Patent Publication Number: US-2023154492-A1

Title: Magnetic Tape Having Alternating Sections For Use In Ultra-High Areal Density Tape Storage Systems

Description:
BACKGROUND OF THE DISCLOSURE 
     Field of the Disclosure 
     Embodiments of the present disclosure generally relate to a tape utilized with a tape drive including a tape head. 
     Description of the Related Art 
     Tape heads of tape drive systems are used to record and read back information on tapes by magnetic processes. Magnetic transducers of the tape heads read data from and write data onto magnetic recording media. Data is written on the magnetic recording media by moving a magnetic write transducer to a location over the media where the data is to be stored. The magnetic write transducer then generates a magnetic field, which encodes the data into the magnetic media. Data is read from the media by the magnetic read transducer through sensing of the magnetic field of the magnetic media. 
     Often times, data is written to the magnetic media or tape in a serpentine fashion, where the tape moving over the tape head stops moving after the tape head writes a few data tracks of the tape, and then turns around to allow the tape head to continue writing adjacent data tracks of the tape. After writing the adjacent tracks, the tape stops once more and turns around to allow the tape head to write additional data tracks. As such, there are several areas on the tape where the tape head repeatedly stops and turns around about the tape. Such areas are more susceptible to damage, are often unusable to store data, and result in a decreased lifetime of the tape, as well as subjecting the tape head to increased wear. 
     Therefore, there is a need in the art for an improved tape to be utilized with a tape drive comprising a tape head. 
     SUMMARY OF THE DISCLOSURE 
     The present disclosure generally relates to a tape utilized with a tape drive including a tape head. The tape comprises a plurality of writeable portions configured to store data and a plurality of non-writeable portions that are unable to store data. The writeable portions comprise one or more materials selected from the group consisting of: Ru, Pt, Ta, and Co, and the non-writeable portions comprise a different material than the writeable portions. Each writeable portion is defined between two non-writeable portions, and each writeable portion has a greater area on the tape than each non-writeable portion. The non-writeable portions are utilized during stop-start and turn-around operations of the tape head, are configured to lubricate the tape head, clean the tape head, and remove debris from the tape head. The non-writeable portions enable improved performance of the tape drive while reducing a cost of the tape, and the surface characteristics of the non-writeable portions can be selected to mitigate stop-start stiction effects. 
     In one embodiment, a magnetic tape comprises a plurality of writeable portions comprising one or more materials selected from the group consisting of: Ru, Pt, Ta, Co, Ni, Fe, W, Cr, Ti, and Zr, the plurality of writeable portions being able to store data, and a plurality of non-writeable portions, each non-writeable portion being disposed adjacent to at least one writeable portion of the plurality of writeable portions, wherein the plurality of non-writeable portions and the plurality of writeable portions comprise different materials. 
     In another embodiment, a magnetic tape comprises a plurality of writeable portions comprising one or more materials selected from the group consisting of: Ru, Pt, Ta, Co, Ni, Fe, W, Cr, Ti, and Zr, the plurality of writeable portions being able to store data, wherein each writeable portion of the plurality of writeable portions has a first area, and a plurality of non-writeable portions, each non-writeable portion being disposed in contact with at least one writeable portion of the plurality of writeable portions, wherein: the plurality of non-writeable portions each has a second area, the first area is greater than the second area, and the plurality of non-writeable portions and the plurality of writeable portions comprise different materials. 
     In yet another embodiment, a magnetic tape comprises a plurality of writeable portions sputtered with a first coating comprising one or more materials selected from the group consisting of: Ru, Pt, Ta, Co, Ni, Fe, W, Cr, Ti, and Zr, the plurality of writeable portions being able to store data, and a plurality of non-writeable portions sputtered with a second coating comprising one or more materials selected from the group consisting of W, Be, Ti, Ta, Cr, and Si, wherein: the first coating and the second coating comprise different materials, the plurality of writeable portions and the plurality of non-writeable portions alternate along a total length of the magnetic tape, and the plurality of non-writeable portions are unable to store user data. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       So that the manner in which the above recited features of the present disclosure can be understood in detail, a more particular description of the disclosure, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this disclosure and are therefore not to be considered limiting of its scope, for the disclosure may admit to other equally effective embodiments. 
         FIGS.  1 A- 1 C  illustrate a perspective exploded view, a simplified top down, and side profile view of a tape drive, in accordance with some embodiments. 
         FIG.  2    is a schematic illustration of a tape head and tape that are aligned. 
         FIGS.  3 A- 3 B  illustrate a magnetic tape for use with a tape head of a tape drive, according to various embodiments. 
         FIGS.  4 A- 4 C  illustrate a tape head of a tape drive writing to the magnetic media of  FIG.  3 A , according to one embodiment. 
     
    
    
     To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation. 
     DETAILED DESCRIPTION 
     In the following, reference is made to embodiments of the disclosure. However, it should be understood that the disclosure is not limited to specifically described embodiments. Instead, any combination of the following features and elements, whether related to different embodiments or not, is contemplated to implement and practice the disclosure. Furthermore, although embodiments of the disclosure may achieve advantages over other possible solutions and/or over the prior art, whether or not a particular advantage is achieved by a given embodiment is not limiting of the disclosure. Thus, the following aspects, features, embodiments, and advantages are merely illustrative and are not considered elements or limitations of the appended claims except where explicitly recited in a claim(s). Likewise, reference to “the disclosure” shall not be construed as a generalization of any inventive subject matter disclosed herein and shall not be considered to be an element or limitation of the appended claims except where explicitly recited in a claim(s). 
