# Patent

## Title
Backward compatible head for quasi-static tilted reading and/or recording

## Abstract

The present invention, in some embodiments, relates to magnetic heads having modules with arrays of transducers able to read and/or write while the arrays are positioned at different angles relative to a magnetic medium, thereby enabling reading and/or writing in more than one data storage format. An apparatus according to one embodiment includes at least two modules, each of the modules having an array of N+1 transducers. Axes of the arrays are oriented about parallel to each other. N of the N+1 transducers of a first array of a first of the modules are about aligned with N of the N+1 transducers of a second array of a second of the modules when the axes of the arrays are tilted at a first angle between about 0.1° and about 10°.

## Background
BACKGROUND
The present invention relates to data storage systems, and more particularly, this invention relates to modules having arrays of transducers able to read and/or write while the arrays are positioned at different angles relative to a magnetic medium, thereby enabling reading and/or writing in more than one data storage format.
In magnetic storage systems, data is read from and written onto magnetic recording media utilizing magnetic transducers. Data is written on the magnetic recording media by moving a magnetic recording transducer to a position over the media where the data is to be stored. The magnetic recording transducer then generates a magnetic field, which encodes the data into the magnetic media. Data is read from the media by similarly positioning the magnetic read transducer and then sensing the magnetic field of the magnetic media. Read and write operations may be independently synchronized with the movement of the media to ensure that the data can be read from and written to the desired location on the media.
An important and continuing goal in the data storage industry is that of increasing the density of data stored on a medium. For tape storage systems, that goal has led to increasing the track and linear bit density on recording tape, and decreasing the thickness of the magnetic tape medium. However, the development of small footprint, higher performance tape drive systems has created various problems in the design of a tape head assembly for use in such systems.
In a tape drive system, magnetic tape is moved over the surface of the tape head at high speed. Usually the tape head is designed to minimize the spacing between the head and the tape. The spacing between the magnetic head and the magnetic tape is crucial and so goals in these systems are to have the recording gaps of the transducers, which are the source of the magnetic recording flux in near contact with the tape to effect writing sharp transitions, and to have the read elements in near contact with the tape to provide effective coupling of the magnetic field from the tape to the read elements.
The quantity of data stored on a magnetic tape may be increased by increasing the number of data tracks across the tape. More tracks are made possible by reducing feature sizes of the readers and writers, such as by using thin-film fabrication techniques and MR sensors. However, for various reasons, the feature sizes of readers and writers cannot be arbitrarily reduced, and so factors such as lateral tape motion transients and tape lateral expansion and contraction (e.g., perpendicular to the direction of tape travel) must be balanced with reader/writer sizes that provide acceptable written tracks and readback signals. One issue limiting areal density is misregistration caused by tape lateral expansion and contraction. Tape width can vary by up to about 0.1% due to expansion and contraction caused by changes in humidity, tape tension, temperature, aging, etc. This is often referred to as tape dimensional stability (TDS).
If the tape is written in one environment and then read back in another, the TDS may prevent the spacing of the tracks on the tape from precisely matching the spacing of the reading elements during readback. In current products, the change in track spacing due to TDS is small compared to the size of the written tracks and is part of the tracking budget that is considered when designing a product. As the tape capacity increases over time, tracks are becoming smaller and TDS is becoming an increasingly larger portion of the tracking budget and this is a limiting factor for growing areal density.
BRIEF SUMMARY
An apparatus according to one embodiment includes at least two modules, each of the modules having an array of N+1 transducers. An axis of each array is defined between opposite ends thereof. The axes of the arrays are oriented about parallel to each other. N of the N+1 transducers of a first array of a first of the modules are about aligned with N of the N+1 transducers of a second array of a second of the modules when the axes of the arrays are positioned towards a first position, the first position being characterized by the axes of the arrays each being oriented at a first angle between about 0.1° and about 10° relative to a line oriented perpendicular to an intended direction of tape travel thereacross. N+1 of the N+1 transducers of the first array are about aligned with N+1 of the N+1 transducers of the second array when the axes of the arrays are positioned towards a second position, the axes of the arrays each being oriented at a second angle that is smaller than the first angle relative to the line oriented perpendicular to the intended direction of tape travel.
Any of these embodiments may be implemented in a magnetic data storage system such as a tape drive system, which may include a magnetic head, a drive mechanism for passing a magnetic medium (e.g., recording tape) over the magnetic head, and a controller electrically coupled to the magnetic head.
Other aspects and embodiments of the present invention will become apparent from the following detailed description, which, when taken in conjunction with the drawings, illustrate by way of example the principles of the invention.



BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
FIG. 1A is a schematic diagram of a simplified tape drive system according to one embodiment.
FIG. 1B is a schematic diagram of a tape cartridge according to one embodiment.
FIG. 2 illustrates a side view of a flat-lapped, bi-directional, two-module magnetic tape head according to one embodiment.
FIG. 2A is a tape bearing surface view taken from Line 2A of FIG. 2.
FIG. 2B is a detailed view taken from Circle 2B of FIG. 2A.
FIG. 2C is a detailed view of a partial tape bearing surface of a pair of modules.
FIG. 3 is a partial tape bearing surface view of a magnetic head having a write-read-write configuration.
FIG. 4 is a partial tape bearing surface view of a magnetic head having a read-write-read configuration.
FIG. 5 is a side view of a magnetic tape head with three modules according to one embodiment where the modules all generally lie along about parallel planes.
FIG. 6 is a side view of a magnetic tape head with three modules in a tangent (angled) configuration.
FIG. 7 is a side view of a magnetic tape head with three modules in an overwrap configuration.
FIGS. 8A-8C are partial top-down views of one module of a magnetic tape head according to one embodiment.
FIGS. 9A-9C are partial top-down views of one module of a magnetic tape head according to one embodiment.
FIGS. 10A-10C are partial top-down views of an apparatus having two modules, according to one embodiment.
FIG. 10D is a diagram of the system having the apparatus of FIGS. 10A-10B.
FIG. 11 is a partial top-down view of an apparatus having three modules, according to one embodiment.
FIG. 12A is a diagram of a tape with shingled tracks written in a non-serpentine fashion according to one embodiment.
FIG. 12B is a diagram of a tape with shingled tracks written in a serpentine fashion according to one embodiment.



