Abstract:
A magnetic data recording system and apparatus providing the flexibility of using a magnetoresistive read/write head in other than its standard orientation. The invention includes a plurality of magnetic recording disks supported on a spindle rotated by a motor. A plurality of arms, each mounted to a common actuator for arcuate motion, support at their distal ends the magnetoresistive read/write heads. The arms suspend the heads in close proximity to upper and lower surfaces of the disks so that the heads may record signals thereto and read signals therefrom. Generally such systems comprise two sets of such heads, a set of up-heads designed for facing upward to read the bottom surface of a disk and another set of down-heads designed to face downward to read an upper surface of a disk. The present invention provides circuitry allowing the up heads to be used in a downward direction and conversely allows a down head to be used in an upward direction, thereby eliminating the need to manufacture and store an equal number of two different configurations of heads.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The present invention relates to magnetic disk data storage systems, and more particularly to systems utilizing multiple disks and multiple read/write heads. 
     Magnetic disk drives are used to store and retrieve data for digital electronic apparatuses such as computers. In FIGS. 1A and 1B, a magnetic disk data storage system of the art is illustrated which includes a sealed enclosure  12  and a plurality of magnetic disks  14  each of which has an upper surface  16  and a lower surface  18 . The disks are supported for rotation by a spindle  20  of a motor  22 . 
     An actuator  24 , includes an E-block  25  having at a distal end a plurality of actuator arms  26 . The actuator  24  also includes a bearing  27  which mounts the actuator  24  pivotally within the enclosure  12  and further includes a voice coil  28  at its proximal end. The voice coil  28  is disposed between a pair of magnets  30  which are fixedly connected with respect to the enclosure  12 . Generating an electrical current in the coil  28  induces a magnetic field about the coil. Interaction between the magnetic fields of the coil  28  and the magnets  30  provides a desired, controlled pivotal movement of the actuator about a pivot point  31  of the bearing. 
     The actuator arms  26  support a plurality of suspensions  32 , each of which supports at its distal end a magnetic head  34 . Each suspension  32  holds its corresponding magnetic head  34  in close proximity to a surface of one of the disks  14  to facilitate reading and recording data to and from the disk  14 . 
     With reference now also to FIGS. 2A and 2B, as well as to FIGS. 1A and 1B, the suspension  32  includes suspension trace circuitry  36  which conducts electrical signals from the head  34  to a set of contacts  38  along an edge of the suspension  32 . A bridge flex connector  40 , having trace circuitry  41 , electrically connects the suspension trace circuitry  36  with circuitry  42  (see FIG. 1A) attached to the E-block  25 . The heads  34 , suspensions  32 , bridge flex connectors  40  and E-block  25  with E-block circuitry  42  together form a Head Stack Assembly  44  (HSA). 
     The motor  22  and spindle  20  cause the disks  14  to rotate. As the disks  14  rotate, the air immediately adjacent the disks  14  moves with the disks  14  as a result of friction and the viscosity of the air. This moving air passes between each of the heads  34  and its adjacent disk surface  16 ,  18  forming an air bearing. This air bearing causes the head to fly a very small distance from the disk surface  16 ,  18 . 
     With reference to FIGS. 2C and 2D, as well as FIGS. 1A and 1B, each of the heads  34  includes a read element  46  and a write element  48  (FIG.  2 E). As the disk surface  16  or  18  moves past the head  34  the write element  48  generates a magnetic field leaving magnetic data on the passing disk  14 . Such write elements are generally in the form of an electrical coil  50  passing through a magnetic yoke  52 . As a current passes through the coil  50  it induces a magnetic field which in turn generates a magnetic flux in the yoke  52 . A gap (not shown) in the yoke causes the magnetic flux in the yoke to generate a magnetic field which fringes out from the gap. Since the gap is purposely located adjacent the disk, this magnetic fringing field imparts a magnetic data onto the passing magnetic disk  14 . 
