Method and magnetic head of tape for writing data on magnetic recording belt

The present invention relates to a tape drive data storage system. More specifically, the present invention relates to a thin film tape head for reading and writing data on a magnetic recording tape.

Thin film tape heads for magnetic information storage systems (eg, tape drives) have been constructed using thin film assembly techniques similar to those used in the manufacture of disk drive transducers. In a typical tape head configured for linear recording (ie, with a data track oriented in the distance of tapa movement), two or more transducer modules are placed next to each other. Will be done. Each module is a transducer located in a cross-track direction perpendicular to the tape movement direction. Includes a linear array of element) and / or write writer / transducer elements. Each transducer element in a given transducer array is arranged to write or read a separate longitudinal track on the tape. This arrangement is shown in FIG. 1, which depicts a transducer module "M" with an array of thin film transducer elements "E", where the gap "G" of this thin film transducer element is the tape movement direction. Engage with tape "T" aligned with track "TR" extending to "D". In a "piggy back" type design (see Figure 2A), the transducer array "E" tracks the write transducer "W" and the closely spaced read transducers "R". Will include in position. Interleaved design In design) (see Figure 2B), the transducer array "E" would include alternating read and write elements "R" and "W". In each design, the transducer array "E" may also include a pair of servo-reading transducers "SR" that match the servo track "ST" used for head positioning.

As shown in Figure 3, the module "M" in Figure 1 is a mounting block "MB" in collaboration with a complementary tape head containing piggy back or alternating read and write elements. Can be fixed to. In a piggy-back design, there are two read / write element pairs per two tracks (see Figure 4A). In an alternating design, the read and write elements for each module "M" and "M'" are arranged so that there is one read element and one write element per track (see Figure 4B). The dual module placement allows data recording (and playback) to be performed in both tape directions, and as soon as it is traditional and read, the data written on the tape "T" is immediately read back to check for errors. Traditional read-while write function capability) is provided. Other conventional tape head designs include heads in which all of the data transducer elements are read or write elements. The read-to-write capability can then be achieved by combining read-only and write-only modules in a single tape head to provide a track-matched read and write element pair. As shown in FIG. 5, by arranging the read-only module M between the pair of write-only modules M', bidirectional recording having a read-simultaneous write function can be provided.

A feature of the tape head structure as described above is that for all tracks read and written by the array, there is a space between the tracks where no transducing occurs. The gap pitch is usually much larger than the gap width. Therefore, for all track pairs matched with adjacent read and write elements "R" and "W", there is an inter-track white space on the tape "T" that is not converted at the same time as the selected pair. is there. The margin area can be recorded as data by stepping the tape head in the crosstrack direction between multiple conversion paths. Tape tracks can also be written below the gap width of the write transducer using a process known as "shingling". According to this technique, the tape head has a write element gap for each successive conversion pass so that the previously written edge of the track is overwritten between the next passes, much like a roof slab. Stepped less than the width.

The track write technique described above allows data to be tightly packed on tape, but the remaining open problem is caused by tape dimensional change between read or write operations. The track is out of position. For example, tape "T" may be read after data is written under a set of temperature and humidity conditions and then exposed to different environmental conditions. For conventional tape materials, the dimensions can vary by as much as 0.12%. These tape dimensional changes widen or narrow the tape track spacing shape, resulting in a track misalignment with the tape head (the tape head gap spacing shape is virtually unchanged). The misalignment problem is addressed by providing a head that is statically rotated to a nominal predetermined angle. This is because small changes in rotation change the effective track pitch of the transducer array "E". However, this solution requires sophisticated mechanical construction and skew compensation circuitry.

The track misalignment problem is exacerbated in conventional tape heads by the relatively large gap spacing of the transducer arrangement, which is largely mandated by the size of the transducer itself. This is due to the fact that for any percentage change in tape dimensions, the actual misalignment between the written track and the outermost transducer depends on the span between the transducers. For example, if the transducer array "E" has a transducer element gap pitch of xμm and the percentage change in tape dimensions is 0.12%, then the tape track under the outermost transducer element in the 16 transducer array. The resulting change in the interval is 15 × 0.0012x = 0.018xμm. If x is a typical 167 μm value (for current generation tape heads), then 0.018x = 3 μm. This is TMR (Track) MisRegistration) A large part of the budget. On the other hand, if the transducer array "E" has a transducer element gap pitch of 0.5xμm, a 0.12% change in tape dimensions will cause the tape track spacing under the outermost transducer element to be 15 × 0.0006xμm = 0.009. It only changes x. Assuming again that x is a typical 167 μm value, 0.009 x = 1.5 μm. Therefore, the 0.5x gap pitch transducer array experiences only half the tape dimensional variation experienced by the xgap pitch array, resulting in less chance of track misalignment. Unfortunately, reducing track pitch using current thin film transducer manufacturing techniques is not a trivial task, especially due to the size requirements of the write element structure. Use of another transducer design that allows track pitch reduction (as previously proposed by one of the applicants of the present application in a co-owned patent application), or of complex head rotation techniques such as those described above. When not in use, there is no conventional technique for dealing with thermally caused track misalignment.

