Abstract:
A slider with an intake heater near front edge heating air passing between air bearing surface and rotating disk surface to reduce change in flying height caused by water condensation. Method of operating the slider. Head gimbals assembly including slider. Head stack assembly including at least one HGA. Operating hard disk drive by receiving temperature and humidity reading to determine heater control and asserting heater control to stimulate intake heater to heat air. Embedded processor directing hard disk drive at least partly implementing operations. Embedded circuit including embedded processor. A hard disk drive including temperature, humidity sensors, embedded circuit and head stack assembly. Manufacturing methods for slider, head gimbals assembly, head stack assembly, embedded processor, embedded circuit and hard disk drive, and these items as products of their manufacturing processes.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This patent application claims priority to U.S. Provisional Patent Application No. 60/816,162 filed Jun. 23, 2006 , which is incorporated herein by reference. 
    
    
     TECHNICAL FIELD 
     This invention relates to slides in hard disk drives, in particular to methods and mechanisms for heating the air flowing between sliders and the disk surfaces they access to reduce the drop in flying height which occurs in humid conditions. 
     BACKGROUND OF THE INVENTION 
     Contemporary hard disk drives employ a voice coil motor pivoting about an actuator pivot to position one or more sliders over rotating disk surfaces. Each slider is supported a very short distance above its rotating disk surface by an air bearing formed by the flow of air through the gap between the air bearing surface of the slider and the disk surface. The slider is positioned at a pitch angle to disk surface, with the trailing edge being closest to it and the front edge furthest. Near the trailing edge, the read-write head operate to access the data typically stored in a track on the disk surface. Recently the inventors discovered that the flying height drops significantly in humid conditions, as disclosed in U.S. Provisional Patent Application No. 60/816,162 referenced above. 
     What is needed is a way to minimize this the drop in flying height due to water condensation. 
     SUMMARY OF THE INVENTION 
     One way to reduce the air bearing pressure drop and the corresponding drop in flying height is to increase the water vapor saturation pressure by increasing the temperature of the air flowing between a slider&#39;s air bearing surface and the rotating disk surface it accesses. Embodiments of the invention&#39;s slider may preferably include an intake heater positioned near the front edge. Alternatively, embodiments of the slider may include a means for heating the air flowing between the air bearing surface and the rotating disk surface, which may further preferably include the intake heater. The intake heater preferably provides heat to the air bearing formed between the air bearing surface and the rotating disk surface as shown in  FIG. 1C , in particular, when electrically stimulated by a heating control signal.  FIG. 1A  shows the change in flying height due to the increase in temperature. 
     The slider may further preferably include the intake heater and a thermal insulator, which acts to direct the heat generated by the intake heater away from the surrounding environment and toward the intake as shown in  FIGS. 1B and 1C . 
     The air bearing surface may further include a variety of features as shown in  FIGS. 2A ,  2 B,  12 B and  12 C. Most notably, the air bearing surface may include pads with diamond like carbon (PDLC) for use in Contact Start-Stop hard disk drives which park their sliders on disk surfaces and may not include pads PDLC for use in hard disk drives which uses ramps to park their sliders off the disk surfaces. 
     The slider may include a vertical micro-actuator employing any one or more of a piezoelectric effect, a thermo-mechanical effect and/or an electrostatic effect to further alter the flying height, as shown in  FIGS. 5A ,  7 A,  7 B, and  9 . 
     Manufacturing the slider may preferably include forming the intake heater near the front edge of the slider to create the slider and preferably forming the intake heater with the thermal insulator also near the front edge. The slider is a product of this manufacturing process. 
     Alternatively, manufacturing the slider may include forming the means for heating the air to create the slider. As before, the slider is a product of this manufacturing process. Manufacturing the slider may further include forming the means for heating may further include forming a thermal insulator near the front end. Forming the means for heating may further include forming the intake heater near the front edge. 
     The invention&#39;s head gimbal assembly preferably includes an embodiment of the invention&#39;s slider coupling through a flexure finger to a load beam. The head gimbal assembly may preferably include a micro-actuator assembly, which alters at least the lateral position of the slider and its read-write head over a track on the rotating disk surface. The micro-actuator may employ a piezoelectric effect and/or a thermo-mechanical effect and/or an electrostatic effect. 