DETAILED DESCRIPTION
The following description is made for the purpose of illustrating the general principles of the present invention and is not meant to limit the inventive concepts claimed herein. Further, particular features described herein can be used in combination with other described features in each of the various possible combinations and permutations.
Unless otherwise specifically defined herein, all terms are to be given their broadest possible interpretation including meanings implied from the specification as well as meanings understood by those skilled in the art and/or as defined in dictionaries, treatises, etc.
It must also be noted that, as used in the specification and the appended claims, the singular forms “a,” “an” and “the” include plural referents unless otherwise specified.
The following description discloses several preferred embodiments of magnetic storage systems having data transducers compatible with multiple data storage formats, as well as operation and/or component parts thereof. In various embodiments herein, the transducer arrays may read and/or write data while being oriented at different angles relative to a magnetic tape, thereby enabling compatibility with different data storage formats. Additionally, by enabling selective rotation of the transducers relative to a magnetic tape being written to and/or having data read therefrom, some embodiments herein are preferably also able to compensate for varying conditions of the magnetic tape being written to and/or having data read therefrom, as will be discussed in further detail below.
In one general embodiment, an apparatus includes at least two modules, each of the modules having an array of N+1 transducers. An axis of each array is defined between opposite ends thereof. The axes of the arrays are oriented about parallel to each other. N of the N+1 transducers of a first array of a first of the modules are about aligned with N of the N+1 transducers of a second array of a second of the modules when the axes of the arrays are positioned towards a first position, the first position being characterized by the axes of the arrays each being oriented at a first angle between about 0.10 and about 10° relative to a line oriented perpendicular to an intended direction of tape travel thereacross. N+1 of the N+1 transducers of the first array are about aligned with N+1 of the N+1 transducers of the second array when the axes of the arrays are positioned towards a second position, the axes of the arrays each being oriented at a second angle that is smaller than the first angle relative to the line oriented perpendicular to the intended direction of tape travel.
FIG. 1A illustrates a simplified tape drive 100 of a tape-based data storage system, which may be employed in the context of the present invention. While one specific implementation of a tape drive is shown in FIG. 1A, it should be noted that the embodiments described herein may be implemented in the context of any type of tape drive system.
As shown, a tape supply cartridge 120 and a take-up reel 121 are provided to support a tape 122. One or more of the reels may form part of a removable cartridge and are not necessarily part of the system 100. The tape drive, such as that illustrated in FIG. 1A, may further include drive motor(s) to drive the tape supply cartridge 120 and the take-up reel 121 to move the tape 122 over a tape head 126 of any type. Such head may include an array of readers, writers, or both.
Guides 125 guide the tape 122 across the tape head 126. Such tape head 126 is in turn coupled to a controller 128 via a cable 130. The controller 128, may be or include a processor and/or any logic for controlling any subsystem of the drive 100. For example, the controller 128 typically controls head functions such as servo following, data writing, data reading, etc. The controller 128 may operate under logic known in the art, as well as any logic disclosed herein. The controller 128 may be coupled to a memory 136 of any known type, which may store instructions executable by the controller 128. Moreover, the controller 128 may be configured and/or programmable to perform or control some or all of the methodology presented herein. Thus, the controller may be considered configured to perform various operations by way of logic programmed into a chip; software, firmware, or other instructions being available to a processor; etc. and combinations thereof.
The cable 130 may include read/write circuits to transmit data to the head 126 to be recorded on the tape 122 and to receive data read by the head 126 from the tape 122. An actuator 132 controls position of the head 126 relative to the tape 122.
An interface 134 may also be provided for communication between the tape drive 100 and a host (integral or external) to send and receive the data and for controlling the operation of the tape drive 100 and communicating the status of the tape drive 100 to the host, all as will be understood by those of skill in the art.
FIG. 1B illustrates an exemplary tape cartridge 150 according to one embodiment. Such tape cartridge 150 may be used with a system such as that shown in FIG. 1A. As shown, the tape cartridge 150 includes a housing 152, a tape 122 in the housing 152, and a nonvolatile memory 156 coupled to the housing 152. In some embodiments, the nonvolatile memory 156 may be embedded inside the housing 152, as shown in FIG. 1B. In more embodiments, the nonvolatile memory 156 may be attached to the inside or outside of the housing 152 without modification of the housing 152. For example, the nonvolatile memory may be embedded in a self-adhesive label 154. In one preferred embodiment, the nonvolatile memory 156 may be a Flash memory device, ROM device, etc., embedded into or coupled to the inside or outside of the tape cartridge 150. The nonvolatile memory is accessible by the tape drive and the tape operating software (the driver software), and/or other device.
By way of example, FIG. 2 illustrates a side view of a flat-lapped, bi-directional, two-module magnetic tape head 200 which may be implemented in the context of the present invention. As shown, the head includes a pair of bases 202, each equipped with a module 204, and fixed at a small angle α with respect to each other. The bases may be “U-beams” that are adhesively coupled together. Each module 204 includes a substrate 204A and a closure 204B with a thin film portion, commonly referred to as a “gap” in which the readers and/or writers 206 are formed. In use, a tape 208 is moved over the modules 204 along a media (tape) bearing surface 209 in the manner shown for reading and writing data on the tape 208 using the readers and writers. The wrap angle θ of the tape 208 at edges going onto and exiting the flat media support surfaces 209 are usually between about 0.1 degree and about 3 degrees.
The substrates 204A are typically constructed of a wear resistant material, such as a ceramic. The closures 204B made of the same or similar ceramic as the substrates 204A.
The readers and writers may be arranged in a piggyback or merged configuration. An illustrative piggybacked configuration comprises a (magnetically inductive) writer transducer on top of (or below) a (magnetically shielded) reader transducer (e.g., a magnetoresistive reader, etc.), wherein the poles of the writer and the shields of the reader are generally separated. An illustrative merged configuration comprises one reader shield in the same physical layer as one writer pole (hence, “merged”). The readers and writers may also be arranged in an interleaved configuration. Alternatively, each array of channels may be readers or writers only. Any of these arrays may contain one or more servo track readers for reading servo data on the medium.
FIG. 2A illustrates the tape bearing surface 209 of one of the modules 204 taken from Line 2A of FIG. 2. A representative tape 208 is shown in dashed lines. The module 204 is preferably long enough to be able to support the tape as the head steps between data bands.
In this example, the tape 208 includes 4 to 22 data bands, e.g., with 8 data bands and 9 servo tracks 210, as shown in FIG. 2A on a one-half inch wide tape 208. The data bands are defined between servo tracks 210. Each data band may include a number of data tracks, for example 1024 data tracks (not shown). During read/write operations, the readers and/or writers 206 are positioned to specific track positions within one of the data bands. Outer readers, sometimes called servo readers, read the servo tracks 210. The servo signals are in turn used to keep the readers and/or writers 206 aligned with a particular set of tracks during the read/write operations.
FIG. 2B depicts a plurality of readers and/or writers 206 formed in a gap 218 on the module 204 in Circle 2B of FIG. 2A. As shown, the array of readers and writers 206 includes, for example, 16 writers 214, 16 readers 216 and two servo readers 212, though the number of elements may vary. Illustrative embodiments include 8, 16, 32, 40, and 64 active readers and/or writers 206 per array, and alternatively interleaved designs having odd numbers of reader or writers such as 17, 25, 33, etc. An illustrative embodiment includes 32 readers per array and/or 32 writers per array, where the actual number of transducer elements could be greater, e.g., 33, 34, etc. This allows the tape to travel more slowly, thereby reducing speed-induced tracking and mechanical difficulties and/or execute fewer “wraps” to fill or read the tape. While the readers and writers may be arranged in a piggyback configuration as shown in FIG. 2B, the readers 216 and writers 214 may also be arranged in an interleaved configuration. Alternatively, each array of readers and/or writers 206 may be readers or writers only, and the arrays may contain one or more servo readers 212. As noted by considering FIGS. 2 and 2A-B together, each module 204 may include a complementary set of readers and/or writers 206 for such things as bi-directional reading and writing, read-while-write capability, backward compatibility, etc.
FIG. 2C shows a partial tape bearing surface view of complimentary modules of a magnetic tape head 200 according to one embodiment. In this embodiment, each module has a plurality of read/write (R/W) pairs in a piggyback configuration formed on a common substrate 204A and an optional electrically insulative layer 236. The writers, exemplified by the write transducer 214 and the readers, exemplified by the read transducer 216, are aligned parallel to an intended direction of travel of a tape medium thereacross to form an R/W pair, exemplified by the R/W pair 222. Note that the intended direction of tape travel is sometimes referred to herein as the direction of tape travel, and such terms may be used interchangeable. Such direction of tape travel may be inferred from the design of the system, e.g., by examining the guides; observing the actual direction of tape travel relative to the reference point; etc. Moreover, in a system operable for bi-direction reading and/or writing, the direction of tape travel in both directions is typically parallel and thus both directions may be considered equivalent to each other.
