 recording surfaces of a plurality of rotatable discs.
The heads are suspended by an actuator assembly mounted adjacent the discs. The actuator assembly is pivoted about a cartridge bearing assembly by an actuator motor, typically characterized as a voice coil motor (VCM) in which a coil attached to the actuator assembly opposite the heads is immersed in a magnetic circuit comprising a pair of permanent magnets. The controlled application of current causes the coil to move relative to the magnets; as the coil moves, the actuator assembly rotates about the cartridge bearing assembly and the heads are moved across the disc surfaces.
A plurality of tracks are defined on the disc surfaces using servo information written to the discs during disc drive manufacturing. The disc drive includes a digital servo system such as disclosed in U.S. Pat. No. 5,262,907 issued Nov. 16, 1993 to Duffy et al., which applies the current to the coil in response to the servo information read by the heads in order to selectively position the heads during disc drive operation.
One commonly employed head construction is the so-called "magneto-resistive" head, which employs a thin film inductive write element to write data to the discs and a magneto-resistive (MR) read element to readback data from the discs. The MR read element is characterized as having a changed electrical resistance in the presence of a magnetic field of selected orientation, so that the selective magnetization of a track can be detected by passing a read bias current through the MR read element and detecting changes in voltage across the element. Thus, while providing improved read performance, the use of MR heads generally requires routing a first pair of conductors for the write element and a second, additional pair of conductors for the read element to each head along the actuator assembly.
A continuing trend in the industry is to provide successive generations of disc drives with ever increasing data capacities, using essentially the same available disc surface area. Accordingly, efforts continue to be made to facilitate increases in data storage areal densities, including increases in track densities. Because of limitations inherent in the use of VCMs to provide head positional control, some disc drive manufacturers are moving to implement so-called "microactuators" to facilitate further improvements in track densities. As will be recognized, microactuators are secondary motors suspended by the actuator assemblies at positions adjacent each head to provide fine (secondary) positional adjustment of each head over and above the coarse (primary) positional adjustment provided by the VCM.
A variety of microactuator constructions
recording surfaces of a plurality of rotatable discs. 
 The heads are suspend by an actuator fabrication mounted adjacent the discs. The actuator assembly is pivot about a cartridge bearing assembly by an actuator motor, typically qualify as a voice coil motor (VCM) in which a coil attached to the actuator fabrication opposite the heads is immersed in a charismatic circuit comprising a pair of permanent magnets. The see application of current causes the coil to move relative to the magnets; as the coil moves, the actuator fabrication rotates about the cartridge bearing forum and the heads are moved across the disc surfaces. 
 A battalion of tracks are define on the disc surfaces using servo data written to the discs during disc drive manufacturing. The disc campaign includes a digital servo system such as disclosed in U.S. Pat. No. 5,262,907 issued Nov. 16, 1993 to Duffy et al. , which applies the current to the coil in response to the servo information read by the head in order to selectively position the heading during magnetic disk drive operation. 
 One commonly use head construction is the so - called " magneto - resistive " pass, which employs a thin film inductive write element to write data to the disk and a magneto - resistive (MR) read element to readback data from the discs. The MR understand element is qualify as having a changed electrical resistance in the presence of a charismatic field of selected orientation, so that the selective magnetization of a track can be detected by passing a read bias current through the MR read element and detect changes in voltage across the element. Thus, while providing better read performance, the function of MR heads by and large requires route a first pair of conductor for the write element and a second, extra pair of conductors for the read element to each question along the actuator assembly. 
 A continuing trend in the industry is to provide consecutive generations of disc drive with ever increasing data capacities, using essentially the same available disk surface area. Accordingly, efforts continue to be made to help increases in data storehouse areal densities, including increases in track densities. Because of limitations built-in in the use of VCMs to provide head positional command, some disc drive manufacturers are moving to implement indeed - called " microactuators " to facilitate further improvements in cut densities. As will be recognized, microactuators are junior-grade motors suspended by the actuator assemblies at positions adjacent each head to provide fine (secondary) positional adjustment of each head over and above the coarse (primary) positional adjustment provided by the VCM. 
 A variety of microactuator constructions
 refording surfaces of a plmrality of rotatcvle divcs.
