U.S. patent application number 11/012795 was filed with the patent office on 2006-06-15 for dual actuators for read-while-write recording system.
This patent application is currently assigned to Imation Corp.. Invention is credited to James S. Anderson, Denis J. Langlois.
Application Number | 20060126212 11/012795 |
Document ID | / |
Family ID | 36462680 |
Filed Date | 2006-06-15 |
United States Patent
Application |
20060126212 |
Kind Code |
A1 |
Anderson; James S. ; et
al. |
June 15, 2006 |
DUAL ACTUATORS FOR READ-WHILE-WRITE RECORDING SYSTEM
Abstract
The invention provides a read-while-write recording system for a
linear data storage medium, such as magnetic tape or other data
storage medium in which data is stored on parallel data tracks that
extend along a length of the medium. The invention makes use of
separate sliders for the read and write elements, and separate
actuators to control the positioning of the sliders. Each of the
sliders may also include servo elements to read servo marks. In
this manner, the write elements of a first slider can be positioned
independently from the read elements of a second slider in order to
achieve improved head positioning with respect to data tracks on
the linear data storage medium.
Inventors: |
Anderson; James S.; (Hugo,
MN) ; Langlois; Denis J.; (River Falls, WI) |
Correspondence
Address: |
Attention: Eric D. Levinson;Imation Corp.
Legal Affairs
P.O. Box 64898
St. Paul
MN
55164-0898
US
|
Assignee: |
Imation Corp.
|
Family ID: |
36462680 |
Appl. No.: |
11/012795 |
Filed: |
December 14, 2004 |
Current U.S.
Class: |
360/75 ;
360/78.02; G9B/5.008; G9B/5.203 |
Current CPC
Class: |
G11B 5/00826 20130101;
G11B 5/584 20130101 |
Class at
Publication: |
360/075 ;
360/078.02 |
International
Class: |
G11B 21/02 20060101
G11B021/02; G11B 5/55 20060101 G11B005/55 |
Claims
1. A read-while-write recording system for a linear data storage
medium comprising: a first slider including a write element to
write data to the linear data storage medium and a first servo
element to read servo marks from the linear data storage medium; a
first actuator to define positioning of the first slider, wherein
the first actuator includes fine and coarse positioning elements; a
second slider including a read element to read the data written by
the write element, and a second servo element to read, the servo
marks from the linear data storage medium; and a second actuator to
define positioning of the second slider, wherein the second
actuator includes fine and coarse positioning elements.
2. The system of claim 1, wherein the first actuator positions the
first slider in response to servo signals detected by the first
servo element and the second actuator positions the second slider
in response to servo signals detected by the second servo
element.
3. The system of claim 2, further comprising a controller to
receive the servo signals detected by the first and second servo
elements and to control the actuators based on the servo
signals.
4. The system of claim 1, wherein a track pitch of the linear data
storage medium is less than approximately 5 microns.
5. The system of claim 4, wherein a track pitch of the linear data
storage medium is less than approximately 2 microns.
6. The system of claim 5, wherein a track pitch of the linear data
storage medium is less than approximately 1 micron.
7. The system of claim 1, further comprising: a third slider
including a read element to read the data written by the write
element and a third servo element to read the servo marks from the
linear data storage medium; and a third actuator to define
positioning of the third slider, wherein the write element of the
first slider and the read element of the second slider perform
read-while-write functions in a first tape direction and the write
element of the first slider and the read element of the third
slider perform read-while-write functions in a second tape
direction.
8. The system of claim 1, wherein: the first slider includes a
plurality of write elements; and the second slider includes a
plurality of read elements.
9. The system of claim 8, wherein a number of write elements of the
first slider corresponds to a number of read elements of the second
slider such that the read elements verify data written by the write
elements.
10. The system of claim 8, wherein adjacent write elements on the
first slider define a channel pitch and adjacent read elements of
the second slider are spaced from one another according to the
channel pitch.
11. The system of claim 8, wherein the channel pitch is less than
approximately 5 microns.
12. The system of claim 11, wherein the channel pitch is less than
approximately 2 microns.