     The present disclosure generally relates to a tape utilized with a tape drive including a tape head. The tape comprises a plurality of writeable portions configured to store data and a plurality of non-writeable portions that are unable to store data. The writeable portions comprise one or more materials selected from the group consisting of: Ru, Pt, Ta, and Co, and the non-writeable portions comprise a different material than the writeable portions. Each writeable portion is defined between two non-writeable portions, and each writeable portion has a greater area on the tape than each non-writeable portion. The non-writeable portions are utilized during stop-start and turn-around operations of the tape head, are configured to lubricate the tape head, clean the tape head, and remove debris from the tape head. The non-writeable portions enable improved performance of the tape drive while reducing a cost of the tape, and the surface characteristics of the non-writeable portions can be selected to mitigate stop-start stiction effects. 
       FIGS.  1 A- 1 C  illustrate a perspective exploded view, a simplified top down, and side profile view of a tape drive  100 , in accordance with some embodiments. The tape drive  100  may be a tape embedded drive (TED). Focusing on  FIG.  1 B , for example, the tape drive comprises a casing  105 , one or more tape reels  110 , one or more motors (e.g., a stepping motor  120  (also known as a stepper motor), a voice coil motor (VCM)  125 , etc.), a head assembly  130  with one or more read heads and one or more write heads, and tape guides/rollers  135   a ,  135   b , and a controller  140  coupled to the head assembly  130 . In the descriptions herein, the term “head assembly” may be referred to as “magnetic recording head”, interchangeably, for exemplary purposes. Focusing on  FIG.  1 C , for example, the tape drive further comprises a printed circuit board assembly (PCBA)  155 . In an embodiment, most of the components are within an interior cavity of the casing, except the PCBA  155 , which is mounted on an external surface of the casing  105 . The same components are illustrated in a perspective view in  FIG.  1 A . In the descriptions herein, the term “tape” may be referred to as “magnetic media”, interchangeably, for exemplary purposes. 
     In the illustrated embodiments, two tape reels  110  are placed in the interior cavity of the casing  105 , with the center of the two tape reels  110  on the same level in the cavity and with the head assembly  130  located in the middle and below the two tape reels  110 . Tape reel motors located in the spindles of the tape reels  110  can operate to wind and unwind the tape media  115  in the tape reels  110 . Each tape reel  110  may also incorporate a tape folder to help the tape media  115  be neatly wound onto the reel  110 . One or more of the tape reels  110  may form a part of a removable cartridge and are not necessarily part of the tape drive  100 . In such embodiments, the tape drive  100  may not be a tape embedded drive as it does not have embedded media, the drive  100  may instead be a tape drive configured to accept and access magnetic media or tape media  115  from an insertable cassette or cartridge (e.g., an LTO drive), where the insertable cassette or cartridge further comprises one or more of the tape reels  110  as well. In such embodiments, the tape or media  115  is contained in a cartridge that is removable from the drive  100 . The tape media  115  may be made via a sputtering process to provide improved areal density. The tape media  115  comprises a base film, which can be PEN, PET, aramid or any similar plastic material, a magnetic recording layer on the front side of the tape media, and a back coat. The magnetic recording layer can be particulate in nature (e.g., barium ferrite or strontium ferrite particles, or metal particles), or fabricated using thin film sputtering techniques. The magnetic recording layer is the surface that can be magnetically manipulated (written to or read from) by one or more read/write heads. The back coat is applied to the reverse side of the base film to improve the mechanical characteristics of the tape media and aid in packing the tape  115  onto the tape reels and guide the tape  115  through the tape path components. 
     Tape media  115  from the tape reels  110  are biased against the guides/rollers  135   a ,  135   b  (collectively referred to as guides/rollers  135 ) and are movably passed over the head assembly  130  by movement of the reels  110 . The illustrated embodiment shows four guides/rollers  135   a ,  135   b , with the two guides/rollers  135   a  furthest away from the head assembly  130  serving to change direction of the tape media  115  and the two guides/rollers  135   b  closest to the head assembly  130  by pressing the tape media  115  against the head assembly  130 . 
     As shown in  FIG.  1 A , in some embodiments, the guides/rollers  135  utilize the same structure. In other embodiments, as shown in  FIG.  1 B , the guides/rollers  135  may have more specialized shapes and differ from each other based on function. Furthermore, a lesser or a greater number of rollers may be used. 
     The voice coil motor  125  and stepping motor  120  may variably position the tape head(s) transversely with respect to the width of the recording tape. The stepping motor  120  may provide coarse movement, while the voice coil motor  125  may provide finer actuation of the head(s). In an embodiment, servo data may be written to the tape media to aid in more accurate position of the head(s) along the tape media  115 . 
     In addition, the casing  105  comprises one or more particle filters  141  and/or desiccants  142 , as illustrated in  FIG.  1 A , to help maintain the environment in the casing. For example, if the casing is not airtight, the particle filters may be placed where airflow is expected. The particle filters and/or desiccants may be placed in one or more of the corners or any other convenient place away from the moving internal components. For example, the moving reels may generate internal airflow as the tape media winds/unwinds, and the particle filters may be placed within that airflow. 
     There is a wide variety of possible placements of the internal components of the tape drive  100  within the casing  105 . In particular, as the head mechanism is internal to the casing in certain embodiments, the tape media  115  may not be exposed to the outside of the casing  105 , such as in conventional tape drives. Thus, the tape media  115  does not need to be routed along the edge of the casing  105  and can be freely routed in more compact and/or otherwise more efficient ways within the casing  105 . Similarly, the head(s)  130  and tape reels  110  may be placed in a variety of locations to achieve a more efficient layout, as there are no design requirements to provide external access to these components. 