     With continued reference to FIGS. 2C and 2D, to read data from a disk  14 , the read element  46  detects changes in surrounding magnetic fields caused by the disk  14  passing thereby. Several read elements have been used to read such data. A very effective read element currently in use is a GMR Spin Valve sensor. Such sensors take advantage of the changing electrical resistance exhibited by some materials when a passing magnetic field affects the magnetic orientation of adjacent magnetic layers. At its most basic level, a GMR spin valve includes a free magnetic layer and a pinned magnetic layer separated by a non-magnetic layer such as copper. The pinned layer has magnetization which is pinned in a pre-selected direction. The free layer, on the other hand, has a direction of magnetization which is perpendicular with the pinned layer, but is free to move under the influence of an external magnetic field such as that imparted by a passing magnetic recording medium. As the angle between the magnetic directions of the free and pinned layers changes, the electrical resistance through the sensor changes as well. By sensing this change in electrical resistance, the magnetic signal passing by the read element can be detected. 
     With continued reference to FIGS. 2A and 2C, in order to deliver an electrical signal to the write element or to receive an electrical signal from a read element, a set of electrical head contacts  54  are provided in the surface at the distal end of the head  34 . These contacts  54  connect with the suspension trace circuitry  36  at the distal end of the suspension  32 . The suspension  32  and the actuator arm  26  together form an arm assembly  33 .(see FIGS.  1 A and  1 B). 
     The process of manufacturing the heads  34  and assembling them onto an arm assembly  33  causes slight variations in the magnetic directions of free and pinned layers of the spin valve. These changes can have devastating effects on the performance of the read element. In order to ensure correct alignment of the magnetic layers, after all of the Head Stack Assemblies (HSAs)  44  have been assembled the assemblies are passed through a carefully controlled magnetic field which ensures proper alignment of the magnetization within the read element. This process is known as Head Stack Assembly Reinitialization (HSA Reinitialization). 
     Please note that as used in the following discussion, and throughout this specification, the term “configuration” will be used to refer to the sequence of read elements and write elements and their contacts in a given head, and this configuration shall not chance regardless of the direction that this head is facing. The term “orientation” will refer to the order or sequence of elements or contacts presented by a head as it faces in different directions, i.e. facing upwards or downwards. 
     Note also that there will be a distinction made between an “up head” of the prior art and an “upward facing head”, and likewise a distinction between a “down head” of the prior art and a “downward facing head”, so that an up head may be used as a downward facing head, or a down head as an upward facing head. In the prior art, up heads and down heads required usually mirror image configurations. For example, an up head  34   a  facing downward may have a configuration of R−, R+, W− and W+, as shown by the symbols in boxes in FIG. 2D, and a down head  34 B, also facing downward in the figure, would then have a configuration of W+, W−, R+ and R−, as also shown by the symbols in boxes in FIG.  2 C. The “configurations” of the up and down heads do not change when the up heads and down heads are turned to face downward. In terms of their “orientation”, however, the sequences do change, so that an up head now facing upward would now have an orientation of W+, W−, R+ and R−, shown by the symbols in parentheses in FIG. 2D, while a down head, now facing upward, would have an orientation of R−, R+, W− and W+, as shown by the symbols in parentheses in FIG.  2 C. 
     Simply put, for this discussion, “configuration” is fixed by manufacture and “orientation” is achieved by turning the head rightside-up or upside-down. 
     Also, please note that for the sake of clarity in this discussion, the term “matching” will be used in describing a configuration of head, especially in the prior art, which is used in the same orientation for which its configuration is named (i.e., an up head facing upward or a down head used facing downwards). The term “non-matching” shall be used for the opposite cases (i.e. an up head facing downwards or a down head facing upwards). 
     With continued reference to FIGS. 1A and 2C, prior art systems require that two sets of heads  34  be used. One set of heads  34   a  is designed to face upward to read the lower surface of the disk  14 , while the other set  34   b  is designed to face downward to read the upper surface of the disk  14 . This required production of two sets of magnetic heads increases production and inventory costs but has been necessitated by several factors. 
     First, the HSA reinitialization of all heads simultaneously requires that the read elements  46 , all face in the same directions in the assembly. This requires that the configuration of the read element  46  in an up head  34   a  be manufactured in an opposite sequence than that of a sensor in a down head  34   b . Simply flipping a head  34  about its longitudinal axis would result in a read element  46  being oriented in the wrong direction. 