13. The system of claim 12, wherein the channel pitch is less than
approximately 1 micron.
14. The system of claim 1, wherein the linear data storage medium
comprises magnetic data storage tape.
15. A read-while-write recording system for magnetic data storage
tape comprising: a first slider including a first write element to
write data to the magnetic tape in a first tape direction, a first
read element to read data from the magnetic tape in a second tape
direction, and a first servo element to read servo marks from the
magnetic tape, wherein the first read element and the first write
element are substantially aligned within the first slider along a
direction of tape motion and the first servo element is not
substantially aligned with the first read element and the first
write element along the direction of tape motion; a first actuator
to define positioning of the first slider; a second slider
including a second write element to write data to the magnetic tape
in the second tape direction, a second read element to read data
from the magnetic tape in the first tape direction, and a second
servo element to read servo marks from the magnetic tape, wherein
the second read element and the second write element are
substantially aligned within the second slider along the direction
of tape motion and the second servo element is not substantially
aligned with the second read element and the second write element
along the direction of tape motion; and a second actuator to define
positioning of the second slider.
16. The system of claim 15, wherein the first actuator positions of
the first slider in response to servo signals detected by the first
servo element and the second actuator positions of the second
slider in response to servo signals detected by the second servo
element, wherein the first and second actuators each include fine
and coarse positioning elements.
17. The system of claim 15, wherein the first and second sliders
each include a plurality of write elements and a plurality of read
elements substantially aligned along the direction of tape
motion.
18. The system of claim 17, wherein a channel pitch of the
plurality of write elements on the first and second sliders and the
plurality of read elements on the first and second sliders is less
than approximately 2 microns.
19. The system of claim 15, wherein a track pitch of the magnetic
tape is less than approximately 2 microns.
20. A method comprising: writing data on a linear data storage
medium via a write element on a first slider; verifying the data on
the linear data storage medium via a read element on a second
slider; positioning the write element of the first slider via a
first actuator in response to servo signals detected by a first
servo element on the first slider, wherein the first actuator
includes fine and coarse positioning elements; and positioning the
read element of the second slider via a second actuator in response
to servo signals detected by a second servo element on the second
slider, wherein the second actuator includes fine and coarse
positioning elements.
Description
TECHNICAL FIELD
[0001] The invention relates to linear data storage media such as
magnetic tape and, more particularly, to heads for reading and
writing data to linear data storage media.
BACKGROUND
[0002] Linear data storage media refers to data storage media, such
as magnetic tape, in which data is stored in parallel tracks that
extend linearly along the length of the media. Examples of linear
data storage media include magnetic tape, magneto-optic tape,
optical tape, holographic tape, and possibly other tape-like media
formats. Magnetic tape media remains an economical medium for
storing large amounts of data. For example, magnetic tape
cartridges, or large spools of magnetic tape are often used to back
up large amounts of data for large computing centers. Magnetic tape
cartridges also find application in the backup of data stored on
smaller computers such as workstations, desktop or laptop
computers.
[0003] In magnetic tape, data is typically stored as magnetic
signals that are magnetically recorded on the medium surface. The
data stored on the magnetic tape is often organized along data
tracks, and read/write heads are positioned relative to the data
tracks to write data to the tracks or to read data from the tracks.
As the number of data tracks increases, the data storage capacity
of the magnetic tape likewise increases. However, as the number of
data tracks increases, the tracks become narrower and more crowded
on the surface of the data storage tape. Servo tracks are also
commonly defined on magnetic media to provide reference points for
tracking the location of data tracks. Servo tracks can improve the
ability to locate data tracks, particularly as the tracks become
narrower and more crowded on the surface of the data storage
tape.
[0004] A wide variety of heads have been designed to write data to
magnetic tape. Various heads have also been designed to read data
stored on magnetic tape. A magnetic data tape recording system
often includes both write heads and read heads to facilitate the
writing of information to the magnetic medium and readout of such
information for verification that the data was written properly.
Read-while-write sliders, for example, typically include a read
head and a write head precisely mounted on a slider to facilitate
readout and verification of data written by the write head.
