Dynamic magnetic information storage or retrieval – Automatic control of a recorder mechanism – Controlling the head
Reexamination Certificate
1994-11-16
2002-08-20
Sniezek, Andrew L. (Department: 2651)
Dynamic magnetic information storage or retrieval
Automatic control of a recorder mechanism
Controlling the head
C360S078040, C360S078080, C360S077020
Reexamination Certificate
active
06437935
ABSTRACT:
FIELD OF THE INVENTION
The present invention relates generally to data storage systems, and more particularly, to a method and architecture for optimizing the data zone on data storage disks employed in load/unload data storage systems.
BACKGROUND OF THE INVENTION
A typical data storage system includes one or more data storage disks coaxially mounted on a hub of a spindle motor. The spindle motor rotates the disks at speeds typically on the order of several thousand revolutions-per-minute. Digital information, representing various types of data, is typically written to and read from the data storage disks by one or more transducers, or read/write heads, which are mounted to an actuator and passed over the surface of the rapidly rotating disks.
The actuator typically includes a plurality of outwardly extending arms with one or more transducers being mounted resiliently or rigidly on the extreme end of the arms. The actuator arms are interleaved into and out of the stack of rotating disks, typically by means of a coil assembly mounted to the actuator. The coil assembly generally interacts with a permanent magnet structure, and the application of current to the coil in one polarity causes the actuator arms and transducers to shift in one direction, while current of the opposite polarity shifts the actuator arms and transducers in an opposite direction.
In a typical digital data storage system, digital data is stored in the form of magnetic transitions on a series of concentric, closely spaced tracks comprising the surface of the magnetizable rigid data storage disks. The tracks are generally divided into a plurality of sectors, with each sector comprising a number of information fields. One of the information fields is typically designated for storing data, while other fields contain sector identification and synchronization information, for example. Data is transferred to, and retrieved from, specified track and sector locations by the transducers being shifted from track to track, typically under the control of a controller. The transducer assembly typically includes a read element and a write element. Other transducer assembly configurations incorporate a single transducer element used to write data to the disks and read data from the disks.
Writing data to a data storage disk generally involves passing a current through the write element of the transducer assembly to produce magnetic lines of flux which magnetize a specific location of the disk surface. Reading data from a specified disk location is typically accomplished by a read element of the transducer assembly sensing the magnetic field or flux lines emanating from the magnetized locations of the disk. As the read element passes over the rotating disk surface, the interaction between the read element and the magnetized locations on the disk surface results in the production of electrical pulses in the read element. The electrical pulses correspond to transitions in the magnetic field.
Conventional data storage systems generally employ a closed-loop servo control system for accurately and rapidly positioning the actuator and read/write transducers to specified data storage locations on the data storage disk. A servo writing procedure is typically employed to record servo information on the surface of one or more data storage disks comprising the data storage system during the manufacture of the data storage system. In accordance with a known servo information format, termed an embedded servo, servo information is written between the data storing sectors of each track. The servo data is thus embedded in the data storing tracks on each of the data storage disks, typically resulting in an alternating sequence of data and servo sectors comprising each track. In accordance with another known servo information format employed in data storage systems, termed a dedicated servo, the servo writer records servo information typically on only one of the data storage disks comprising the disk stack, and often on only one of the surfaces of the dedicated servo disk. The servo information stored on the dedicated servo disk is used to maintain accurate positioning and alignment of the read/write transducers associated with each of the data storage disks. During normal data storage system operation, a servo transducer, generally mounted proximate the read/write transducers, is typically employed to read the servo sector data for the purpose of locating specified track and data sector locations on the disk. It is noted that a servo sector typically contains a pattern of data bits, often termed a servo burst pattern, used to maintain optimum alignment of the read/write transducers over the centerline of a track when reading and writing data to specified data sectors on the track.
Turning now to
FIG. 3
, there is shown a prior art data storage disk
24
formatted in a conventional manner to include a data zone
73
biased toward, and registered with respect to, the inner diameter of the data storage disk
24
. A traditional procedure for writing servo information to a data storage disk
24
includes establishing a data zone starting location
66
typically located near the central disk aperture
71
. The innermost data track
64
of a conventional data storage disk
24
is generally situated proximate the clamp engagement surface
62
provided along the circumference of the central disk aperture
71
. It is noted that the clamp engagement surface
62
represents a portion of the disk
24
surface area dedicated for clamping or mounting the disk
24
to the hub of a spindle motor (not shown) similar to a spindle motor
26
shown in FIG.
1
. It is further noted that axial and radial clamping forces imparted to the disk
24
surface generally result in a high concentration of stress localized along the inner diameter of the disk
24
, often resulting in some degree of disk surface distortion or curvature. Accordingly, the innermost data track
64
is generally spaced a short distance apart from the clamp engagement surface
62
to ensure a minimum level of data storage and data transfer reliability.
Having established a data zone starting location
66
and an innermost data track
64
, often referred to as track zero, servo information is then transferred to the other disk locations to form a plurality of concentric data tracks
50
as shown in
FIG. 1
, defining the data zone
73
. For example, after writing servo information to define the innermost data track
64
, the servo writing transducer is moved a short distance away from the innermost data track
64
in a direction toward the outer periphery
67
of the data storage disk
24
. A second concentric data track is then formatted on the disk
24
, thereby leaving a narrow gap between the innermost data track
64
and the newly formatted data track. Formatting in this manner generally proceeds until an outermost data track
68
is defined. A data zone ending location
70
is generally defined to be the last data storage or servo sector location on the outermost data track
68
.
In load/unload data storage systems, a load/unload ramp
60
is typically employed to engage a read/write transducer
27
assembly near the outer perimeter of the data storage disk
24
during periods in which the data storage system
20
is not in use. The transducer
27
is typically mounted to a slider body
63
to which a load tang
65
is affixed. During the power-down sequence of a load/unload data storage system
20
as shown in
FIG. 1
, the transducer
27
and slider body
63
assembly is lifted away from the surface of the data storage disk
24
by engagement between the load tang
65
and a load/unload ramp
60
. It is generally understood that prolonged direct contact between the slider body
63
and the disk surface
24
results in an increase in static friction, commonly referred to as stiction, between the slider body
63
and disk surface
24
. A high level of stiction between the slider body
63
and disk surface
24
is generally associated with excessive wear of the disk surface
24
, and increa
Boigenzahn Jeffrey Fred
Fracek Todd Phillip
Johnson Douglas Wayne
Hollingsworth Mark A.
Sniezek Andrew L.
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