Device select system for multi-device electronic system

A device select system according to one embodiment includes an array of first electrical contacts adapted for coupling to a cable; an array of second electrical contacts adapted for coupling to an array of transducers, there being more second electrical contacts than first electrical contacts each of the first electrical contacts being associated with at least two of the second electrical contacts; and a select mechanism for selectively placing each of the first electrical contacts in electrical communication with one of the second electrical contacts associated therewith.

FIELD OF THE INVENTION

The present invention relates to magnetic storage system components, and more particularly, this invention relates to a device select system for selecting devices on a magnetic head.

BACKGROUND OF THE INVENTION

Business, science and entertainment applications depend upon computers to process and record data, often with large volumes of the data being stored or transferred to nonvolatile storage media, such as magnetic discs, magnetic tape cartridges, optical disk cartridges, floppy diskettes, or optical diskettes. Typically magnetic tape is the most economical means of storing or archiving the data. Storage technology is continually pushed to increase storage capacity and storage reliability. Improvement in data storage densities in magnetic storage media, for example, has resulted from improved medium materials, improved error correction techniques and decreased areal bit sizes. The data capacity of half-inch magnetic tape, for example, is now measured in hundreds of gigabytes on 512 or more data tracks.

The improvement in magnetic medium data storage capacity arises in large part from improvements in tile magnetic head assembly used for reading and writing data on the magnetic storage medium. A major improvement in transducer technology arrived with the magnetoresistive (MR) sensor originally developed by the IBM® Corporation. Later sensors using tile GMR effect were developed. AMR and GMR sensors transduce magnetic field changes to resistance changes, which are processed to provide digital signals. Data storage density can be increased because AMR and GMR sensors offer signal levels higher than those available from conventional inductive read heads for a given read sensor width and so enable smaller reader widths and thus more tracks per inch. Moreover, the sensor output signal depends only on the instantaneous magnetic field intensity in the storage medium and is independent of the magnetic field time-rate-of-change arising from relative sensor/medium velocity. In operation the magnetic storage medium, such as tape or a magnetic disk surface, is passed over the magnetic read/write (R/W) head assembly for reading data therefrom and writing data thereto.

However, increased storage capacity does not come without cost. For instance, as the number of R/W elements on a given head increases, so too must the number of electrical connections to the head. This means that the cable(s) connecting the head to the controller must accommodate the increased number of connections. One problem that arises is that cables tend to get more complex and costly as the number of devices in the head and therefore the number of leads in the cable, increases. Further, cables tend to get wider, and thus stiffer and more massive as the number of leads increases, which in turn can negatively affect actuator bandwidth and make cable routing for freedom of motion more difficult. Generally, shrinking the dimensions of the leads in the cable is not all option, as DC resistance and AC impedance would also change undesirably.

Current technology fails to address tape head cabling problems that will be posed by bourgeoning I/O needs for future multi-track, multi-format or multi-function tape heads.

SUMMARY OF THE INVENTION

A device select system according to one embodiment includes an array of first electrical contacts adapted for coupling to a cable; an array of second electrical contacts adapted for coupling to an array of transducers, there being more second electrical contacts than first electrical contacts, each of the first electrical contacts being associated with at least two of the second electrical contacts; and a select mechanism for selectively placing each of the first electrical contacts in electrical communication with one of take second electrical contacts associated therewith.

A magnetic data system according to one embodiment includes a magnetic head; a device select system coupled to the magnetic head, the device select system comprising: a first portion having an array of first electrical contacts; a second portion having an array of second electrical contacts, there being more second electrical contacts than first electrical contacts, the second portion being coupled to the magnetic head, each of the first electrical contacts being associated with at least two of the second electrical contacts; and a select mechanism for selectively placing each of the first electrical contacts in electrical communication with one of the second electrical contacts associated therewith. A cable is electrically coupled to the first portion of the device select system. A drive mechanism is also present for passing a magnetic recording medium over the head. A controller electrically coupled to the cable.

