The present disclosure relates to apparatus and methods for recording heads, including magnetic recording heads. Particularly, the present disclosure relates to apparatus and methods for magnetic recording heads with tape guides. More particularly, the present disclosure relates to apparatus and methods for magnetic recording heads with embedded tape guides.
Tape edge guiding is an important issue in high density recording using flexible tape. Optimization of the lateral stability of the tape is desirable in order to go to higher track densities.
In the magnetic tape data storage industry, data is stored as a sequential stream of magnetic transitions, written in a series of adjacent tracks down the length of tape. A track may also be referred to herein as a band. Magnetic write and read heads follow the bands of data down the length of tape, writing and reading the information contained in the magnetic transitions.
When the magnetic heads read and write the data of a chosen band, it is important that the heads not read from, or write data on, adjacent bands. In read-back operations, failure to stay on the chosen track or band may result in contaminated data from detection of adjacent band transitions. In writing operations, failure to stay on the chosen track or band, may result in the adjacent band data being overwritten, and hence data loss.
As magnetic tape is a flexible media, many degrees of motion and motion characteristics are present in the tape while it is streaming over the read/write heads during recording operations. Some of these motions consist of in-plane lateral motion modes. Motion of the tape surface perpendicular to the tape streaming direction may be referred to herein as Lateral Tape Motion (LTM). LTM includes motion of the tape in the direction of the adjacent data bands, and hence may be undesirable. This motion is a primary source of tracking errors during recording operations.
LTM can be roughly thought of in two categories, written-in and read-back. Written-in LTM is the LTM written in during magnetic writing (formatting) of the servo band. As the tape streams over the servo formatting magnetic head, the LTM characteristic of the tape path is written into the servo band on tape. During read back operations, the detected LTM consists of this written-in portion, and the portion produced by the read-back tape path. In general, the read-back tape path is of significantly lower quality than the servo formatting tape path.
In current generations of magnetic tape, the width of the data bands and the distance between adjacent data bands are sufficiently small. Typically, LTM and other undesirable motions of the tape must be compensated for to allow proper tracking during read/write operations. This can be accomplished through active servo-following of the chosen band, e.g., utilizing servo bands.
Magnetic servo bands are typically written into the media in the tape manufacturer production facility. These servo bands are written into the tape in specific and well controlled positions on the tape. The type of servo bands used depends on the specific tape format. A typical format is Linear Tape Open (LTO).
There are usually multiple servo bands formatted into the tape. These bands are designed to functionally span the tape width, and are generally not over-written while the tape is in use. Servo bands are the system metric used for track following, and hence should be written as accurately as possible. Servo bands are sensed by a magnetic read head while the tape is streaming. By actively monitoring the position and movement of these servo bands during streaming, the read/write data heads can be dynamically positioned to a desired location.
A system used to stream tape over a magnetic read/write head may be referred to herein as a tape transport, and are known in the art. The course the tape follows while streaming through a tape transport may be referred to herein as a tape path.
Motion of the tape while streaming through any tape transport mechanism is a characteristic of the particular tape path used. Throughout the magnetic tape data storage industry, a significant amount of development occurs for a given tape path. This development typically focuses on controlling the tapes many modes of motion and removing unwanted motion. Differing degrees of undesirable motion can be present along differing sections of the tape path. The minimization of LTM can be a significant design criteria for a given tape path.
The motion of the tape can be controlled through the implementation of tape guides. The tape guides, used to control the position and motion of the tape as it moves along portions of the tape path, can be designed as a component of the system. Some types of tape guides are currently used in the industry. The most common family of guides are tape edge guides. This family of guides acts on the tape edge, either as a barrier/constraint, or as a reference edge/datum.
Tape guiding systems are present in the user tape drive and tape guiding systems and in the formatting of the tape at the tape manufacturer. While both uses are envisioned to be improved upon by the embodiments of the present disclosure, the embodiments of the present disclosure will generally be explained with exemplary embodiments of formatting of a tape at the tape manufacturing facility.
IBM has developed a fixed lower edge guide coupled to a forcing or compliant upper edge guide, as illustrated in
However, one limitation of current tape guiding systems, independent of the type of guiding that is used, is the existence of a guide-free span across the head region. In general, the longer the free span of tape in a tape path, the larger the amplitude of undesirable motions, such as LTM. In critical regions of the tape path, such as the head region, it may therefore be desirable to limit the free span lengths. The free span may be minimized with such techniques referred to herein as close edge guiding. In such a system, for example a servo format system, the tape guides are brought as close to the read/write head as practical.