     Second, the orientation of a head  34  is dictated in part by the topography of an air bearing surface  56 . FIG. 2E shows an air-bearing surface of a head  34 , enlarged. The air-bearing surface includes a pair of rails  58  and has a leading edge  60  and a trailing edge  62 . In order to maintain proper flight characteristics it is necessary to have the leading edge oriented into the direction of the oncoming air stream. For this reason it is not possible to simply flip a head about its lateral axis, as this would cause the trailing edge  62  of the air-bearing surface  56  to be oriented into the oncoming air stream. 
     Third, with reference to FIGS. 1A,  2 A and  2 C, signals from the contact pads  54  connect electrically with circuitry on the bridge flex connector  40  and circuitry  42  on the E-block  25 . This requires that two different sets of heads  34   a  and  34   b  be used to ensure that the contacts  54  of both the up head  34   a  and the down head  34   b  connect with the appropriate circuitry  42  on the E-block  25 . 
     This use of two different heads  34   a  and  34   b  adds to manufacturing expense and time as well as inventory cost. Additionally, oftentimes a manufacturing run will be more successful for one set of heads than another, leading to, for example, a greater inventory of up heads  34   a  than down heads  34   b . Since the prior art requires that an equal number of each type of head be used, many heads become wasted. Valuable time is wasted as well while additional heads are manufactured. Therefore there remains a need for a system for allowing the use of a single configuration of head to be used in either the upward or downward orientation. 
     SUMMARY OF THE INVENTION 
     The present invention provides a system, and apparatus for using magnetoresistive heads of a single configuration in either an upward direction or a downward direction in a multiple disk magnetic storage device. The invention includes a plurality of arms each supporting a magnetic head. The arms are connected with an actuator which causes them to move about a pivot point to locate the heads in a desired location on the disks. According to the present invention, the arms are of two types. The first type of arm is for use with a head mounted in its “matching” orientation (i.e., an up head facing upward) and includes circuitry which electrically connects the contact pads of the head with a set of contact pads of a predetermined arrangement on the arm. The second arm is intended for use with a head oriented in other than its “matching” orientation, for example, an up head used in the downward direction. This second arm includes circuitry, different from that of the first arm, which directs electrical signals from the contacts of its attached head to contacts on the arm in the same predetermined arrangement as on the first arm. In this way any circuitry designed to pick up an array of signals from the first arm will be able to pick up the correct signal from the second arm in spite of the fact that the head of the second arm is being used in a “non-matching” orientation. 
     In a preferred embodiment of the invention, the first and second arms each include at their distal portions a suspension. The suspension is a flexible member which is attached at its proximal end, in a cantilevered fashion, to a distal end of an actuator arm and its distal end includes a gimbal for positioning the head. The actuator arm attaches at its proximal end to the actuator for arcuate movement about a pivot point of the actuator in unison with all other such arms similarly attached. 
     The suspension includes trace circuitry which conducts signals from the head contacts to a set of suspension contacts located on an edge of the suspension. The first and second arm assemblies both use suspensions with the same arrangement of suspension contacts. 
     Both the first and second arm assemblies include a Bridge Flex Connector (BFC), the BFC of the first arm assembly being unique as compared with that of the second arm assembly. The BFC used on the first arm assembly is a Standard BFC. It attaches at its distal end to the edge of the suspension and includes circuitry which picks up electrical signals from the suspension contacts located on that edge of the suspension. The circuitry of the Standard BFC routes the signals from the suspension contacts to a set of head stack assembly window contacts (HSA window contacts) located on the BFC and arranged in the aforementioned contact arrangement. From the BFC contacts, various circuitry can pick up and deliver signals as needed to record and read data. 
     The second arm assembly uses an Uni-Wafer BFC. Like the Standard BFC, the Uni-Waver BFC attaches at its proximal end to an edge of the actuator arm and at its distal end to an edge of the suspension. Also similar to the Standard BFC, the Uni-Wafer BFC picks up signals from the suspension contacts and includes circuitry which routes those signals to HSA window contacts arranged in the same predetermined arrangement as the Standard BFC at a location along the length of the Uniwafer BFC. The circuitry of the Uni-Wafer BFC, however, differs from the circuitry of the Standard BFC. 