A magnetic head according to one embodiment includes an array of first electrical contacts adapted for operative coupling to a cable; a plurality of transducers, there beings more transducers than first electrical contacts, each of the first electrical contacts being associated with at least two of the transducers; and a select mechanism for selectively placing each of the first electrical contacts in electrical communication with one of the transducers associated therewith.

A magnetic head according to one embodiment includes a substrate; an array of first electrical contacts formed on the substrate; a plurality of transducers formed above the substrate, there being more transducers than first electrical contacts, each of the first electrical contacts being associated with at least two of the transducers; and a select mechanism for selectively placing each of the first electrical contacts in electrical communication with one of the transducers associated therewith.

Any of these embodiments may be implemented in a tape drive system, which may include a magnetic head, a drive mechanism for passing a magnetic recording tape over the magnetic head, and a controller electrically coupled to the magnetic head.

BEST MODE FOR CARRYING OUT THE INVENTION

The following description is the best mode presently contemplated for carrying out the present invention. This 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 on with other described features in each of the various possible combinations and permutations.

In the drawings, like and equivalent elements are numbered the same throughout the various figures.

The embodiments described below disclose a new device select system that allows selective creation of electrical connections between electrical contacts for such things as selecting particular groups of transducers and not others. The system may be fabricated as a standalone unit, or integrated into an intermediate or final device. In particularly preferred approaches directed to tape-based data storage systems, the device select system contains circuitry that enables reader (and/or writer) transducer device selection, thereby reducing the number of leads in the cable. The only other known solution is a complex, stiffer cable, which suffers from the drawbacks mentioned above and is more costly. Alternatively, shrinking lead widths and spacing can negatively impact cable resistance and impedance.

While much of the present description is presented in terms of implementation in a tape-based data storage system for clarity and to place the invention in a context, it should be kept in mind that the general concepts presented herein have broad applicability to electronic devices of other types.

FIG. 1illustrates a device select system10according to one general embodiment. As shown, the system10includes an array of first electrical contacts12adapted for coupling to a cable. The first electrical contacts12may be pads present on the surface of the structure, apertures adapted to receive pins, pins adapted for insertion in apertures, pads or other contact mechanism located under subsequently-formed layers, etc.

An array of second electrical contacts14is also present and is adapted for coupling to devices such as transducers of a magnetic head. More second electrical contacts14are present than first electrical contacts. Each of them first electrical contacts12is associated with at least two of the second electrical contacts14. It follows that each of the first electrical contacts12may be associated with three, four, five or more second electrical contacts14. The second electrical contacts14may be pads present on the surface of the structure, apertures adapted to receive pins, pins adapted for insertion in apertures, pads or other contact mechanism located under subsequently-formed layers, etc.

A select mechanism16selectively places each of the first electrical contacts12in electrical communication with one of the second electrical contacts14associated therewith.

In one embodiment, the select mechanism16includes an array of switches S1, S2, the array being for selectively placing each of the first electrical contacts12in electrical communication with one of the second electrical contacts14associated therewith. To control tire select mechanism16, one or more third electrical contracts18may be in electrical communication with the select mechanism16for passing control signals thereto.

The switches S1, S2, may simply be transistors, such as field effect transistors, bipolar junction transistors, or any of the many types of semiconductor gates. More elaborate switching mechanisms comprised, for example, of gate arrays known in the art may also be employed.

In one approach, the first and second electrical contacts and select mechanism of the device select system are formed in a common structure.

Referring toFIG. 2A, one particularly preferred embodiment designed for coupling to a tape head includes a semiconductor chip20, a first potion22of which may be coupled to a tape head cable26and a second portion24of which may be coupled to a magnetic tape head28.

The first portion22has an array of first electrical contacts12that cooperate with electrical contacts or exposed conductors on the cable26when coupled thereto. The electrical contacts or exposed conductors of the cable26may be attached to the chip20via any suitable bonding method known in the art. Preferred approaches use ultrasonic bonding methods or anisotropic conductive film (ACF).

The second portion24has an array of second electrical contacts14, there being more second electrical contacts14than first electrical contacts12. Each of the first electrical contacts12is associated with at least two of the second electrical contacts14.

