公开(公告)号：JPH1196684A

公开(公告)日：1999-04-09

申请号：JP24270197

申请日：1997-09-08

Applicant: IBM

Inventor： TSUCHIMOTO KAZUNARI ,  TAKAHASHI YOSHIYO ,  YOKOE YUJI ,  SUGANUMA SHIGEMI

IPC: G11B20/10 ,  G06F12/16 ,  G11B20/12 ,  G11B20/18 ,  G11C29/04

Abstract: PROBLEM TO BE SOLVED: To process defects on a recording medium with a small memory capacity by recording leading addresses of blocks in which defects are present and block lengths of defects, and performing recordings with respect to blocks other than recorded defective blocks. SOLUTION: Defective sectors detected by checking physical sectors at the time of manufacturing or at the time of performing a low level formating are registered in a defect map and LBAs(Logical block addresses) are assigned to remaining normal sectors. The defect map is recorded in a determined area being on a magnetic disk 1. The MPU 12 of a control part 5 reads out the defect map from the disk 1 to a RAM 14 at an operating time to instruct the recording and reproducing of data with respect to sectors to which the LBAs are assigned. Here, addresses of leading sectors of defects and lengths of defective sector group are recorded in two bytes and one byte respectively by using a variable length defect map and the map is constituted of recording areas equivalent to, for example, 2000 pairs.

公开(公告)号：JPH08106619A

公开(公告)日：1996-04-23

申请号：JP23371894

申请日：1994-09-28

Applicant: IBM

Inventor： OGASAWARA KENJI ,  SUGANUMA SHIGEMI ,  SATO KENICHIRO

IPC: G11B5/39 ,  G11B5/56 ,  G11B5/596 ,  G11B21/10

Abstract: PURPOSE: To control the position of an MR head so as to place at a predetermined position by previously storing the corresponding relation between distance information corresponding to the deviation of the head from a reference position and the information reproduced from an information recording disk in response to the deviation. CONSTITUTION: An HDC 30 has a controller body 40 of a microcomputer. The body 40 has a memory 42 for storing a table for positioning a magnetic head to decide a microjog amount in the case of recording and reproducing processes of a disk. The body 40 is connected to a driver 28 having a D-A converter 28a, amplifier 28b, and voice coil motor VCM 28c. Accordingly, the digital signal output from the body 40 is converted into an analog signal by the D-A 28a, amplified by predetermined magnification by the amplifier 28b, and then supplied to the VCM 28c. The VCM 28c rotates at a predetermined angle responsive to the supplied signal, and turns access arms 22A to 22D at a predetermined angle.