     Because the head used on the second arm assembly has been flipped over and is not in its standard, matching orientation, the arrangement of the signals delivered to the suspension contacts from the head contacts will be different on the second arm than on the first arm. For example, if the head contacts are arranged on the head such that the suspension circuitry delivers that signal to the most distal contact in the suspension contact arrangement of the first arm assembly, that same signal would end up at the most proximal contact in the arrangement of suspension contacts on the second arm. 
     This is the reason that the circuitry of the Uni-Wafer BFC is different from the circuitry of the Standard BFC. The circuitry of the Uni-Wafer BFC picks up an arrangement of signals from the suspension of the second arm assembly which is essentially the mirror image of the arrangement of signals provided on the suspension of the first arm assembly. The circuitry of the Uni-Wafer BFC then routes those signals so that they appear in the same predetermined arrangement at the HSA window contacts as is delivered to the HSA window contacts of the first arm using the standard BFC. 
     An alternate embodiment of the invention also provides first and second arms. However this embodiment uses a Long Tail Trace Suspension Assembly (Long Tail TSA), and does not include a BFC. This embodiment includes a Standard Long Tail TSA in conjunction with an Uni-Wafer TSA. The Standard Long Tail TSA holds at its distal end a head which is mounted according to its matching orientation. The Standard Long Tail TSA includes circuitry which routs signals from the head contacts to a series of TSA window contacts, the signals arriving in a predetermined arrangement at the TSA window contacts. The circuitry resides on a thin stainless steel plate which is affixed to a suspension, thus forming the long tail trace suspension assembly. While the preferred embodiment employs a stainless steel plate, those skilled in the art will appreciate that the plate could be constructed of many other materials. 
     The Uni-Wafer Long Tail TSA holds at its distal end a head which is mounted opposite to its matching orientation, (i.e. flipped about its longitudinal axis). The Uni-Wafer Long Tail TSA includes circuitry which picks up signals from the contacts of this head (which are arranged as a mirror image of those of the head of the first arm) and routes those signals to a series of TSA window contacts located along the length of the Uni-Wafer TSA. As with the Standard Long Tail TSA, the circuitry of the UniWafer Long Tail TSA resides on a thin plate which is affixed to a suspension to form the TSA. The circuitry of the Uni-Wafer Long Tail TSA is routed such that the predetermined arrangement of signals at the Uni-Wafer TSA contacts is the same as the predetermined arrangement of the contacts of the Standard Long Tail TSA. 
    
    
     From the above, those skilled in the art will appreciate that the present invention provides a cost effective option for using heads of a single configuration in either the up or down direction as needed, saving valuable-time and money. These and other advantages of the present invention will become apparent to those skilled in the art upon a reading of the following descriptions of the invention and a study of the several figures of the drawings. 
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The present invention will be readily understood by the following detailed description in conjunction with the accompanying drawings, with like reference numerals designating like elements. 
     FIG. 1A is a partial cross-sectional front elevation view of a magnetic data storage system; 
     FIG. 1B is a top plan view taken along line  1 B— 1 B of FIG. 1A; 
     FIG. 2A is a view taken from line  2 A— 2 A of FIG. 1A, shown enlarged; 
     FIG. 2B is a view taken from line  2 B— 2 B of FIG. 2A; 
     FIG. 2C is a view of a down head taken from line  2 C— 2 C of FIG. 2A, shown enlarged; 
     FIG. 2D is a view of an up head taken from line  2 C— 2 C of FIG. 2A, shown enlarged, 
     FIG. 2E is a perspective view of a slider showing an air-bearing surface of the slider; 
     FIG. 3A is a plan view showing a standard bridge flex connector; 
     FIG. 3B is a plan view showing a Uni-Wafer bridge flex connector; 
     FIG. 4A is a plan view showing a Uni-Wafer long tail trace suspension assembly: and 
     FIG. 4B is a plan view showing a standard long tail trace suspension assembly. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
     With reference to FIGS. 1A and 1B, the present invention is embodied in a magnetic data storage system  10  housed within a sealed enclosure  12 . The system  10  includes a plurality of magnetic disks  14  each of which has an upper surface  16  and a lower surface  18 . The disks  14  are supported for rotation by a spindle  20  of a motor  22 . An actuator  24 , driven by a voice coil  28  to pivot about a pivot point  31  upon a pivot bearing  27 , controls a plurality of actuator arms  26  which extend from an E-block  25  which pivots on the bearing  27 . A suspension  32  extends from each actuator arm  26 , each supporting at its distal end a magnetic head  34 . Each suspension  32  holds its corresponding magnetic head  34  in close proximity to a disk  14  to facilitate reading and recording data to and from the disk  14 . The suspension  32  and the actuator arm  26  together form an arm assembly  33 . The heads  34 , suspensions  32 , bridge flex connectors  40  and E-block  25 , including actuator arms  26  and E-block circuitry  42 , together form a Head Stack Assembly  44  (HSA). 