     As illustrated in  FIG.  1 C , the casing  105  comprises a cover  150  and a base  145 . The PCBA  155  is attached to the bottom, on an external surface of the casing  105 , opposite the cover  150 . As the PCBA  155  is made of solid state electronics, environmental issues are less of a concern, so it does not need to be placed inside the casing  105 . That leaves room inside casing  105  for other components, particularly, the moving components and the tape media  115  that would benefit from a more protected environment. 
     In some embodiments, the tape drive  100  is sealed. Sealing can mean the drive is hermetically sealed or simply enclosed without necessarily being airtight. Sealing the drive may be beneficial for tape film winding stability, tape film reliability, and tape head reliability. Desiccant may be used to limit humidity inside the casing  105 . 
     In one embodiment, the cover  150  is used to hermetically seal the tape drive. For example, the drive  100  may be hermetically sealed for environmental control by attaching (e.g., laser welding, adhesive, etc.) the cover  150  to the base  145 . The drive  100  may be filled by helium, nitrogen, hydrogen, or any other typically inert gas. 
     In some embodiments, other components may be added to the tape drive  100 . For example, a pre-amp for the heads may be added to the tape drive. The pre-amp may be located on the PCBA  155 , in the head assembly  130 , or in another location. In general, placing the pre-amp closer to the heads may have a greater effect on the read and write signals in terms of signal-to-noise ratio (SNR). In other embodiments, some of the components may be removed. For example, the filters  141  and/or the desiccant  142  may be left out. 
     In various embodiments, the drive  100  includes controller integrated circuits (IC) (or more simply “a controller”) (e.g., in the form of one or more System on Chip (SoC)), along with other digital and/or analog control circuitry to control the operations of the drive. For example, the controller and other associated control circuitry may control the writing and reading of data to and from the magnetic media, including processing of read/write data signals and any servo-mechanical control of the media and head module. In the description below, various examples related to writing and reading and verifying of written data, as well as control of the tape head and media to achieve the same, may be controlled by the controller. As an example, the controller may be configured to execute firmware instructions for the various same gap verify embodiments described below. 
       FIG.  2    is a schematic illustration of a tape head module assembly  200  and a tape  204  that are aligned. The tape head module assembly  200  comprises a tape head body  202  that is aligned with the tape  204 . The tape  204  moves past the tape head module assembly  200  during read and/or write operations. The tape head module assembly  200  has a media facing surface (MFS)  214  that faces the tape  204 . The tape head module assembly  200  is coupled to a controller  240 . 
     The tape head body  202  comprises a first servo head  206 A and a second servo head  206 B spaced therefrom. It is to be understood that while two servo heads have been shown, the disclosure is not limited to two servo heads. Rather, it is contemplated that more or less servo heads may be present. A plurality of data heads  208 A- 208 G is disposed between the first servo head  206 A and the second servo head  206 B. It is to be understood that while seven data heads have been shown, the disclosure is not limited to seven data heads. Rather, the number of data heads can be more or less than seven, depending on the requirements of the embodiment. For example there can be sixteen, thirty two, sixty four or more data heads utilized in the tape head body  202 . 
     A plurality of pads  220 A- 220 N is electrically coupled to the data head body  202 . The plurality of pads  220 A- 220 N coupled to the data head body  202  is not limited to the number shown in  FIG.  2   . Rather, more or less pads are contemplated. The pads  220 A- 220 N are used to connect the drive electronics to the servo heads  206 A,  206 B and to data read and writer elements. The pads  220 A- 220 N are used to establish the potential across the servo reader by means of a power supply (not shown) embedded in the tape head  200 . 
     The tape  204  comprises a first servo track  210 A and a second servo track  210 B. The first servo track  210 A and the second servo track  210 B are spaced apart allowing the tape head  200  to monitor and control the average position of the data heads  208 A- 208 G relative to the data tracks  212 A- 212 G on the tape  204 . It is to be understood that while two servo tracks have been shown, the disclosure is not limited to two servo tracks. Rather, the number of servo tracks can be more or less than two, depending on the requirements of the embodiment. 
     The tape  204  further comprises a plurality of data tracks  212 A- 212 G disposed between the first servo track  210 A and the second servo track  210 B. It is to be understood that while seven data tracks have been shown, the disclosure is not limited to the seven data tracks. Rather, the number of data tracks can be more or less than seven, depending on the requirements of the embodiment. In the embodiment of  FIG.  2   , the first servo head  206 A reads its lateral position information (e.g., alignment) over the first servo track  210 A. The second servo head  206 B is aligned with the second servo track  2108 . The combined information allows the servo actuator of the tape drive  200  to align the data heads  208 A- 208 G such that the center data track (e.g.,  208 D) is centered on tape  204 . The plurality of data heads  208 A- 208 G is thus individually aligned with the plurality of data tracks  212 A- 212 N for best case positioning. In this embodiment the first servo head  206 A, the second servo head  2068 , the first servo track  210 A, the second servo track  210 B, the plurality of data heads  208 A- 208 G, and the plurality of data tracks  212 A- 212 G are able to read and/or write the data accurately because all are aligned perpendicular to the direction of travel of the tape  204 . 
       FIGS.  3 A- 3 B  illustrate magnetic tapes  300 ,  350  for use with a tape head of a tape drive, according to various embodiments. Each of the magnetic tapes  300 ,  350  may be the tape  204  of  FIG.  2   , and may be utilized with a tape head module assembly, such as the tape head module assembly  200  of  FIG.  2   , or a tape drive, such as the tape drive  100  of  FIG.  1   . The tape drive utilized with the tapes  300 ,  350  may be an ultra-high areal data density tape drive. As such, aspects of  FIG.  2    may be referred to in the description of  FIGS.  3 A- 3 B . 