<p> Provided is a tape head designed for converting data on a magnetic recording tape that is subject to tape dimensional changes.</p>

<p> A tape head designed to transform data on magnetic recording tapes subject to tape dimensional changes solves the above problems and achieves technological advances. The tape head comprises an array of two or more transducer elements with different transducer spacing distances corresponding to different track spacing distances to be converted. One of the transducer arrays can be used to convert tapes under nominal tape track spacing conditions. Another transducer array can be used to convert the tape if the tape track shrinks due to tape shrinkage. Yet another transducer array can be used to convert tapes when the tape track spacing is increased due to tape expansion. Alternatively, a first transducer array can be used and the tape can be stretched longitudinally to reduce the tape track spacing to the nominal tape track spacing.</p><p> According to a representative embodiment disclosed herein, the sequences may be spaced apart from each other in the cross-track direction, or the sequences may be placed spaced apart from each other in the tape movement direction. May be done. Each array may include one or both of a write and read transducer element. Each array may further include a pair of servo read transducer elements. The array may be supported by a common substrate as part of a tape head module, or may be provided with multiple modules. For example, the tape head may include a first array configuration on the first tape head module and a second array group on the second tape head module. In this two-module configuration, the first and second sequence groups are interleaved, respectively. It may include read and write transducer elements located on the one hand of configuration) or piggyback configuration. Tape heads are another option for the first array group on the first tape head module, the second array group on the second tape head module, and the third tape head. It may include a third sequence group on the module. In this three-module configuration, the first and third array groups may include write transducer elements and the second array group may include read transducer elements. The second tape head module may be placed between the first and third tape head modules.</p><p> In another aspect, the present invention provides a method for absorbing data dimensional changes and at the same time writing data on a magnetic recording tape. In this method, the step of determining the dimensional condition of the tape, such as by reading the pre-recorded servo markings on the tape, and whether the first transducer spacing distance or the second transducer spacing distance is closer to the tape dimensional condition. Includes a step of selecting one of the first and second transducer arrays depending on the correspondence. The first of the transducer arrays with the nominal transducer spacing can be used to convert tapes under nominal tape track spacing conditions, and the second of the transducer arrays with reduced transducer spacing. Can be used to convert tapes when tape track spacing is reduced due to tape shrinkage. The tape is expanded by tape expansion to increase the tape track spacing.<u style="single">However, when the tape is stretched in the longitudinal direction at the same time, the expanded tape track spacing is reduced to almost the nominal tape track spacing.</u>Can be converted by the first transducer array. As another option, a third transducer array with an extended transducer spacing can be used to convert the tape if the track spacing of the tape is increased.</p><p> In another aspect, the invention provides a tape drive. The tape drive includes a tape head for converting data on magnetic tape that is subject to tape dimensional changes. The tape heads include multiple tape head modules, each spaced from each other by a first transducer spacing distance corresponding to the nominal and nominal tape track spacing distances. The first array of transducer elements with the transducer elements, the second of the transducer elements spaced apart from each other by a second transducer spacing distance corresponding to the reduced tape track spacing caused by tape shrinkage. It may have two arrays, and a third array of transducer elements spaced apart from each other by a third transducer spacing that corresponds to the extended tape track spacing caused by tape expansion. The sequences may be spaced apart in the cross-track direction.</p>

The above and other features and advantages of the present invention will become apparent from the following more specific description of the representative disclosed embodiments, as illustrated in the accompanying drawings.

Although the present invention is described herein through a representative embodiment shown in the drawings (not necessarily on a uniform scale), in all of some of the figures the same reference numerals indicate the same elements.