Several R/W pairs 222 may be present, such as 8, 16, 32 pairs, etc. The R/W pairs 222 as shown are linearly aligned in a direction generally perpendicular to a direction of tape travel thereacross. However, the pairs may also be aligned diagonally, etc. Servo readers 212 are positioned on the outside of the array of R/W pairs, the function of which is well known.
Generally, the magnetic tape medium moves in either a forward or reverse direction as indicated by arrow 220. The magnetic tape medium and head assembly 200 operate in a transducing relationship in the manner well-known in the art. The piggybacked MR head assembly 200 includes two thin-film modules 224 and 226 of generally identical construction.
Modules 224 and 226 are joined together with a space present between closures 204B thereof (partially shown) to form a single physical unit to provide read-while-write capability by activating the writer of the leading module and reader of the trailing module aligned with the writer of the leading module parallel to the direction of tape travel relative thereto. When a module 224, 226 of a piggyback head 200 is constructed, layers are formed in the gap 218 created above an electrically conductive substrate 204A (partially shown), e.g., of AlTiC, in generally the following order for the R/W pairs 222: an insulating layer 236, a first shield 232 typically of an iron alloy such as NiFe (−), CZT or Al—Fe—Si (Sendust), a sensor 234 for sensing a data track on a magnetic medium, a second shield 238 typically of a nickel-iron alloy (e.g.,  ̃80/20 at % NiFe, also known as permalloy), first and second writer pole tips 228, 230, and a coil (not shown). The sensor may be of any known type, including those based on MR, GMR, AMR, tunneling magnetoresistance (TMR), etc.
The first and second writer poles 228, 230 may be fabricated from high magnetic moment materials such as  ̃45/55 NiFe. Note that these materials are provided by way of example only, and other materials may be used. Additional layers such as insulation between the shields and/or pole tips and an insulation layer surrounding the sensor may be present. Illustrative materials for the insulation include alumina and other oxides, insulative polymers, etc.
The configuration of the tape head 126 according to one embodiment includes multiple modules, preferably three or more. In a write-read-write (W-R-W) head, outer modules for writing flank one or more inner modules for reading. Referring to FIG. 3, depicting a W-R-W configuration, the outer modules 252, 256 each include one or more arrays of writers 260. The inner module 254 of FIG. 3 includes one or more arrays of readers 258 in a similar configuration. Variations of a multi-module head include a R-W-R head (FIG. 4), a R-R-W head, a W-W-R head, etc. In yet other variations, one or more of the modules may have read/write pairs of transducers. Moreover, more than three modules may be present. In further embodiments, two outer modules may flank two or more inner modules, e.g., in a W-R-R-W, a R-W-W-R arrangement, etc. For simplicity, a W-R-W head is used primarily herein to exemplify embodiments of the present invention. One skilled in the art apprised with the teachings herein will appreciate how permutations of the present invention would apply to configurations other than a W-R-W configuration.
FIG. 5 illustrates a magnetic head 126 according to one embodiment of the present invention that includes first, second and third modules 302, 304, 306 each having a tape bearing surface 308, 310, 312 respectively, which may be flat, contoured, etc. Note that while the term “tape bearing surface” appears to imply that the surface facing the tape 315 is in physical contact with the tape bearing surface, this is not necessarily the case. Rather, only a portion of the tape may be in contact with the tape bearing surface, constantly or intermittently, with other portions of the tape riding (or “flying”) above the tape bearing surface on a layer of air, sometimes referred to as an “air bearing”. The first module 302 will be referred to as the “leading” module as it is the first module encountered by the tape in a three module design for tape moving in the indicated direction. The third module 306 will be referred to as the “trailing” module. The trailing module follows the middle module and is the last module seen by the tape in a three module design. The leading and trailing modules 302, 306 are referred to collectively as outer modules. Also note that the outer modules 302, 306 will alternate as leading modules, depending on the direction of travel of the tape 315.
In one embodiment, the tape bearing surfaces 308, 310, 312 of the first, second and third modules 302, 304, 306 lie on about parallel planes (which is meant to include parallel and nearly parallel planes, e.g., between parallel and tangential as in FIG. 6), and the tape bearing surface 310 of the second module 304 is above the tape bearing surfaces 308, 312 of the first and third modules 302, 306. As described below, this has the effect of creating the desired wrap angle α2 of the tape relative to the tape bearing surface 310 of the second module 304.
Where the tape bearing surfaces 308, 310, 312 lie along parallel or nearly parallel yet offset planes, intuitively, the tape should peel off of the tape bearing surface 308 of the leading module 302. However, the vacuum created by the skiving edge 318 of the leading module 302 has been found by experimentation to be sufficient to keep the tape adhered to the tape bearing surface 308 of the leading module 302. The trailing edge 320 of the leading module 302 (the end from which the tape leaves the leading module 302) is the approximate reference point which defines the wrap angle α2 over the tape bearing surface 310 of the second module 304. The tape stays in close proximity to the tape bearing surface until close to the trailing edge 320 of the leading module 302. Accordingly, read and/or write elements 322 may be located near the trailing edges of the outer modules 302, 306. These embodiments are particularly adapted for write-read-write applications.
A benefit of this and other embodiments described herein is that, because the outer modules 302, 306 are fixed at a determined offset from the second module 304, the inner wrap angle α2 is fixed when the modules 302, 304, 306 are coupled together or are otherwise fixed into a head. The inner wrap angle α2 is approximately tan−1(δ/W) where δ is the height difference between the planes of the tape bearing surfaces 308, 310 and W is the width between the opposing ends of the tape bearing surfaces 308, 310. An illustrative inner wrap angle α2 is in a range of about 0.3° to about 1.1°, though can be any angle required by the design.
Beneficially, the inner wrap angle α2 on the side of the module 304 receiving the tape (leading edge) will be larger than the inner wrap angle α3 on the trailing edge, as the tape 315 rides above the trailing module 306. This difference is generally beneficial as a smaller α3 tends to oppose what has heretofore been a steeper exiting effective wrap angle.
Note that the tape bearing surfaces 308, 312 of the outer modules 302, 306 are positioned to achieve a negative wrap angle at the trailing edge 320 of the leading module 302. This is generally beneficial in helping to reduce friction due to contact with the trailing edge 320, provided that proper consideration is given to the location of the crowbar region that forms in the tape where it peels off the head. This negative wrap angle also reduces flutter and scrubbing damage to the elements on the leading module 302. Further, at the trailing module 306, the tape 315 flies over the tape bearing surface 312 so there is virtually no wear on the elements when tape is moving in this direction. Particularly, the tape 315 entrains air and so will not significantly ride on the tape bearing surface 312 of the third module 306 (some contact may occur). This is permissible, because the leading module 302 is writing while the trailing module 306 is idle.
Writing and reading functions are performed by different modules at any given time. In one embodiment, the second module 304 includes a plurality of data and optional servo readers 331 and no writers. The first and third modules 302, 306 include a plurality of writers 322 and no data readers, with the exception that the outer modules 302, 306 may include optional servo readers. The servo readers may be used to position the head during reading and/or writing operations. The servo reader(s) on each module are typically located towards the end of the array of readers or writers.
By having only readers or side by side writers and servo readers in the gap between the substrate and closure, the gap length can be substantially reduced. Typical heads have piggybacked readers and writers, where the writer is formed above each reader. A typical gap is 20-35 microns. However, irregularities on the tape may tend to droop into the gap and create gap erosion. Thus, the smaller the gap is the better. The smaller gap enabled herein exhibits fewer wear related problems.
In some embodiments, the second module 304 has a closure, while the first and third modules 302, 306 do not have a closure. Where there is no closure, preferably a hard coating is added to the module. One preferred coating is diamond-like carbon (DLC).
In the embodiment shown in FIG. 5, the first, second, and third modules 302, 304, 306 each have a closure 332, 334, 336, which extends the tape bearing surface of the associated module, thereby effectively positioning the read/write elements away from the edge of the tape bearing surface. The closure 332 on the second module 304 can be a ceramic closure of a type typically found on tape heads. The closures 334, 336 of the first and third modules 302, 306, however, may be shorter than the closure 332 of the second module 304 as measured parallel to a direction of tape travel over the respective module. This enables positioning the modules closer together. One way to produce shorter closures 334, 336 is to lap the standard ceramic closures of the second module 304 an additional amount. Another way is to plate or deposit thin film closures above the elements during thin film processing. For example, a thin film closure of a hard material such as Sendust or nickel-iron alloy (e.g., 45/55) can be formed on the module.
With reduced-thickness ceramic or thin film closures 334, 336 or no closures on the outer modules 302, 306, the write-to-read gap spacing can be reduced to less than about 1 mm, e.g., about 0.75 mm, or 50% less than commonly-used LTO tape head spacing. The open space between the modules 302, 304, 306 can still be set to approximately 0.5 to 0.6 mm, which in some embodiments is ideal for stabilizing tape motion over the second module 304.