The section of the tape path exemplarily focused on herein is the active path length associated with encoding of the servo pattern into the media in a servo formatting tape path. The characteristics of the tape path, local to the servo formatting region, may be a primary concern for limiting written-in LTM. By limiting the free span of tape across the servo formatting head, it can be possible to limit the amplitude of the undesirable modes of tape motion. For this reason, the systems responsible for servo formatting are sometimes designed with edge guides in close proximity to the servo formatting magnetic head. However, the region of tape path designated for the servo formatting head constitutes an operational free tape span.
Thus, there is a need in the art for improved magnetic recording heads that guide streaming tape across the contour of the head. Additionally, there is a need in the art for magnetic recording heads that minimize the free span across the contour of the head. There is a need in the art for magnetic recording heads with tape guides.
The present disclosure, in one embodiment, relates to a magnetic recording head having a contour modified to include a tape guide. The tape guide may include a single edge, non-compliant edge guide, a double edge, non-compliant edge guide, a single edge, compliant edge guide, a double edge, compliant tape guide, or a combination of a single edge, non-compliant edge guide and single edge, compliant edge guide.
The present disclosure, in another embodiment, relates to a magnetic recording head having a contour that is configured to impart a lateral force on the surface of tape streaming over the head. To impart the lateral force, the head may include air-bleed slots that are non-perpendicular to the streaming direction of the tape, air skiving edges that are non-perpendicular to the streaming direction of the tape, non-symmetrical head surfaces, specific contour topographies, strategically located negative pressure elements, or any combination thereof. The magnetic recording head may further include a tape edge guide.
The present disclosure, in yet another embodiment, relates to a method of making a magnetic recording head. The method includes providing a tape edge guide on a contour of a magnetic head. The method may also include providing air-bleed slots on the contour of the head configured to impart a lateral force on the surface of tape streaming over the head.
The present disclosure, in one embodiment, relates to a magnetic recording head having a tape bearing surface comprising means for guiding streaming tape over the tape bearing surface.
The present disclosure, in still a further embodiment, relates to a method of formatting magnetic tape. The method includes streaming magnetic tape over a tape bearing surface of a magnetic recording head, the magnetic recording head comprising a tape edge guide.
The present disclosure, in one embodiment, relates to magnetic media having magnetic transitions. The magnetic transitions are written on the tape while the magnetic tape is guided over the contour of a magnetic recording head. The contour of the magnetic recording head is modified to include a tape edge guide. In other words, in some embodiments, the magnetic media is made by streaming the magnetic media over a tape bearing surface of a magnetic recording head, the magnetic recording head comprising a tape edge guide.
The present disclosure, in another embodiment, relates to a magnetic drive system including a tape transport, a tape path, and a magnetic recording head in the tape path. The contour of the head is modified to include a tape guide. The magnetic recording head may be a data read/write head or a servo read/write head.
The present disclosure, in yet another embodiment, relates to magnetic tape having substantially eliminated written-in lateral tape motion.
While multiple embodiments are disclosed, still other embodiments of the present invention will become apparent to those skilled in the art from the following detailed description, which shows and describes illustrative embodiments of the invention. As will be realized, the invention is capable of modifications in various obvious aspects, all without departing from the spirit and scope of the present invention. Accordingly, the drawings and detailed description are to be regarded as illustrative in nature and not restrictive.
While the specification concludes with claims particularly pointing out and distinctly claiming the subject matter that is regarded as forming the present invention, it is believed that the invention will be better understood from the following description taken in conjunction with the accompanying Figures, in which:
The present disclosure relates to novel and advantageous apparatus and methods for recording heads, including magnetic recording heads. Particularly, the present disclosure relates to apparatus and methods for magnetic recording heads with tape guides. More particularly, the present disclosure relates to apparatus and methods for magnetic recording heads with embedded tape guides. The embodiments of the present disclosure may utilize tape edge guides, embedded into the head contour, to minimize the amplitude of unwanted lateral motion. A tape edge guide may be designed into the tape head contour as an integral part of the tape head. This may allow the integration of tape edge guiding techniques into intimate proximity to a servo formatting region. In addition, it may allow for minimization of the effective free tape span, local to the servo formatting process, and can add design flexibility to the tape path. The embodiments of the present disclosure may reduce, substantially reduce, or substantially eliminate the written-in component of LTM and decrease the tracking errors in servo-following operations for data writing and recovery.
There are many types of edge guides that can be used in tape paths. Some guides are discussed above and illustrated in
The head 30 may be a head such as that described in U.S. Pat. No. 6,678,116, issued Jan. 13, 2004, and titled “Thin-film Magnetic Recording Head Having a Timing-Based Gap Pattern for Writing a Servo Track on Magnetic Media,” U.S. Pat. No. 6,496,328, issued Dec. 17, 2002, and titled “Low Inductance, Ferrite Sub-Gap Substrate Structure for Surface Film Magnetic Recording Heads,” U.S. patent application Ser. No. 11/017,529, filed Dec. 20, 2004, published as U.S. Publ. No. 2005/0157422, and titled “Timing-Based Servo Verify Head and Method Thereof,” and U.S. patent application Ser. No. 11/120,640, filed May 3, 2005, published as U.S. Publ. No. 2005/0254170, and titled “Integrated Thin Film Subgap Subpole Structure for Arbitrary Gap Pattern Magnetic Recording Heads and Method of Making the Same,” each of which is hereby incorporated by reference herein. In other embodiments, the head 30 may be any suitable recording head.