     Each tape  300 ,  350  has a length  301  in the x-direction of about 500 m to about 1200 m, and a width  303  in the y-direction of about 1 cm to about 5 cm. As such, it is noted that  FIGS.  3 A- 3 B  are not to scale. Furthermore, while two embodiments of magnetic tapes  300 ,  350  are shown in  FIGS.  3 A- 3 B , aspects shown in only one of the magnetic tapes  300 ,  350  may apply to both magnetic tapes  300 ,  350 , and as such, elements of the magnetic tapes  300 ,  350  may be used in combination. 
     Each tape  300 ,  350  comprises one or more dedicated servo tracks  302   a ,  302   b  and a plurality of data tracks  304 . The dedicated servo tracks  302   a ,  302   b  may collectively be referred to herein as servo tracks  302 . It is to be understood that while two servo tracks  302   a ,  302   b  are shown in each of  FIGS.  3 A- 3 B , the disclosure is not limited to two servo tracks  302 . Rather, the number of servo tracks  302  can be more or less than two, depending on the requirements of the embodiment. Similarly, the number of data tracks  304  is not intended to be limiting, and a greater or fewer number of data tracks  304  than shown may be used. 
     In each tape  300 ,  350 , sections of data tracks  304  are grouped together in a plurality of writeable portions  310  or writeable zones. Tape heads, such as the tape head module assembly  200  of  FIG.  2   , are able to write data to and read data from the writeable portions  310 . Each tape  300 ,  350  may be coupled to reels  320  of a tape drive. Each writeable portion  310  extends in the y-direction from the first servo tracks  302   a  to the second servo track  302   b . During formation of each tape  300 ,  350 , the plurality of writeable portions  310  are sputtered with a first coating comprising one or more materials selected from the group consisting of: Ru, Pt, Ta, Co, Ni, Fe, W, Cr, Ti, and Zr. The writeable portions  310  comprising such precious metals enable the tapes  300 ,  350  to be utilized with ultra-high areal data density tape drives. 
     In the magnetic tape  300  of  FIG.  3 A , a plurality of non-writeable portions  306   a - 306   d  or non-writeable zones are disposed between each writeable portion  310 . Thus, each non-writeable portion  306   a - 306   d  is disposed adjacent to and in contact with at least one writeable portion  310 . The plurality of non-writeable portions  306   a - 306   d  may collectively be referred to as the non-writeable portions  306 . The writeable portions  310  and the non-writeable portions  306  alternate down the length  301  of the tape  300 , or alternate down at least a portion of the tape  300 . User data is unable to be stored in the non-writeable portions  306 . In some embodiments, the non-writeable portions  306  may support writing of embedded servo patterns, which have a lower linear density as compared to the ultra-high areal density of the writeable portions  310 . As such, the dedicated servo tracks  302   a ,  302   b  may be written partially on both the writeable portions  310  and the non-writeable portions  306 . 
     Each non-writeable portion  306  is sputtered with a second coating comprising one or more materials selected from the group of W, Be, Ti, Ta, Cr, and Si, among others. As such, the writeable portions  310  and the non-writeable portions  306  comprise different materials. The material of the non-writeable portions  306  may be selected based on a number of factors, such as surface lubrication, surface roughness, high or enhanced thermal and mechanical properties or mechanical strength, improve moisture barrier to a base film material of the tape  300 , an ability to reduce wear of the tape  300 , an ability to improve tape dimensional stability (TDS) (e.g., preventing the tape  300  from expanding or contracting), an ability to absorb TDS effects, an ability to mitigate stop-start stiction effects, and an ability to absorb stiction. The plurality of non-writeable portions  306  have different mechanical properties than the plurality of writeable portions  310  to mitigate tape dimensional stability issues or changes in the plurality of writeable portions  310 . For example, the non-writeable portions  306  are more rigid than the writeable portions  310 , the non-writeable portions  306  have a higher mechanical stability than the writeable portions  310 , the non-writeable portions  306  have lower coefficients of thermal and humidity expansion and/or contraction than the writeable portions  310 , and the writeable portions  310  are more elastic than the non-writeable portions  306 . The elastic properties of both the writeable portions  310  and the non-writeable portions  306  may be selected to enhance the mechanical stability of writeable portions  310 . 
     The non-writeable portions  306  physically support the writeable portions  310  at the junction between the two types of sections and when wound into a tape pack on either reel  320 . The non-writeable portions  306  physically supporting the writeable portions  310  mitigates any expansion or contraction of the writeable portions  310  due to the viscoelastic nature of the writeable portions  310  by enhancing the rigidity and mechanical stability of the non-writeable portions  306  and by reducing any humidity induced dimensional changes of the writeable portions  310 . Moreover, the surface characteristics of the non-writeable portions  306  portions are selected such that these non-writeable portions  306  mitigate or absorb stiction effects when the tape  300  motion is stopped, and the tape  300  is held in tension stationary on a recording head. 
     In the magnetic tape  300 , each non-writeable portion  306  has a same longitudinal length  314  in the x-direction of about 10 cm to about 1 m, and each writeable portion  310  has a same longitudinal length  308  in the x-direction of about 2 m to about 12 m. Thus, the writeable portions  310  have a greater area than the non-writeable portions  306 . The non-writeable portions  306  and the writeable portions  310  may have a same length  303  in the y-direction. Each writeable portion  310  is defined between two non-writeable portions  306  in the x-direction. A thickness in the z-direction of the writeable portions  310 , or the coating of the writeable portions  310 , ranges from about 20 nm to about 60 nm, and a thickness in the z-direction of the non-writeable portions  306 , or a coating of the non-writeable portions  306 , ranges from about 20 nm to about 100 nm. 
