Patent application number | Description | Published |
20090063938 | Decoding Error Correction Codes Using A Modular Single Recursion Implementation - Systems and methods are provided for performing error correction decoding. The coefficients of the error locator polynomial are iteratively determined for each codeword using a modular implementation of a single recursion key-equation solver algorithm. According to this implementation, modules are used to calculate the current and previous coefficients of the error locator polynomial. One module is used for each correctable error. The modular single recursion implementation is programmable, because the number of modules can be easily changed to correct any number of correctable errors. Galois field tower arithmetic can be used to calculate the inverse of an error term. Galois field tower arithmetic greatly reduces the size of the inversion unit. The latency time can be reduced by placing the computations of the inverse error term outside the critical path of the error locator polynomial algorithm. | 03-05-2009 |
20090164544 | Dynamic range enhancement for arithmetic calculations in real-time control systems using fixed point hardware - A digital processing system and method are described that encodes a fixed point number into a mantissa by removing redundant sign bits by shifting the significant bits to the left. The number of bits shifted is recorded as the exponent. In one embodiment the mantissa and exponent are combined into a single word of memory for the system which allows efficient loading of the value from memory. The mantissa and exponent can be used in multiplication calculations with a second fixed point number to achieve increased dynamic range. When the mantissa is multiplied by the fixed point number, the initial result is larger by a factor of 2 | 06-25-2009 |
20090168230 | Mixed format disk drive - A magnetic disk for a hard disk drive comprising a plurality of physical sector sizes is disclosed. The magnetic disk includes a first sector size area physically formatted according to a first physical sector size and a second sector size area physically formatted according to a second physical sector size different from the first sector size by a multiple of the first sector size wherein the second sector size can be presented externally as multiple sectors of said first sector size. | 07-02-2009 |
20130148225 | SHINGLED MAGNETIC RECORDING (SMR) DISK DRIVE WITH VERIFICATION OF WRITTEN DATA - A “write-squeeze-verify” method is used for verification of the data that has been written in the annular bands of a shingled magnetic recording disk drive. The writing of data along a track overwrites a portion of the previously written track and thus “squeezes” the data of the previously written track to thereby form a “shingled data track” (SDT). The data in each SDT is read back and verified by performing an error correction check using error correction bits associated with the data written in the SDT, or by comparing the readback data with the data stored in memory. If the data read back is not verified, a write error counter is incremented and a write error frequency is calculated. One or more attempts to write the data can be performed. If the data in the SDT cannot be verified after the attempted rewrite(s), then a “re-try fail” is reported. | 06-13-2013 |
20140101515 | SCALABLE REPAIR BLOCK ERROR CORRECTION FOR SEQUENTIAL MULTIPLE DATA BLOCKS IN A MAGNETIC DATA STORAGE DEVICE - A technique for recovering of “squeezed” sectors in a set of sequential sectors such as are used in Shingled Magnetic Recording (SMR) is described. Embodiments of the invention use a programmable erased sector recovery scheme, which is a concatenation of a “Cauchy-type” track erasure correction code, together with a media-error correction code that generates N-weighted parity-sectors per track and is capable of replacing up to N-erased sectors per track in any possible combination. | 04-10-2014 |
20140177086 | Disk Drive with Servo System with Timing Adjustments to Master Timer for SAM Detection Errors - A disk drive is described with a single servo master timer that is used to control timing critical signals such as servo gate, SAM windows, channel power save, PREAMP power save and so on. The master timer is adjusted to compensate for SAM detection errors (early, late or missed) and provides improved servo timing quality. In an embodiment the adjustable master timer can be selectably clocked by either the DLC/DSW clock or the system clock. | 06-26-2014 |
20150128008 | TRACK-BAND SQUEEZED-SECTOR ERROR CORRECTION IN MAGNETIC DATA STORAGE DEVICES - Data storage devices using a two-level ECC scheme are described. Embodiments of the invention allow the recovery of sectors in a squeezed group of tracks in a that includes both a single track level ECC scheme and a track band ECC scheme that functions across the set of tracks in the band. The track band ECC scheme uses additional parity information calculated using input data from multiple tracks to allow correction across tracks. | 05-07-2015 |