公开(公告)号：CA961416A

公开(公告)日：1975-01-21

申请号：CA159468

申请日：1972-12-20

Applicant: IBM

Inventor： HANSON CHARLES C ,  HOUDEK MERLE E ,  HO JOSEPH P L

IPC: G06F3/02 ,  H03M11/22

公开(公告)号：CA831643A

公开(公告)日：1970-01-06

申请号：CA831643D

Applicant: IBM

Inventor： HANSON CHARLES C

公开(公告)号：CA1066407A

公开(公告)日：1979-11-13

申请号：CA235797

申请日：1975-09-18

Applicant: IBM

Inventor： HANSON CHARLES C ,  KING FRANCIS K

IPC: G11B21/08 ,  G11B5/55

Abstract: INITIALIZATION CIRCUITRY FOR MAGNETIC RECORDING SYSTEM A magnetic disk, particularly of the thin flexible type, has a magnetic head traversing the disk in order to come into registry with various concentric tracks on the disk. An electric motor of the stepping type is mechanically connected with the head for so moving the head, and a "present track number" counter is so electrically connected with the stepping motor as to keep track of the particular magnetic track on which the head is located. On a certain contingency, such as a cessation of power to the system, the circuitry includes components so connected as to cause the stepping motor to move the magnetic head to an outer limit on the disk, outwardly of a prerecorded reference track on the disk. When this point is reached, a switch is actuated by the movement of the head, and connected circuitry causes the head to move back onto the reference track. When a maximum amplitude is detected by the head due to passage over the reference track, the circuitry includes components that reset the content of the "present track number" counter to zero; and all of the inner tracks within the reference track are counted from the zero count in the "present track number" counter, so as to thereby compensate for any changes in dimension of the magnetic disk.

公开(公告)号：CA1028053A

公开(公告)日：1978-03-14

申请号：CA192005

申请日：1974-02-07

Applicant: IBM

Inventor： HANSON CHARLES C

IPC: G11B5/02 ,  G11B5/09 ,  G11B5/55 ,  G11B15/12 ,  G11B5/00

Abstract: A magnetic read/write head having a single gap is mounted to a carriage positionable to locate the head at selected tracks on a magnetic disk by means of a lead screw and stepping motor. The pitch of the lead screw requires a multiple number of steps to move the read/write head one track position. Control circuitry is provided whereby the read/write head is either in the read or the write mode. A write operation is performed by first switching into the read mode and moving the head to the desired track. The stepping motor is then operated to offset the head to the right of the desired track. The sector identification is read with the head in the offset position and immediately after reading the identification, the operation is switched into the write mode to perform a D.C. erase of the sector. Upon reaching the end of the sector, the operation switches to the read mode and during the remainder of the revolution, the stepping motor offsets the head to the left of the desired track. The erased sector is then relocated by reading the identification for that sector and the operation again switches into the write mode and the desired data is written into the sector over the previously recorded data, if any, with a write current, i.e., using non-return to zero recording, which upon recording the new data destroys the old data. The head is then returned to the nominal position, i.e., not offset, and the operation switches into the read mode so as to read the written data and verify that the data has been properly written.

公开(公告)号：FR2374724A1

公开(公告)日：1978-07-13

申请号：FR7733082

申请日：1977-10-24

Applicant: IBM

Inventor： DIX GARY LEE ,  HANSON CHARLES C ,  JAHNKE ROBIN C ,  KING FRANCIS K

IPC: G11B21/02 ,  G11B5/55 ,  G11B17/02 ,  G11B21/08

公开(公告)号：FR2292303A1

公开(公告)日：1976-06-18

申请号：FR7530735

申请日：1975-10-01

Applicant: IBM

Inventor： HANSON CHARLES C ,  KING FRANCIS KONG

IPC: G11B21/08 ,  G11B5/55 ,  G11B21/00 ,  G06K7/015

Abstract: A magnetic disk, particularly of the thin flexible type, has a magnetic head traversing the disk in order to come into registry with various concentric tracks on the disk. An electric motor of the stepping type is mechanically connected with the head for so moving the head, and a "present track number" counter is so electrically connected with the stepping motor as to keep track of the particular magnetic track on which the head is located. On a certain contingency, such as a cessation of power to the system, the circuitry includes components so connected as to cause the stepping motor to move the magnetic head to an outer limit on the disk, outwardly of a prerecorded reference track on the disk. When this point is reached, a switch is actuated by the movement of the head, and connected circuitry causes the head to move back onto the reference track. When a maximum amplitude is detected by the head due to passage over the reference track, the circuitry includes components that reset the content of the "present track number" counter to zero; and all of the inner tracks within the reference track are counted from the zero count in the "present track number" counter, so as to thereby compensate for any changes in dimension of the magnetic disk.