The magnetic head28has contacts corresponding to the second electrical contacts14on the chip20, the head contacts typically being coupled to reader (and/or writer) transducers on the head28. The second electrical contacts14of the chip20may be coupled to the electrical contacts on the magnetic bead28via wires50using any, suitable bonding method known in the art. Preferred approaches use ultrasonic or thermocompression bonding methods.

In a preferred implementation, the head28is bonded to the edge of the chip20using any known method, such as by application of an adhesive52.

The arrangement of the electrical contacts12,14on the various portions is not critical, and may vary depending on the cable and/or head design.

FIG. 2Bdepicts a variation of the embodiment ofFIG. 2A. As shown inFIG. 2B, a bridge cable56, sometimes called a coupon, is used to create the coupling between the second electrical contacts14on the chip20to the electrical contacts of the bead28.

The chip20includes the circuitry of the select mechanism that enables reader (and/or writer) transducer device selection, thereby reducing the number of required leads in the connecting cable26. Preferably, the cable26has the only the leads needed to connect to one bank of reader (and/or writer) transducer devices on the head28. For the conductive path to reader devices, the closed switch resistance is preferably small compared to the device resistance, which is typically 50-100 ohms. The open switch resistance is preferably >10 Kohm. Switching time is not typically a critical factor. The lines typically carry up to 15 mA DC or smaller. The signal is AC modulation of the DC bias voltage and has a bandwidth of approximately 10-50 MHz. For writer devices, the closed switch resistance is again preferably small compared to the DC coil resistance of the writer coil, which is typically 5-20 ohms. The writer currents are typically 10-50 milliamperes and the write frequency is typically in the range of 100-300 MHz, or higher.

FIG. 2Cillustrates another embodiment in which the chip20is positioned in a recess formed in a beam58supporting the head28. The electrical connections between the chip20, cable26, and head28may be similar to those set forth above.

FIG. 2Dillustrates yet another embodiment in which the second electrical contacts14of the chip20cooperate directly with the electrical contacts on the head28. The electrical contacts or exposed conductors of the cable26bay be attached to the first contacts12of the chip20, and the contacts of the head28may be connected to the second electrical contacts14of the chip20, via any suitable bonding method known in the art. Preferred approaches use ultrasonic bonding methods or anisotropic conductive film (ACF).

FIG. 2Eillustrates yet another embodiment in which the first and second electrical contacts12,14of chip20are positioned on different surfaces.

Referring toFIG. 2F, of the embodiment designed for coupling to a tape head includes a semiconductor chip20, a first surface22of which may be coupled to a tape head cable26and a second surface24of which may be coupled to a magnetic tape head28.

The first surface22has an array of first electrical contacts12that cooperate with electrical contacts on the cable26when coupled thereto. The cable26may be attached to the chip20via any suitable bonding method known in the art. Preferred approaches use anisotropic conductive film (ACF) or ultrasonic methods.

The second surface24has an array of second electrical contacts14, there being more second electrical contacts14than first electrical contacts12. Each of the first electrical contacts12is associated with at least two of the second electrical contacts14. The second surface24may be coupled to the magnetic head28, the magnetic head28having contacts corresponding to the second electrical contacts14on the chip20, the head contacts typically being coupled to reader (and/or writer) transducers on the head28. In a preferred implementation, the head28is bonded to the edge of the chip20. The gold plate pads of the chip20and head28may be connected via stitch bonding.

The arrangement of the electrical contacts12,14on the various surfaces is not critical, and may vary depending on the cable and/or head design.FIG. 2Gillustrates how a first surface22may be configured.FIG. 2Hillustrates one illustrative embodiment in which the second electrical contacts14for one set of devices are in one group, and the second electrical contacts14for a second set of devices are in another group.

Note that additional contacts may be present on either surface for such things as shared servo elements, control lines, etc. For example, as shown inFIG. 2G, one or more third electrical contacts30may be present on the first surface, and being in electrical communication with the select mechanism, allow passing of control signals thereto. The various additional contacts may include direct connections (with no select capability), selectable connections, and combinations thereof.