     In the embodiment shown in  FIG.  3 A , the non-writeable portions  306  are spaced equidistance apart (i.e., by the length  308  of a writeable portion  310 ). However, in other embodiments, the non-writeable portions  306  may be spaced apart by varying distances, similar to as shown in  FIG.  3 B . The length  308  of the writeable portions  310  may vary, resulting in one or more writeable portions  310  being different sizes. In some embodiments, a customer may choose the length  308  of each writeable portion  310 . 
     The length  314  of each non-writeable portion  306  is based on one or more of: dimensions of the magnetic tape  300 , a density of the magnetic tape  300 , a tension of the magnetic tape  300 , the length  308  of each of the writeable portions  310 , a tape  300  stop-start or turn-around operation efficiency of a tape drive, head-tape friction, tape velocity over the tape head, and a specified number of passes required by the tape drive, among others. The mechanical characteristics of the non-writeable portions  306  are selected to have significant resistance to dimensional changes caused by temperature, pressure, humidity, and tension (among other effects). The magnetic tape  300  may comprise any number of non-writeable portions  306 , such as about 5 non-writeable portions  306  to about 100 non-writeable portions  306 . In some embodiments, a first non-writeable portion  306   a  disposed at a beginning of the tape  300  (BOT) is attached to a first reel  320 , and a second non-writeable portion  306   d  disposed at an end of the tape  300  (EOT) is attached to a second reel  320 . In such embodiments, the non-writeable portions  306   b ,  306   c  disposed inwards from the beginning and end of the tape  300  are disposed adjacent to and in contact with two writeable portions  310 . 
     The magnetic tape  350  of  FIG.  3 B  is similar to the magnetic tape  300  of  FIG.  3 A  in that a plurality of non-writeable portions  356   a - 356   e  or non-writeable zones are disposed between each writeable portion  310 , where each non-writeable portion  356   a - 356   e  is disposed adjacent to and in contact with at least one writeable portion  310 . The plurality of non-writeable portions  356   a - 356   e  may collectively be referred to as the non-writeable portions  356 . The writeable portions  310  and the non-writeable portions  356  alternate down the length  301  of the tape  350 , or alternate down at least a portion of the tape  350 . User data is unable to be stored in the non-writeable portions  356 ; however, servo data could be stored in the non-writeable portions  356 . As such, the dedicated servo tracks  302   a ,  302   b  may be written partially on both the writeable portions  310  and the non-writeable portions  356 . Each non-writeable portion  356  is coated or sputtered with a second coating comprising one or more materials selected from the group consisting of W, Be, Ti, Ta, Cr, and Si, among others. As such, the writeable portions  310  and the non-writeable portions  356  comprise different materials. 
     The material of the non-writeable portions  356  may be selected based on a number of factors, such as surface lubrication, surface roughness, high or enhanced thermal and mechanical properties or mechanical strength, improve moisture barrier to a base film material of the tape  350 , an ability to reduce wear of the tape  350 , an ability to improve TDS (e.g., preventing the tape  350  from expanding or contracting), an ability to or absorb TDS effects, an ability to mitigate stop-start stiction effects, and an ability to absorb stiction. The plurality of non-writeable portions  356  have different mechanical properties than the plurality of writeable portions  310  to mitigate tape dimensional stability issues or changes in the plurality of writeable portions  310 . For example, the non-writeable portions  356  are more rigid than the writeable portions  310 , the non-writeable portions  356  have a higher mechanical stability than the writeable portions  310 , the non-writeable portions  356  have lower coefficients of thermal and humidity expansion and/or contraction than the writeable portions  310 , and the writeable portions  310  are more elastic than the non-writeable portions  356 . The elastic properties of both the writeable portions  310  and the non-writeable portions  356  may be selected to enhance the mechanical stability of writeable portions  310 . 
     The non-writeable portions  356  physically support the writeable portions  310  at the junction between the two types of sections and when wound into a tape pack on either reel  320 . The non-writeable portions  356  physically supporting the writeable portions  310  mitigates any expansion or contraction of the writeable portions  310  due to the viscoelastic nature of the writeable portions  310  by enhancing the rigidity and mechanical stability of the non-writeable portions  356  and by reducing any humidity induced dimensional changes of the writeable portions  310 . Moreover, the surface characteristics of the non-writeable portions  356  portions are selected such that these non-writeable portions  356  mitigate or absorb stiction effects when the tape  350  motion is stopped, and the tape  350  is held in tension stationary on a recording head. 
     The magnetic tape  350  differs from the magnetic tape  300  in that at least two non-writeable portions  356   a ,  356   b  have a different longitudinal lengths  316   a ,  316   b . Each non-writeable portion  356  has a length in the x-direction of about 10 cm to about 1 m. In the embodiment shown in  FIG.  3 B , each non-writeable portion  356   a ,  356   b ,  356   c ,  356   d , and  356   e  has a different length  316   a ,  316   b ,  316   c ,  316   d , and  316   e  in the x-direction. For example, the fifth non-writeable portion  356   e  shown has a smaller length  316   e  than each of the first through fourth non-writeable portions  356   a - 356   d , and the fourth non-writeable portion  306   d  has a greater length  316   d  than each of the first, second, third, and fifth non-writeable portions  356   a ,  356   b ,  356   c ,  356   e . However, one or more non-writeable portions  356  may have a same length in the x-direction, similar to as shown in  FIG.  3 A . 