SUMMARY
[0005] In general, the invention provides a read-while-write
recording system for a linear data storage medium, such as magnetic
tape or other data storage medium in which data is stored on
parallel data tracks that extend along a length of the medium. The
invention makes use of separate sliders for the read and write
elements, and separate actuators to control the positioning of the
sliders. Each of the sliders may also include servo elements to
read servo marks. In this manner, the write elements of a first
slider can be positioned independently from the read elements of a
second slider in order to achieve improved head positioning with
respect to data tracks on the linear data storage medium. The
invention can avoid problems with conventional read-while-write
sliders that include both the read and write elements. These
problems generally manifest in the conventional sliders at very
small track pitches, such as track pitches less than 5 microns,
less than 2 microns and especially less than 1 micron.
[0006] In one embodiment, the invention provides a read-while-write
recording system for a linear data storage medium comprising a
first slider including a write element to write data to the linear
data storage medium, and a first servo element to read servo marks
from the linear data storage medium. A first actuator defines
positioning of the first slider. The system also includes a second
slider including a read element to read the data written by the
write element, and a second servo element to read the servo marks
from the linear data storage medium. A second actuator defines
positioning of the second slider.
[0007] In another embodiment, the invention provides a
read-while-write recording system for magnetic data storage tape
comprising a first slider including a first write element to write
data to the magnetic tape in a first tape direction, a first read
element to read data from the magnetic tape in a second tape
direction, and a first servo element to read servo marks from the
magnetic tape. A first actuator defines positioning of the first
slider. The system also includes a second slider including a second
write element to write data to the magnetic tape in the second tape
direction, a second read element to read data from the magnetic
tape in the first tape direction, and a second servo element to
read servo marks from the magnetic tape. A second actuator defines
positioning of the second slider.
[0008] In another embodiment, the invention provides a method
comprising writing data on a linear data storage medium via a write
element on a first slider, verifying the data on the linear data
storage medium via a read element on a second slider, positioning
the write element of the first slider via a first actuator in
response to servo signals detected by a first servo element on the
first slider, and positioning the read element of the second slider
via a second actuator in response to servo signals detected by a
second servo element on the second slider.
[0009] The various embodiments of the invention may be capable of
providing one or more advantages. Specifically, the invention can
improve head to track alignment of read heads and write heads. By
implementing separate sliders and separate actuators for the read
and write heads, the invention can avoid problems with conventional
read-while-write sliders that manifest at very small track pitches,
such as track pitches less than 5 microns, less than 2 microns and
especially less than 1 micron. In some embodiments, the invention
can allow for bi-directional read-while-write capabilities with the
improved head to track alignment.
[0010] Various bi-directional slider arrangements are disclosed,
including an arrangement in which each slider includes both write
elements and read elements. In that case, however, in accordance
with the invention, the write elements of a given slider are used
for writing in one direction and the read elements of the slider
are used for verification in the other direction. Thus, in each
direction, the set of read elements and write elements that are
used reside on different sliders, which are controlled by different
actuators. These embodiments having write elements and read
elements on each slider can provide manufacturing advantages by
allowing conventional manufacturing techniques to be used in the
creation of the sliders that are used to implement the
invention.
[0011] The details of one or more embodiments of the invention are
set forth in the accompanying drawings and the description below.
Other features, objects, and advantages of the invention will be
apparent from the description and drawings, and from the
claims.
BRIEF DESCRIPTION OF DRAWINGS
[0012] FIG. 1 is a conceptual diagram illustrating a conventional
read-while-write slider positioned over a linear data storage
medium.
[0013] FIG. 2 is a conceptual diagram illustrating a
read-while-write system that includes separate sliders for read
elements and the write elements.
[0014] FIG. 3 is another conceptual diagram illustrating a
read-while-write system that includes separate sliders for a
plurality of read elements and a plurality of write elements.
[0015] FIGS. 4-6 are block diagrams illustrating various
read-while-write systems according to embodiments of the
invention.
[0016] FIG. 7 is a flow diagram illustrating a technique according
to an embodiment of the invention.