Depending on tape tension and stiffness, it may be desirable to angle the tape bearing surfaces of the outer modules relative to the tape bearing surface of the second module. FIG. 6 illustrates an embodiment where the modules 302, 304, 306 are in a tangent or nearly tangent (angled) configuration. Particularly, the tape bearing surfaces of the outer modules 302, 306 are about parallel to the tape at the desired wrap angle α2 of the second module 304. In other words, the planes of the tape bearing surfaces 308, 312 of the outer modules 302, 306 are oriented at about the desired wrap angle α2 of the tape 315 relative to the second module 304. The tape will also pop off of the trailing module 306 in this embodiment, thereby reducing wear on the elements in the trailing module 306. These embodiments are particularly useful for write-read-write applications. Additional aspects of these embodiments are similar to those given above.
Typically, the tape wrap angles may be set about midway between the embodiments shown in FIGS. 5 and 6.
FIG. 7 illustrates an embodiment where the modules 302, 304, 306 are in an overwrap configuration. Particularly, the tape bearing surfaces 308, 312 of the outer modules 302, 306 are angled slightly more than the tape 315 when set at the desired wrap angle α2 relative to the second module 304. In this embodiment, the tape does not pop off of the trailing module, allowing it to be used for writing or reading. Accordingly, the leading and middle modules can both perform reading and/or writing functions while the trailing module can read any just-written data. Thus, these embodiments are preferred for write-read-write, read-write-read, and write-write-read applications. In the latter embodiments, closures should be wider than the tape canopies for ensuring read capability. The wider closures may require a wider gap-to-gap separation. Therefore a preferred embodiment has a write-read-write configuration, which may use shortened closures that thus allow closer gap-to-gap separation.
Additional aspects of the embodiments shown in FIGS. 6 and 7 are similar to those given above.
A 32 channel version of a multi-module head 126 may use cables 350 having leads on the same or smaller pitch as current 16 channel piggyback LTO modules, or alternatively the connections on the module may be organ-keyboarded for a 50% reduction in cable span. Over-under, writing pair unshielded cables may be used for the writers, which may have integrated servo readers.
The outer wrap angles α1 may be set in the drive, such as by guides of any type known in the art, such as adjustable rollers, slides, etc. or alternatively by outriggers, which are integral to the head. For example, rollers having an offset axis may be used to set the wrap angles. The offset axis creates an orbital arc of rotation, allowing precise alignment of the wrap angle α1.
To assemble any of the embodiments described above, conventional u-beam assembly can be used. Accordingly, the mass of the resultant head may be maintained or even reduced relative to heads of previous generations. In other embodiments, the modules may be constructed as a unitary body. Those skilled in the art, armed with the present teachings, will appreciate that other known methods of manufacturing such heads may be adapted for use in constructing such heads.
As noted above, tape lateral expansion and contraction present many challenges to increasing data track density on conventional products. Conventional products have attempted to compensate for tape lateral expansion and contraction by controlling tape width by tension and improving the characteristics of the media itself. However, these methods fail to fully cancel the tape lateral expansion and contraction, and actually lead to other problems, including tape stretch and media cost increases, respectively.
FIGS. 8A-8C are intended to depict the effect of tape lateral expansion and contraction on transducer arrays position relative thereto, and are in no way intended to limit the invention. FIG. 5A depicts a module 800 relative to the tape 802, where the tape has a nominal width. As shown, the transducers 804 are favorably aligned with the data tracks 806 on the tape 802. However, FIG. 8B illustrates the effect of tape lateral contraction. As shown, contraction of the tape causes the data tracks to contract as well, and the outermost transducers 808 are positioned along the outer edges of the outer data tracks as a result. Moreover, FIG. 8C depicts the effect of tape lateral expansion. Here expansion of the tape causes the data tracks to move farther apart, and the outermost transducers 808 are positioned along the inner edges of the outer data tracks as a result. If the tape lateral contraction is greater than that shown in FIG. 8B, or the tape lateral expansion is greater than that shown in FIG. 5C, the outermost transducers 808 will cross onto adjacent tracks, thereby causing the data stored on adjacent tracks to be overwritten during a writing operation and/or resulting in readback of the wrong track during a readback operation. Moreover, running effects, such as tape skew and lateral shifting may exacerbate such problems, particularly for tape having shingled data tracks.
Thus, it would be desirable to develop a tape drive system able to read and/or write tracks onto the tape in the proper position, regardless of the extent of tape lateral expansion and/or contraction at any given time. Various embodiments described and/or suggested herein overcome the foregoing challenges of conventional products, by orienting at least two modules of a tape drive system, such as by rotating, pivoting and/or tilting, thereby selectively altering the pitch of the transducers in their arrays, as will soon become apparent.
By selectively orienting a module, the pitch of the transducers on the module is thereby altered, preferably aligning the transducers with the tracks on a tape for a given tape lateral expansion and/or contraction. Tape contraction (shrinkage) can be dealt with by orienting a nominally non-offset head, but tape expansion (dilation) cannot. Thus, to accommodate both shrinkage and dilation about a “nominal,” the head must be statically positioned at a nominal angle of at least approximately 0.1° as will be explained below. Thereafter, smaller angular adjustments (e.g., about 1° or lower, but could be more) may be made to the already-oriented module in order to compensate for any variation of the tape lateral expansion and/or contraction, thereby keeping the transducers aligned with tracks on the tape.
FIGS. 9A-9C illustrate representational views of the effects of orienting a module having transducer arrays. It should be noted that the angles of orientation illustrated in FIGS. 9A-9C are an exaggeration (e.g., larger than would typically be observed), and are in no way intended to limit the invention.
Referring to FIG. 9A, the module 900 is shown relative to the tape 902, where the tape has a nominal width. As illustrated, the module 900 is oriented at an angle θnom such that the transducers 904 are favorably aligned with the data tracks 906 on the tape 902. However, when the tape 902 experiences tape lateral contraction and/or expansion, the data tracks 906 on the tape contract and/or expand as well. As a result, the transducers on the module are no longer favorably aligned with the data tracks 906 on the tape 902.
In FIG. 9B, the tape 902 has experienced tape lateral contraction. Therefore, in a manner exemplified by FIG. 8B, the transducers 904 on the module 900 of FIG. 9B would no longer be favorably aligned with the data tracks 906 on the tape 902 if no adjustment were made. However, as alluded to above, smaller angular adjustments may be made to the already-oriented module 900 in order to compensate for tape lateral contraction. Therefore, referring again to FIG. 9B, the angle of orientation >θnom of the module 900 is further positioned at an angle greater than θnom. By increasing the angle >θnom the effective width w2 of the array of transducers decreases from the effective width w1 illustrated in FIG. 9A. This also translates to a reduction in the effective pitch between the transducers, thereby realigning the transducers along the contracted data tracks 906 on the tape 902 as shown in FIG. 9B.
On the other hand, when the tape experiences tape lateral expansion, the data tracks on the tape expand as well. As a result, the transducers on the module would no longer be favorably aligned with the data tracks on the tape if no adjustments were made. With reference to FIG. 9C, the tape 902 has experienced tape lateral expansion. As a result, further angular adjustments may be made to the angle of orientation of the module in order to compensate for the tape lateral expansion. Therefore, referring again to FIG. 9C, the angle of orientation <θnom of the module 900 is reduced to an angle less than θnom. By decreasing the angle of orientation <θnom the effective width w3 of the array of transducers 904 increases from the effective width w1 illustrated in FIG. 9A. Moreover, reducing the effective width of the array of transducers 904 also causes the effective pitch between the transducers to be reduced, thereby realigning the transducers along the data tracks 906 on the tape 902.
In a preferred embodiment, magnetic tape systems have two or more modules, each having an array of transducers, typically in a row. Depending on the desired embodiment, the additional rows of transducers may allow the system to read verify during the write process, but is not limited thereto. As mentioned above, the foregoing conventional challenges may be overcome, e.g., by rotating a given module about an axis orthogonal to the plane in which its array resides (e.g., parallel to the plane of the tape bearing surface), thereby selectively altering the pitch of the transducers in the array.
By providing a system that compensates for tape lateral expansion and/or contraction, various embodiments enable use of wider readers, resulting in a better signal to noise ratio (SNR), and/or smaller data tracks, resulting in a higher capacity per unit area of the media.
Furthermore, an apparatus capable of writing and/or reading data written in multiple data storage formats may be incorporated with any of the embodiments described above. This may preferably increase the data read and/or write performance of various embodiments presented herein by improving compensation with tape skew, shifting, lateral contraction and/or expansion, etc. In various embodiments, compatibility with multiple storage formats may be achieved by incorporating selectively tiltable data transducers, e.g., as described above with reference to FIGS. 9A-9C, as will soon become apparent.
FIGS. 10A-10D depict an apparatus 1000, in accordance with one embodiment. As an option, the present apparatus 1000 may be implemented in conjunction with features from any other embodiment listed herein, such as those described with reference to the other FIGS. Of course, however, such apparatus 1000 and others presented herein may be used in various applications and/or in permutations which may or may not be specifically described in the illustrative embodiments listed herein. Further, the apparatus 1000 presented herein may be used in any desired environment. Thus FIGS. 10A-10D (and the other FIGS.) should be deemed to include any and all possible permutations.