     Similarly, at least two writeable portions  310  have different lengths  358   a ,  358   b  in the x-direction. Each writeable portion  310  has a length  358   a - 358   d  in the y-direction of about 2 m to about 12 m. In some embodiments, the non-writeable portions  356  extend over the first servo track  302   a  and the second servo track  302   b  in the y-direction, like shown in  FIG.  3 A . Each writeable portion  310  is defined between two non-writeable portions  306  in the x-direction. A thickness in the z-direction of the writeable portions  310 , or the coating of the writeable portions  310 , ranges from about 20 nm to about 60 nm, and a thickness in the z-direction of the non-writeable portions  356 , or a coating of the non-writeable portions  356 , ranges from about 20 nm to about 100 nm. 
     In the embodiment shown in  FIG.  3 B , each writeable portion  310  has a different length  358   a ,  358   b ,  358   c ,  358   d  in the x-direction. However, one or more writeable portions  310  may have a same length in the x-direction, similar to as shown in  FIG.  3 A . Because each writeable portion  310  has a different length  358   a - 358   d  in the x-direction in the magnetic tape  350 , the non-writeable portions  356  are spaced apart by varying distances. In other embodiments, the non-writeable portions  356  may have different lengths  358   a - 358   d  in the x-direction while each writeable portion  310  has a same length in the x-direction, in which the non-writeable portions  356  would be spaced equidistance apart. In some embodiments, a customer may choose the length  358   a - 358   d  of each writeable portion  310 . 
     The non-writeable portions  356  and the writeable portions  310  may have a same width  303  in the y-direction. Thus, the writeable portions  310  have a greater area than the non-writeable portions  356 . The length  314  of each non-writeable portion  356  is based on one or more of: dimensions of the magnetic tape  350 , a density of the magnetic tape  350 , a tension of the magnetic tape  350 , the length  308  of each of the writeable portions  310 , a tape  350  stop-start or turn-around operation efficiency of a tape drive, head-tape friction, tape velocity over the tape head, and a specified number of passes required by the tape drive, among others. The mechanical characteristics of the non-writeable portions  356  are selected to have significant resistance to dimensional changes caused by temperature, pressure, humidity, and tension (among other effects). 
     The magnetic tape  350  may comprise any number of non-writeable portions  356 , such as about 5 non-writeable portions  356  to about 100 non-writeable portions  356 . In some embodiments, a first non-writeable portion  356   a  disposed at a beginning of the tape  350  is attached to a first reel  320 , and a second non-writeable portion  356   e  disposed at an end of the tape  350  is attached to a second reel  320 . In such embodiments, the non-writeable portions  356   b - 306   d  disposed inwards from the beginning and end of the tape  350  are disposed adjacent to and in contact with two writeable portions  310 . Additionally, the first non-writeable portion  356   a  attached to the first reel  320  and the second non-writeable portion  356   e  attached to the second reel  320  may have a greater length  316   a ,  316   e  than the non-writeable portions  356   b - 306   d  disposed inwards from the beginning and end of the tape  350 . 
     Both the non-writeable portions  306  of  FIG.  3 A  and the non-writeable portions  356  of  FIG.  3 B  can provide several additional benefits to a tape drive, such as adding lubrication to a tape head during turn-around operations, cleaning the tape head, and removing debris from the tape head and/or the writeable portions  310  of the tape  300 ,  350 . Additionally, in the absence of a conventional cleaning tape being usable or available, such as in TEDs, the non-writeable portions  306 ,  356  can act to remove smearing and other surface contaminates collected on a tape head during normal operation, which helps enable ultra-high areal data densities. Moreover, because the non-writeable portions  306 ,  356  comprise a different material than the writeable portions  310  (i.e., the non-writeable portions  306 ,  356  do not comprise one or more of Ru, Pt, Ta, and Co), the overall cost of the tape  300 ,  350  can be reduced, as precious metal materials used in the writeable portions  310  are generally expensive. 
     The non-writeable portions  306 ,  356  may further be utilized as “parking zones” for a tape head, where the tape  300 ,  350  can be stopped when the tape head is in contact with the non-writeable portions  306 ,  356 , rather than in contact with the writeable portions  310 . In embodiments utilizing a TED system, the tape media  300 ,  350  is never removed from the drive—unlike for example an LTO tape drive. While it is feasible to retract the tape head from being in contact with the tape  300 ,  350  in this type of tape drive, retracting the tape  300 ,  350  adds complexity and cost while also increasing possible tape drive failure mechanisms, thereby decreasing the overall system reliability. If the tape head is left in contact with any of the writeable portions  310  of the tape  300 ,  350 , there is a significantly increased propensity for the tape head to stick to the tape  300 ,  350  due to the extremely smooth nature of both the writeable portions  310  of the tape  300 ,  350  and the tape head, which is necessary to reduce the head-tape separation thereby enabling increased areal densities. 
     When the tape motion is re-initiated, the tape head sticking to the tape  300 ,  350  significantly increases the chance of the tape movement damaging the tape  300 ,  350  which is in contact with the tape head. Thus, the tape head can be parked in contact with the tape  300 ,  350  in one of the plurality of non-writeable portions  306 ,  356 , which can be rougher and have different surface properties than the writeable portions  310 . Parking the tape  300 ,  350  in a non-writeable portion  306 ,  356  mitigates any potential stiction issues on start-up, and completely overcomes the possibility of the tape head damaging the writeable portions  310  when parked between tape drive operations, as the material and surface characteristics of the non-writeable portions  306 ,  356  are selected to mitigate head-tape stiction when the tape  300 ,  350  is held in tension and stationary against the recording head. 
       FIGS.  4 A- 4 C  illustrate a tape head  400  of a tape drive writing to the magnetic tape  300  of  FIG.  3 A  in a start-stop or turn-around operation, according to one embodiment. While  FIGS.  4 A- 4 C  refer back to the tape  300  of  FIG.  3 A , the tape  350  of  FIG.  3 B  may be utilized with the tape head  400  of  FIGS.  4 A- 4 C  in the same manner. Additionally,  FIGS.  4 A- 4 C  are not drawn to scale, but are intended merely to illustrate a start-stop or turn-around operation. 