DETAILED DESCRIPTION
[0017] The invention provides a read-while-write recording system
for a linear data storage medium. A linear data storage medium
refers to a medium in which data is stored on parallel data tracks
that extend along a length of the medium. Examples of linear data
storage media include magnetic tape, magneto-optic tape, optical
tape, holographic tape, and possibly other tape-like media formats.
It is highly desirable to increase the data storage density of
linear data storage medium, and this often entails reducing the
track pitch between adjacent data tracks such that a larger number
of data tracks can be recorded in a given area.
[0018] Conventional read-while-write systems for magnetic tape make
use of sliders that include read elements and write elements. The
read elements are precisely aligned with the write elements on the
slider for every channel of the slider, such that for each channel,
a write element can write data to magnetic tape and a read element
can read the data to verify that it was properly recorded. The
slider may also include a servo element to read servo marks of the
medium. An actuator can position the slider in response to the
detected servo signals in order to properly align the write and
read elements with respect to data tracks of the magnetic tape.
[0019] As track pitches become smaller, however, it becomes
increasingly more difficult to align the write elements with the
read elements on a slider. At very small track pitches, such as
track pitches less than 5 microns, alignment becomes particularly
difficult. As track pitches become less than 2 micron or less than
1 micron, alignment of read elements with write elements on a
slider may be extremely difficult, or even impossible, particularly
for mass production. Very slight tilt of the slider can cause
misalignment with respect to data tracks at these very small track
pitches. Also, thermodynamics can cause expansion of the medium or
the head, which can also cause misalignment problems at these small
track pitches. Media stretching or width variations can further
compound such problems.
[0020] In order to address these alignment concerns, the invention
proposes the use of separate sliders for the read elements and the
write elements of a read-while-write system. Separate servo
tracking can then be performed for each slider, and each slider can
be controlled by its own actuator. This avoids the need to
precisely align the read element of a given channel with the write
element of the given channel, as alignment of the write elements
with respect to the data tracks can be performed by servo tracking
of the first slider and alignment of the read elements with respect
to the data tracks can be performed by servo tracking of the second
slider
[0021] FIG. 1 is a conceptual diagram illustrating a conventional
system 10 comprising a conventional read-while-write slider 12
positioned over a linear data storage medium 14. A slider refers to
a structure that includes one or more elements for reading or
writing data to linear data storage media. Sliders can provide an
air bearing surface or a contact surface that interfaces with a
linear data storage medium, such as magnetic tape, to properly
position read or write elements with respect to the medium
surface.
[0022] Slider 12 of conventional read-while-write system 10
comprises a read element 16 and a write element 18. Importantly,
read element 16 is precisely aligned with write element 18 on
slider 12 such that write element 18 can write data to magnetic
tape 14 and read element 16 can read the data to verify that it was
properly recorded. Conventional slider 12 may also include a servo
element 15 to read servo marks of magnetic tape. An actuator (not
shown in FIG. 1) positions slider 12 in response to the detected
servo signals in order to properly align write element 18 and read
element 16 with respect to data tracks of the magnetic tape.
[0023] As mentioned above, however, as track pitches become
smaller, it becomes increasingly more difficult to align the write
elements with the read elements on a slider. In order to address
these alignment concerns, the invention proposes the use of
separate sliders for the read and write elements of a
read-while-write system.
[0024] FIG. 2 is a conceptual diagram illustrating a
read-while-write system 20 that includes separate sliders for read
elements and write elements, in accordance with an embodiment of
the invention. In particular, a first slider 22 includes a write
element 24 and a servo element 25, whereas a second slider 26
includes a read element 28 and a servo element 29. As illustrated,
as magnetic tape 21 moves past sliders 22, 26 from right-to-left,
write element 24 writes data into data track 27 of magnetic tape
21, e.g., as magnetic transitions. Read element 28 of second slider
26 reads the data written by write element 24 in order to verify
the accuracy and integrity of the data. If data is not properly
recorded, read element 28 can detect the inaccurate data and write
element 24 can re-write the data again, e.g., at another location
along medium 14. In this manner, system 20 provides
read-while-write functionality.