Referring now to FIGS. 10A-10C, the apparatus 1000 includes a magnetic head 1050 having two modules 1002, 1004. Moreover, each of the modules 1002, 1004 has an array 1006, 1008 of N+1 transducers 1010, respectively. The modules 1002, 1004 of the apparatus 1000 may additionally include servo transducer pairs S1, S2 as illustrated, which may include any type of servo transducer described and/or suggested herein, e.g., see 212 of FIG. 2C.
Although there are only two modules in the embodiment depicted in FIGS. 10A-10D, according to other embodiments, the apparatus 1000 may include at least two modules e.g., 2, 3, 4, etc. modules, depending on the desired embodiment. Moreover, it should be noted that the variable identifier “N” is used in several instances herein, to more simply designate the final element of a series of related or similar elements. The repeated use of such variable identifiers is not meant to imply a correlation between the sizes of such series of elements, although such correlation may exist. The use of such variable identifiers does not require that the series of elements has the same number of elements as another series delimited by the same variable identifier. Rather, in each instance of use, the variable identified by “N” may hold the same or a different value than other instances of the same variable identifier.
For example, which is in no way intended to limit the invention, in the embodiment illustrated in FIGS. 10A-10C, there are a total of 17 transducer pairs. Thus, N+1 (i.e., the total number of transducers)=17, thereby setting the value of N as 16. However, in other embodiments, the apparatus may include more or fewer transducers, thereby changing the value of “N” accordingly, depending on the embodiment.
With continued reference to FIGS. 10A-10C, according to a preferred embodiment, each of the transducers 1010 of the first and second arrays 1006, 1008 are reader/writer pairs. Thus, each transducer pair includes a reader and a writer, thereby preferably enabling read while write capability for the modules 1002, 1004 of the apparatus 1000. However, in another embodiment, the transducers for each of the modules of an apparatus may include arrays of single reader and/or writer transducers, e.g., see FIG. 11. In such embodiments having arrays of single transducers, at least three arrays may be incorporated, e.g., to enable read while write functionality as will be discussed in detail below.
With continued reference to FIGS. 10A-10C, the modules 1002, 1004 are preferably fixed relative to each other. In view of the present description, “fixed” is intended to mean constrained from a directional movement relative to each other such that the arrays of each maintain a fixed position relative to each other. According to various embodiments, the modules may be fixed relative to each other by using rods, fasteners, adhesives, cables, wire, etc. Moreover, according to different embodiments, the modules are preferably fixed relative to each other prior to being installed in the system 1000, head, etc. depending on the desired embodiment. However, the modules are preferably selectively orientable (e.g., tiltable and/or rotatable) as a single structure about a pivot point while remaining fixed relative to each other, as will soon become apparent.
The modules 1002, 1004, are also preferably fixed such that the axes 1012, 1013 of the arrays 1006, 1008 are oriented about parallel to each other, respectively, e.g., at a relative angle of less than 0.1°. As illustrated in FIGS. 10A-10C, the axes 1012, 1013 of each array of transducers are defined by the dashed lines that lie between opposite ends thereof, e.g., positioned farthest apart.
As mentioned above, the modules 1002, 1004 are preferably selectively orientable (e.g., tiltable and/or rotatable) between a first position and a second position, e.g., about a pivot point. Looking now to FIG. 10A, in one embodiment, the modules 1002, 1004 may be oriented such that the axes 1012, 1013 of the arrays 1006, 1008 are oriented at a first angle φ, relative to a line 1030 oriented perpendicular to an intended direction 1020 of tape travel thereacross. According to various embodiments, the first angle φ may be between about 0.1° and about 10°, but may be higher or lower depending on the desired embodiment.
When the axes 1012, 1013 of the arrays 1006, 1008 are positioned towards a first position (tilted), as shown in FIG. 10A, N of the N+1 transducers 1010 of the first array 1006 of a first module 1002 are preferably about aligned with N of the N+1 transducers of the second array 1008 of a second of the modules 1004. Furthermore, the N of the N+1 transducers 1010 of the first and second arrays 1006, 1008 are preferably aligned within the data tracks of a tape (not shown) when positioned towards and/or at the first position. Thus, the N of the N+1 transducers 1010 may preferably write to and/or read from N corresponding data tracks of a magnetic tape (e.g., see 902 and 906 of FIGS. 9A-9C).
However, referring now to FIG. 10B, when the axes 1012, 1013 of the arrays 1006, 1008 are positioned towards a second position (vertical) and aligned approximately with line 1030, N+1 of the N+1 transducers 1010 of the first array 1006 are preferably about aligned with N+1 of the N+1 transducers 1010 of the second array 1008. In order to achieve such alignment, the transducers and/or modules are preferably not offset in the crosstrack direction (orthogonal to the intended direction 1020 of tape travel) when positioned towards and/or at the second position.
Furthermore, the apparatus is preferably configured to read and/or write with the N+1 transducers when the axes 1012, 1013 of the arrays 1006, 1008 are positioned towards and/or at the second position. In various embodiments, the apparatus 1000 may use a mechanism 1014 and/or a controller 1016 to enable reading and/or writing with the N+1 and/or N of the N+1 transducers, depending on the desired embodiment, as described in detail below with reference to FIG. 10D.
Referring still to FIGS. 10A-10B, according to preferred embodiments, the second position corresponds to the axes 1012, 1013 of the arrays 1006, 1008 each being oriented at an angle that is smaller than the first angle, e.g., relative to the line 1030 oriented perpendicular to the intended direction 1020 of tape travel. As illustrated in FIG. 10B, the axes 1012, 1013 of the arrays 1006, 1008 are oriented about perpendicular to the intended direction 1020 of tape travel. Thus according to one embodiment, the second position may be characterized by the axes 1012, 1013 of the arrays 1006, 1008 being aligned about perpendicular to the intended direction 1020 of tape travel thereacross, e.g., the second angle is about 0 degrees.
However, according to a further embodiment, the modules 1002, 1004 may be selectively orientable between a first position, a second position, and/or a third position. Depending on the desired embodiment, the third position may correspond to a third angle that may be greater than the first angle (e.g., see FIG. 10C), or less than the second angle (e.g., see FIG. 11). Thus, in various embodiments, the modules may be positioned in a clock-wise or a counter clock-wise direction relative to the line 1030 depending on the direction the tape is moving, as will soon become apparent.
Referring now to FIG. 10C, the axes 1012, 1013 of the arrays 1006, 1008 are illustrated as being oriented at about a third position. As mentioned above, according to one embodiment, the third position may correspond to a third angle β that has a value greater than that of the first angle φ. Thus, depending on the value of the first angle, the third angle β may be between about 0.5° and about 15°, but may be higher or lower depending on the desired embodiment.
As illustrated in FIG. 10C, by orienting the axes 1012, 1013 of the arrays 1006, 1008 at a third angle β larger than that of the first angle (e.g., φ as shown in FIG. 10A), different transducer pairs align with each other along the intended direction 1020 of tape travel. According to one embodiment, N−1 of the N+1 transducers 1010 of the first array 1006 may be about aligned with N−1 of the N+1 transducers 1010 of the second array 1008 when the axes 1012, 1013 of the arrays 1006, 1008 are positioned towards the third position. However, depending on the angle at which the axes 1012, 1013 of the arrays 1006, 1008 are oriented when positioned at and/or towards a third position, different combinations of transducers from each of the arrays may align with each other.
Furthermore, the N−1 of the N+1 transducers 1010 of the first and second arrays 1006, 1008 are preferably aligned within the data tracks of a tape (not shown) when positioned towards and/or at the third position. Thus, the N−1 of the N+1 transducers 1010 may preferably write to and/or read from N−1 corresponding data tracks of a magnetic tape (e.g., see 902 and 906 of FIGS. 9A-9C).
The transducers 1010 of each array 1006, 1008 may also be positioned according to a logical numerical sequence. Looking to the embodiment illustrated in FIGS. 10A-10C, the transducers 1010 are numbered in ascending, numerical order according to one embodiment. Although the logical numerical sequence associated with the transducers 1010 of each of the arrays 1006, 1008 is shown as beginning at the top end of both of the modules 1002, 1004 (e.g., the topmost transducer pair is labeled as “1”), according to other embodiments, the logical numerical sequence may begin at the bottom of both of the modules. Moreover, according to another embodiment, the logical numerical sequence may begin at the top end of one of the modules, while beginning at the bottom end of the other module, e.g., at opposite ends thereof.
Thus, as illustrated in FIG. 10A, when the axes 1012, 1013 of the arrays 1006, 1008 are positioned towards the first position, the transducers 1010 of the first array 1006 at even positions (e.g., represented by even numbers next to the transducers 1010) in the numerical sequence are about aligned with the transducers 1010 of the second array 1008 at odd positions (e.g., represented by odd numbers next to the transducers 1010) in the numerical sequence. As mentioned above, the numerical sequences of the transducers in the arrays 1006, 1008 are illustrated as starting at a top of the modules 1002, 1004, but may alternatively start at a bottom of the modules 1002, 1004, or at opposite ends thereof, to achieve a similar result.
However, looking to FIG. 10B, the transducers 1010 of the first array 1006 at even positions (e.g., represented by even numbers next to the transducers 1010) in the numerical sequence may be about aligned with the transducers 1010 of the second array 1008 at even positions (e.g., represented by even numbers next to the transducers 1010) in the numerical sequence when the axes of the arrays 1006, 1008 are positioned towards the second position. Again, looking to FIG. 10B, when the arrays 1006, 1008 are positioned towards the second position, each of the N+1 transducers 1010 of each of the modules 1002, 1004 are about aligned with each other.