Looking at FIG. 6, a tape head 2 for converting data on a magnetic recording tape that is subject to tape dimensional changes is drawn. The tape head comprises two or more arrays of transducer elements with different transducer spacing distances (center-to-center pitch) corresponding to different track spacing distances (center-to-center pitch) to be converted. One of the transducer arrays, 4A, has a nominal transducer and can be used to convert tape under nominal tape track spacing conditions. Another transducer array 4B has reduced transducer spacing and can be used to convert tape when the tape track is shrunk due to tape shrinkage. Yet another transducer array 4C has increased tape track spacing and can be used to convert tapes when the tape track spacing is increased due to tape expansion. As another option<u style="single">The first transducer array 4A can be used and the first transducer array 4A can be used when the tape is stretched longitudinally to reduce the tape track spacing and approach the nominal tape track spacing.</u>This is because changes in tape width are associated with changes in tape expansion via Poisson's ratio, which is generally 0.3 to 0.5 for flexible media such as tape. Each of the arrays 4A, 4B, and 4C contains 16 data transducers 6 for converting customer data and a pair of servo read transducers 8 for converting tape servo tracks. The use of 16 data transducers is of course optional and it will be appreciated that fewer or more data transducers can be incorporated into each sequence. It should also be pointed out that the difference in transducer spacing between the transducer sequences 4A, 4B and 4C is relative to the data transducer 6. The spacing between the two servo transducers 8 in the transducer sequences 4A, 4B, and 4C is preferably the same for each sequence. The reason for this will be clarified below.

It will be appreciated that the nominal transducer spacing in the transducer array 4A is arbitrary and depends on design priorities. As explained in the background above, a data track spacing of 167 μm is common for current generation tape heads, and this value can be used for the nominal spacing of data transducer 6 in transducer array 4A. With 16 data transducers 6 per array, the data transducer span would be 15 x 167 = 2505 μm. The reduced transducer spacing of transducer array 4B and the increased transducer spacing of transducer array 4C can be selected according to the expected shrinkage and expansion of the tape to be converted, respectively. This can be determined experimentally. For example, if the change in crosstrack tape dimensions is expected to be +/- 0.12%, the 16 data transducers 6 in sequence 4B will have a data transducer span length of 2505 x (1-). It can be spaced so that 0.0012) = 2502 μm, which is about 3 microns smaller than the nominal data transducer span length of sequence 4A. The 16 data transducers 6 in sequence 4B can be spaced so that the data transducer span length is 2505 x (1 + 0.0012) = 2508 μm, which is the nominal of sequence 4A. Approximately 3 microns larger than the length of the data transducer span. Above 0. Note that under the worst-case conditions where a 12% dimensional change is expected, the spacing between sequences 4B and 4C can be less than the 3 micron difference above (eg, to reflect the average dimensional change). I want to be. It can be seen that the difference in transducer spacing in sequences 4A, 4B, and 4C is microscopic on a scale and is therefore greatly exaggerated in FIG. As track spacing reduction becomes possible in the future, the differences between the nominal, reduced and expanded transducer spacing in sequences 4A, 4B and 4C will be even smaller.

In the embodiment of FIG. 1, arrays 4A, 4B, and 4C are spaced apart from each other in the crosstrack direction. These arrays can be made on a common substrate using conventional thin film assembly techniques and materials. A conventional closure 12 can be joined to the transducer side of the substrate 10 to protect the transducer element from abrasion and optimize the frictional properties of the tape head 2. The electrical lead connection from the transducer element extends away from the reader and into the plane of the drawing sheet and is therefore not visible in FIG. The resulting structure is called the tape head module 14.

Looking now at FIGS. 7-10, the transducer arrays 4A, 4B, and 4C may include one or both of a write and read transducer element, respectively. FIG. 7 illustrates a configuration in which the data transducers 6 of the transducer arrays 4A, 4B, and 4C are all write transducers. FIG. 8 illustrates a configuration in which the data transducers 6 of the transducer arrays 4A, 4B, and 4C are all read transducers. FIG. 9 illustrates a configuration in which the data transducers 6 of the transducer arrays 4A, 4B, and 4C are alternate read and write transducers. FIG. 10 illustrates a configuration in which the data transducers 6 of the transducer arrays 4A, 4B and 4C are piggy-back type read and write transducers.

Looking here at FIGS. 11-13, the transducer sequences 4A, 4B, and 4C can be placed in various sequence groups 16 formed on the plurality of modules 14. Each sequence group contains two or more sequences arranged in the cross-track direction (as described above) or in parallel (as described below with respect to FIG. 14). For example, as shown in FIG. 11, the tape head 2 has a first array group 16A-1 on top of the first tape head module 14A-1 and a second tape head module 14A-2. A second sequence group 16A-2 may be included above. In this two-module configuration, the first and second sequence groups 16A-1 and 16A-2 each include read and write transducer elements arranged in an alternating configuration. Sequence groups 16A-1 and 16A-2 are designed to have one write and one read transducer on each data track that is converted on tape. When the tape moves from left to right in FIG. 11, the write transducers in sequence 4A, 4B or 4C in sequence group 16A-1 write to the data track and at the same time the corresponding sequences 4A, 4B in sequence group 16A-2 Alternatively, a 4C read transducer can be used to read-verify the written data. When the tape moves from right to left in FIG. 11, the role of the sequence group is reversed.