     Manufacturing the head gimbal assembly preferably includes coupling the slider through the flexure finger to the load beam to create the head gimbal assembly as a product of this manufacturing process. 
     The invention&#39;s head stack assembly including at least one of head gimbal assembly coupled to a head stack. The head stack assembly may include more than one head gimbal assembly coupled to the head stack. Manufacturing the head stack assembly includes coupling the head gimbal assemblies to the head stack to create the head stack assembly as a product of this manufacturing process, often preferably done by swaging the base plates of the head gimbal assemblies to the actuator arms of the head stack. An actuator arm may be thus coupled to one or two head gimbal assemblies. 
     The hard disk drive preferably includes both a temperature sensor and a humidity sensor, which sensor-couple to an embedded circuit and further preferably sensor-couples to an embedded processor. The embedded circuit, and preferably the embedded processor, directs the hard disk drive to operate by receiving a temperature reading from the temperature sensor and a humidity reading from the humidity sensor. A heater control signal is determined based upon the temperature reading and the humidity reading, which is then asserted to stimulate the intake heater on the slider to increase the air temperature between the air bearing surface and the rotating disk surface. 
     The embedded processor may preferably include at least one instance of a controller. As used herein each controller receives at least one input, maintains at least one state and generates at least one output. 
     At least one of the states includes at least one of a non-redundant digital representation, a redundant digital representation and/or an analog representation. A non-redundant digital representation frequently comprises at least one digit, which may frequently represent a bit with values of 0 and 1, a byte including eight bits, and so on. A redundant digital representation of a non-redundant digital representation may include a numerically redundant digital representation, an error control representation and/or a logically redundant representation. The following examples will serve to illustrate these non-redundant representations:
         An example of a numerically redundant representation may be found in a standard multiplier, which will often use a local carry propagate adder to add three or four numbers together to generate two numeric components which redundant represent the numeric result of the addition.   An example of an error control representation will frequently use the non-redundant digital representation and an additional component formed as the function of the non-redundant digital representation. If this error control representation is altered by a few number of bits, a error correcting function reconstructs the original non-redundant digital representation. Quantum computers are considered as controllers which will tend to use this kind of error control representations for at least some states.   An example of a logically redundant representation may be found in the definition and implementation of many finite state machines, which often require that a single state be represented by any member of a multi-element set of non-redundant digital representations. Often the members of this set differ from at least one other member of the set by just one bit. Use of such logically redundant representations insure that the generation of glitches is minimized.       

     The controllers may each include at least one instance of at least one of the following: A computer directed by a program system and accessibly coupled to via a buss a memory, wherein the program system includes at least one program step residing in the memory. Where the computer includes at least one data processor and at least one instruction processor, and each data processor is directed by at least one of the instruction processors. A finite state machine. An inferential engine. And a neural network. 
     Embodiments of the embedded processor may implement this method of operation by including means for receiving the temperature reading from the temperature sensor and the humidity reading from the humidity sensor and means for determining the heater control signal based upon the temperature reading and the humidity reading. 
     The hard disk drive may include the means for asserting the heater control signal to stimulate the intake heater on the slider to increase the air temperature between the air bearing surface and the rotating disk surface. Alternatively, the embedded circuit and further, the embedded processor may include the means for asserting. 
     The means group consisting of the means for receiving  700 , the means for determining  702  and the means for asserting  704  may be implemented using at least one instance of at least one of the following: A computer accessibly coupled a memory and directed by a program system including at least one program step residing in the memory. As used herein, a computer will include at least one instruction processor and at least one data processor, wherein each of the data processors is directed by at least one instruction processor. A finite state machine. An inference engine. And a neural network. 
     Manufacturing the embedded circuit may include providing the means for receiving and the means for determining to create the embedded circuit, which may preferably include programming a non-volatile memory component of the memory accessibly coupled to the computer. The embedded circuit is a product of this manufacturing process. 
