
A system according to one embodiment includes a processor; logic in the processor and/or a memory configured to determine a furthest physical position on a magnetic medium that unobscured data has been written to; and logic configured to store an indicator of the furthest physical position on at least one of the magnetic medium and a memory coupled thereto. A system according to another embodiment includes a processor; logic in the processor and/or a memory configured to receive an instruction to obscure data on a magnetic medium; logic configured to read an indicator of a furthest physical position on the magnetic medium that unobscured data has been written to; and logic configured to cause obscuring of the unobscured data on the magnetic medium, and terminating the obscuring upon reaching the physical position in the indicator.
摘要:
A system according to one embodiment includes a processor; logic in the processor and/or a memory configured to determine a furthest physical position on a magnetic medium that unobscured data has been written to; and logic configured to store an indicator of the furthest physical position on at least one of the magnetic medium and a memory coupled thereto. A system according to another embodiment includes a processor; logic in the processor and/or a memory configured to receive an instruction to obscure data on a magnetic medium; logic configured to read an indicator of a furthest physical position on the magnetic medium that unobscured data has been written to; and logic configured to cause obscuring of the unobscured data on the magnetic medium, and terminating the obscuring upon reaching the physical position in the indicator.
摘要:
A method, system and computer-usable medium are disclosed for reordering User Data Segment (UDS) lists to reduce seek times when accessing data stored on tape media. A host application sends a list of UDSs to a target tape drive and requests the tape drive to reorder the list to provide better performance. An ordered list of target User data Segments to retrieve from a target tape media is received. Information related to the location of each UDS on the target media is processed to determine its corresponding physical position on the tape media. The resulting physical positions are then processed to generate a reordered UDS list, where the order of the User Data Segments is reordered according to their physical location on the target tape media. The reordered list of User Data Segments is then used to perform seek, reposition and read operations to read User Data Segments from the tape media.
摘要:
A method, system and computer-usable medium are disclosed for reordering User Data Segment (UDS) lists to reduce seek times when accessing data stored on tape media. A host application sends a list of UDSs to a target tape drive and requests the tape drive to reorder the list to provide better performance. An ordered list of target User data Segments to retrieve from a target tape media is received. Information related to the location of each UDS on the target media is processed to determine its corresponding physical position on the tape media. The resulting physical positions are then processed to generate a reordered UDS list, where the order of the User Data Segments is reordered according to their physical location on the target tape media. The reordered list of User Data Segments is then used to perform seek, reposition and read operations to read User Data Segments from the tape media.
摘要:
A magnetic tape drive simultaneously senses on a magnetic tape three evenly spaced-apart servo track areas for servoing a multi-track magnetic head to follow a concurrent set of data tracks on the magnetic tape. The data tracks are arranged into a plurality of track groups. Each track group has a first and second subgroup of data tracks. The first subgroup of tracks are scanned in a first relative motion of the magnetic tape and magnetic head as a forward direction (tape is being spooled from a supply tape reel). The second subgroup of tracks are scanned in a second relative motion of the magnetic tape and magnetic head that is opposite in direction to the first relative direction and is a forward direction of scanning. While writing data in any one of the plural track groups, a servo dropout affecting most of the servo track areas is detected and indicated as a servo error. Writing is aborted. The relative position of the magnetic tape and head is detected at both longitudinal ends of the servo dropout. A servo dropout block (SDB), a tape control block, is written at each longitudinal end of the servo dropout only in the group of tracks in which data are being written. The tape space between the two SDBs is termed a limited portion of the tape in which no recording is permitted.
摘要:
A method to erase a magnetic tape, where the magnetic tape is first mounted in a magnetic tape in a tape drive, where that magnetic tape includes a physical beginning of tape (“PBOT”), a physical end of tape (“PEOT”), and information written thereon between the PBOT and the PEOT. The method then establishes one or more critical areas located on the magnetic tape, attempts to erase the information, and determines if each of the one or more critical areas have been erased. In the event each of said one or more critical areas have not been erased, Applicants' method provides an error message.
摘要:
A method and system are disclosed for efficiently reading and processing multiple data blocks stored in a removable data storage medium within a data storage system, wherein each data block includes a header portion containing selected parameters necessary to identify and process an associated data block, and a data portion. Each data block is accessed within the removable data storage medium utilizing track logic circuitry and then coupled to a data block buffer for temporary storage. A header processing logic circuit is interposed between the track logic circuitry and the data block buffer and is utilized to initiate processing of only the header portion of each data block prior to storage of the data block within the data block buffer. After completion of processing of the header portion of a data block and completion of storage of that data block within the data block buffer, the data block is efficiently processed utilizing selected parameters contained within the header portion. In this manner, data blocks may be efficiently transferred, processed or coupled to an error recovery procedure from the data block buffer without the delay associated with processing each header portion of a data block after storage of that data block within the data block buffer.
摘要:
A peripheral data storage system employing a data buffer connected to a plurality of data storage devices, such as tape recorders, dynamically reallocates data buffer storage segments among the various data storage devices. A normalized elapsed-time period is established based upon the number of accesses to the data storage devices. When the number of accesses reaches a threshold the need for dynamic reallocation is examined. During the elapsed-time period the system monitors which of the allocated buffer segments have any data transfer activity at all and also measures the intensity of the activity for the respective buffer segments. In a peripheral system, the intensity is indicated by the number of channel command retries submitted to a connected host processor for the respective allocated buffer segment. Based upon the allocation status of the buffer segments and intensity of activities of the respective buffer segments, the buffer allocations are selectively reallocated among the data storage devices.