     The tape head  400  may be the tape head module assembly  200  of  FIG.  2    within a tape drive, such as the tape drive  100  of  FIG.  1   . The tape drive comprising the tape head  400  may be an ultra-high areal data density tape drive. While not shown, the tape head  400  comprises one or more write heads and one or more read heads, such as the plurality of data heads  208 A- 208 G of  FIG.  2   . The tape  300  comprises the plurality of writeable portions  310   a - 310   c , the plurality of non-writeable portions  306  (or the plurality of non-writeable portions  356  of  FIG.  3 B ), and the dedicated servo tracks  302 . While six data tracks  304   a - 304   f  are shown in  FIGS.  4 A- 4 C , the tape  300  may comprise a greater or lesser number of data tracks  304   a - 304   f , and the number of data tracks  304   a - 304   f  is not intended to be limiting. 
       FIG.  4 A  illustrates the tape  300  moving in a first direction  402  (e.g., the x-direction) such that the tape head  400  moves over the tape  300  from a first non-writeable portion  306   a  to write data to at least a portion of a first data track  304   a  and at least a portion of a second data track  304   b  of a first writable portion  310   a . Upon reaching a second non-writeable portion  306   b  in  FIG.  4 B , the tape  300  stops and moves in a second direction  404  (e.g., the y-direction) along the second non-writeable portion  306   b  such that the tape head  400  moves over the tape  300  in the second direction  404 . The tape  300  then starts and turns around to move in a third direction  406  (e.g., the −x-direction) such that the tape head  400  moves over the tape  300  from the second non-writeable portion  306   b  to write data to at least a portion of a third data track  304   c  and at least a portion of a fourth data track  304   d  of the first writable portion  310   a.    
     Upon reaching the first non-writeable portion  306   a  in  FIG.  4 C , the tape  300  stops and moves in the second direction  404  (e.g., the y-direction) such that the tape head  400  moves over the tape  300  along the first non-writeable portion  306   a . The tape  300  then starts again and turns around to move in the first direction  402  (e.g., the x-direction) such that the tape head  400  moves over the tape  300  from the first non-writeable portion  306   a  to write data to at least a portion of a fifth data track  304   e  and at least a portion of a sixth data track  304   f  of the first writable portion  310   a  until the tape head  400  reaches the second non-writeable portion  306   b  once again. Thus, as shown in  FIGS.  4 A- 4 C , the tape head  400  moves over the tape  300  in a serpentine fashion between adjacent non-writeable portions  306   a ,  306   b  to write data to a writeable portion  310   a  disposed between the adjacent non-writeable portions  306   a ,  306   b.    
     The tape  300  and tape head  400  continue moving in such a serpentine manner in the first, second, and third directions  402 ,  404 ,  406  between the adjacent non-writeable portions  306   a ,  306   b  until each data track  304  in the first writeable portion  310   a  is storing data. Upon writing data to each data track  304  in the first writeable portion  310   a , the tape  300  may then move such that the tape head  400  is disposed over or near the second writeable portion  310   b  to begin the serpentine writing process over again on the second writeable portion  310   b.    
     While the tape head  400  is shown and described as writing to two data tracks  304  at a time, the tape head  400  may write to any number of data tracks  304  at a time (e.g., when writing in the first direction  402  and in the second direction  406 ), or only a portion of a data track  304 . For example, depending on the number of write heads the tape drive comprises, the tape head  400  writes N tracks on each pass where N is the number of parallel channel (e.g., 16, 32, 64, etc.) in the tape drive. The tape head  400  is then moved, the tape direction is reversed, and the next set of N tracks is written until a non-writeable portion  306  is reached. The tape  300  is then stopped again, the tape direction is reversed, and the next set of N tracks is written adjacent to the previously written set of N tracks. Thus, the data tracks  304  being written need not be adjacent to one another. The tape head  400  may write to at least a portion of a first, third, and fifth data track when writing in the first direction the first time, and then write to at least a portion of a second, fourth, and sixth data track when writing in the second direction  406  the first time. As such, the exemplary embodiment described in  FIGS.  4 A- 4 C  is not intended to be limiting, but for exemplary purposes only to show the tape head  400  writing in a serpentine fashion to a writeable portion  310   a.    
     To compare to conventional methods of writing data to a tape that does not comprise non-writeable portions  306 , a tape head would start at the beginning of the tape, similar to shown in  FIG.  4 A , but would continue writing data to data tracks along an entire length  301  of the tape until reaching the end of the tape. Writing data to a conventional tape in such a manner thus makes finding desired data more difficult, as more data must first be read by a tape head before reaching the desired data. As a result, the tape head is more susceptible to wear. 
     Because data is written to a smaller area of the tape  300 ,  350  (i.e., the first writeable portion  310   a ) as compared to conventional tapes (i.e., one or more data tracks extending from a beginning of the tape the end of the tape), the data within a writeable portion  310  can be accessed and read quicker and more efficiently compared to data stored on conventional tapes. Being able to access and read desired data from the tape  300 ,  350  quicker and more efficiently further results in reduced power budget for tape drives in seek operations for reading and/or writing data and reduced wear on the tape head, whereas conventional tapes must read more data before reaching the desired data. The overall performance of a tape drive utilizing the tape  300 ,  350  is further increased, as data may be found, updated, replaced, and/or erased faster due to the data being confined in the writeable portions  310 . 
