The disclosure is related to systems and methods of On the Fly Formatting. Various parameters that influence areal density of hard disc regions can be changed on the fly based on storage capacity and reliability needs. Further adjustments can be made to the formatting of the region to fine tune achievable storage capacity and reliability values. In some cases, the formatting can include error correction code strength, gap widths between user data sectors and servo data sectors, other characteristics or parameters, or any combinations thereof.

A RAID controller stores data in a hybrid asymmetric mix of a RAID 1 mirror and a parity-based RAID array, wherein a first side of the RAID 1 mirror includes a single data storage device storing an operating system image and a second side of the RAID 1 mirror includes a plurality of data storage devices forming a parity-based RAID array. The RAID controller normally calculates parity using data from both the single data storage device and the plurality of data storage devices. However, in response to a user command, the RAID controller recalculates parity stripes on each of the plurality of data storage devices using a predetermined data pattern for a logical data storage device logically replacing the single data storage device storing the operating system. Accordingly, the same stripe count is maintained and the parity-based RAID array maintains redundancy despite physical separation of the single data storage device.

A method is disclosed for positioning a transducer over a magnetic recording medium having a plurality of tracks. The method includes positioning the transducer over a first track using a voice coil motor (VCM) and a microactuator. The method further includes applying a feedforward voltage profile to the microactuator to position the transducer over a second track.

A data memory system is described, where there may be an asymmetry in the time needed to write or erase data and the time needed to read data. The data may be stored using a RAID data storage arrangement and the reading, writing and erasing operations on the modules arranged such that the erasing and writing operations may be performed without significant latency for performing a read operation. Where a failure of a memory module in the memory system occurs, methods for recovering the data of the failed module are disclosed which may selected in accordance with policies that may relate to the minimizing the possibility of irretrievable data loss, or degradation of latency performance.

Systems and methods are provided for reusing existing test structures and techniques used to test memory data to also test error correction code logic surrounding the memories. A method includes testing a memory of a computing system with an error code correction (ECC) logic block bypassed and a first data pattern applied. The method further includes testing the memory with the ECC logic block enabled and a second data pattern applied. The method also includes testing the memory with the ECC logic block enabled and the first data pattern applied.

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.

A method for writing data onto a medium on which data are stored in tracks includes encoding the data into at least one codeword, and writing a respective portion of each of the at least one codeword onto respective different tracks on the medium. The writing may include writing a respective portion of each of the at least one codeword onto respective different adjacent tracks on the medium. Another method for reading data includes positioning a plurality of read heads to read codewords that have been written across multiple tracks of a medium. Each read head in the plurality of read heads reads a different portion of the first group of the multiple tracks, and where each different portion of the multiple tracks overlaps at least one other different portion of the multiple tracks. Signals are detected from the plurality of read heads, and the detected signals are decoded.

A first tone is written at a first frequency to outer tracks that surround an inner track of a magnetic recording medium. A second tone is written at a second frequency different from the first frequency to the inner track. The first and second frequencies are both lower than a frequency of an AC erase signal. A crosstrack profile of the inner track is determined based on reading amplitude of the second frequency via the read/write head.

A disk drive is operable to determine degradation associated with writing to a disk surface by a head which has written existing data at a first areal density. A second areal density less than the first areal density is determined that remediates the degradation. The disk drive performs subsequent writes to the disk surface at the second areal density, and continues to read the existing data at the first areal density.

A disk drive is operable to determine degradation associated with writing to a disk surface by a head which has written existing data at a first areal density. A second areal density less than the first areal density is determined that remediates the degradation. The disk drive performs subsequent writes to the disk surface at the second areal density, and continues to read the existing data at the first areal density.