Dynamic magnetic information storage or retrieval – Automatic control of a recorder mechanism – Controlling the head
Reexamination Certificate
1998-04-16
2001-07-17
Sniezek, Andrew L. (Department: 2651)
Dynamic magnetic information storage or retrieval
Automatic control of a recorder mechanism
Controlling the head
C360S048000, C360S135000, C360S077080
Reexamination Certificate
active
06262860
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to a magnetic disk apparatus which is used as a storage apparatus for a computer, a video apparatus or a like apparatus, and more particularly to a magnetic disk apparatus which allows high speed recording and reproduction of data.
Various magnetic apparatus are known, and an exemplary one of related art magnetic disk apparatus is described with reference to
FIG. 10
which shows a general construction of a magnetic disk apparatus and
FIG. 11
which illustrates tracking control of the magnetic disk apparatus of FIG.
10
.
Referring first to
FIG. 10
, the magnetic disk apparatus
110
shown includes a plurality of magnetic disks
80
secured to a spindle
81
in a predetermined spaced relationship from each other, and a plurality of magnetic heads
82
for recording and reproduction individually provided for the magnetic disks
80
. The magnetic disk apparatus
110
further includes a carriage
84
on which a plurality of pivotal arms
83
are held in a connected condition to each other, a bearing
85
for supporting the carriage
84
for pivotal motion thereon, a voice coil motor (VCM)
86
for generating a pivoting force for the carriage
84
, a load beam
87
provided on each of the pivotal arms
83
which are pivoted by the voice coil motor
86
, and a slider
88
provided at a free end of the load beam
87
. The slider
88
is made of a ceramics material or the like, and a magnetic head
82
for recording and reproduction formed by a thin film technique or a like technique is placed at a free end of the slider
88
.
Referring now to
FIG. 11
, each of the magnetic disks
80
employed in the magnetic disk apparatus
110
having the construction described above is circumferentially divided into sectoral data areas
91
and servo areas
92
. Further, each of the servo areas
92
is divided into servo mark areas
93
and address code areas
94
, in which servo marks A and B and address codes are recorded, respectively. A tracking error signal for the magnetic heads
82
is produced based on reproduction signals of several tens of the servo marks A and B located on each one circumference of each of the magnetic disks
80
.
In each of the servo mark areas
93
, a servo mark A and a servo mark B are provided on the opposite sides of a track center
96
of each of tracks
95
. Each of the servo marks A and B is formed from a burst of repetitive magnetization reversals, and a tracking error signal for the magnetic heads
82
is obtained depending upon a difference between the recorded positions of the servo marks A and B and a magnitude of a reproduction output.
Subsequently, production of a tracking error signal mentioned above is described.
First, it is assumed that a magnetic head
82
is positioned at an odd-numbered track and is thereafter displaced to the outer circumferential side of the disk. In this instance, the reproduction signal from the servo mark A increases in magnitude while the reproduction signal from the servo mark B decreases in magnitude. However, if the magnetic head
82
is displaced conversely to the inner circumferential side, then the reproduction signal from the service mark B increases while the reproduction signal from the service mark A decreases.
Now, it is assumed that the magnetic head
82
is positioned at an even-numbered track and is thereafter displaced to the outer circumferential side. In this instance, the reproduction signal from the servo mark B increases in magnitude while the reproduction signal of the servo mark A decreases in magnitude. However, if the magnetic head
82
is displaced conversely to the inner circumferential side, then the reproduction signal from the service mark A increases while the reproduction signal from the service mark B decreases.
Consequently, the direction in which the magnetic head
82
is displaced can be discriminated from the magnitudes of the reproduction signals of the servo marks A and B and distinction between an even number and an odd number of the track address recorded in the address code area
94
of the track
95
at which the magnetic head
82
is positioned, and tracking control of the magnetic head
82
is performed based on the information.
A tracking error signal is obtained from the track address from which reproduction by the magnetic head
82
is performed and the magnitudes of the reproduction signals of the servo marks A and B as described above, and the voice coil motor
86
is driven based on the tracking error signal so that the magnetic head
82
may be positioned on the track center
96
to effect tracking control.
However, since the tracking control described above is performed for one magnetic head selected from the plurality of magnetic heads, usually the other magnetic heads are not registered fully with opposing tracks of corresponding magnetic disks. In other words, from dispersions of the mounted positions of the magnetic heads, the thermal expansions and the vibration modes of the pivotal arms and the load beams on which the magnetic heads are carried and so forth, only the selected magnetic head is controlled to a tracking condition optimum to recording and reproduction. Accordingly, simultaneous recording and/or reproduction by a plurality of magnetic heads is practically unavailable.
In recent years, as development of multimedia proceeds, demands for various video services of a high quality are increasing, and demands also for video servers or non-linear video editing systems which have higher performances and higher functions than video tape recorders are increasing for production and sending out of video information. Here, a “non-linear” system signifies a system wherein a tape is not used as a recording medium.
A disk apparatus which is superior in high speed accessing is suitable for use with a non-linear video editing system. However, even though a magnetic disk apparatus which has exhibited development as, for example, an external storage apparatus for a computer includes a plurality of built-in magnetic disks as described above, the magnetic disk apparatus allows a recording or reproducing operation only by a selected one magnetic head so that the data transferring rate is limited to approximately 30 Mbit/sec. Therefore, in order to obtain a data transfer rate of 100 Mbit/sec or more which is demanded for a non-linear video editing system or the like, a plurality of magnetic disk apparatus must operate in parallel to each other. This increases the scale and the cost of the system, and consequently, systems of the type mentioned are actually used in only limited applications.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a magnetic disk apparatus suitable for use with a non-linear video editing system or a like system which is superior in high speed accessing and capable of recording and reproducing data at a high speed and can provide high quality video services.
In order to attain the object described above, according to the present invention, there is provided a magnetic disk apparatus which includes one or more disk type magnetic recording media securely mounted on a rotary shaft of a rotational driving apparatus, and a plurality of magnetic heads individually provided for recording faces of the disk type magnetic recording medium or media to perform recording and reproduction, comprising a plurality of recording signal processing means individually provided for the magnetic heads, a plurality of reproduction signal processing means individually provided for the magnetic heads, recording signal control means for controlling a relationship of recording signals to be inputted to the magnetic heads, reproduction signal control means for controlling a relationship of reproduction signals outputted from the magnetic heads, first driving means for pivoting all of the magnetic heads integrally with each other to position the magnetic heads roughly to predetermined information tracks of the corresponding recording faces of the disk type magnetic recording medium or media, and a pluralit
Maioli Jay H.
Sniezek Andrew L.
Sony Corporation
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