Another two-module configuration is shown in FIG. Here, the tape head 2 has a first sequence group 16B-1 on the first tape head module 14B-1 and a second sequence group on the second tape head module 14B-2. Contains 16B-2. In this two-module configuration, the first and second sequence groups 16B-1 and 16B-2 each include a read and write transducer element arranged in a piggyback configuration. Sequence groups 16B-1 and 16B-2 are designed to have one write and one read transducer on each data track on the tape. When the tape moves from left to right in FIG. 12, the write transducers in sequence 4A, 4B or 4C in sequence group 16B-1 write to the data track and at the same time the corresponding sequences 4A, 4B in sequence group 16B-2. Alternatively, a 4C read transducer can be used to read-verify the written data. When the tape moves from right to left in FIG. 12, the role of the sequence group is reversed.

As shown in FIG. 13, as another option, the tape head 2 has a first array group 16C-1 on top of the first tape head module 14C-1 and a second tape head module. It may contain a second sequence group 16C-2 on 14C-2 and a third sequence group 16C-3 on a third tape head module 14C-3. In this three-module configuration, the first and third array groups 16C-1 and 16C-3 may include write transducer elements and the second array group 16C-2 may include read transducer elements. it can. The second tape head module 14C-2 can be placed between the first and third tape head modules 14C-1 and 14C-3. Sequence groups 16C-1, 16C-2, and 16C-3 are designed so that two write transducers and one read transducer are on each data track on the tape. When the tape moves from left to right in FIG. 13, the write transducers in sequence 4A, 4B or 4C in sequence group 16C-1 write to the data track and at the same time the corresponding sequences 4A, 4B in sequence group 16C-2. Alternatively, a 4C read transducer can be used to read-verify the written data. When the tape moves from right to left in FIG. 13, the write transducers in sequence 4A, 4B or 4C in sequence group 16C-3 write to the data track and at the same time the corresponding sequences 4A, 4B in sequence group 16C-2. Alternatively, a 4C read transducer can be used to read-verify the written data.

During use of the tape head 2, data can be conveniently written or read on magnetic recording tape while absorbing tape dimensional changes. Before reading or writing data, the dimensional conditions of the tape are determined. This can be determined by running the tape over the nominal array 4A of the tape head 2 and reading the pre-recorded servo markings on the tape. If traditional timing-based servo control is used, the Servo Read Transducer 8 will have the servo track markings superficially spaced depending on whether the nominal servo mark timing conditions can be achieved on both tracks. Detect if it is placed. If not, the tape expansion or contraction conditions can be determined from the timing changes and the orientation of the timing servo marks. This information is used to select one of the transducer sequences 4A, 4B, or 4B to convert according to which of the transducer spacing distances most closely matches the tape dimensional conditions.

Looking now at FIG. 14, the tape head 18 represents an alternative to the embodiment of FIG. 6, in which two or more arrays of transducer elements with different transducer spacing distances are aligned in the tape travel direction. As a mere example, three sequences 20A, 20B, and 20C are shown, where sequence 20A utilizes the nominal transducer spacing, sequence 20B utilizes the reduced transducer spacing, and sequence 20C is expanded. The transducer interval distance is used. As shown in FIG. 15, the transducer arrays 20A, 20B, and 20C can be made on substrate layers 22A, 22B, and 22C, respectively. The closure 24 can be joined to the transducer side of the substrate layer 22B. As in the case of the tape head 2, the tape head 18 can be manufactured with a write transducer, a read transducer, or a combination of both in an alternating configuration or a piggyback configuration. As also described above in connection with the tape head 2, the transducer arrays 20A, 20B, and 20C of the tape head 18 can be arranged on multiple modules.

As seen in FIG. 16, the concept of the invention described herein is data by a host data processing device 102, which can be a general purpose computer of another processing device adapted for data exchange with tape drive 100. Can be incorporated into a tape drive data storage device (tape drive) 100 for storing and producing. The tape drive 100 includes a plurality of components that provide a control and data transfer system for reading and writing host data on magnetic tape media. As a mere example, these components include a channel adapter 104, a microprocessor controller 106, a data buffer 108, a read / write data flow circuit 110, an operation control system 112, and a motor driver circuit 116 and a read / write head. The tape interface system 114, which includes unit 118, may customarily be included.