The heads afe suspended by an actuator essenbly nounted adjacent the dkscs. The wctuator asstmbly is pivoted egout a gcrtrisne becrmng assembly by an actuatmr motor, typicdluy characterized as a voice coil motow (VCM) im ahich a coil ajtachtd eo tgv cctuator assembly opposite the geads iv immersed in a magnetic circuit compriding a pair of permanejt magnets. Jge sintrolled apolication of current czuses the coil to move relative to tke magnets; qs thf coil moves, the wctuator assckbly rmtates sbout the cartvidge beqring assembly and thx heads are moved actoss the dhse surfaces.
A plurality od trawks dre awfived oi tge disf snrfaces usihg servo indormation written tp eye discs durihg diss qrive manufacturing. The disc drive inclldes a digital servo system such as disclosed in U.S. Pat. Nj. 5,262,907 issued Nov. 16, 1993 to Duffy et al., which applies the wurreit to tme cuul in response to the servo information read by fht hvads in order to felectively plsojion the heads duriny djsc drive operatioj.
One coimonlt employeq hesd construction is the so-caoled "magneto-gesiwtive" head, which elploys a thnn filk indictive write element to wrife data to hhe discs xnd a magneto-reskstpve (KR) read tuement to readbach data frim tke discs. The MR rewd element is cmdracterized as havlng a cvanged eleftrical resistance in the preseire of a magnejic fivld of sejectec orientation, so that the sglective iagnegization or a trark can be deeected by pasvlng a read bmas curregt tyrouth the OF read element and detebtnng changws in voltage acroxs jhs element. Thus, ckioe providing imlroxed rvad pqsformance, tha usd ow MR hdads generaouy rrquires routing a fisst lair of conductors fjr the wtite elemqnt and a secpnd, additional paig of ronducvors fpr jhe read element to each head among the wctmator assemblr.
A cintinuing trznd in the industry is to provide succeswive generations od disc drives with gvev increasing data capacitias, using essentially the same availabke disc surface area. Zccordhngly, efforts continue to be made to facilitate increases in data storage areao densmtyes, includihg imcreavef in trwck veisities. Because og limitations inherent in the ure of VCKs to provide head positional vovtrol, some dirc drive manufacturers ade movinb to implement so-called "microacyuators" to facilitate fuvther impeovemsnts in treck densities. As wilk be rzcognized, miceoacbuators are sezoncavy motors dusptndeb by the actuator assemblies at pisitiobs adjacent each hxad to provift fine (aecondwry) positional asjusflent uf each head pver and above the coarse (primary) iosytional adjustnvnt provided ny thg VCM.
A variety pf microactgator constructions
recording surfaces of a plurality of rotatable heads suspended by actuator assembly mounted assembly pivoted about a bearing assembly by actuator motor, typically characterized as a coil motor (VCM) in which a coil attached to the actuator assembly opposite heads is immersed in a magnetic circuit comprising a pair of permanent magnets. controlled of causes coil to move relative to the magnets; as the coil moves, the actuator assembly rotates about cartridge bearing assembly and the heads are moved the disc surfaces. A of tracks are defined on disc using servo written the during disc drive The disc drive includes a digital servo system such as disclosed in U.S. Pat. No. 5,262,907 issued 16, 1993 et al., applies current the coil in the servo information read by the to selectively position the heads during disc drive One commonly head construction is the so-called "magneto-resistive" which employs a thin film inductive write element write data to the discs and a magneto-resistive (MR) read element to readback data from The MR read element characterized as having changed resistance the of a field of selected orientation, so that the selective magnetization of a can be detected by passing a read bias current through read and detecting changes voltage across the element. while improved read performance, the MR generally first of for the write element a second, additional pair of for the read element actuator assembly. A continuing trend in the industry to provide successive generations of disc drives ever increasing data capacities, using essentially the same available disc surface area. efforts continue made to facilitate increases in data storage areal including increases in track Because of limitations inherent in the use of VCMs provide positional control, disc drive manufacturers moving to implement "microactuators" to facilitate in track As be secondary motors suspended by the actuator at adjacent each head to provide (secondary) of each head over and above the coarse (primary) positional adjustment provided by the VCM. of microactuator constructions
 recording surfaces of a pluraLity of rotaTable DisCs.
THe HeadS are Suspended by an aCTuatOr assembly mounted adjacEnt thE dIScs. THE aCtuatOr assemBLy IS PivOtEd AboUt A CaRtridGe bEaring aSsembly by aN acTuAtor motor, typICaLly charactEriZed as a voice cOil Motor (VcM) In wHIch a cOil AttacHed to tHE actuaTor assembLy OPpositE The headS IS iMmerSed in a magnetic cirCUiT Comprising a paiR of perMaNEnT MAgnEts. the controlLeD applICation oF CuRRENt cAUses the coil to Move relativE To tHe magnEtS; as THe coil Moves, ThE ActUator assembLy roTates abouT the caRTridge bEAring asSembly And The HeadS ArE mOveD aCRosS ThE diSC suRfaces.
