A magnetic disk device includes a plurality of tracks and a controller. The controller receives write data to be written to a first sector of a track, generates a first data string based on the write data and a logical identifier for the first sector, attempts to cause the first data string to be written to the first sector, determines whether a write error has occurred while the first data string is written to the first sector, generates a second data string based at least in part on the first data string, and in response to determining that no write error has occurred while the first data string is written to the first sector, writes a parity data string that is based at least in part on the second data string to a second sector of the track that stores parity data for the track.

An optical storage system includes an optical head configured to split a light beam into a higher power main beam and at least one lower power side beam. The optical storage system also includes a controller configured to alter an optical medium, via modulation of the higher power main beam according to a writing strategy waveform that defines at least n pulses for every n bits of data to be written to the medium, while processing a first signal resulting from the at least one lower power side beam being reflected from the medium and a second signal indicative of the writing strategy waveform to remove noise from the first signal caused by the higher power main beam to generate output indicative of the data directly after writing.

Techniques for verifying a magnetic tape are disclosed. The techniques include obtaining a position signal generated by reading a magnetic tape using a stationary tape head. Next, a simulated current for adjusting a position of the tape head to follow a track on the magnetic tape is updated using the position signal. The simulated current is then compared to one or more saturation limits to generate a verification result for a servo pattern on the magnetic tape, wherein the verification result classifies the magnetic tape as usable or unusable. Finally, the verification result is outputted for use in managing subsequent use of the magnetic tape.

Techniques for verifying a magnetic tape are disclosed. The techniques include obtaining a position signal generated by reading a magnetic tape using a stationary tape head. Next, a simulated current for adjusting a position of the tape head to follow a track on the magnetic tape is updated using the position signal. The simulated current is then compared to one or more saturation limits to generate a verification result for a servo pattern on the magnetic tape, wherein the verification result classifies the magnetic tape as usable or unusable. Finally, the verification result is outputted for use in managing subsequent use of the magnetic tape.

An optical storage system includes an optical head configured to split a light beam into a higher power main beam and at least one lower power side beam. The optical storage system also includes a controller configured to alter an optical medium, via modulation of the higher power main beam according to a writing strategy waveform that defines at least n pulses for every n bits of data to be written to the medium, while processing a first signal resulting from the at least one lower power side beam being reflected from the medium and a second signal indicative of the writing strategy waveform to remove noise from the first signal caused by the higher power main beam to generate output indicative of the data directly after writing.

A system includes a read/write module and a caching module. The read/write module is configured to access a first portion of a recording surface of a rotating storage device. Data is stored on the first portion of the recording surface of the rotating storage device at a first density. The caching module is configured to cache data on a second portion of the recording surface of the rotating storage device at a second density. The second portion of the recording surface of the rotating storage device is separate from the first portion of the recording surface of the rotating storage device. The second density is less than the first density.

According to one embodiment, a magnetic disk device includes a read control system that extracts scrambled data from media data read from a medium and inspection data associated with a seed value at the time of write, generates inspection data for data extracted from the media data, obtains from the inspection data and inspection data extracted from the media data, a seed value associated with both, compares this seed value with the seed value expected by the controller, and evaluates, when the comparison result is a mismatch, the data as an error, whereas when match, descrambles the data extracted from the media data using the seed value.

According to the embodiment, an HDC receives a plurality of data segments from a host, and executes generation and addition of a first code and output of a data segment to which the first code is added to each data segment. An HDC calculates exclusive OR with respect to the first codes, and outputs obtained first information. The RWC performs data conversion and calculation of exclusive OR on the plurality of data segments to which the first code is added, and outputs the plurality of data segments after the data conversion and a track parity obtained by the calculation of the exclusive OR. The RWC acquires the first code from the plurality of data segments. The RWC calculates exclusive OR with respect to a group of the second codes which are the acquired first codes to acquire second information. The RWC compares the first information with the second information.

A storage system includes a final level cache (FLC) module coupled to a storage medium. The storage medium includes a bulk storage portion having a higher data density than a cache storage portion. The cache storage portion is configured as an FLC cache accessed by the FLC module prior to accessing the bulk storage portion. The FLC module receives a request for data from a processor coupled to one or more levels of cache that are separate from the FLC cache. The processor generates the request if the data is not cached in the one or more levels of cache. The FLC module determines whether the data requested is cached in the FLC cache, retrieves the data from the FLC cache if the data is cached in the FLC cache, and retrieves the data from the bulk storage portion if the data is not cached in the FLC cache.

A recording medium is written to using an energy source that heats the medium during the writing. A read error in a sector is determined when reading via a read transducer. While traversing a part of the recording medium that includes data, a write coil is activated before attempting to re-read the sector. The energy source does not heat the recording medium sufficiently to change a state of the data during the activation of the write coil. The activation of the write coil removes a magnetic instability of the read transducer.