In another approach, the device select system may be integral to a larger system having the devices to be switched. As an example,FIG. 3illustrates a magnetic head40with an integral device select system according to one embodiment. As shown, the head40includes an array of first electrical contacts12adapted for operative coupling to a cable. A plurality of reader and/or write transducers42are present on the head40(one shown) for reading or writing to the tape108, there being more transducers42than first electrical contacts12. Preferably, each of the first electrical contacts12is associated with at least two of the transducers42. Again, additional electrical contacts30may be present for such things as servo reading, control of the select mechanism, etc. Further, additional transducers may be present, such as shared servo readers, etc.

The select mechanism44selectively places each of the first electrical contacts12in electrical communication with one of the transducers42associated therewith. The select mechanism may be implemented using any suitable fabrication technique including thin film processing, printed circuit techniques etc.

In a preferred approach, the select mechanism44includes a complementary metal-oxide-semiconductor (CMOS) circuit having a plurality of gates that perform the switching. The CMOS circuit may be formed above a substrate46. Where the substrate46is a silicon wafer, for example, conductive vias48from the cable-side surface to the CMOS circuit may be formed by the silicon anisotropic etching process that is well known. The first electrical contacts12may include pads formed above the vias.

The transducers42may be formed above the substrate46and the layer housing the select mechanism44using traditional silicon insulator processes.

The following description describes several environments in which various embodiments of the present invention may be implemented or integrated.

FIG. 4illustrates a traditional flat-lapped bi-directional, two-module magnetic tape head100, in accordance with one embodiment. As shown, the head includes a pair of bases102, each equipped with a module104. The bases are typically “U-beams” that are adhesively coupled together. Each module104includes a substrate104A and a closure104B with readers and writers106situated therebetween. In use, a tape108is moved over the modules104along a tape bearing surface109in the manner shown for reading and writing data on the tape108using the readers and writers106. Conventionally, a partial vacuum is formed between the tape108and the tape bearing surface109for maintaining the tape108in close proximity with the readers and writers106.

FIG. 4Aillustrates the tape bearing surface109of one of the modules104. The tape108its shown in dashed lines. The module is long enough to be able to support the tape as the head steps between data tracks.

As the tape108includes four data bands (Band0-3) that are defined between servo tracks202. Each data band may include a number of data tracks, for example 96 data tracks (not shown). During read/write operations, the elements106are positioned within one of the data bands. Outer readers, sometimes called servo readers, read the servo tracks202. The servo signals are in turn used to keep the elements106aligned with a particular track during the read/write operations. Typically, a coarse positioner (worn gear, etc.) places the head generally adjacent a given data track, then a fine positioner (voice coil, etc.) keeps the heads aligned using the servo tracks.

FIG. 4Bdepicts a plurality of read/write elements106formed in a gap208on the module104ofFIG. 4A. As shown, the array of elements106includes, for example, sixteen writers209, sixteen readers210, and two servo readers212. As noted by consideringFIGS. 4 and 4A-B together, each module104will include a complementary set of elements106.

As mentioned above with reference toFIG. 4, a typical tape head includes two modules, each module having an array of data elements thereon for reading and/or writing data in a particular data format. The present invention may be implemented in the context of a two module head capable of reading and/or writing in two different data formats. One skilled in the art will also appreciate that the embodiments herein can also be expanded to heads having a single module (where, for example the single module may be formed on a single substrate) and heads having more than two modules. The present invention may also be implemented in the context of a head where modes such as the ability to read and/or write are selectively enabled.

The device select system is particularly useful with multi-format heads. Some illustrative multi-format heads are presented below. The device select system allows selection of the various transducer arrays without requiring cabling for each individual transducer. The device select system may thus be used for multi-format arrays in which the multiple formats are separated into different modules built on multiple planes on the same module, built using a scheme of interleaving and sharing and/or side by side.