     Manufacturing the hard disk drive may include coupling the temperature sensor and the humidity sensor to the embedded circuit to provide the temperature reading and the humidity reading, and couple the embedded circuit to the head stack assembly to provide the heating control to stimulate the intake heater of the slider, thereby creating the hard disk drive. The hard disk drive is a product of this process. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1A  shows the relationship between heating the air flowing between embodiments of the slider and the rotating disk surface and the change in flying height that results; and 
         FIGS. 1B and 1C  show some aspects of embodiments of the slider in accord with the invention; 
         FIGS. 2A and 2B  show some further aspects of the slider embodiments of  FIGS. 1B and 1C ; 
         FIGS. 3A and 3B  show some aspects of embodiments of the head gimbal assembly using the invention&#39;s embodiments of the slider; 
         FIGS. 4A and 4B  show some embodiments of the head stack assembly and hard disk drive using the head gimbal assembly of  FIGS. 3A and 3B ; 
         FIGS. 5A and 5B  show an example of a head gimbal assembly embodiment using a micro-actuator assembly employing an electrostatic effect; 
         FIGS. 6 to 8A ,  8 I and  9  show further aspects of the hard disk drive employing embodiments of the invention&#39;s head stack assembly, head gimbal assembly and slider; 
         FIGS. 8B to 8H  show some details of some aspects various embodiments of the embedded processor of  FIG. 8A ; 
         FIGS. 10A to 11A  show some details of the program system of  FIG. 9 ; 
         FIGS. 11B to 11D  show some aspects of the means of  FIG. 8B ; 
         FIG. 12A  shows an embodiment of the embedded circuit and/or embedded processor including an integrated circuit; and 
         FIGS. 12B and 12C  show more examples of the air bearing surfaces which may be included in embodiments of the slider of previous Figures. 
     
    
    
     DETAILED DESCRIPTION 
     This invention relates to slides in hard disk drives, in particular to methods and mechanisms for heating the air flowing between sliders and the disk surfaces they access to reduce the drop in flying height which occurs in humid conditions. 
     One way to reduce the air bearing pressure drop and the corresponding drop in flying height is to increase the water vapor saturation pressure by increasing the temperature of the air flowing between a slider&#39;s air bearing surface  92  and the rotating disk surface  120  it accesses. An embodiment of the invention&#39;s slider includes an intake heater  90 H positioned near the front edge FE of the air bearing surface of the slider  90 , as shown in  FIGS. 1B to 3A ,  5 A,  12 B and  12 C. The intake heater provides heat to the air bearing formed between air bearing surface and the rotating disk surface as shown in  FIG. 1C , in particular, when electrically stimulated by a heating control Htrctl as shown in  FIGS. 7A to 9 . 
     The intake heater  90 H alters the saturation water pressure in the air bearing between said air bearing surface  92  and said rotating disk surface  120  to reduce the change in flying height DeltaFH versus the change in air temperature DeltaT as shown in  FIG. 1A . The relationship of the change in air bearing temperature represented by the horizontal axis (DeltaT) and the change in flying height shown as the vertical axis (DeltaFH) is summarized by the trace labeled DeltaFH/T. The units of the horizontal axis are in degrees Centigrade and the units of the vertical axis are in nanometers. The ambient conditions in this experiment were 60° C. and 70% relative humidity. With no air bearing temperature increase, the flying height FH suffers a change in flying height DeltaFH of 2.5 nanometers (nm) below the flying height under dry air conditions, whereas with an air bearing temperature change DeltaT of 30° C., the change in flying height is 1.25 nm, roughly a fifty percent improvement. 
     By way of example, consider how much power is required to heat the air bearing by 30° C. Assume that the front height h of the intake between the front edge FE and the rotating disk surface  120  is about 0.5 micrometer (μm) and the intake length L of the air bearing is about 1 millimeter (mm). The air speed u is will be assumed to be 20 meters/sec, which is compatible with a 3.5 inch hard disk drive  10  rotating its disk  12  at 7200 Revolutions Per Minute (rpm). Then the volume of air flowing into the intake is about 1 mm*0.5 μm*20 m/sec=10 −8  m/sec. Assuming for the moment typical air conditions for 60° C., then the density is 1.072 kg/m 3  and the specific heat us 1007.13 J/(kg*C) making the power to hear the air bearing 30° C. to be about (10 −8  nm/sec)*(1.072 kg/m 3 )*(1007.13 J/(kg*C))*(30° C.)=0.32 mW. One skilled in the art will recognize that the heater will require more than this, but this is offered as an example of the kind of heat delivery which is useful for the intake heater  90 H. 