Moreover, referring again to FIG. 10C, by positioning the axes 1012, 1013 of the arrays 1006, 1008 at a third angle β larger than that of the first angle, the transducers 1010 of the first array 1006 at even positions (e.g., represented by even numbers next to the transducers 1010) in the numerical sequence may be about aligned with the transducers 1010 of the second array 1008 at even positions (e.g., represented by even numbers next to the transducers 1010) in the numerical sequence, different than the even positions of the first array 1006. For example, which is in no way intended to limit the invention, looking to the first module 1002, the transducer pair at position 4 is aligned in the intended direction 1020 of tape travel, with the transducer pair at position 2 of the second module 1004.
As the arrays 1006, 1008 are positioned between and/or at the first and second positions, the center to center pitch of the transducers 1010 as presented to a tape varies as described above with reference to FIGS. 9A-9C. With reference to the present description, the pitch as presented to tape is measured perpendicularly to the intended direction 1020 of tape travel between imaginary parallel lines extending through the data transducers along the intended direction 1020 of tape travel.
It follows that, according to one embodiment, when the axes 1012, 1013 of the arrays 1006, 1008 are positioned at and/or towards the first position (e.g., see FIG. 10A), the transducers of the first array 1006 and the transducers of the second array 1008 may be compatible with a first data storage format, e.g., having a first center to center data track pitch. However, according to another embodiment, when the axes 1012, 1013 of the arrays 1006, 1008 are positioned towards the second position (e.g., see FIG. 10B), the transducers of the first array 1006 and the transducers of the second array 1008 may be compatible with a second format, where the second format specifies a different center to center data track pitch than the first format. In other words, each of the first and second positions may correspond to a unique data storage format, e.g., having a unique center to center data track pitch.
In view of the description above, the first format may specify N concurrently written and/or read data tracks, which preferably correspond to the N of the N+1 transducers 1010 of the first and second arrays 1006, 1008 that are about aligned when the arrays 1006, 1008 are positioned towards the first position, as illustrated in FIG. 10A. Furthermore, the second format may specify N+1 concurrently written and/or read data tracks as opposed to the N concurrently written and/or read data tracks of the first format. The N+1 concurrently written and/or read data tracks also preferably correspond to the N+1 transducers 1010 of the first and second arrays 1006, 1008 that are about aligned when the arrays 1006, 1008 are positioned towards the second position, However, according to another embodiment, the second format may specify N/2 concurrently-written and/or concurrently-read data tracks. In various embodiments, N=2*M, wherein M is an integer, preferably in a range of 1 to 65.
Referring now to FIG. 10D, the apparatus 1000 may additionally include a mechanism 1014, such as a tape dimensional instability compensation mechanism, for orienting the modules to control a transducer pitch presented to a tape. The mechanism 1014 preferably allows for the orienting of the modules to be done while the modules are reading and/or writing. According to various embodiments, the mechanism 1014 may be any known mechanism suitable for orienting the modules. Illustrative mechanisms 1014 include worm screws, voice coil actuators, thermal actuators, piezoelectric actuators, etc.
The apparatus 1000 is also depicted as including a controller 1016. In one embodiment the controller 1016 may be configured to control the mechanism 1014 based on a readback signal of the tape, e.g., servo signals, data signals, a combination of both, etc. According to another embodiment, the controller 1016 may be configured to control the mechanism 1014 for orienting the modules 1002, 1004 based on a skew of the tape.
Furthermore, the controller 1016 may be configured to write data in a serpentine and/or non-serpentine fashion to a tape.
With continued reference to FIG. 10D, according to various embodiments, the dimensional conditions of the tape and/or orientation of the modules when the tape was written may be retrieved e.g., from a database, cartridge memory, etc., and the orientation may be set based thereon to about match the transducer pitch of the current operation to that of the previous operation. Furthermore, additional logic, computer code, commands, etc., or combinations thereof, may be used to control the mechanism 1014 for adjusting the orientation of the modules based on a skew of the tape. Moreover, any of the embodiments described and/or suggested herein may be combined with various functional methods, depending on the desired embodiment.
In one mode of use, when in a read only mode of operation with head the quasi-statically rotated or vertically oriented, and a reader becomes dysfunctional, then the head may index by 1, 2, or more positions corresponding generally to the transducer pitch along the line 1030 that is oriented orthogonal to the intended direction 1020 of tape travel, and still read the tape with all good readers. Accordingly, in one embodiment, a controller may be configured to shift a position of the array of transducers by one or more transducer pitches as measured in the direction (along line 1030) perpendicular to the intended direction of tape travel when one of the operating transducers is dysfunctional, e.g., not operating correctly, has failed, has an erratic output or error rate above a threshold, etc. As an example, referring to FIG. 10A, assume odd numbered transducers 1-15 of module 1004 are reading M tracks, where N=2M, or 8 in this example. Assume transducer 3 becomes dysfunctional. Upon detecting the dysfunction, the controller shifts the module such that the array shifts up by one position along line 1030, thereby aligning even transducers 2-16 over the tracks being read.
As mentioned above, although two modules 1002, 1004 are illustrated in FIGS. 10A-10D, in other embodiments, a system may include any number of modules e.g., at least two, at least three, at least four, a plurality, etc. depending on the desired embodiment. Referring to the illustrative embodiment depicted in FIG. 11, which may be considered a modification of apparatus 1000 of FIGS. 10A-10B, the apparatus 1100 shown may include a third module 1102 positioned between the first and second modules 1002, 1004. Accordingly, various components of FIG. 11 may have common numbering with those of FIGS. 10A-10D.
Looking to FIG. 11, the apparatus 1100 includes modules having arrays of transducers 1010. Moreover, as described above, the axes 1012, 1013, 1104 of the arrays 1006, 1008, 1106 are preferably oriented about parallel to each other respectively, in addition to being fixed relative to each other.
According to preferred embodiments, each of the N+1 transducers 1010 of a given array 1006, 1008, 1106 are of the same type. In other words, each of the N+1 transducers 1010 of the first array 1006 are of the same type, while the N+1 transducers 1010 of the second and third arrays 1008, 1106 are of the same type. Moreover, depending on the desired embodiment, the transducers of each of the arrays may be the same or different as the transducers of the other arrays. Thus, in various embodiments, the transducers 1010 of the first, second and/or third arrays 1006, 1008, 1106 may be readers and/or writers.
According to exemplary embodiments, the first second and/or third modules 1002, 1004, 1102 may be used for data writing and/or data reading, depending on the desired embodiment. Thus, the apparatus 1100 may serve as a write-read-write (WRW) device if the first and second modules 1002, 1004 are designed for at least data writing and the third module 1102 is designed for at least data reading. As an option, the first and second modules 1002, 1004 may be designed for data writing and not for data reading, and/or the third module 1102 maybe designed for data reading and not for data writing.
In another embodiment, the apparatus 1100 may serve as a read-write-read (RWR) device if the first and second modules 1002, 1004 are designed for at least data reading and optionally not for data writing, while the third module 1102 is designed for at least data writing and optionally not for data reading. However, this is in no way meant to limit the invention; according to various other embodiments, a third, fourth, fifth, etc. module may be positioned with any orientation relative to other modules of the system, depending on the desired embodiment.
With continued reference to FIG. 11, the axes 1012, 1013, 1104 of the arrays 1006, 1008, 1106 may be positionable towards a third position, according to one embodiment. As illustrated, the third position may be characterized by the axes 1012, 1013, 1104 of the arrays 1006, 1008, 1106 each being oriented at a third angle  ̃φ, relative to the line 1030 oriented perpendicular to the intended direction 1020 of tape travel, e.g., thereby having a negative value. According to various embodiments, when the axes 1012, 1013, 1104 are positioned in and or towards the third position, the third angle −φ may be between about −0.1° and about −10°, but may be higher or lower depending on the desired embodiment. However, when the axes 1012, 1013, 1104 of the arrays 1006, 1008, 1106 are positioned towards and/or at the third position, the axes 1012, 1013, 1104 of the arrays 1006, 1008, 1106 are each oriented at a third angle having a greater absolute value than the first angle φ, but the third angle may be the same and/or smaller than the first angle in some embodiments.
As described above, the transducers 1010 of each array 1006, 1008, 1106 may be positioned according to a logical numerical sequence. Referring still to the embodiment illustrated in FIG. 11, the transducers 1010 may be numbered in ascending, numerical order according to one embodiment. In a further embodiment, the logical numerical sequence associated with the transducers 1010 of each of the array 1006, 1106, 1008 may begin at the top end of both of all three of the modules 1002, 1004, 1104 (e.g., the topmost transducer may be labeled as “1” as illustrated in FIGS. 10A-10B). However, in other embodiments, the logical numerical sequence may begin at the bottom of all three of the modules 1002, 1004, 1104 of FIG. 11, and/or combinations thereof. For example, the logical numerical sequence may begin at the top end of two of the modules, while beginning at the bottom end of the other module, e.g., at opposite ends thereof.
