Alps Electric Co., Ltd.

Other

Sony Corporation

Takayuki Sugawara

Takahiro Kawauchi

Yoshiyasu Kubota

Hiroshi Wakuda

Masayoshi Nakagawa

Isao Asano

Kyoichi Shirane

Katsuji Suzuki

Masahiro Nasu

Hiroki Hirashima

Tetsuya Mitsuishi

Shigeru Yamaguchi

Makoto Moriya

Masahiro Tenpaku

Kazuya Seta

A disk device for performing error-correction processing is loaded with a high-reliability disk to which a C1 code as a low-level error-correction code (ECC) is added for every sector, and a C2 code as a high-level ECC is added for every plurality of sectors. A host computer includes a device driver corresponding to the high-reliability disk. When data written to the high-reliability disk is read, low-level error-correction is performed based on the C1 code in units of one block corresponding to one sector, and the corrected data is notified to the host computer. Simultaneously, the C2 code along with the data for a plurality of blocks is loaded, and high-level error correction based on the C2 code is thereby performed.

Disk device with improved error-correction capability

A magnetic disk apparatus is capable of reading normal data following a read error of a reference signal that has occurred due to a scratch or the like on a disk surface. In the magnetic disk apparatus, if a reference signal (STM) fails to be read at point P, then an elapsed time (Tw) is measured, and a time T indicating the difference between a time T at which a read gate is supposed to be opened and the time Tw is determined. The read gate is opened after the time T has passed, thereby making it possible to properly read data and subject the read data to a decoding process.

Magnetic disk apparatus with lower probability of occurrence of read errors due to scratch or the like on magnetic disk surface

A parameter value is set in a register. A signal is read based on the parameter value. When an error is recognized from an MSE value calculated by a Viterbi decoder, the parameter value is changed and the signal is reread. A new parameter value is calculated based on a change value by which the parameter value is changed and the MSE value. The new parameter value is stored in the register. Thus, an error rate can be converged as a result of the retry.

Disk drive capable of rereading same signal from disk in case of error in read signal

The radius range of a formatted zone in each medium differs. A floppy disk and an another-standard high-capacity medium are distinguished by reading a reproduction output at an inside position in the formatted zone by heads. Since the another-standard high-capacity medium has a formatted zone starting from a more inside position than that for the floppy disk, both media can be distinguished by reading a reproduction output by the heads to check a difference in the inside position of the formatted zone.

Medium distinguishing method of a disk used in a disk drive

A method for detecting a defective sector on a recording medium in a method for recording and/or reproducing data for the signal recording medium. A read gate is opened to reproduce data from a data field at a pre-set timing derived from a timing reference signal obtained on detecting a servo timing mark recorded in a servo field. If the timing reference signal has not been detected with success, the read gate is opened at a timing obtained based on a detection signal of a previously detected servo timing mark to reproduce the data from the data field. In detecting the defective sector, the state of deviation between the timing of opening the read gate and the data field is detected to detect the defective sector of the disc.

Data recording and/or reproducing apparatus and method for detecting sector defects

A recording/reproduction device includes a reading mechanism to read information data stored in a floppy disk and constituted by a plurality of byte data and first inspection data and second inspection data to detect an error of the information data. First and second calculation mechanism calculate a first and second syndrome value from the byte data and the first and second inspection data, respectively. First and second error correction mechanisms perform error correction for the information data on the basis of the first and second syndrome value, respectively. A computer includes the second error correction mechanism. Because the second error correction is not performed in the floppy disk drive, the capacity of a storage unit is decreased, a memory in the floppy disk drive can be considerably smaller than that of a conventional floppy disk drive, and the cost of the floppy disk drive can be reduced. In addition, since secondary correction is not performed in the floppy disk drive, an increase in data transfer rate from the floppy disk drive to the computer can be realized.

Recording/reproduction system

The present invention relates to a magnetic recording medium and a magnetic recording/reproducing apparatus for the same. In the magnetic recording medium there are provided a read/write region which permits modification of written data and a read-only region dedicated to the reading of data, which is used for reading only once writing is done. In recording servo information to a data format region of the magnetic recording medium, the time width of servo information in the read-only region is set shorter than that in the read/write region.

Growing community of inventors

Fukushima-ken, Japan

Takayuki Sugawara