FIG. 5illustrates a multi-format head300. As shown, the head300includes two sets of modules, an outer pair of modules302A,302B, and an inner pair of modules303A,303B aligned in a direction parallel to the direction of tape travel relative to each other. The outer pair of modules302A,302B each has an array of complementary elements304A,304B arranged according to a first format, while the inner pair of modules303A,303B each has an array of complementary elements306A,306B arranged for a second format different than the first data format. In both pairs, the complementary elements (304A with304B,306A with306B) are displaced from each other in the direction of tape travel. When media in the first format is presented to the system, the array of elements304A,304B in the outer pair of modules302A,302B are operated. When media in the second format is presented to the system, the array of elements306A,306B in the inner pair of modules303A,303B are operated.

In read-while-write operation in the first format for example, the readers on the trailing module302B read the data that was just written by the leading module302A so that the system can verify that the data was written correctly. If the data is not written correctly, the system recognizes the error and rewrites the data.

Another multi-format head400is shown inFIG. 6. This tape head400is composed of Read-Read-Write (R-R-W) modules. Tape head400includes merged primary data format read/write elements404A,404B and secondary data format read elements406A,406B on each module402A,402B. In this instance, head400is capable of reading a secondary format corresponding to secondary format read elements406A,406B. Head400is further capable of both reading and writing with the primary format corresponding to primary read/write elements404A,404B.

With continued reference toFIG. 6A, the primary and secondary elements404A,404B,406A,406B are aligned parallel to the direction of tape travel, relative to each other. Typically, each row of elements is fabricated in sequential fabrication sequences. For example, elements404A,404B may be formed first. Then the secondary elements406A,406B are fabricated above the primary elements404A,404B.

FIG. 6Bdepicts an alternate embodiment450with elements of the reduced span array (new format)404A interleaved with, and possibly sharing, elements404B of the legacy array (old format).

FIG. 7illustrates a tape bearing, surface view of a module500having a first array502of elements associated with a first data format, and a second array504of elements associated with a second data format, where the first and second data formats are different. Again, the elements can include readers, writers, or both, and typically at least two modules are present to provide read-while-write capability.

The tape510is shown in dashed lines. While it is not typical to write data in two different formats on the same tape, the present embodiment would enable this feature, as described below. To illustrate different formats,FIG. 7shows data in the first and second formats overlapping. This is for illustration purposes, and one skilled in the an will appreciate that the data bands in the two formats would not typically be concurrently present on the same area of the tape. Data in the first format is associated with servo tracks512and data bands (Band0-3). Data in the second format is associated with servo tracks512and514. The data bands516in the second format are significantly smaller and so are not individually identified alphanumerically. However, a representative data band516is shown inFIG. 7for illustrative purposes.

The second data format may be a new generation relative to the first data format. The first and second data format may also be a formats used by competing vendors, used in different standards, etc. Typically, the differences between formats will include one or more of differing servo band locations, differing written track width, differing track density per data hand or tape width, differing track centerline-to-centerline spacing, differing element centerline-to-centerline spacing, etc. Accordingly, the arrays will have servo reader position, element spacing, element width, etc. that are designed to function in the format with which associated. Another embodiment includes two arrays that each use different read and/or write gaps to allow reading and/or writing in different data densities.

In one embodiment, the second format is a scaled-down version of the first format, especially in feature size. Accordingly, the second array504would then be a scaled-down version of the first array502. For example, the second array504may have the same number of data tracks per band, but is scaled down from the first array502, for example by a factor of about 5. In other words, the second array504is about 20% the width of the first array502. Thus, the format characteristics are also scaled down. For example, the track density on the tape should increase by approximately 5× in the second format as compared to the first format. If the linear data density also doubles, the tape capacity in the second format will be 10× the first format.

Furthermore, the advanced format data organization, e.g. track layout, is not necessarily in any way coupled to the legacy format. Coupling as by forcing a sharing of elements, as depicted inFIG. 6B, may not be desirable as it may force compromised future areal density, or degraded head performance.

With continued reference toFIG. 7, the first and second arrays502,504are formed in the same gap on the module500and are generally aligned laterally adjacent to each other in a direction transverse to the direction of media travel.