     One embodiment of the slider  90  may preferably include the intake heater  90 H and a thermal insulator  90 I, which acts to direct the heat generated by the intake heater away from the surrounding environment and toward the intake as shown in  FIGS. 1B and 1C . The air bearing surface  92  may further include a variety of features as shown in  FIGS. 2A ,  2 B,  12 B and  12 C. The air bearing surface may preferably provide a central island CI near the trailing edge TE, in part to protect the read-write head  94  from particle collisions. The air bearing surface may provide a front bulwark FB, which may include a front bulwark channel FBC effectively dividing the front bulwark into a first front bulwark FB 1  and a second front bulwark FB 2 . The air bearing surface may include at least one pad PDLC (pad with diamond like carbon), which are frequently used to reduce static friction (stiction) during takeoff and landing in a Contact Start-Stop (CSS) hard disk drive  10 . These pads are labeled in  FIG. 2A  and shown there and in  FIGS. 12B and 12C  as circles. Air bearing surfaces without these pads are often used in hard disk drives which park their sliders with ramps, located either near the inside diameter ID or the outside diameter OD of the disk surface  120 , as shown in  FIG. 4A . 
     Alternatively an embodiment of the slider  90  may include means for heating  90  MH air moving between the air bearing surface  92  of the slider and the rotating disk surface  120  to increase the temperature of the air as shown in  FIG. 1B . The means for heating may preferably include an intake heater  90 H near a front edge FH of the slider for heating the air moving between the air bearing surface and the rotating disk surface. The slider may further include a thermal insulator  90 Ins to direct the heat toward an intake formed by the front edge and the rotating disk surface as shown in  FIG. 1C . 
     The slider  90  may further include a vertical micro-actuator  98  which when stimulated by a vertical actuation control signal VcAC, alters the flying height FH of the slider  90 , in particular the distance of the trailing edge TE and read-write head  94  from the rotating disk surface  120 , as shown in  1 B,  5 A,  7 A,  7 B and  9 . While the vertical micro-actuator may employ a piezoelectric effect, an electrostatic effect and/or a thermo-mechanical effect, today it is often preferred that it employ a thermo-mechanical effect, heating a deformation region  97 , which causes the read-write head to be moved closer to the rotating disk surface, reducing the flying height. The slider may further include a vertical heater governor  95 , which may limit the thermal conditions of the deformation region and prevent overheating of this region. 
     The read-write head  94  may preferably include a read head  94 -R and a write head  94 -W, where the read-write signal bundle rw includes a read differential signal pair r 0  and a write differential signal pair w 0 . The slider  90  may include an amplifier  96  receiving the read differential signal pair from the read head  94 -R to create an amplified ar 0  which is then included read-write signal bundle rw. 
     Manufacturing the slider  90  may include forming the intake heater  90 H near the front edge FE of the slider to create the slider and preferably forming the intake heater with the thermal insulator  901  near the front edge. The slider is a product of this manufacturing process. 
     Alternatively, manufacturing the slider  90  may include forming the means for heating  90  MH to create the slider. As before, the slider is a product of this manufacturing process. Manufacturing the slider may further include forming the means for heating may further include forming a thermal insulator  90 Ins near the front end FE. Forming the means for heating may further include forming the intake heater  90 H near the front edge. 
     The head gimbal assembly  60  preferably includes an embodiment of the invention&#39;s slider coupling through a flexure finger  20  to a load beam  74 , as shown in  FIGS. 3A to 4A ,  5 A, and  6  to  9 . A hinge plate  70  couples the load beam a base plate  72 . 
     The head gimbal assembly  60  may preferably include a micro-actuator assembly  80  which preferably alters at least the lateral position LP of the slider  90  and its read-write head  94  over a track  122  on the rotating disk surface  120 . The micro-actuator  80  may employ a piezoelectric effect as shown in  FIG. 3A  and/or a thermo-mechanical effect and/or an electrostatic effect as shown in  FIG. 5A , and in greater detail in  FIG. 5B . The micro-actuator assembly is preferably stimulated by a micro-actuator control signal bundle  82 , which typically includes at least one lateral control signal LcAC. The micro-actuator assembly may further include ports receiving one or more shared signals, such as a shared ground signal shown as signal SP 1  in the flexure finger  20  and port  82 P 1  in  FIGS. 7A and 7B . 