     With reference to FIG. 1A, it will be appreciated that some of the magnetic heads  34   a  extend upward from the suspension  32  to read lower surfaces  18  of the disks  14 , while other magnetic heads  34   b  extend downward from their corresponding suspensions  32  to read upper surfaces  16  of magnetic disks  14 . The present invention allows the same configuration of magnetic head to be used in either the upward or downward facing direction. 
     As discussed above, please note that as used in this discussion, the term “configuration” will be used to refer to the sequence of read elements and write elements and their contacts in a given head, and this configuration shall not change regardless of the direction that this head is facing. The term “orientation” will refer to the order or sequence of elements presented by a head as it faces in different directions, i.e. facing upwards or downwards. 
     Note also that there will be a distinction made between an “up head” of the prior art and an “upward facing head”, and likewise a distinction between a “down head” of the prior art and a “downward facing head”, so that an up head may be used as a downward facing head, or a down head as an upward facing head. In the prior art, up heads and down heads required usually mirror image configurations. For example, an up head  34   a  facing downward may have a configuration of R−, R+, W− and W+, as shown by the symbols in boxes in FIG. 2D, and a down head  34 B, also facing downward in the figure, would then have a configuration of W+, W−, R+ and R−, as also shown by the symbols in boxes in FIG.  2 C. The “configurations” of the up and down heads do not change when the up heads and down heads are turned to face downward. In terms of their “orientation”, however, the sequences do change, so that an up head now facing upward would now have an orientation of W+, W−, R+ and R−, shown by the symbols in parentheses in FIG. 2D, while a down head, now facing upward, would have an orientation of R−, R+. W− and W+, as shown by the symbols in parentheses in FIG.  2 C. Thus, an up head facing upward has an orientation of contacts of W+, W−, R+ and R− (FIG. 2D in parentheses) and a down head facing downward has the same orientation of contacts, W+, W−, R+, R−, (FIG. 2C in boxes). This is what allowed the prior art to use a single type of Bridge Flex Connector for both an up head facing upward and a down head facing downward. 
     In contrast, the present invention uses only a single configuration of head, so there are no longer “up heads” and “down heads”, there are only upward facing heads and downward facing heads. As before, the “orientation” of the heads will change, so that there is a first orientation when a head is used as an upward facing head and a second orientation when a head is used as a downward facing head. Thus there must be a second type of Bridge Flex Connector for this second orientation, and this type is referred to here as a Uni-wafer Bridge Flex Connector  74 , as will be discussed below. It is however much more cost-effective to manufacture a second type of suspension contact array than to manufacture separate “up heads” and “down heads”. 
     Also, please note that for the sake of clarity in this discussion, the term “matching” will be used in describing a configuration of head, especially in the prior art, which is used in the same orientation for which its configuration is named (i.e., an up head facing upward or a down head used facing downwards). The term “non-matching” shall be used for the opposite cases (i.e. an up head facing downwards or a down head facing upwards). 