In operation, the tape drive system or host system can identify the format of the servo pattern on the tape and/or the format of the data on the tape using one of several techniques. One way to determine the format(s) is by reading a cartridge memory chip in the tape cartridge that identifies the format. Another way to identify the format is by reading a small portion of the data bands and matching, for example, the servo tracks to a look up table (LUT). Note that all arrays may be active at this time, or the system may sequentially operate the arrays. In other embodiments, the user may indicate which format is used on the tape. Once the format is identified, the controller host, or user selects the proper array for reading and writing. The system energizes the array associated with the identified format, such as by energizing the leads coupled to the desired array. Now active, the desired array is aligned with one of the data bands in a standard way, e.g., by servoing, and the tape is passed over the head for reading/writing. Preferably, either one array or the other is energized at a time during, standard read/write operations.

In one embodiment, the elements for both arrays502,504are built simultaneously during thin film buildup. For instance, consider elements in a “piggy back” configuration. This type of element typically includes a reader formed on a substrate, with a writer formed thereon. The reader and writer may be positioned so that one of the reader shields also functions as a component of one of the writer poles. During construction of a multi-format piggyback head, the readers of the first array502are formed concurrently with the readers of the second array504. Then the writers of the first array502are formed concurrently with the writers of the second array504. The readers of the first and second arrays502,504are aligned along a line transverse to the direction of media travel, and thus the writers of both arrays are also aligned. Likewise, for an interleaved head, the readers for both arrays502,504can all be formed during a single processing sequence, and the writers can be formed in another processing sequence.

The arrays can be slightly offset in a vertical direction for design considerations. For example, the upper shields for readers in the first array may be formed concurrently with the lower shields for readers in the second array. Then the readers in the second array are completed in subsequent steps. Thus, in some embodiments, the elements are formed concurrently in the same processing sequences though only some of the processing steps affect both arrays502,504

In further embodiments, the arrays can be formed by independent processing sequences. For example, one array can be completed prior to forming the other array. The arrays may be aligned in a direction transverse to the direction of tape motion, or can be displaced transverse to the direction of tape travel and offset in a direction parallel to the direction of tape travel.

Further, each array can be formed on an individual module, where the arrays in each format are displaced transverse to the direction of tape travel.

Forming the various arrays concurrently reduces process steps over the contemplated methods described above, such as forming elements in tandem parallel to the tape travel direction or even placing R/W arrays for different formats on different modules. One skilled in the art will appreciate the advantages achieved by processing all of the elements concurrently including lower cost, faster production time, reduced chance of error, etc. Write and read transducer magnetic gaps may be independently optimized for each format.

Because the arrays502,504of elements are adjacent each other laterally, the width of the head may need to be increased slightly to ensure that the tape bearing surface support the entire tape at all possible positions. However, the width of the head does not necessarily need to increase.

One embodiment of the present invention is illustrated inFIG. 8, wherein two arrays502,504are formed on a module500. As shown, the elements602of the first array502and the elements604of the second array504are positioned generally laterally adjacent each other. In some embodiments, including this one, the first and second arrays502,504can share one of the servo readers606. However, it may be advantageous to space the second array504laterally from the first array502, as shown inFIG. 9.

One advantage of spacing the arrays502,504apart is that, because portions of the tape near or at the edges of the tape may tend to induce more wear on the head than other parts of the tape, the area of greatest wear may then be between the arrays (when reading outer data bands). This is particularly so with older tapes that tend to be rougher and thicker, and produce more wear than newer tapes, as newer tapes are designed to reduce wear. The consequence of the uneven wear pattern is that when reading and writing the outer band of a tape in the first format with the first array502, the edge of the tape might cause wear adjacent to the first array502, and thus on the second array504. By having the arrays spaced apart sightly wear from the edge portions of the tape will occur between the arrays, e.g., in area702.

It is worth noting that the same uneven wear patterns might occur when reading and writing using the second array504, i.e., the edge portions of the tape will cause more wear adjacent the second array504, and as such, the wear will likely occur on the first array502. However, assuming the second array504is for a format that is more modern than the format of the first array502, the tape will likely be a newer tape that is smoother. Further, the first array502, probably having larger elements and reading a lower linear density, may be more tolerant to wear. Furthermore, all elements may be provided with a wear resistant coating such as diamond-like carbon.