     The micro-actuator assembly  80  employing an electro-static effect is shown in  FIG. 5A  coupling a slider  90  with a flexure flinger  20  on a load beam  74 . The micro-actuator assembly includes a first micro-actuator  220  as shown in  FIG. 5B . The first micro-actuator  220  includes the following. A first pivot spring pair  402  and  408  coupling to a first stator  230 . A second pivot spring pair  400  and  406  coupling to a second stator  250 . A first flexure spring pair  410  and  416 , and a second flexure spring pair  412  and  418 , coupling to a central movable section  300 . A pitch spring pair  420 - 422  coupling to the central movable section  300 . The central movable section  300  includes signal pair paths coupling to the read differential signal pair R+− and the write differential signal pair W+− of the read-write head of the slider. This kind of micro-actuator assembly is discussed in greater detail in the U.S. patent application Ser. No. 10/986,345 and filed Nov. 10, 2004, and is incorporated herein by reference. 
     The invention&#39;s head stack assembly  50  including at least one of head gimbal assembly  60  coupled to a head stack  54 . The head stack assembly may include more than one head gimbal assembly coupled to the head stack, as shown in  FIG. 4B . Manufacturing the head stack assembly includes coupling the head gimbal assemblies to the head stack to create the head stack assembly as a product of this manufacturing process, often preferably done by swaging the base plate  72  of each head gimbal assembly to an actuator arm  54  of the head stack. An actuator arm may be thus coupled to one or two head gimbal assemblies. 
     A CSS hard disk drive  10  typically parks its slider  90  on the disk surface  120  near the inside diameter ID and may preferably employ a tab ramp  78  on the load beam  74  of a head gimbal assembly including the slider  90  as shown in  FIG. 3B  to engage with a beveled surface on the spindle motor  270 , a disk spacer  310  and/or a disk clamp  300  as shown in  FIG. 4B . 
     Manufacturing the head gimbal assembly  60  preferably includes coupling the slider  90  through a flexure finger  20  to a load beam to create the head gimbal assembly as a product of this manufacturing process. 
     In general, the hard disk drive  10  preferably includes both a temperature sensor  16 T and a humidity sensor  16 H which sensor-couple  16 C to an embedded circuit  500  and further preferably sensor-couples to an embedded processor  502  as shown in  FIGS. 8A ,  8 B,  8 I,  9  and  10 A. The embedded circuit, and preferably the embedded processor, directs the hard disk drive to operate by receiving a temperature reading  170 T from the temperature sensor  16 T and a humidity reading  170 H from the humidity sensor  16 H. A heater control signal HCS is determined based upon the temperature reading and the humidity reading, which is then asserted to stimulate the means for heating  90  MH, and preferably the intake heater  90 H on the slider  90  to increase the air temperature between the air bearing surface  92  and the rotating disk surface  120 . 
     Embodiments of the embedded processor  502  may preferably include at least one instance  504  of a controller  506 , as shown in  FIG. 8B . As used herein each controller receives at least one input  506 In , maintains and updates at least one state  506 S and generates at least one output  506 Out based upon at least one of the inputs and/or at least one of the states, as shown in  FIG. 8C . 
     At least one state  506 S may include at least one member of a state representation group  506 SRG consisting of a non-redundant digital representation NDR, a redundant digital representation RDR and/or an analog representation AR, as shown in  FIG. 8D . A non-redundant digital representation frequently comprises at least one digit, which may frequently represent a bit with values of 0 and 1, a byte including eight bits, and so on. 
     A redundant digital representation RDR of a non-redundant digital representation NDR may include a numerically redundant digital representation NRR, and/or an error control representation ECR and/or a logically redundant representation LRR. The following examples will serve to illustrate these non-redundant representations:
         An example of a numerically redundant representation NRR may be found in a standard multiplier, which will often use a local carry propagate adder to add three or four numbers together to generate two numeric components which redundant represent the numeric result of the addition.   An example of an error control representation ECR will frequently use the non-redundant digital representation NDR and an additional component formed as the function of the non-redundant digital representation. If this error control representation is altered by a few number of bits, a error correcting function reconstructs the original non-redundant digital representation. Quantum computers are considered as controllers, which will tend to use this kind of error control representations for at least some states.   An example of a logically redundant representation LRR may be found in the definition and implementation of many embodiments of a finite state machine FSM, which often require that a single state  506 S be represented by any member of a multi-element set of non-redundant digital representations. Often the members of this set differ from at least one other member of the set by just one bit. Use of such logically redundant representations insures that the generation of glitches is minimized.       