In one embodiment of the present disclosure, illustrated in
In one embodiment, the edge guide 40 may be an integral component of the contour of the tape head 30 and may be manufactured integrally and substantially simultaneously with the tape head 30. Thus, the edge guide 40 may be manufactured using deposition techniques, lithographic techniques, or any other suitable method, including each of the methods described in U.S. Pat. No. 6,678,116, U.S. Pat. No. 6,496,328, U.S. patent application Ser. No. 11/017,529, and U.S. patent application Ser. No. 11/120,640, each of which was previously incorporated by reference herein, or any other suitable method of manufacturing the edge guide 40 integrally with the tape head 30. In other embodiments, the edge guide 40 may be added to the tape head 30 subsequent manufacture of the tape head 30. That is, the edge guide 40 may be manufactured independently from the head 30. The edge guide 40 may then be bonded, adhesively applied, or otherwise combined with, or accepted by, the head 30.
During streaming, the tape 20 may be held under tension, and lateral or other undesirable motions can be partially reduced by existing guides in the tape path, such as those described previously with respect to
Alignment of a built-in, or contour, edge guide into the tape path may be held to high or very high tolerances. Extending the head guide to include the span of the head mount may allow the precision of guide alignment to the tape edge 42 to be referenced to the head mount in a high precision mounting operation. This can have several advantages. One advantage may include that the head mount can contain high precision locating surfaces to allow easy alignment in the tape path. Another advantage, is that the alignment of the contour edge guide to the head mount reference surfaces can be done outside the production facility using accurate tooling and metrology to ensure proper alignment. This may increase the ease and precision to which the head and contour edge guide can be integrated into the tape path.
In another embodiment, illustrated in
The length of the edge guides 60, 62 may be extended to any suitable length beyond the width of the head 30. In yet other embodiments, the length of the edge guides 60, 62 may be shorter than the width of the head 30. Additionally, the length of the edge guide 60 may be different than the edge guide 62. For example, the length of edge guide 60 may be substantially the width of the head 30 while the length of edge guide 62 may be substantially the width of a head mount.
In some embodiments, pushing on one edge of tape with a compliant edge guide to reference the opposite edge of the tape can sometimes cause undesirable tension gradients, as well as ripple and buckling of the tape 20. Tension gradients can be undesirable, as they may affect the Head-to-Tape Interface (HTI), and hence the read/write performance of the system. Additionally, a tape edge, in some embodiments, may be used as a streaming reference throughout the tape path. Therefore, tape edge damage can negatively affect the motion characteristics of the tape and can increase the native LTM. Current generations of magnetic tape can be on the order of 5-8 um thick and over 12.5 mm wide. As tape is generally flexible, such a thickness to width ratio can mean that pushing on a tape edge, which is dynamically streaming past, should be done with great care and, in some embodiments, can lead to undesirable edge damage. Thus, in some embodiments, in order to reference the tape against an edge guide with suitable care, it may be desirable to apply a lateral force to the tape uniformly over the entire tape surface. This can minimize potential tension gradients and prevent the occurrence of tape edge damage.
In alternative embodiments, other features provided on the head 70 may be used to impart the lateral force 76, including but not limited to, air skiving edges that are non-perpendicular to the tape streaming direction, strategically located negative pressure elements, etc.
In other embodiments, the lateral force 76 may be imparted by characteristics of the head 70 itself, such as but not limited to, non-symmetrical head surfaces, specific contour topographies, etc. Similarly, any combination of features or characteristics may be provided to impart the lateral force 76. That is, it need not be necessary for the lateral force 76 to be a result of angled air-bleed slots, skiving edges, or surfaces. Any suitable contour geometry, surface, or other quality or characteristic that produces a net lateral force 76 could be sufficient.
Although the various embodiments of the present disclosure have been described with reference to preferred embodiments, persons skilled in the art will recognize that changes may be made in form and detail without departing from the spirit and scope of the present disclosure.
This application is a continuation of International Patent Application No. PCT/US2009/031798 filed Jan. 23, 2009, which claims priority to U.S. Ser. No. 61/022,872 filed Jan. 23, 2008, the contents of each of which are herein incorporated by reference.
Number | Date | Country | |
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61022872 | Jan 2008 | US |
Number | Date | Country | |
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Parent | PCT/US2009/031798 | Jan 2009 | US |
Child | 12841788 | US |