摘要:
Access to encrypted data on a removable computer media such as a computer tape is controlled via a uniquely-structured header on the medium having a symmetrical key wrapped by asymmetrical encryption plus a public key associated with the asymmetrical encryption. The data on the medium is encrypted using the symmetrical key. Prior to automated reading of the data by a reader, a challenge is issued to a host system including the public key and preferably a nonce value. The host responds by signing the nonce using a private key associated with the public key in order to prove it has rights to decrypt the data. The symmetrical key is unwrapped using the private key, and finally the unwrapped symmetrical key is used to decrypt the data on the medium, thereby allowing automated reading of the tape data without the need or risk of two administrators sharing a symmetrical key value.
摘要:
Provided are a method, system, and program for writing data in a tape medium having wraps. A layout of the tape is provided including at least one segment within a full available length of a first set of wraps for writing user data and at least one segment within a full length of a second set of wraps for writing a work copy of the user data. User data is received to write to the tape medium and detecting is performed as to whether the data being written is occurring in a specified write mode. If the data writing is not occurring in the specified write mode, then writing the received user data to one segment in the first set of wraps. If the data writing is occurring in the specified write mode, then writing a work copy to available full length wraps not having user data.
摘要:
A recording system of a magnetic tape drive is operated to cause one separate set of write heads to write data discontinuously to magnetic tape as received, and to save the data, and, during the same operation, to cause another separate set of write heads to rewrite data to magnetic tape in a continuous arrangement. The writing may be in parallel and simultaneous. Thus, during the same operation, and at the same time, the separate sets of the plurality of write heads, temporarily write the received data to magnetic tape so that the sender can erase its copy, and rewrite the saved data to the magnetic tape in a permanent arrangement, without waiting to complete first writing received data, to complete subsequently rewriting the data, and repeating.
摘要:
A sequential buffer for a magnetic tape data storage system comprises a plurality of segments. A buffer management system buffers data in the sequential buffer, conducting a data transfer process. Subsequently, some of the buffered data is maintained in some, but less than all, the segments of the buffer. Additionally, the maintained buffered data is indicated as VALID data. Thus, a subsequent process may be conducted directly using the data maintained in the buffer, and avoids moving the tape to reread the data.
摘要:
Provided is a method, system, and program for encoding and decoding input data. A key is generated comprising a list of a plurality of binary values, wherein the key is available to a user during decoding. The input data is encoded by using the key to initialize a replacement list. A determination is made whether to replace strings in the input data with a string reference to a matching string value, wherein the input data not replaced with reference to one matching string value comprises one or more literals. Each literal is replaced with a literal reference to one entry in the replacement list matching the literal. The encoded input data is decoded by accessing the generated key in response to user input and using the accessed key to decode the literals replaced with literal references to entries in the replacement list.
摘要:
Provided is a method, system, and program for storing input groups of uncoded binary data on a storage medium. A plurality of uncoded data blocks in a data stream are received. An encoded data stream is obtained from concatenating successive encoded blocks such that the encoded data stream includes a predetermined bit pattern comprising a plurality of bits. The bit pattern always occurs within a first number of bits and two occurrences of a “1” or “0” occur within a second number of bits. The encoded data blocks are stored on the storage medium.
摘要:
In magnetic tape having separate longitudinal servo bands of servo information with superimposed data information, the separate servo bands have selected different superimposed data information, to identify the separate servo bands for independent addressability. The servo information comprises non-parallel laterally extending transitions to indicate lateral positioning, and the selected different superimposed data information may comprise a lack thereof in portion(s) of the servo bands. Where the superimposed data information is longitudinal position information of the tape, the selected different superimposed data information may comprise different longitudinal position information of one or more servo band(s). The selected different superimposed data information may comprise a band identifier in the superimposed data information of one or more of the servo bands.
摘要:
Authentication of an upgrade to computer readable program code of a target embedded device is accomplished by causing the computer processor of the embedded device to access an unique machine identifier; to access an identifier key associated with the upgrade; to process the identifier key and/or unique machine identifier, such as by decrypting the key and/or encrypting the identifier; to compare the identifier key with the unique machine identifier; and causing the computer processor, if the identifier key matches the unique machine identifier, to enable the upgrade; else, to fail the upgrade.
摘要:
Adjustment of a read detection equalizer filter of a magnetic tape drive is conducted utilizing a required control pattern signal which comprises a required portion of a normal recording format of the magnetic tape. An example comprises a data set separator signal. The sensed required control pattern signal is processed with respect to a target reference pattern signal to adapt the read detection equalizer filter to the target reference pattern signal.
摘要:
A detector and method for detecting data modulated into a timing based servo pattern prerecorded on a media, comprising shifts of pairs of non-parallel transition stripes arranged in a frame of two bursts. Timing intervals between sequential transition stripes are detected. Interval comparison logic compares selected timing intervals and indicates whether the compared intervals represent a “0”, or a “1”. First and second counters respectively increment the number of the compared intervals representing a “0” and representing a “1” in each frame. Bit comparison logic compares, for each frame, the incremented numbers representing a “0” and a “1” to a predetermined criteria and, upon one of the numbers meeting the criteria, identifies the corresponding “0” or “1” as the bit value for the frame. The bits are data comprising longitudinal position words arranged in a linear sequence. Sequence logic calculates the next sequential position word from an immediately preceding word and determines whether the detected word is in the linear sequence as a validity check, and provides the calculated word as the output. Thus, the correct position word is provided at the output even if the detected word is invalid.