公开(公告)号：GB2544586A

公开(公告)日：2017-05-24

申请号：GB201614813

申请日：2016-09-01

Applicant: IBM

Inventor： SIMEON FURRER ,  STEVEN ROSS BENTLEY ,  ROY DARON CIDECIYAN ,  KEISUKE TANAKA

IPC: G11B20/18 ,  G11B5/008

Abstract: A tape drive includes a magnetic head having a plurality of read sensors, each read sensor being configured to read data simultaneously, a controller, and logic integrated with and/or executable by the controller. The logic is configured to read, using the plurality of read sensors, encoded data from a plurality of tracks of a magnetic tape medium simultaneously. The logic is also configured to perform track-dependent erasure decoding on the encoded data based on detection of one or more time-varying signal quality issues associated with at least one of the plurality of tracks read simultaneously from the magnetic tape medium. The time varying signal quality may be determined based on reliability of detected bytes within C1 codewords or number of run-length limited (RLL) error detection flags per C1 codeword. C2 decoding on a plurality of erasure enabled C1 codewords may be performed with C2 error and erasure decoding. Erasure pointers may be inserted in place of each C1 codeword when a probability of byte errors in the C1 codeword exceeds a threshold.

公开(公告)号：GB2576666B

公开(公告)日：2022-03-16

申请号：GB201917258

申请日：2018-05-30

Applicant: IBM

Inventor： GIOVANNI CHERUBINI ,  ROY CIDECIYAN ,  SIMEON FURRER ,  MARCEL KOSSEL ,  HAZAR YÜKSEL

IPC: H03M13/41 ,  H03M13/39 ,  H04L1/00 ,  H04L25/03

Abstract: Calculating path metrics, associated with respective states of an n-state trellis, by accumulating branch metrics in a sequence detector. Each path metric is represented by N bits plus a wrap-around bit for indicating wrap-around of the N-bit value of that path metric.

公开(公告)号：GB2545964B

公开(公告)日：2021-05-05

申请号：GB201618530

申请日：2016-11-03

Applicant: IBM

Inventor： KEISUKE TANAKA ,  STEVEN ROSS BENTLEY ,  SIMEON FURRER ,  ROY DARON CIDECIYAN

IPC: G11B20/18

Abstract: In one embodiment, a tape drive includes a magnetic head having a plurality of read sensors, each read sensor being configured to read data simultaneously. The tape drive also includes a controller and logic integrated with and/or executable by the controller. The logic is configured to receive encoded data read from a plurality of tracks of a magnetic tape medium simultaneously. The logic is also configured to perform priority-based decoding on the encoded data based on erasure coefficients associated with at least one codeword of the encoded data. In another embodiment, a controller-implemented method includes receiving encoded data read from a plurality of tracks of a magnetic tape medium simultaneously and performing priority-based decoding on the encoded data based on erasure coefficients associated with at least one codeword of the encoded data.

公开(公告)号：GB2545964A

公开(公告)日：2017-07-05

申请号：GB201618530

申请日：2016-11-03

Applicant: IBM

Inventor： KEISUKE TANAKA ,  STEVEN ROSS BENTLEY ,  SIMEON FURRER ,  ROY DARON CIDECIYAN

IPC: G11B20/18

Abstract: A tape drive includes a magnetic head having a plurality K of read sensors, each read sensor being configured to read data simultaneously. The tape drive also includes a controller and logic integrated with and/or executable by the controller. The logic is configured to receive encoded data read from a plurality of tracks of a magnetic tape medium simultaneously. The logic is also configured to perform priority-based decoding on the encoded data based on erasure coefficients associated with at least one codeword of the encoded data. Erasure pointers for C2 decoding may be enabled if, and only if, C1 codewords include a large number of byte errors. Each erasure pointer may have an erasure coefficient (wi fig. 6) indicating probability that the C2 decoder should treat the corresponding C1 bytes as erasures.

公开(公告)号：GB2545785A

公开(公告)日：2017-06-28

申请号：GB201618143

申请日：2016-10-27

Applicant: IBM

Inventor： SIMEON FURRER ,  ANGELIKI PANTAZI ,  GIOVANNI CHERUBINI ,  MARK ALFRED LANTZ

IPC: G11B5/584

Abstract: Lateral position of a tape head 108 of a magnetic tape drive is controlled. A first servo signal is determined by reading position marks from a first servo band 114 on a magnetic tape using a first sensor 110 and a second servo signal is determined by reading position marks from a second servo band 114 on the magnetic tape using a second sensor 112. One of the servo signals is delayed relative to the other and an average signal is calculated based on the first servo signal and the delayed second servo signal. Lateral position of the tape head is determined from the average signal and the tape head position is controlled to decrease deviation of lateral position. The delay is based on the frequency of longitudinal oscillation of the magnetic tape 102. Disturbance contained in the delayed second servo signal caused by longitudinal oscillation of the tape will cancel out the disturbance in the first servo signal. The delay can be caused by tilting the tape head and can equal an odd numbered multiple of half the inverse frequency f, e.g. Δt = n/2f ± δ where n= 1, 3, 5, and 0 ≤δ ≤ 1/6f.

公开(公告)号：MXPA03006207A

公开(公告)日：2003-09-22

申请号：MXPA03006207

申请日：2002-01-14

Applicant: IBM

Inventor： SIMEON FURRER

IPC: H04L12/28