[0025] First slider 22 and second slider 26 are separately
controllable by different actuators (not shown in FIG. 2). In
particular, first slider 22 can be controlled in response to servo
signals detected by servo element 25 whereas second slider 26 can
be controlled in response to servo signals detected by servo
element 29. Such separate control of the positioning of write
element 24 and read element 28 can improve head to track alignment.
In particular, with separate positioning control, write element 24
and read element 28 can be positioned more accurately with respect
to data track 27. Separate positioning control can also simplify
the creation of a read-while-write system by avoiding the need to
precisely align read heads with write heads on a given slider, as
is the case for system 10 of FIG. 1.
[0026] In general, read element 28 and write element 24 may
comprise magnetic heads that define magnetic gaps for readout or
recording, respectively. A wide variety of such heads have been
developed for such read and/or write functionality, including
magneto-resistive (MR) heads, giant magneto-resistive (gMR) heads,
inductive heads, thin film heads, C-core heads that include an
excitation coil around the C-core, and a wide variety of other
types of heads. In general, a write element refers to an element or
head that can write data, and a read element refers to an element
or head that can read data written by the write element, e.g., for
verification. Some heads can both read and write data and could be
used as either a read element or a write element, while other types
of heads are only suited for reading or writing. A servo element is
a more specific type of read element, designed specifically to read
servo marks, e.g., of a time-based or amplitude-based servo
pattern.
[0027] FIG. 3 is another conceptual diagram illustrating a
read-while-write system 30 that includes separate sliders for a
plurality of read elements and a plurality of write elements. In
particular, a first slider 32 includes a plurality of write
elements 34 and a servo element 35, whereas a second slider 36
includes a plurality of read elements 38 and a servo element 39. As
magnetic tape 31 moves past sliders 32, 36 from right-to-left,
write elements 34 write data into data tracks 37 of magnetic tape
31, e.g., as magnetic transitions. Read elements 38 of second
slider 36 read the data written by write elements 34 in order to
verify the accuracy and integrity of the data. If data is not
properly recorded, one of read elements 38 can detect the
inaccurate data and the corresponding one of write elements 34 can
re-write the data again. In this manner, system 30 provides
read-while-write functionality. Read-while-write functionality
generally refers to the read-out verification of data as it is
written. The described invention facilitates such read-while-write
functionality at unconventionally small track pitches.
[0028] In the embodiment of FIG. 3, each of read elements 38 of
slider 36 corresponds to one of write elements 34 of slider 32. In
this manner, the read and write elements define pairs that
correspond to each of data tracks 37. The distance between adjacent
read elements 38 or adjacent write elements 34 defines the channel
pitch of system 30. The channel pitch is labeled "P.sub.CHANNEL" in
FIG. 3. The distance between adjacent tracks 37 of magnetic tape 31
is referred to as the track pitch of medium 31. The track pitch is
labeled "P.sub.TRACK" in FIG. 3. The track pitch and channel pitch
are generally identical.
[0029] First slider 32 and second slider 36 are separately
controllable by different actuators (not shown in FIG. 3). In
particular, first slider 32 can be controlled in response to servo
signals detected by servo element 35, whereas second slider 36 can
be controlled in response to servo signals detected by servo
element 39. Such separate control of the positioning of write
elements 34 and read elements 38 can improve head to track
alignment. In particular, with separate positioning control, write
elements 34 and read element 38 can be positioned more accurately
with respect to data tracks 37. As mentioned, separate positioning
control can also simplify the creation of a read-while-write system
by avoiding the need to precisely align read heads with write heads
on a given slider, as is the case for system 10 of FIG. 1. For very
small data tracks, e.g., track pitches less than 5 micron, less
than 2 microns, and particularly less than 1 micron, the use of
separate positioning control becomes very important. At these track
pitches, element alignment as shown in FIG. I becomes difficult or
impossible, particularly for sliders being mass produced. In
accordance with the invention, the channel pitch (P.sub.CHANNEL)
may be less than 5 microns, less than 2 microns, or less than 1
micron.