Thus, when the axes 1012, 1013, 1104 of the arrays 1006, 1008, 1106 are positioned towards a third position, N−1 of the N+1 transducers of the first array 1006 may be about aligned with N−1 of the N+1 transducers of the second array 1008. Additionally, when positioned towards the third position, N of the N+1 transducers 1010 of the first array 1006 may be about aligned with N of the N+1 transducers 1010 of the third array 1106, i.e., the adjacent array. Furthermore, N of the N+1 transducers 1010 of the third array 1106 may be about aligned with N of the N+1 transducers 1010 of the second array 1008.
Depending on the desired embodiment, the transducers of the first, second and/or third modules may be used in conjunction with each other, e.g., by incorporating a controller as illustrated in FIG. 10D. However, depending on the configuration of modules used in combination, a different number of transducers thereon may be used to read from and/or write to data tracks on the tape.
In various embodiments, the transducers 1010 of the arrays 1006, 1008, 1106 may preferably have a RWR configuration to conduct non-serpentine writing. A RWR configuration allows the same writer array to write each adjoining data track, despite reversal of the tape direction and/or orientation of the arrays 1006, 1008, 1106 while writing thereto. This may reduce writing errors, readback errors, data loss, etc., as well as reducing the misregistration budgeting requirements, as only one set of track tolerances comes into play. Moreover, using the same writer array to write adjoining data tracks ensures consistency while writing (e.g., by enabling symmetrical servo pattern reading), overall higher areal density, etc.
Thus, as illustrated in the representational diagram of FIG. 12A, which is in no way intended to limit the invention, the angles of orientation of the magnetic transitions on the tape 902 may be different such that the magnetic transitions written in the shingled data tracks 1202 in one direction are at a different angle than the magnetic transitions in shingled data tracks 1204 written in the opposite direction. Moreover, when reading a data track, the reader array may be oriented to about match the angle of the written transitions of each shingled data track to read the data thereon. Thus, if the reader array drifts over one of the adjacent data tracks, the off-track reading rejection SNR is higher, because the angle of orientation of the magnetic transitions on the adjacent data track will not match the angle of orientation of the read array.
Note that, while not ideal, a WRW configuration could be used for non-serpentine writing in some embodiments. In such embodiments, it is preferable that, while writing data to adjoining data tracks, especially shingled data tracks, the same writer array is used for the adjoining data tracks. Moreover, similar to the description presented immediately above, different writer arrays are not typically identical, as they have different alignment characteristics, and therefore write data differently. For example, the write transducers of one writer array may not have the same pitch, spacing, etc. as the write transducers of another writer array. Thus, using multiple writer arrays to write data to adjoining data tracks may result in readback errors, as the data written to the tracks may be aligned differently on each pass. According to another example, using different writer arrays may result in overwriting data on an adjoining track, thereby causing data loss.
Referring again to FIG. 11, as mentioned above, according to another illustrative embodiment, the transducers 1010 of the arrays 1006, 1008, 1106 may have a WRW configuration (e.g., the data transducers 1010 of the first and second arrays 1006, 1008 may include writers, wherein the data transducers of the third array 1106 may include readers), e.g., which is a preferable configuration when conducting serpentine writing. While writing data with a WRW configuration, the leading writer and reader are preferably active, while the trailing writer is not active, depending on the intended direction 1020 of tape travel. As a result, the leading writer array may be used to write adjoining data tracks for one direction 1020 of tape travel, while the trailing writer array may be used to write adjoining data tracks for the opposite direction of tape travel.
Thus, as illustrated in the representational diagram of FIG. 12B, which is in no way intended to limit the invention, the angles of orientation of the magnetic transitions on the tape 902 may be about the same for shingled data tracks 1202 written in a first direction of tape travel, but different than the angles of orientation of the magnetic transitions in the shingled data tracks 1204 written during the opposite direction of tape travel. This preferably reduces writing errors, readback errors, data loss, etc. and ensures consistency while writing, e.g., by enabling symmetrical servo pattern reading.
According to yet another embodiment, the arrays 1006, 1008, 1106 may have a RWR configuration as described above, for conducting serpentine writing. While writing data with a RWR configuration, the writer and corresponding trailing reader may preferably be active, while the leading reader is not active, depending on the direction 1020 of tape travel. As a result, the same writer may be used to write each adjoining data track for both directions of tape travel, despite reversal thereof while writing.
It will be clear that the various features of the foregoing systems and/or methodologies may be combined in any way, creating a plurality of combinations from the descriptions presented above.
As will be appreciated by one skilled in the art, aspects of the present invention may be embodied as a system, method or computer program product. Accordingly, aspects of the present invention may take the form of an entirely hardware embodiment, an entirely software embodiment (including firmware, resident software, micro-code, etc.) or an embodiment combining software and hardware aspects that may all generally be referred to herein as “logic,” a “circuit,” “module,” or “system.” Furthermore, aspects of the present invention may take the form of a computer program product embodied in one or more computer readable medium(s) having computer readable program code embodied thereon.
Any combination of one or more computer readable medium(s) may be utilized. The computer readable medium may be a computer readable signal medium or a non-transitory computer readable storage medium. A computer readable storage medium may be, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples (a non-exhaustive list) of the non-transitory computer readable storage medium include the following: a portable computer diskette, a hard disk, a random access memory (RAM), a read-only memory (ROM), an erasable programmable read-only memory (EPROM or Flash memory), a portable compact disc read-only memory (e.g., CD-ROM), a Blu-ray disc read-only memory (BD-ROM), an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a non-transitory computer readable storage medium may be any tangible medium that is capable of containing, or storing a program or application for use by or in connection with an instruction execution system, apparatus, or device.
A computer readable signal medium may include a propagated data signal with computer readable program code embodied therein, for example, in baseband or as part of a carrier wave. Such a propagated signal may take any of a variety of forms, including, but not limited to, electro-magnetic, optical, or any suitable combination thereof. A computer readable signal medium may be any computer readable medium that is not a non-transitory computer readable storage medium and that can communicate, propagate, or transport a program for use by or in connection with an instruction execution system, apparatus, or device, such as an electrical connection having one or more wires, an optical fibre, etc.
Program code embodied on a computer readable medium may be transmitted using any appropriate medium, including but not limited to wireless, wireline, optical fibre cable, RF, etc., or any suitable combination of the foregoing.
Computer program code for carrying out operations for aspects of the present invention may be written in any combination of one or more programming languages, including an object oriented programming language such as Java, Smalltalk, C++ or the like and conventional procedural programming languages, such as the “C” programming language or similar programming languages. The program code may execute entirely on the user's computer, partly on the user's computer, as a stand-alone software package, partly on the user's computer and partly on a remote computer or entirely on the remote computer or server. In the latter scenario, the remote computer may be connected to the user's computer through any type of network, including a local area network (LAN) or a wide area network (WAN), or the connection may be made to an external computer, for example through the Internet using an Internet Service Provider (ISP).
Aspects of the present invention are described herein with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems) and computer program products according to embodiments of the invention. It will be understood that each block of the flowchart illustrations and/or block diagrams, and combinations of blocks in the flowchart illustrations and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions/acts specified in the flowchart and/or block diagram block or blocks.
These computer program instructions may also be stored in a computer readable medium that can direct a computer, other programmable data processing apparatus, or other devices to function in a particular manner, such that the instructions stored in the computer readable medium produce an article of manufacture including instructions which implement the function/act specified in the flowchart and/or block diagram block or blocks.
The computer program instructions may also be loaded onto a computer, other programmable data processing apparatus, or other devices to cause a series of operational steps to be performed on the computer, other programmable apparatus or other devices to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide processes for implementing the functions/acts specified in the flowchart(s) and/or block diagram block or blocks.
It will be further appreciated that embodiments of the present invention may be provided in the form of a service deployed on behalf of a customer.
While various embodiments have been described above, it should be understood that they have been presented by way of example only, and not limitation. Thus, the breadth and scope of an embodiment of the present invention should not be limited by any of the above-described exemplary embodiments, but should be defined only in accordance with the following claims and their equivalents.