     With reference to FIG. 2E, the magnetic head  34 , in cases such as the one shown, include a separate read head  46  and a separate write head  48 , which together are commonly referred to as a head  34 . The head  34  is usually mounted on a structure called a slider  35 , which includes an air bearing surface  56 . As a disk  14  spins, the viscosity of the surrounding air causes the air immediately adjacent to the disk to move with the disk. This causes air located between the slider  35  and the disk  14  to pass over the air bearing surface  56  of the slider  35  in the direction of arrow R, thereby creating an air bearing between the slider  35  and the disk  14 . In this way the head  34 , mounted on the slider  35 , flies ever so slightly over the disk  14 . The air bearing surface  56  has a leading edge  60  and a trailing edge  62 . The air bearing surface  56  also includes rails  58  and a rear pad  64  which are specially configured to maximize the flight profile of the head  34  over the disk  14 . A read element  46  and a write element  48  are provided in the head  34  and are generally disposed at the trailing edge  62  of the slider  35 . As will be appreciated, in order to maintain proper flight characteristics, the head  34  on the slider  35  must be properly oriented with respect to the rotating disk  14  so that the leading edge  60  will be directed into the passing stream of air. 
     With reference now also to FIGS. 2C and 2D, the distal end of the head  34  adjacent the trailing edge  62  (FIG. 2E) includes a plurality of contacts  54  to provide electrical connection with the read and write elements  46 ,  48  (FIG. 2E) located within the head  34 . In viewing FIGS. 2C and 2D, it is to be understood that the head  34  is taken to include the write head  48 , which is visible here, and the read head  46  which is visible in FIG. 2E but not in FIGS. 2C and 2D, and the array of electrical contacts  54  connected to the read and write heads. Generally four contacts are provided, including a positive and a negative contact R+ and R− for the read sensor  46  as well as a positive and a negative contact W+ and W for the write sensor  48 . A conductive coil  50  of the write sensor  48  can be seen to be centrally located at the end of the head  34 . The coil  50  provides magneto-motive force to the write element and is covered with a dielectric layer. As discussed in the background of the invention, prior art systems have required the use of heads of different configurations, an up head for facing upward  34   a  (FIG. 2D) and a down head for facing downward  34   b  (FIG.  2 C). Further reference to FIGS. 2C and 2D will make apparent that the arrangement of the contacts of the up head  34   a  is a mirror image of the arrangement of the contacts of the down head  34   b.    
     With reference now also to FIGS. 2A and 2B, a gimbal  66  (FIG. 2B) connects the head  34  with the suspension  32 . The contacts  54  (FIGS. 2A and 2C) of the head  34 connect electrically with a set of distal suspension contacts  37  on the suspension  32 . The suspension traces  36  provide individual electrical paths from the distal suspension contacts  37  to a set of proximal suspension contacts  38  located at an edge of the suspension  32  near its proximal end. A Bridge Flex Connector (BFC)  40  attaches to the suspension  32  in the location of the proximal suspension contacts  38  and includes a series of BFC traces  41  which provide electrical conduits from the distal BFC contacts  67  to a Head Stack Assembly Window (HSA window)  68  (see FIGS. 2B and 3A) which locally exposes a portion of each of the trace circuits  41  to provide proximal BFC contacts  70  which can be seen more clearly with reference to FIG.  3 A. With reference to FIG. 3A, at the distal end of the BFC  40 , a window  65  exposes the BFC traces  41  to provide distal BFC contacts  67 . The proximal BFC contacts  70  allow electrical connection with E-block circuitry  42  (FIG. 1A) for reading and writing signals during operation of the system  10 . In order to allow the BFC  40  to attach to the side of the E-block  25 , the BFC is bent about a bend line  72 . 
     The BFC  40  shown in FIG.  3 A(Prior Art) will be referred to as a Standard BFC  39 , to distinguish it from the Uni-Wafer BFC  74  to be discussed below. 
     It will be appreciated that in order to use an up-head  34   a  in a downward orientation or conversely to use a down-head  34   b  in an upward orientation it is necessary to flip the head over. In order to ensure that the air bearing surface  56  remains correctly oriented with its leading edge  60  (FIG. 2E) facing into the air-stream, it is necessary to flip the head  34  about its longitudinal axis, that is, about the axis parallel with the length of the suspension  32 . However, as can be seen with reference to FIGS. 2C and 2D, flipping over the heads  34   a  and  34   b  in this manner will alter the arrangement of the head contacts  54  with which the suspension traces  41  (FIG. 2A) must connect. This inverted orientation is shown in FIGS. 2C and 2D in parentheses below each set of contacts, where the configurations are shown in boxes. 