     Therefore, by utilizing a tape comprising one or more non-writeable portions and a plurality of writeable portions, the life of the tape can be prolonged, as the tape is less susceptible to damage during turn-around operations of a tape head of a tape drive and during parking of the tape head, while the overall cost of the tape is reduced and the performance of the tape drive in increased. Furthermore, the non-writeable portions may add lubrication to the tape head during turn-around operations, clean the tape head, and remove debris from the tape head and/or the writeable portions  310  of the tape  300 ,  350 . As such, utilizing the tape comprising one or more non-writeable portions and a plurality of writeable portions reduces wear of the tape and tape head while improving TDS. 
     In one embodiment, a magnetic tape comprises a plurality of writeable portions comprising one or more materials selected from the group consisting of: Ru, Pt, Ta, Co, Ni, Fe, W, Cr, Ti, and Zr, the plurality of writeable portions being able to store data, and a plurality of non-writeable portions, each non-writeable portion being disposed adjacent to at least one writeable portion of the plurality of writeable portions, wherein the plurality of non-writeable portions and the plurality of writeable portions comprise different materials. 
     The plurality of writeable portions are sputtered with a first coating comprising the one or more materials selected from the group consisting of: Ru, Pt, Ta, Co, Ni, Fe, W, Cr, Ti, and Zr. The plurality of non-writeable portions are sputtered with a second coating comprising one or more materials selected from the group consisting of W, Be, Ti, Ta, Cr, and Si. Each of the plurality of non-writeable portions have a length of about 10 cm to about 1 m, and each writeable portion of the plurality of writeable portions have a length of about 2 m to about 12 m. The plurality of non-writeable portions and the plurality of writeable portions are alternating along a total length of the magnetic tape. The plurality of non-writeable portions and the plurality of writeable portions are alternating along at least a portion of the magnetic tape. 
     A magnetic tape drive comprises the magnetic tape, and a tape head configured to write data to and read data from the plurality of writeable portions. The plurality of non-writeable portions are unable to store user data. The plurality of non-writeable portions are able to store embedded servo data. A first non-writeable portion of the plurality of non-writeable portions is disposed at a beginning of the magnetic tape, and a second non-writeable portion of the plurality of non-writeable portions is disposed at the end of the magnetic tape. The first non-writeable portion is configured to be attached to a first reel in the tape drive, and the second non-writeable portion is configured to be attached to a second reel in the tape drive. 
     In another embodiment, a magnetic tape comprises a plurality of writeable portions comprising one or more materials selected from the group consisting of: Ru, Pt, Ta, Co, Ni, Fe, W, Cr, Ti, and Zr, the plurality of writeable portions being able to store data, wherein each writeable portion of the plurality of writeable portions has a first area, and a plurality of non-writeable portions, each non-writeable portion being disposed in contact with at least one writeable portion of the plurality of writeable portions, wherein: the plurality of non-writeable portions each has a second area, the first area is greater than the second area, and the plurality of non-writeable portions and the plurality of writeable portions comprise different materials. 
     The plurality of writeable portions are sputtered with a first coating comprising the one or more materials selected from the group consisting of: Ru, Pt, Ta, Co, Ni, Fe, W, Cr, Ti, and Zr. The plurality of non-writeable portions are sputtered with a second coating comprising one or more materials selected from the group consisting of W, Be, Ti, Ta, Cr, and Si. The plurality of writeable portions and the plurality of non-writeable portions alternate along a total length of the magnetic tape. Each writeable portion of the plurality of writeable portions is defined between two non-writeable portions of the plurality of non-writeable portions. Each of the plurality of non-writeable portions have a length of about 10 cm to about 1 m. Each writeable portion of the plurality of writeable portions have a length of about 2 m to about 12 m. The plurality of non-writeable portions are about 5 non-writeable portions to about 100 non-writeable portions. At least two of the non-writeable portions of the plurality of non-writeable portions have different lengths. At least two writeable portions of the plurality of writeable portions have different lengths. 
     The plurality of non-writeable portions are configured to mitigate tape dimensional stability issues or changes in the plurality of writeable portions of the magnetic tape. Mechanical properties of both the plurality of non-writeable portions and the plurality of writeable portions are selected such that a balance of elasticities and coefficients of expansion and contraction with temperature and humidity are configured to mitigate tape dimensional stability. A magnetic tape drive comprises the magnetic tape, and a tape head configured to write data to and read data from the plurality of writeable portions, wherein the plurality of non-writeable portions are unable to store user data. 
     In yet another embodiment, a magnetic tape comprises a plurality of writeable portions sputtered with a first coating comprising one or more materials selected from the group consisting of: Ru, Pt, Ta, Co, Ni, Fe, W, Cr, Ti, and Zr, the plurality of writeable portions being able to store data, and a plurality of non-writeable portions sputtered with a second coating comprising one or more materials selected from the group consisting of W, Be, Ti, Ta, Cr, and Si, wherein: the first coating and the second coating comprise different materials, the plurality of writeable portions and the plurality of non-writeable portions alternate along a total length of the magnetic tape, and the plurality of non-writeable portions are unable to store user data. 
     Each writeable portion of the plurality of writeable portions is defined between two non-writeable portions of the plurality of non-writeable portions. Each writeable portion of the plurality of writeable portions have a greater area than each of the one or more non-writeable portions. A magnetic tape drive comprises the magnetic tape, and a tape head configured to write data to and read data from the plurality of writeable portions. The plurality of non-writeable portions have different mechanical properties than the plurality of writeable portions. The plurality of non-writeable portions are configured to lubricate the tape head, clean the tape head, remove debris from the tape head, and to mitigate tape dimensional stability issues or changes in the plurality of writeable portions of the magnetic tape. 
     While the foregoing is directed to embodiments of the present disclosure, other and further embodiments of the disclosure may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.