[0030] FIG. 4 is a block diagram illustrating a read-while-write
system 40 according to an embodiment of the invention. System 40
includes a first slider 42 including one or more write elements 44
to write data to a linear data storage medium, and a servo element
45 to read servo marks from the linear data storage medium. A first
actuator 46 defines positioning of first slider 42. Controller 47
may receive detected servo signals from servo element 45 and
control first actuator 46 based on the detected servo signals.
[0031] System 40 also includes a second slider 48 including one or
more read elements 49 to read the data written by the write
elements 44 of first slider 42. Second slider 48 also includes a
servo element 50 to read the servo marks from the linear data
storage medium. A second actuator 51 defines positioning of second
slider 48. Controller 47 may receive detected servo signals from
servo element 50 and control second actuator 51 based on such servo
signals. In this manner, sliders 42 and 48 are independently
controlled based on servo signals detected by the respective
sliders. Again, this avoids problems and limitations of
conventional sliders that have write elements and read elements
aligned on the slider for each channel.
[0032] Read element 49 and write elements 44 may comprise magnetic
heads that define magnetic gaps for readout or recording,
respectively. A wide variety of such heads have been developed for
read and/or write functionality, including magneto-resistive (MR)
heads, giant magneto-resistive (gMR) heads, inductive heads, thin
film heads, C-core heads that include an excitation coil around the
C-core, and a wide variety of other types of heads. Servo elements
45 and 50 may comprise similar magnetic heads, but are sized and/or
patterned with gaps specific for servo detection. The size and
shape of magnetic gaps used for servo elements 45, 50 will depend
on the type of servo pattern used for the medium. A wide variety of
time based and amplitude-based servo patterns have been developed,
and each pattern defines a specific head structure used for servo
readout.
[0033] The actuators described herein may be any type of actuators,
including voice coil actuators, piezoelectric actuators, or any
other positioning element. In some cases, each actuator may include
both fine and coarse positioning elements, e.g., a stepper motor
for coarse positioning and a voice coil for fine positioning. In
still other embodiments, a common coarse positioning element may be
used for both sliders 42 and 48, with different fine positioning
elements being used for the different sliders 42 and 48. In that
case, actuators 46 and 51 may be the fine positioning elements for
the respective sliders that share a coarse positioning element.
[0034] FIG. 5 is a block diagram illustrating a bi-directional
read-while-write system 60 according to an embodiment of the
invention. System 60 is similar to system 40 of FIG. 4, but
includes an additional slider having read elements.
[0035] System 60 includes a first slider 62 including one or more
write elements 64 to write data to a linear data storage medium,
and a servo element 65 to read servo marks from the linear data
storage medium. A first actuator 66 defines positioning of first
slider 62. Controller 67 may receive detected servo signals from
servo element 65 and control first actuator 66 based on such servo
signals.
[0036] System 60 also includes a second slider 68 including one or
more read elements 69 to read the data written by the write
elements 64 of first slider 62 when the magnetic tape moves
right-to-left. Second slider 68 also includes a servo element 70 to
read the servo marks from the linear data storage medium. A second
actuator 71 defines positioning of second slider 68. Controller 67
may receive detected servo signals from servo element 69 and
control second actuator 71 based on such servo signals. In this
manner, sliders 62 and 68 are independently controlled based on
servo signals detected by the respective sliders. Again, this
avoids problems and limitations of conventional sliders that have
write elements and read elements aligned for each channel.
[0037] System 60 also includes a third slider 74 including one or
more read elements 75 to read the data written by the write
elements 64 of first slider 62 when the magnetic tape moves
left-to-right. Third slider 74 also includes a servo element 76 to
read the servo marks from the linear data storage medium, providing
for independent servo control of third slider 74. A third actuator
78 defines positioning of third slider 74. Controller 67 may
receive detected servo signals from servo element 75 and control
third actuator 78 based on such servo signals.
[0038] In the embodiment of FIG. 5, write elements 64 of first
slider 62 can be used to write data in both directions. Read
elements 69 of second slider 68 read and verify data in a first
tape direction, whereas read elements 75 of third slider 74 read
and verify data in a second tape direction. In this manner, system
60 allows for bi-directional read-while-write functionality with
improved head-to-track positioning.