Additional embodiments have more than two arrays of elements aligned on a single modulate, each array associated with a different format.FIG. 10illustrates an embodiment where three arrays502,504,802of elements are present. Again the arrays may share servo elements or not.

If head width is a critical issue, and assuming that the second array504is not was wide as the first array502in a direction transverse to the array of elements, a second array504and a substantially identical third array902can be formed, one on either side of the first array502. This embodiment is shown inFIG. 11. For data tracks in the second format and positioned on the left side of the tape, the third array902(on the left) will read and write data track in the second format on the left side of the tape. For data tracks in the second format and on the right side of the tape, the second array504(on the right) will read and write. In this way, the head does not need to have a width that is more than would be required to read or write using the first array502. Rather, one or both of the second array504and the third array902will be over data tracks in the second format at any point where the first array502is over the tape, thereby reducing the lateral range of motion required for the head to access all data tracks on the tape. Thus, for example, the head need not be wide enough to allow the first array502to extend beyond the left edge of the tape to allow the second array504to read data along the left tape edge. Rather, the data along the left tape edge can be read by the third array902. Additionally, fabricating both the second and third arrays504,902may enable using, only one chip image for fabricating both left and right modules in a two module head rather than requiring individual chip images or wafers for left and right modules.

FIG. 12illustrates a head having two identical arrays904that are spaced apart. This embodiment addresses the issue of head width constraints, as the outer arrays do in the embodiment ofFIG. 11. Thus, the head ofFIG. 12operates in a substantially similar manner as the head ofFIG. 11when reading or writing in the new format.

In another mode of use, multiple formats can be written to the same tape. Because the arrays are aligned transverse to the tape travel direction data in each format can be simultaneously written along the tape. This feature would allow, for instance, data to be written in two parallel tracks on the same tape and sent to users having a tape drive capable of reading only one of the formats. Because many blank tapes are sold with servo information already written thereto, some embodiments may require tapes that have servo information for both formats thereon. Other embodiments may write servo information simultaneously with the data, and servo writers would be present in each array. Yet other embodiments may allow writing of the new format onto an adjacent data band. For example, if the tape has four data bands, the bands can be grouped into two pairs. Using the servo track between the pair of bands to align the arrays over each band, one format can be written to one band and another format to the other band. The latter may not be optimal for the newer format, which might requite an improved servo data band.

As mentioned above, one way to build the head is to have two modules, in a configuration similar to existing heads, e.g., the head ofFIG. 4. One such embodiment, shown inFIG. 13, includes a flat-lapped bi-directional, two-module magnetic tape head1000. As shown, the head includes a pair of bases1002, each equipped with a module1004. The bases may be conventional U-beams that are adhesively coupled together. Each module1004includes a substrate1004A and a closure1004B with multiple arrays502,504situated therebetween. Cables1010connect the elements to a controller. The cables1010are shown as split into leads for the two formats, but can be joined, fused, intermixed, overlayed, etc. In use, a tape1008is moved over the modules1004along the tape bearing surfaces1009thereof for reading and writing data on the tape1008. Depending on the format of the data or servo on the tape, the array502or504on each module corresponding to that format is activated and used to read and/or write to the tape.

Another way to build the head is to have the functions of reading and writing performed on different modules. As shown in the write-read-write (W-R-W) head1100ofFIG. 14, outer writing modules1102,1104flank a single reading module1106. As the names imply, the outer modules1102,1104include two or more arrays of writers in a configuration, for example, as shown inFIGS. 8-12. The reading module1106includes two or more arrays of readers. The modules1102,1104,1106are offset and set in relationship with each other such that internal wrap angles are defined between the modules1102,1104,1106. Cables1109connect the elements to a controller. The cables1109are shown as split into leads for the two formats, but can be joined, fused, intermixed, overlayed, etc.

