Dynamic magnetic information storage or retrieval – Record copying – Contact transfer
Reexamination Certificate
2000-12-07
2002-10-15
Faber, Alan T. (Department: 2651)
Dynamic magnetic information storage or retrieval
Record copying
Contact transfer
C360S077080, C360S078140, C360S135000, C360S048000
Reexamination Certificate
active
06466385
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a magnetic disk apparatus that performs recording and playback by means of a head on a magnetic disk capable of recording and playing back information, and more particularly relates to a format of data tracks on the magnetic disk. This invention further relates to a magnetic information disk provided with data track format information, and a magnetic disk apparatus comprising a magnetic disk to which the format information is transferred and recorded by using the master information desk.
BACKGROUND ART
As personal computers have advanced and come into widespread use in recent years, magnetic disk apparatus such as hard disk drives have come to be widely used as external storage devices because of their large capacity and high speed. Along with the increasing size of computer software and the quantities of data handled, ever larger capacities are also demanded of these magnetic disk apparatuses in their role as external storage devices. Moreover, disk drives offering high speed and large capacity are used not only for computers, but also in digital AV products, etc., that record and play back video and voice data using digital technology, and there is a demand for large-capacity magnetic disks for recording and playing back digital AV information that comprises enormous quantities of data.
Conventional magnetic disk apparatuses will be described below.
FIG. 8
is a schematic diagram showing an example of a conventional magnetic disk apparatus. In
FIG. 8
, the magnetic disk
1
is the medium on which data is recorded: the magnetic head
2
is means for performing recording and playback of information to and from the magnetic disk
1
; the actuator
3
has the magnetic head
2
mounted at its tip, and is means for performing positioning operations to an arbitrary radial position on the magnetic disk
1
; the head amplifier
5
is means for detecting and amplifying playback signals from the magnetic head
2
; the controller
4
is means for detecting the relative position of the magnetic head
2
with respect to the magnetic disk
1
from the output of the head amplifier
5
, and outputting a control signal to position the actuator
3
at the prescribed position on the magnetic disk
1
; and the driver
6
is means for supplying a current corresponding to the control signal to the actuator
3
.
Further, the actuator
3
is composed of a carriage
3
a
, suspension
3
b
, drive coil
3
c
, and permanent magnet
3
d
or the like.
The carriage
3
a
is means for causing oscillating motion with point c as the center of rotation. The suspension
3
b
is attached to the carriage
3
a
, and is means for causing the magnetic head
2
to float at a constant distance of several tens of nanometers above the surface of the magnetic disk
1
by means of a floatation mechanism called a slider. The drive coil
3
c
is means for generating a driving force by means of the permanent magnet
3
d
provided opposite to it, and as a result rotating the actuator
3
. The permanent magnet
3
d
is means for generating a driving force together with the drive coil
3
c
and rotating the actuator
3
.
Also provided, although not illustrated, are a spindle motor for rotational drive of the magnetic disk
1
, an interface section that performs exchange of digital information with the host, a buffer that stores this information for efficient recording and playback to and from the magnetic disk
1
, together with a buffer control unit, an information recording and playback circuit, etc.
The operation of a conventional disk apparatus will be described below. When the magnetic disk
1
performs information recording and playback, it is rotated at a given speed (5,400 rpm in this conventional example) by the spindle motor (not illustrated). At this time, the magnetic head
2
is positioned above the magnetic disk
1
by means of the actuator
3
, and is maintained in a floating state in the position at which the pressure of the suspension
3
b
provided at the tip of the actuator
3
, and the active force of the airflow between the slider formed integrally with the magnetic head
2
(not illustrated) and the magnetic disk
1
are in balance. Position information (b in the drawing) is recorded in advance on each of the tracks forming concentric circles (one track is shown by a dashed line at a in the drawing) on the magnetic disk
1
. The position information b is recorded at fixed intervals on each track, and the magnetic head
2
plays back the position information at fixed time intervals in accordance with the rotation of the magnetic disk
1
(this time interval is called the sampling period, and the reciprocal of the sampling period is called the sampling frequency, which is 5.4 kHz in this conventional example). The area in which this position information b is recorded is called a servo area. Information is recorded in or played back from areas other than these servo areas; these areas are called data areas. The playback signal output from the magnetic head
2
is detected and amplified by the head amplifier
5
, and input to the controller
4
. In the controller
4
, position information is detected from the input signal, the positional error relative to the target track a of the magnetic head
2
at that time is computed, the control amount necessary to drive the actuator
3
in order to reduce this positional error is computed, and a control signal is output. In this case, a control method such as phase compensation, for example, is used. The driver
6
supplies the necessary current to the drive coil
3
c
of the actuator
3
on the basis of the input control signal. By this means, a driving force is generated by the drive coil
3
c
and the permanent magnet
3
d
located opposite, and the actuator rotates about point c and constantly positions the magnetic head
2
above the target track a. In this state, information recording and playback is performed on the data area by the magnetic head
2
. When information recording and playback is performed in this way, a closed loop positioning control system that positions the magnetic head
2
above the target track is used.
FIG. 9
shows details of the position information formed in the servo area
7
a
. In this servo area
7
a
, track identification information, burst patterns, etc., are recorded as servo information for positioning the head
14
which has a write head
15
and a read head
16
. The track identification information is information that denotes the track numbers of each data area; it is read by the magnetic head
2
, and makes it possible to determine the track position at which the magnetic head
2
is currently positioned. The burst patterns are a plurality (4 in this conventional example) of patterns with mutually differing phases. On the basis of the signals output from these patterns, the amount of drift of the head
2
is detected, and this is used by the controller
4
to constantly follow the prescribed track and position the magnetic head
2
at that track by controlling the actuator
3
. To be specific, AGC
9
is an area for fixing the amplitude of the playback waveform by means of an AGC circuit, Sync
10
is an area for achieving clock synchronization, SAM (Servo Address Mark)
11
is an area that denotes the start position of the servo area, Track No. and Wedge No.
12
are the track number and wedge number called the Gray code, and Burst
13
comprises a burst area for generating intra-track position signals.
Therefore, Track No. and Wedge No.
12
constitute track identification information, and Burst
13
corresponds to the burst patterns. When the head detects the SAM (Servo Address Mark)
11
, the Track No. and Wedge No.
12
are detected based on that point in time, and the track number and wedge number are identified, and then the burst signal is detected in Burst
13
at the prescribed point in time from that reference point in time, and head positioning is performed by means of the closed loop control system on the basis of that signal.
FIG. 10
shows an example of a 2-phas
Ishida Tatsuaki
Miyata Keizo
Shimizu Ryosuke
Tohma Kiyokazu
Umeda Yoshio
Faber Alan T.
RatnerPrestia
LandOfFree
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