     Each of controller  506  may include at least one instance of at least one of the following:
         A computer  600  directed by a program system  800  and accessibly coupled  602  via a buss a memory  604 , wherein the program system includes at least one program step residing in the memory. Where a computer includes at least one data processor and at least one instruction processor, and each data processor is directed by at least one of the instruction processors as shown in  FIG. 9 .   A finite state machine FSM as shown in  FIG. 8F .   An inferential engine IE as shown in  FIG. 8G .   And a neural network NN as shown in  FIG. 8H .       

     Embodiments of the embedded processor may implement this method of operation by including means for receiving the temperature reading from the temperature sensor and the humidity reading from the humidity sensor and means for determining the heater control signal based upon the temperature reading and the humidity reading. 
     The embedded circuit directs the hard disk drive to operate by receiving  700  a temperature reading  170 T from the temperature sensor and a humidity reading  170 H from the humidity sensor  16 H, and preferably includes an embedded processor  502 . A heater control signal HCS is determined  702  based upon the temperature reading and the humidity reading, which is then asserted  704  to stimulate the intake heater  90 H on the slider  90  to increase the air temperature between the air bearing surface  92  and the rotating disk surface  120 . In many embodiments, the embedded circuit and possibly the embedded processor may communicate via a main coupling MC through a ribbon cable to a second coupling EC as shown in  FIGS. 8A and 8I . 
     The embedded circuit  500  may implement this method of operation by including means for receiving  700  the temperature reading  170 T from the temperature sensor and the humidity reading  170 H from the humidity sensor  16 H. Means for determining  704  the heater control signal HCS based upon the temperature reading and the humidity reading. 
     The hard disk drive  10  may include the means for asserting  704  the heater control signal to stimulate the intake heater  90 H on the slider  90  to increase the air temperature between the air bearing surface  92  and the rotating disk surface  120 , as shown in  FIG. 8 . Alternatively, the embedded circuit  500  may include the means for asserting, as shown in  FIG. 9 . 
     The means group consisting of the means for receiving  700 , the means for determining  702  and the means for asserting  704  may be implemented using at least one instance of at least one of the following:
         A computer  600  accessibly coupled  602  a memory  604  and directed by a program system  800  including at least one program step residing in the memory as shown in  FIG. 9 . As used herein, a computer will include at least one instruction processor and at least one data processor, wherein each of the data processors is directed by at least one instruction processor.   A finite state machine  710  as shown in  FIG. 11B .   An inference engine  712  as shown in  FIG. 11C .   And a neural network  714  as shown in  FIG. 11D .       

     Some of the following figures show flowcharts of at least one method of the invention, possessing arrows with reference numbers. These arrows will signify of flow of control and sometimes data supporting implementations including:
         at least one program operation or program thread executing upon a computer  600 ,   at least one inferential link in an inferential engine EE,   at least one state transitions in a finite state machine FSM,   and/or at least one dominant learned response within a neural network NN.       

     The operation of starting a flowchart is designated by an oval with the text “Start” in it, and refers to at least one of the following:
         Entering a subroutine in a macro instruction sequence in a computer  600 .   Entering into a deeper node of an inferential graph of an inference engine IE.   Directing a state transition in a finite state machine FSM, possibly while pushing a return state.   And triggering a list of at least one neuron and/or at least one synaptic connection in a neural network NN.       

     The operation of termination in a flowchart is designated by an oval with the text “Exit” in it, and refers to the completion of those operations, which may result in at least one of the following:
         return from a subroutine in a computer  600 ,   traversal of a higher node in the inferential graph of an inference engine IE,   popping of a previously stored state in a finite state machine FSM,   and/or return to dormancy of the firing neurons of the neural network NN.       

     The program system  800  may preferably include at least one of the operations of  FIG. 10A :
         Operation  802  supports receiving  700  the temperature reading  170 T from the temperature sensor  16 T and the humidity reading  170 H from the humidity sensor  16 H.   Operation  804  supports determining  702  the heater control signal HCS based upon the temperature reading and the humidity reading.   And operation  806  supports asserting  704  the heater control signal to stimulate the intake heater  90 H of the slider  90 .       

