A method for fast calculation of a frame error rate (FER) of an error correcting code (ECC) soft decoder using a soft read process includes determining an MI-FER conversion data structure based on a relationship between mutual information (MI) of input channels and output channels of a memory, and FER of the ECC soft decoder, and decoding an encoded data codeword stored in a memory page of the memory and read using a soft read process. The method further includes generating a set of joint probability values using the information from the soft read process and data indicating true bit values for the data codeword, determining an MI value using the set of joint probability values, and determining an FER estimate using the MI-FER conversion data structure.

A method includes generating a plurality of blocks of a block chain wherein the plurality of blocks is associated with components of a storage device. The plurality of blocks is generated by a device other than the storage device when the components are manufactured. The method further includes storing a copy of a ledger associated with the generated blocks on the storage device when the storage device comprises computing power sufficient to generate blocks of a block chain. The method also includes generating additional blocks of the block chain. The additional blocks of the block chain are associated with additional components of the storage device when the additional components are manufactured. The additional blocks are generated independently by the device and by the storage device and wherein respective ledgers are updated.

A computer program product, according to one embodiment, includes a computer readable storage medium having program instructions embodied therewith. The program instructions are readable and/or executable by a processor to cause the processor to: determine, by the processor, a first error location on a magnetic tape where a first error occurred. One or more areas on the magnetic tape to be examined are also determined, by the processor, based on the first error location. Independent of a read and/or write operation, relative motion between a tape head and the magnetic tape is induced by the processor, such that the tape head is positioned adjacent to each of the one or more areas in turn. Moreover, each of the one or more areas having a respective number of measured servo errors which exceeds a threshold value are identified, by the processor, as a damaged area of the magnetic tape.

A computer-implemented method, according to one embodiment, includes: receiving, from a tape drive, a first error location on a magnetic tape where a first error occurred, in addition to determining one or more areas on the magnetic tape to be examined based on the first error location. Independent of a read and/or write operation, the tape drive is instructed to induce relative motion between a tape head and the magnetic tape such that the tape head is positioned adjacent to each of the respective one or more areas in turn. Moreover, each of the one or more areas having a respective number of measured servo errors which exceeds a threshold value is identified as a damaged area of the magnetic tape.

A data storage device is disclosed comprising a head actuated over a disk. A test pattern is read from a first part of the disk to generate a first read signal that is sampled to generate a first sequence of signal samples. The test pattern is read from a second part of the disk to generate a second read signal that is sampled to generate a second sequence of signal samples. A third sequence of signal samples is generated by at least one of amplitude-inverting the second sequence of signal samples, time-inverting the second sequence of signal samples, and amplitude-inverting and time-inverting the second sequence of signal samples. A quality metric is generated based on the first sequence of signal samples and the third sequence of signal samples, and a data density of the disk is configured based on the quality metric.

A data storage device is disclosed comprising a head actuated over a disk. A test pattern is read from a first part of the disk to generate a first read signal that is sampled to generate a first sequence of signal samples. The test pattern is read from a second part of the disk to generate a second read signal that is sampled to generate a second sequence of signal samples. A third sequence of signal samples is generated by at least one of amplitude-inverting the second sequence of signal samples, time-inverting the second sequence of signal samples, and amplitude-inverting and time-inverting the second sequence of signal samples. A quality metric is generated based on the first sequence of signal samples and the third sequence of signal samples, and a data density of the disk is configured based on the quality metric.

A computer-implemented method for determining a damaged area of a magnetic tape loaded in a tape drive, according to one embodiment, includes: determining a first error location on a magnetic tape where a first error occurred in response to experiencing the first error. Moreover, the method includes determining one or more areas on the magnetic tape to be examined. The one or more areas are determined using a predetermined algorithm which incorporates the first error location. Independent of a read and/or write operation, relative motion is induced between a tape head and the magnetic tape such that the tape head is positioned adjacent to each of the respective one or more areas in turn. Furthermore, each of the one or more areas having a respective number of measured servo errors which exceeds a threshold value is identified as a damaged area of the magnetic tape.

A set of patterns written to a magnetic recording medium are found that result in a relatively high and/or low error when read back. Upon writing subsequent to the determining of the set of patterns, one pattern of the set of the patterns is identified within a data segment ready to be written to the magnetic recording medium. The data segment is written with a changed bit spacing in response to identifying that the one pattern of the set of the patterns is within the data segment.

A computer-implemented method for determining a damaged area of a magnetic tape loaded in a tape drive, according to one embodiment, includes: determining a first error location on a magnetic tape where a first error occurred in response to experiencing the first error. Moreover, the method includes determining one or more areas on the magnetic tape to be examined. The one or more areas are determined using a predetermined algorithm which incorporates the first error location. Independent of a read and/or write operation, relative motion is induced between a tape head and the magnetic tape such that the tape head is positioned adjacent to each of the respective one or more areas in turn. Furthermore, each of the one or more areas having a respective number of measured servo errors which exceeds a threshold value is identified as a damaged area of the magnetic tape.

Aged disk storage systems are simulated for testing and evaluation purposes by writing test data to a clean disk using a data allocation policy that writes the test data to mimic the data layout and data distribution of the aged disk to be simulated. The test data may be written using a sequential data block allocation on the disk where blocks are written sequentially to the fresh, or by using either a fixed or a random jump allocation policy where test data is written in data blocks spaced from each other by either a fixed increment or spaced from each other randomly.