## Claims

1. An apparatus, comprising:
at least two modules, each of the modules having an array of N+1 transducers,
wherein an axis of each array is defined between opposite ends thereof,
wherein the axes of the arrays are oriented about parallel to each other,
wherein no more than N of the N+1 transducers of a first array of a first of the modules are about aligned with N of the N+1 transducers of a second array of a second of the modules when the axes of the arrays are positioned towards a first position, the first position being characterized by the axes of the arrays each being oriented at a first angle between about 0.1° and about 10° relative to a line oriented perpendicular to an intended direction of tape travel thereacross,
wherein N+1 of the N+1 transducers of the first array are about aligned with N+1 of the N+1 transducers of the second array when the axes of the arrays are positioned towards a second position, the axes of the arrays each being oriented at a second angle that is smaller than the first angle relative to the line oriented perpendicular to the intended direction of tape travel.

2. An apparatus as recited in claim 1, wherein the transducers of the first array and the transducers of the second array are compatible with a first format when the axes of the arrays are positioned towards the first position, the first format specifying N concurrently-written and/or concurrently-read data tracks, wherein the transducers of the first array and the transducers of the second array are compatible with a second format when the axes of the arrays are positioned towards the second position, the second format specifying a different track pitch than the first format.

3. An apparatus as recited in claim 2, wherein the second format specifies N/2 concurrently-written and/or concurrently-read data tracks, where N=2*M, wherein M is an integer.

4. An apparatus as recited in claim 1, where N=2*M, wherein M is an integer.

5. An apparatus as recited in claim 1, further comprising a controller configured to shift the array of transducers by one or more transducer pitches in a direction perpendicular to the intended direction of tape travel when one of the operating transducers is dysfunctional.

6. An apparatus as recited in claim 1, wherein the transducers of the first array are reader/writer pairs, wherein the transducers of the second array are reader/writer pairs.

7. An apparatus as recited in claim 1, wherein the second position is characterized by the axes of the arrays being aligned about perpendicular to the intended direction of tape travel thereacross.

8. An apparatus as recited in claim 1, further comprising a controller configured to write data in a non-serpentine fashion using the apparatus.

9. An apparatus as recited in claim 1, further comprising a controller configured to write data in a serpentine fashion using the apparatus.

10. An apparatus as recited in claim 1, further comprising a mechanism for orienting the modules to control a transducer pitch presented to a tape.

11. An apparatus as recited in claim 10, further comprising a controller configured to control the mechanism for orienting the modules based on a skew of the tape.

12. An apparatus as recited in claim 1, wherein the apparatus is configured to read and/or write with the N+1 transducers when the axes of the arrays are positioned towards the second position.

13. An apparatus as recited in claim 1, wherein the transducers of each array are positioned according to a logical numerical sequence, wherein the transducers of the first array at even positions in the numerical sequence are about aligned with the transducers of the second array at odd positions in the numerical sequence when the axes of the arrays are positioned towards the first position.

14. An apparatus as recited in claim 1, wherein the transducers of each array are positioned according to a logical numerical sequence, wherein the transducers of the first array at even positions in the numerical sequence are about aligned with the transducers of the second array at even positions in the numerical sequence when the axes of the arrays are positioned towards the second position.

15. An apparatus as recited in claim 1, wherein the axes of the arrays are positionable towards a third position, the third position being characterized by the axes of the arrays each being oriented at a third angle between about −0.1° and about −10° relative to the line oriented perpendicular to the intended direction of tape travel when the axes are in the third position.

16. An apparatus as recited in claim 15, wherein at least three modules are present.

17. An apparatus as recited in claim 1, wherein N−1 of the N+1 transducers of the first array are about aligned with N−1 of the N+1 transducers of the second array when the axes of the arrays are positioned towards a third position, the third position being characterized by the axes of the arrays each being oriented at a third angle greater than the first angle.

18. An apparatus as recited in claim 1, further comprising:
a drive mechanism for passing a magnetic medium over the modules; and
a controller electrically coupled to the modules.