In this embodiment, the tape bearing surfaces of the modules lie oil parallel planes, but are offset in a direction perpendicular to the planes. When the tape1108moves across the head1100as shown, air is skived from below the tape1110by a skiving edge1110of the first outer writing module1102, and instead of the tape1108lifting from the tape bearing surface1112of the first outer module1102(as intuitively it should), the reduced air pressure in the area between the tape1108and the tape bearing surface1112allow atmospheric pressure to urge the tape towards the tape bearing surface1112. A trailing end1120of the outer writing module1102(the end from which the tape leaves the outer writing module1102) is the reference point which defines the wrap angle αoover the tape bearing surface of the inner reading module1106. The same is true of the other outer writing module1104when the tape travel direction is reversed.

Variations an the head1100ofFIG. 14include a R-W-R head, a R-R-W head, a W-W-R head, etc. For example, in a R-W-R head, the outer modules1102,1104perform reading while the middle module1106performs writing. In a R-R-W head, the leading module1102and middle module1106perform reading while the trailing module1104performs writing. In a W-W-R head, the leading module1102and middle module1106performs writing while the trailing module1104performs reading. Again, the leading and trailing modules1102,1104may operate concurrently with each other and the middle module1106, may operate individually, or may operate in combinations of two modules.

An advantage of the multiple module head is that each module has no more wiring leads than a module in a two module head having both read and write elements. For instance, assume a legacy format head has 16 readers and 16 writers per module. Adding an array of second format elements would add 32 more elements, or 64 more wires. However, if each module has only readers or writers, albeit in two formats, the number of wires per module is the same as the legacy read/write head. Accordingly, existing cabling can be used, the number of wires per head is minimized, etc.

Another advantage is that air is entrained between the tape and the trailing outer module (1104inFIG. 14), thereby reducing wear.

The three module design is also preferred, as the total gap thicknesses and build complexity are minimized, and head yield is optimized.

Compatible hardware is not limited to flat profile heads; heads having rounded and other geometric tape bearing surfaces are also within the spirit and scope of the present invention.

Likewise, other types of multi-format heads may include heads having elements of the reduced span array (new format) interleaved with, and possibly sharing, elements of the legacy array (old format).

In any of the embodiments described herein, the heads can be fabricated in conventional ways. To reduce cost and complexity, one lead for an element of the first array may be commoned with one lead for an element of the second array (and so on for additional arrays) to minimize head writing, an on-going goal in head design.

A data storage system as described herein may include one or more of the following components. A device for interfacing with a data medium is present in some embodiments. Examples of such an interface device include a drive, socket, bay, etc. that interfaces with a data medium. For example, in a tape-based data storage system, a drive is used to read and write to tape, the drive including a bay for a tape cartridge. The data storage system may include a plurality of interface devices.

FIG. 15illustrates a simplified tape drive1200which may be employed in the context of the present invention. While one specific implementation of a tape drive1200is shown inFIG. 15, it should be noted that the embodiments of the previous figures may be implemented in the context of any type of tape drive system.

As shown, a tape supply cartridge1220and a take-up reel1221are provided to support a tape1222. These may form part of a removable cassette and are not necessarily part of the system. Guides1225guide the tape1222across a preferably bidirectional tape bead1226, of the type disclosed herein. An actuator1232controls position of the head1226relative to the tape1222. The tape head1226is in turn coupled to a controller assembly1228via an MR connector cable1230. The controller1228, in turn, controls head functions such as servo following, write bursts, read functions, etc. The controller1228runs under the control of computer instructions typically in firmware or software run locally or on a host system.

A tape drive, such as that illustrated inFIG. 15, includes drive motor(s) to drive the tape supply cartridge1220and the take-up reel1221to move the tape1222linearly over the head1226. The tape drive also includes a read/write channel to transmit data to the head1226to be recorded on the tape1222and to receive data read by the head1226from the tape1222. An interface is also provided for communication between the tape drive and a host (integral or external) to send and receive the data and for controlling the operation of the tape drive and communicating the status of the tape drive to the host, all as will be understood by those of skill in the art. Examples of a host system include a computer, server, handheld device, etc. in communication with the interface device.