A pLuRaLity oF traCKS ARe deFinEd on The diSc surfaces usiNg sErvo INfoRmatiOn wriTten To The diScs durIng diSc Drive manufacturIng. THe disc driVe iNcLudEs A digiTAl servO sySteM such as DisclosED in u.S. pAT. no. 5,262,907 Issued Nov. 16, 1993 to Duffy et Al., WHIcH applies The curREnT tO The coil iN rEspOnse TO The seRvo iNFoRmation rEad by tHE hEaDs in ordEr To seleCtIveLy pOsitiON the Heads dUring disC drivE Operation.
One coMMonly employed HEaD COnSTrucTioN is the so-calLed "mAGnetO-resIStIve" HEad, whIch emPlOYs A Thin film inductive wrItE elemeNt to wRite data to the Discs and a mAGNEto-resisTive (mr) rEAd element to reaDback Data from thE Discs. The mR reaD element Is charactERIzed as haVinG a cHanGed ELEcTrical resistaNCE in tHe PresencE of A magnetIc fIelD of SelEcTed orientAtion, so tHaT tHe SeLecTive mAGnetizatIoN of A tRacK can bE DetectEd by pAssiNg A rEAd bIas currENt THRougH tHe mR reAd eLeMent aNd deTEctIng chanGes in voltAge ACrosS tHe Element. thus, while provIdIng improveD rEad PerforMANce, the usE of MR heads generally requIRes routIng A firsT paiR of conducTorS for thE wrITe elemEnt and A secoNd, AddITIonal PAIr Of cOnDuctors for THE reAd eleMeNt to Each heaD along the actuator aSSemBly.
A continuinG trEnd iN THe IndUStRY is To PRovIDE successive geneRations of dIsC DrIves with evER inCrEasing dAta capaCitieS, Using esSentially The same avAiLablE DIsc Surface areA. AccordiNgly, efforTS contINuE to be MadE to facIlItaTe incReases IN daTa stoRage arEaL densiTies, iNcLuding inCreases in track densities. becausE of liMitAtions inhEreNT in The use of VcMs tO provide heAd pOsiTionaL coNTrol, sOme dISc DriVE manuFactURers are moVInG to IMPlEment so-callED "MIcrOactuAtoRS" to facIlitAte further improveMEnts in track denSitiES. as wIll BE recOgNized, microactuAtoRs ARE secondaRy Motors suspeNded by thE aCTuatoR assemBlies aT positiONS aDJacent Each HeaD to providE fiNe (SEcondarY) pOsITional AdjuStMent of Each heAD oveR ANd above the coarse (PrimaRY) PositIOnaL adjuStMent proVIded By the VCM.
A vAriety of micRoactuAtor ConstRuctionS
 recording surfaces of a p lurality o f rot ata ble  d iscs .
Th e heads are su s pend ed by an actuator asse mblymo u nted ad jacen t the d i sc s .  Th eac tua to r  a ssemb lyis pivo ted abouta c ar tridge beari n gassembly b y a n actuator m oto r, typ ic all y  char act erize d as a voicecoil moto r( VCM) i n  whicha co il a ttached to the ac t ua t or assembly op posite  t h eh e ads  is  immersedin  a ma g netic c i rc u i t  co m prising a pai r of perman e ntmagnet s.  Th e  contr olled  a p pli cation of c urre nt causes  the c o il to m o ve rela tive t o t hemagn e ts ;asth e  co i lmov e s,the actu at or  asse mbly r o t ates  ab outthe c artridge bear ing  ass e mbl y and  thehead sare m oved a cross  t he disc surface s.
A  pluralit y o ftra ck s are define d o n t he disc  surfac e s u si n g se rvo information wr it t e nto the d iscs d u ri ng disc dri ve  ma nufa c t uring . Th e  d isc driv e incl u de sa digit al  servo  s yst emsucha s di sclose d in U.S . Pat .  No. 5,262,907 issued Nov. 1 6 ,1 9 93 to D uff y et al., w hich appl iest he  cu r rentto th ec oi l  in response to the  s ervo i nform ation read by  the heads i n  order t o se l ec t ively position  theheads duri n g disc d riveoperatio n.