     With reference to FIG. 3B, the present invention includes a second kind of BFC  40  which will be called a Uni-Wafer BFC  74  which compensates for this inverted orientation of head contacts. Like the BFC  40  discussed above, the Uni-Wafer BFC  74  has an HSA window  76  exposing proximal Uni-wafer BFC contacts  78  and includes trace circuitry  80  which routes signals from a set of distal Uni-wafer BFC contacts  82  to the correct proximal Uni-wafer BFC contact  78  when a head  34  is being used in an orientation other than its matching orientation. Distal Uni-wafer BFC contacts are accessed through distel Uni-wafer window  77 . 
     By way of example, in FIGS. 3A and 3B the orientation of signals of a down head  34   b  used in a downward direction are shown in boxes whereas the orientation of signals of a down head  34   b  used in an upward direction is shown in parentheses. If a down head  34   b  were to be used in an upward direction with the Uni-Wafer BFC  74 , the orientation of signals picked up from suspension contacts  38  (FIG. 2A) by the distal Uni-wafer BFC contacts  82  and delivered to the proximal Uni-wafer BFC contacts  78  would be as shown in parentheses in FIG.  3 B. By comparison with FIG. 3A, wherein the orientation of a down head  34   b  used in a downward direction is shown in boxes, it can be seen that, although the orientation of signals picked up from the proximal suspension contacts  38  (FIG. 2A) are reversed, the orientations of the signals at the proximal BFC contacts  70  and proximal Uni-wafer BFC contacts  78  (FIG. 3A (Prior Art)) are the same for both the Standard BFC  39  and the Uni-Wafer BFC  74 . 
     To see this, compare the set of signal inputs in boxes at the distal BFC contacts  67  of the Standard BFC  39  shown in FIG. 3A (prior art), reading from left to right R−, R+, W−, W+, and the set of signals in parenthesis at the distal Uni-wafer BFC contacts  82  in FIG. 3B, reading W+, W−, R+, R−. These signals are mirror images of each other and represent the two orientations of signals from heads with a single common configuration, one of which has been inverted. Then, compare the order of signals in boxes at the proximal BFC contacts  70  in the Standard BFC  39  (FIG. 3A (prior art)) and the signals in parentheses at the proximal Uni-wafer BFC contacts  78  of the Uni-wafer BFC  74  in FIG.  3 B. Both sets of signals read from top to bottom, W+, W−, R+, R−. 
     If the down head  34   b  were to be used in an upward direction on the Standard BFC  39  as shown in parentheses in FIG. 3A, the orientation of signals at the HSA window  68  and at the proximal BFC contacts  70  would be incorrect. Circuitry picking up signals at these contacts would pick up the wrong signals or would have to be specially configured for two different arrangements of contact orientation, at great expense. 
     By using the standard BFC  39  when a head is being used in its matching orientation, and using a Uni-Wafer BFC  74  when a head is used in the non-matching orientation, a single configuration of head can be used for both orientations reducing cost and manufacturing time. It should be noted that the same Uni-Wafer BFC  74  can be used to allow an up head  34   a  to be used in a downward orientation. 
     Referring to all figures generally now, to construct the system  10  of the present invention, the heads  34 , whether up or down heads, must first be manufactured as well as the suspension  32 , actuator arm  26  and bridges (both Standard BFC  40  and Uni-Wafer  74 ). The head  34  can be manufactured by various photolithographic and other processes familiar to those skilled in the art and is preferably constructed with a GMR spin valve as the read element  46 , although other read elements can also be used. The head  34  is then attached to the gimbal  66  (FIG. 2B) of the suspension  32  using an adhesive and the head contacts  54  are coupled with the corresponding distal suspension contacts  37  (FIG.  2 A). The suspension  32  can then be attached to the actuator arm  26 . 
