公开(公告)号：DE68920523T2

公开(公告)日：1995-07-20

申请号：DE68920523

申请日：1989-08-24

Applicant: IBM

Inventor： EGGENBERGER JOHN SCOTT ,  HODGES PAUL ,  PATEL ARVIND MOTIBHAI

IPC: G06F11/10 ,  G11B20/18 ,  H03M13/00

Abstract: A method is disclosed for correcting multibyte errors in a magnetic medium on which data is recorded in variable length blocks that comprise sub-blocks of data bytes and corresponding check bytes and include error correction code (ECC) for which ECC syndromes are generated during reading. A sequence of N sequential parity check bytes is written at the end of each block. After ECC syndromes are generated during reading, parity syndromes are generated by comparing parity check bytes computed from data bytes and check bytes as read with the parity check bytes as written. When a long-burst error occurs, a pointer points to the first of the N consecutive bytes in a block that could have been influenced by the error burst. After correcting correctable errors in all sub-blocks not affected by the N bytes identified by the pointer, and adjusting the parity syndromes for errors thus corrected, the adjusted parity syndromes are used to correct the errors in the N bytes indicated by the pointer. Unused ECC syndromes are then adjusted for errors corrected by the adjusted parity syndromes and used to correct all correctable errors then remaining.

公开(公告)号：CA1309495C

公开(公告)日：1992-10-27

申请号：CA603836

申请日：1989-06-23

Applicant: IBM

Inventor： EGGENBERGER JOHN S ,  HODGES PAUL ,  PATEL ARVIND M

IPC: G06F11/10 ,  G11B20/18 ,  H03M13/00

Abstract: A method is disclosed for correcting multibyte errors in a magnetic medium on which data is recorded in variable length blocks that comprise subblocks of data bytes and corresponding check bytes and include error correction code (ECC) for which ECC syndromes are generated during reading. A sequence of N sequential parity check bytes is written at the end of each block. After ECC syndromes are generated during reading, parity syndromes are generated by comparing parity check bytes computed from data bytes and check bytes as read with the parity check bytes as written. When a long-burst error occurs, a pointer points to the first of the N consecutive bytes in a block that could have been influenced by the error burst. After correcting correctable errors in all subblocks not affected by the N bytes identified by the pointer, and adjusting the parity syndromes for errors thus corrected, the adjusted parity syndromes are used to correct the errors in the N bytes indicated by the pointer. Unused ECC syndromes are then adjusted for errors corrected by the adjusted parity syndromes and used to correct all correctable errors then remaining. SA9-88-041

公开(公告)号：AU616788B2

公开(公告)日：1991-11-07

申请号：AU3928289

申请日：1989-08-03

Applicant: IBM

Inventor： PATEL ARVIND MOTIBHAI ,  HODGES PAUL ,  EGGENBERGER JOHN SCOTT

IPC: G06F11/10 ,  G11B20/18 ,  H03M13/00

Abstract: A method is disclosed for correcting multibyte errors in a magnetic medium on which data is recorded in variable length blocks that comprise sub-blocks of data bytes and corresponding check bytes and include error correction code (ECC) for which ECC syndromes are generated during reading. A sequence of N sequential parity check bytes is written at the end of each block. After ECC syndromes are generated during reading, parity syndromes are generated by comparing parity check bytes computed from data bytes and check bytes as read with the parity check bytes as written. When a long-burst error occurs, a pointer points to the first of the N consecutive bytes in a block that could have been influenced by the error burst. After correcting correctable errors in all sub-blocks not affected by the N bytes identified by the pointer, and adjusting the parity syndromes for errors thus corrected, the adjusted parity syndromes are used to correct the errors in the N bytes indicated by the pointer. Unused ECC syndromes are then adjusted for errors corrected by the adjusted parity syndromes and used to correct all correctable errors then remaining.

公开(公告)号：CA1081849A

公开(公告)日：1980-07-15

申请号：CA332286

申请日：1979-07-20

Applicant: IBM

Inventor： EGGENBERGER JOHN S ,  HODGES PAUL

IPC: H03K13/24

Abstract: SEQUENTIAL ENCODING AND DECODING OF VARIABLE WORD LENGTH, FIXED RATE DATA CODES A method of encoding or decoding data in a code of variable length words and fixed rate comprises the steps of (1) initially entering a constant number (k) of input bits into a shift register; (2) entering a constant number (m) of input bits into the shift register; (3) encoding or decoding a constant number (n) of bits in response to the contents of the shift register; and (4) repeating steps (2) and (3) until the input bits are exhausted. To complete the encoding or decoding, steps (2) and (3) are further repeated with dummy input bits until (k) dummy bits have been entered into the shift register. The encoding or decoding of (n) bits may be affected by auxiliary state variables which account for the position in the shift register of the boundary between words.

公开(公告)号：BR8904735A

公开(公告)日：1990-05-01

申请号：BR8904735

申请日：1989-09-20

Applicant: IBM

Inventor： EGGENBERGER JOHN SCOTT ,  HODGES PAUL ,  PATEL ARVIND MOTIBHAI

IPC: G06F11/10 ,  G11B20/18 ,  H03M13/00

Abstract: A method is disclosed for correcting multibyte errors in a magnetic medium on which data is recorded in variable length blocks that comprise sub-blocks of data bytes and corresponding check bytes and include error correction code (ECC) for which ECC syndromes are generated during reading. A sequence of N sequential parity check bytes is written at the end of each block. After ECC syndromes are generated during reading, parity syndromes are generated by comparing parity check bytes computed from data bytes and check bytes as read with the parity check bytes as written. When a long-burst error occurs, a pointer points to the first of the N consecutive bytes in a block that could have been influenced by the error burst. After correcting correctable errors in all sub-blocks not affected by the N bytes identified by the pointer, and adjusting the parity syndromes for errors thus corrected, the adjusted parity syndromes are used to correct the errors in the N bytes indicated by the pointer. Unused ECC syndromes are then adjusted for errors corrected by the adjusted parity syndromes and used to correct all correctable errors then remaining.

公开(公告)号：DE2965653D1

公开(公告)日：1983-07-21

申请号：DE2965653

申请日：1979-06-01

Applicant: IBM

Inventor： HODGES PAUL ,  SCHAEUBLE WERNER JOSEF ,  SHAFFER PAUL LEE

IPC: G06F11/10 ,  G06F12/16 ,  H03M13/00 ,  H03M13/13 ,  H03M13/27 ,  G11B5/00 ,  G11C7/00

公开(公告)号：GB1078383A

公开(公告)日：1967-08-09

申请号：GB1118966

申请日：1966-03-15

Applicant: IBM

Inventor： SCHELER TITUS ,  GENG ROLAND ,  KUENDEL GERHARD ,  HODGES PAUL ,  UTLEY BRIAN GEORGE

IPC: G11C21/00

Abstract: 1,078,383. Data storage. INTERNATIONAL BUSINESS MACHINES CORPORATION. March 15, 1966 [March 26, 1965], No. 11189/66. Heading G4C. A recirculating store has (n+1) storage positions to enable a set of n characters stored therein to be read in the reverse order, there being means for reading out every n character times from a particular storage position. Referring to Fig. 1 (not shown), a delay line (LSp) has outputs (N, L) n and (n+ 1) character positions from the input (E), either being connectible to feed the input (E) for recirculation. Reversal is achieved by using the (n+1) output (L) for recirculation and gating (U) a character from the n output every n character times, using a counter (ZZ). Leading zeros may be suppressed by changing the output used for recirculation under control of comparison of the two outputs (N, L). A magnetic drum or disc may replace the delay line.