     In certain embodiments, each member of the means group consisting of the means for receiving  700 , the means for determining  702  and the means for asserting  704  may be implemented in the embedded circuit  500 , as shown in  FIG. 9 , and may further be implemented by a single computer  600 , with the program system  800  including a version of each of the operations of  FIG. 10A . 
     The hard disk drive  10  may further include a pressure sensor  16 P as shown in  FIG. 9 , with the means for receiving  700  further including receiving a pressure reading from the pressure sensor, which is shown supported by operation  810  of  FIG. 10B . The means for determining  702  may further include determining the heater control signal HCS based upon the pressure reading, which is shown supported by operation  812  of  FIG. 11C . 
     The computer  600  may further implement at least one of the operations of  FIG. 11A , as shown by the program system  800  further include at least one of the following:
         Operation  820  supports positioning the slider  90  for the read-write head  94  to follow the track  122  on the rotating disk surface  120 , which is often referred to as track-following mode. In greater detail, the voice coil motor  18  moves the head stack assembly  50  by pivoting the head stack  54  through the actuator pivot  58  based upon the electromagnetic attraction and repulsion of the voice coil  32  with the fixed magnet  34 . The voice coil is stimulated by a voice coil control signal shown sent by the computer to a voice coil driver  30 , which provides the voice coil stimulus  22  to the voice coil as a time-altering electrical signal. This activity provides the coarse control of the lateral position LP over the track on the rotating disk surface. The fine motion control is performed by the micro-actuator driver  28  and directed by the computer to generate the micro-actuator control signal bundle  82 . While the micro-actuator assembly may include a vertical micro-actuator, currently it is often preferred that the slider include it. The vertical actuation control signal VcAC may be provided by a vertical micro-actuator driver  26  as shown in  FIG. 9  in the embedded circuit  500 , or alternatively, it may be part of the main flex circuit  200 , possibly included in the preamplifier  24 . Feedback for the track-following operation comes from the read head  94 -R and is based upon the read differential signal pair r 0 , and possibly the amplified read signal arO provided to the preamplifier, which then sends a Position Error Signal (PES) through the channel interface  26  and a channel interface communications interface  260  to the computer, where the PES signal is frequently stored in the memory. Often a succession of timed samples of PES are stored, filtered and used to calculate the stimulus and controls of the above mentioned drivers stimulating the voice coil motor, the micro-actuator assembly, and the vertical micro-actuator.   Operation  822  supports encoding the data to create the  122 D write data stream used by the read-write head to write the track. Typically, the write data stream is sent through a channel interface  26  to the preamplifier  24 , where it is amplified and sometimes filtered before transmission through the read-write signal bundle to the read-write head, in particular, through the write differential signal bundle w 0  to the write head  94 -W. This operation often entails constructing a header and/or trailer to the data payload that the users are familiar with. Usually, this involves one or more error detecting/correcting coding schemes.   Operation  824  supports decoding the raw data  122 R received from the read-write head  94 , in particular the read head  94 -R, from reading the track  122 . This operation is often the reverse of the encoding operation  822 , in that the header and/or trailer are used to calculate a potentially corrected data payload, which is the retrieved data users see from accessing the track.   Typically, no one computer does all three of the operations of this flowchart. Typically, the first operation  820  is done by one computer, which is often known as the servo computer, and the other operations  822  and  824  are done by a second computer, which is sometimes referred to as the embedded computer.       

     The embedded circuit  500  may further include an integrated circuit IC including the means for receiving  700  the temperature reading  170 T and the humidity reading  170 H, both presented to the means for determining  702  the heater control signal HCS, as shown in  FIG. 12A . 
     Manufacturing the embedded circuit  500  may include providing the means for receiving  700  and the means for determining  702  to create the embedded circuit, which may preferably include programming a non-volatile memory component of the memory  604  accessibly coupled  602  to the computer  600 . The embedded circuit is a product of this manufacturing process. 
     Manufacturing the hard disk drive  10  may include coupling the temperature sensor  16 T and the humidity sensor  16 H to the embedded circuit to provide the temperature reading  170 T and the humidity reading  170 H, and coupling the embedded circuit  500  to the head stack assembly  50  to provide the heating control HtrCtl to stimulate the intake heater  90 H of the slider  90 , thereby creating the hard disk drive. The hard disk drive is a product of this process. 
     The preceding embodiments provide examples of the invention and are not meant to constrain the scope of the following claims.