     It will be appreciated by those skilled in the art that a GMR spin valve generally in use as a read element  46  includes free and pinned magnetic layers, and that proper orientation of the magnetization of these layers is critical to the performance of the read element. However, it has been found that the process of manufacturing the head  34  introduces variances in the orientation of magnetization of these layers. In order to ensure that each head  34  has the correct magnetic orientation, either before or after assembling the head  34  onto the suspension  32  the head  34  must be subjected to a controlled magnetic field prior to assembly onto the E-block  25 . This process is known as HSA Reinitialization. By magnetizing the heads individually rather than simultaneously, the heads can be correctly magnetized in spite of the non-uniform orientations of the read elements  46  therein. 
     With the heads  34  properly magnetized, the heads  34  and suspension  32  can be assembled onto the E-block  25  and the E-Block  25  installed onto the bearing  27 . The disks  14  are assembled onto the spindle  20  and spindle motor  22  such that each head  34  can align with its corresponding disk surface  16  or  18 . The manufacture of circuitry  42  on the E-block  25  for writing and reading signals to and from the head  34  will be familiar to those skilled in the art. 
     With reference to FIGS. 4A and B, another embodiment of the invention also provides the flexibility of using a single configuration of head  34  in both the upward and downward directions. This embodiment includes a long tail trace suspension assembly (TSA)  85 , of which FIG. 4B shows a Standard Long Tail Trace Suspension Assembly (Standard TSA)  84   a . The TSA  85  serves as both an actuator arm and a suspension and has no flexible bridge portion. The invention includes two variations of TSA  85 , the first being a Standard TSA  84   a , (seen in FIG. 4B) and the second being a Uni-Wafer Long Tail TSA (Uni-wafer TSA)  84   b  (seen in FIG.  4 A). 
     With continued reference to FIGS. 4A and 4B, each variation of Long Tail TSA  84   a  and  84   b  includes trace circuitry  86   a    86   b  which extends from distal TSA contacts  93  which connect to the head contacts  54  to proximal TSA contacts  88   a ,  88   b . The trace circuitry  86   a ,  86   b  of this embodiment is preferably continuous from distal TSA contacts  93  to the proximal TSA contacts  88   a ,  88   b . The trace circuitry  86   a ,  86   b  is held upon thin plates  90   a ,  90   b  which are affixed to the rest of the TSA  84   a ,  84   b . The metal plates  90   a ,  90   b  and associated trace circuitry  86   a ,  86   b  are bent along a bend line  92  to provide proper placement of the window contacts  88   a ,  88   b  for connection with other circuitry (not shown) in a similar manner as described in the earlier discussed embodiment. Also, as with the earlier discussed embodiment, the present embodiment includes a bearing  27  and a voice coil  28 . 
     Examination of FIG. 4A, reveals that the trace circuitry  86   b  of the Uni-Wafer TSA  84   b  differs from that of the Standard TSA  84   a , in FIG.  4 B. This ensures that read and write circuitry picking up signals from the TSA window contacts  88   b  will be able to pick up the correct signal from the correct contact regardless of whether the attached head is being used in its matching orientation on the Standard TSA  84   a  or upside down on the Uni-Wafer TSA  84   b.    
     For example, if only up heads  34   a  are available, they can be attached with the Standard TSA  84   a  for use in the up direction. For use in the downward direction, the up heads  34   a  can be attached with the Uni-Wafer TSA  84   b . The circuitry of the Uni-Wafer TSA will ensure that the signal from each of the head contacts  54  gets routed to the correct location at the TSA window contact  88   a ,  88   b.    
     In summary, the present invention provides a cost effect option for using a single set of heads in either the up or down direction as needed, saving valuable time and money. While the invention has been described in terms of multiple embodiments, other embodiments, including alternatives, modifications, permutations and equivalents of the embodiments described herein will be apparent to those skilled in the art from consideration of the specification, study of the drawings, and practice of the invention. The embodiments described should, therefore, be considered as exemplary, with the invention being defined by the appended claims, which include all such alternatives, modifications, permutations and equivalents as fall within the true spirit and scope of the present invention.