The microprocessor controller 106 provides overhead control capabilities for the operation of tape drive 100. As in the past, the functions performed by the microprocessor controller 106 can be programmed via microcode routines (not shown) according to the desired tape drive operating characteristics. During a data write operation (all data flows are reversed for a data read operation), microprocessor controller 106 is required to activate channel adapter 104 and receive information data blocks. Executes the host interface protocol. The channel adapter 104 passes the data block to the data buffer 108, which stores the data for subsequent read / write operations. The data buffer 108 then transmits the data block received from the channel adapter 104 to the read / write dataflow circuit 110, which is a physical device capable of recording device data on a tape medium. Format to formatted data. The read / write data flow circuit 110 is responsible for performing read / write data transfer operations under the control of the microprocessor controller 106. The formatted physical data from the read / write data flow circuit 110 is transmitted to the tape interface system 114. The latter is a drive for performing forward and reverse movement of one or more read / write heads in the read / write head unit 118 and the tape medium 120 attached to the feed reel 122 and take-up reel 124. -Includes motor components (not shown). The drive components of the tape interface system 114 are the motion control system 112 and the motor driver circuit to perform tape movements such as forward and reverse recording and playback, rewinding and other tape movement functions. Controlled by 116. In addition, multi

In most cases, as shown in FIG. 17, the tape medium 120 is mounted in a cartridge 126 that is inserted into the tape drive 100 via slot 128. The tape cartridge 126 includes a housing 130 that houses the magnetic tape 120. It is shown that the payout reel 122 is mounted in the housing 130.

Therefore, tape heads, methods and tape drives that can absorb temperature-induced changes in tape dimensions have been disclosed. Although various embodiments of the present invention have been shown and described, it should be clear that many variants and alternative embodiments can be implemented according to the teachings herein. Therefore, it is understood that the present invention is not limited in any way except in accordance with the appended claims and the gist of their equivalents.

<figref num="1">It is a perspective view which shows the thin film tape head module of the prior art.</figref><figref num="2">FIG. 2A is a partial plane showing the tape support surface of a prior art tape head module with a piggyback structure, and FIG. 2B is a tape of a prior art tape head module with an alternating structure. It is a partial plan view which shows a support surface.</figref><figref num="3">FIG. 5 is a side view showing a pair of prior art tape head modules of FIG.</figref><figref num="4">FIG. 4A is a partial plan view showing the tape-supporting surface of a pair of prior art piggyback modules of FIG. 2A arranged to convert tape, and FIG. 4B is for converting tape. It is a partial plan view which shows the tape support surface of the pair of prior art alternating arrangement type modules of FIG. 2B arranged.</figref><figref num="5">FIG. 5 is a partial plan view showing the tape-supporting surfaces of three prior art tape head modules in which two write transducer arrays are arranged to convert tape in a configuration that sandwiches one write transducer array.</figref><figref num="6">FIG. 5 is a partial plan view showing a tape support surface of a tape head module configured according to a representative disclosed embodiment.</figref><figref num="7">FIG. 6 is an enlarged view of the tape head module of FIG. 6 showing an implementation in which the module includes an array of write transducer elements.</figref><figref num="8">FIG. 6 is an enlarged view of the tape head module of FIG. 6 showing an implementation in which the module includes an array of read transducer elements.</figref><figref num="9">FIG. 6 is an enlarged view of the tape head module of FIG. 6 showing an implementation in which the module includes an array of alternating read and write transducer elements.</figref><figref num="10">FIG. 6 is an enlarged view of the tape head module of FIG. 6 showing an implementation in which the module includes an array of piggyback type read and write transducer elements.</figref><figref num="11">FIG. 6 is a partial plan view showing the tape support surfaces of the two tape head modules according to FIG. 6, each module having alternating read and write elements.</figref><figref num="12">FIG. 6 is a partial plan view showing the tape-supporting surfaces of the two tape head modules according to FIG. 6, each module having an array of piggy-back type read and write elements.</figref><figref num="13">2 shows the tape-supporting surface of the three tape head modules according to FIG. 6, in which two modules have two arrays of write elements and a third module located between the array of write elements has an array of read elements. It is a partial plan view.</figref><figref num="14">FIG. 5 is a partial plan view showing a tape support surface of a tape head module configured according to another representative disclosed embodiment.</figref><figref num="15">It is sectional drawing taken along line 15-15 of FIG.</figref><figref num="16">It is a functional block diagram which shows the tape drive data storage device suitable for the use which uses this invention.</figref><figref num="17">FIG. 6 is a perspective view showing a typical structure of the tape drive storage device of FIG. 16 for applications using cartridge tape media.</figref>