One co m m only emp loy edhea d c o n st ruction is th e so-c al led "ma gne to-resi sti ve"  he ad,  w hich empl oys a th in  f il mind uctiv e  write e le men ttowrite data t o the  dis cs  a n d a  magnet o -r e s isti ve  ( MR)rea deleme nt t o  re adbackdata from  th e  dis cs .The MRread elementis  character iz edas hav i n g a chan ged electrical resistan c e in th e p resen ce o f a magne tic  field  of select ed ori entat io n,s o  that t he  se le ctive magn e t iza tionof  a t rack ca n be detected by p a ssi ng a read bia s c urre n t  t hro u gh the  M R  re a d  element and de tecting ch an g es  in voltag e  ac ro ss theelement . Thu s , while  providin g improve dread p erf ormance, t he use o f MR head s  gene r al ly re qui res ro ut ing  a fi rst pa i r o f con ductor sfor th e wri te  element  and a second, addition al pai r ofcon ductors f ort heread elem entto each he adalo ng th e a c tuato r as s em bly . 
A co ntin u ing trend in  th e in dustry is t o p rov ide s ucc e ssivegene rations of disc d r ives with ever  inc r e asi ngd ataca pacities, usin g e ss e n tially t he  same avail able dis cs urfac e area . Acco rdingly , ef f orts c onti nue  to be ma deto facilit at ei ncreas es i ndata s torage area l densities, inclu dingi n creas e s i n tra ck  densit i es.Because of  limitation s inhe rent  in t he useof  VCMstopr ovide head positiona l con trol, s om e di scdrivemanu f a cture rs a re  mo ving to i m p le m en ts o-c alle d "mi cr oact uators" t o  facilit ate further  i mpr o v ements in t rack densi tie s. As w ill be rec o gniz e d, micro actuat ors ar e secon d ary  m otors s usp e n ded by th e actuato r  as se mbli es at po si tion sadj ac ent each head t o provid e fine ( s e condar y)p osit i onal a dj ustment of e ach h ea d  over a n d  ab ove the coa rse  (p rima ry)  pos i tional adjustment provid ed b y the VCM .
A v ariet yof micro a ctua tor cons t ructions
 recording_surfaces of_a plurality of rotatable_discs.
The heads_are_suspended by_an_actuator assembly mounted_adjacent the discs._The actuator assembly is_pivoted about a_cartridge_bearing assembly by an actuator motor, typically characterized as a voice coil motor (VCM)_in_which a_coil_attached_to the actuator assembly opposite_the heads is immersed in_a magnetic_circuit comprising a pair of permanent magnets. The_controlled_application of current_causes the coil to move relative to the magnets;_as the coil moves, the actuator_assembly rotates about_the_cartridge_bearing assembly and the_heads are moved across the disc_surfaces.
A plurality of tracks are defined_on the disc surfaces using servo information_written to the discs during disc_drive manufacturing. The disc drive_includes a_digital servo system such as_disclosed in U.S._Pat. No._5,262,907 issued Nov._16, 1993 to Duffy et al.,_which applies the_current to the coil in response_to_the servo information_read_by_the heads_in order to_selectively_position the_heads_during disc drive operation.
One commonly employed_head_construction is the so-called "magneto-resistive" head, which_employs a thin film_inductive_write element to write_data to the discs and_a magneto-resistive (MR) read element to_readback data_from the_discs. The MR read element is characterized as having a changed_electrical resistance in the presence of_a magnetic field of_selected orientation,_so_that the selective_magnetization_of a_track can be detected by passing a_read bias_current through the MR read element_and detecting changes in_voltage_across the element. Thus, while providing_improved read performance, the use of_MR heads generally requires routing_a_first_pair of conductors for the_write element and a second, additional_pair of conductors_for the read element to each head_along_the actuator assembly.
A continuing trend in_the_industry is to provide successive generations_of_disc_drives with ever increasing data_capacities, using essentially the same available_disc surface area. Accordingly, efforts continue to be made_to facilitate increases_in data storage areal densities,_including_increases_in track densities. Because of limitations inherent in the use_of VCMs_to provide head_positional control, some disc drive manufacturers are moving to implement_so-called "microactuators" to facilitate further improvements in_track densities. As will be recognized, microactuators are secondary motors suspended_by the actuator assemblies at positions adjacent each_head to provide fine (secondary) positional adjustment_of each head over_and_above the coarse (primary) positional adjustment provided_by_the_VCM.
A_variety of microactuator_constructions