[0039] FIG. 6 is a diagram illustrating another read-while-write
system according to an embodiment of the invention. System 80 of
FIG. 6 includes a first slider 82 including one or more first write
elements 84 to write data to the magnetic tape in a first tape
direction, one or more first read elements 86 to read data from the
magnetic tape in a second tape direction, and a first servo element
88A to read servo marks from the magnetic tape. System 80 also
includes a first actuator 89 to define positioning of first slider
80. In the embodiment of FIG. 6, servo elements 88A and 88B are
illustrated, although only one servo element is actually needed for
a given slider. Either of servo elements 88A, 88B or both of servo
elements 88A, 88B could be used.
[0040] System 80 also includes a second slider 92 including one or
more second write elements 94 to write data to the magnetic tape in
the second tape direction, one or more second read elements 96 to
read data from the magnetic tape in the first tape direction, and a
second servo element 98A to read servo marks from the magnetic
tape. System 80 also includes a second actuator 99 to define
positioning of second slider 92. In the illustrated embodiment,
servo elements 98A and 98B are shown, although only one servo
element is actually needed for slider 92. Either or both of servo
elements 98A could be used.
[0041] In accordance with the invention, first actuator 89
positions first slider 82 in response to servo signals detected by
first servo element 88A. Similarly, second actuator 99 positions
second slider 92 in response to servo signals detected by second
servo element 98A. However, in a first tape direction, write
elements 84 of first slider 82 are used in conjunction with the
read elements 96 of second slider 92 for read-while-write
verification. In particularly, read elements 96 of second slider 92
provide verification of data recorded by write elements 84 of first
slider 82. Similarly, in a second tape direction, write elements 94
of second slider 92 are used in conjunction with the read elements
86 of first slider 82 for read-while-write verification.
Accordingly, the read and write elements used during any given
operation are independently controlled by different actuators,
e.g., in response to different servo signals. Controller 100
receives servo signals detected by one of the servo elements of
first slider 82 and second slider 92, and sends appropriate control
signals to actuators 89, 99 to properly position the heads for
read-while-write operations.
[0042] As described herein, because the read and write elements
used during any given operation are independently controlled by
different actuators, improved track pitch and channel pitch can be
facilitated, e.g., less than 5 microns, less than 2 microns, or
even less than 1 micron. Moreover, the system of FIG. 6 provides
additional advantages in terms of slider fabrication. Sliders 82
and 92 may be fabricated in a manner similar to conventional
sliders, such as slider 12 of FIG. 1. Many distinct fabrication
advantages can be realized by using conventional sliders. However,
in contrast to conventional systems, system 80 of FIG. 6 makes use
of two sliders, and a given set of write elements of a given slider
are not used with the read elements of that slider. Instead, the
write elements 84 of first slider 82 are used in conjunction with
the read elements 96 of second slider 92 in a first tape direction
for read-while-write operation, whereas the write elements 94 of
second slider 92 are used in conjunction with the read elements 86
of first slider 82 for read-while-write verification in a second
tape direction.
[0043] FIG. 7 is a flow diagram illustrating a technique according
to an embodiment of the invention. FIG. 7 will be described with
reference to system 80 of FIG. 6. As shown, controller 100
positions write elements 84 via first actuator 89 in response to
servo signals detected by servo element 88A and/or 88B (102). Write
elements 84 can then properly write data to data tracks of the data
storage media passing slider 82 (104). Controller 100 also
positions read elements 96 via actuator 99 in response to servo
signals detected by servo element 98A and/or 98B (106). Read
elements 96 can then properly read data written to the data tracks
of the data storage media (108). In this manner, separate actuators
can be used to position write heads and read heads for
read-while-write operations. A similar technique is performed for
the opposite tape direction, but read elements 86 of slider 82 are
used in conjunction with write elements 94 of slider 92.
[0044] A number of embodiments of the invention have been
described. For example, various embodiments of read-while-write
recording systems for a linear data storage medium have been
described. These and other embodiments are within the scope of the
following claims.
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