International Business Machines Corporation

Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Electric System Lsi Design Corporation

Tsutomu Numata

Yuji Kigami

Kenji Ogasawara

Tatsuya Sakai

Takashi Nakamura

Yasuhiro Nakamura

Masayuki Murakami

Teruaki Kanzaki

Hiroshi Uchiike

Yuzo Nakagawa

Nobuya Matsubara

Takao Matsui

Sakae Itoh

Yuji Yokoe

Koji Kurachi

Tadayuki Akatsuki

Akio Nakamura

Mayumi Okada

Kenji Shimizu

A microcomputer contains an electrically erasable flash memory for storing a program under development and a debugging circuit 7 having a dedicated input/output terminal for connection to an external ICE 14, and the debugging circuit 7 has a function of communication with a CPU 1, a function of communication with the ICE 14, a function of tracing the operating condition of the CPU 1, a break function of generating a debug interrupt, a function of writing a program code from the ICE 14 into the flash memory 6 and a function of sending the contents of the flash memory 6 to the ICE 14.

Microcomputer

A disk and a disk drive having a servo start mark for identifying a servo-information start position recorded on the disk is provided. The servo start mark has a plurality of bit patterns unused for other areas in servo information. A method for identifying the position of a signal transducer on a disk is also provided in which it is judged that the signal transducer is present at a predetermined position even if an error is present and the error is a one-bit error. This is accomplished by assuming that the position is correct when the following conditions are confirmed: (a) a parity error occurs in a read servo-information bit pattern and (b) read servo-information bit pattern does not coincide with servo information of an adjacent track.

Method and apparatus for indicating start of servo information on a

An improvement in an interleave type error correction method in which more errors can be corrected with less correction codes is provided. Array patterns of code words constituting the information code is form by interleaving. The array patterns comprise a plurality of sequences of a plurality of code words. Correction codes are added to the sequences so that a total number of the correction codes added to a selected sequence is greater than a total number of the correction codes added to the other sequences. An error correction is executed in the selected sequence by identifying a position of an error as a consecutive error code position, when the selected sequence is determined to contain said error having a characteristic feature that the error extends over other sequences. A code word of a position corresponding to said consecutive error code position of the selected sequence among code words in the other sequences is recognized as an erasure. Error correction in the other sequences are executed by a method of correcting a disappearance error based on information on the recognized erasure. In addition, an encoder, decoder, and data communication system which implements the error correction method are provided.

Interleave type error correction method and apparatus

A programmable external storage control apparatus, including a buffer for temporarily storing data to be transferred between a host and an external storage, which stores a program for controlling data transfer between the host and the external storage and controls the data transfer between the host and the external storage by reading the data transfer control program from the buffer and executing it. The apparatus further includes a microprocessor that responds to a command from the host by starting the control of the data transfer by reading the data transfer control program. The microprocessor includes a memory for storing the data transfer control program in addition to other programs to be executed by the microprocessor. The microprocessor loads the data transfer control program from the memory into the buffer at the time of initialization. This allows the microprocessor to do other jobs such as servo control while the data transfer control program is executed.

Programmable external storage control apparatus

A disk drive having embedded servo information accesses data without using sector identifier recorded in each sector. When a signal sector pulse signal (SP) at the end of a servo area is detected in a dead state during start up, a first data state for the start of a sector transits to a second data state for the litter region of the sector being divided in accordance with the capacity stored in a current sector's pointer register. At the beginning of the sector, the contents of a next sector's pointer register is stored in current sector's pointer register and the contents of a next sector's operation register is stored in a current sector's operation register. Upon completion of sector processing, the first data state is maintained when the next sector is contiguous. When a terminate instruction is stored in current sector's operation register, the process moves to dead state. When the servo area arrives, the process moves to idle state. Responsive to this state, the magnetic head is activated to enable read and write operation for sectors having no sector identifier on the disk.

Information recording disk and drive system using no sector ID to

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Sagamihara, Japan

Tsutomu Numata