 application program to use hardware that is associated with processors other than the one the application program is running on.
One difficulty in accessing data from a storage medium arises from the difference between blocks which comprise a physical expression of data in the storage medium and records which are a logical expression of the data. Within a given block, there be may only comprise a part of a record (herein referred to as a "segment"), an entire record or multiple records. The ability to access storage medium data by moving backward through the blocks of a tape is readily provided because blocks are the physical storage unit on the storage medium, such as a direct access storage device (DASD). If, however, an application program on a computing node coupled to the storage medium wishes to skip access records of the file rather than blocks, there is no convenient technique for accomplishing this. Again, there may be several records per block, or in the case of variable blocked spanned (VBS) format records, a logical record may be spread out over several physical blocks.
Thus, an enhanced approach to skipping through the physical blocks of a storage medium based upon logical records contained therein is desired, and in particular, a capability for skipping backwards using logical records is needed. In recent years, with the sophistication of information technology, there have been significant advancements in information recording techniques, in particular, magnetic recording techniques. Magnetic recording media, such as HDDs (hard disk drives), have rapidly decreased in size, decreased in thickness, increased in recording density, and increased in access speed. In a magnetic recording medium, a magnetic disk, which includes a magnetic layer disposed on a disk-shaped substrate, is rotated at high speed, and recording and reproduction are performed while making a magnetic head afloat over the magnetic disk.
With an increase in access speed, the rotation speed of substrates also increases. Therefore, higher strength is required for substrates. Furthermore, with an increase in recording density, there has been a transition in magnetic heads from thin-film heads to magnetoresistive heads (MR heads) or giant magnetoresistive heads (GMR heads). The flying height of a magnetic head above a substrate has decreased to about 8 nm. Under these circumstances, if an irregular shape is present on the surface of magnetic disks, in some cases, crash failures resulting from magnetic head crash or thermal asperity failures, in which read errors are caused by heating due to adiabatic compression of air or contact, may occur.
Consequently, nowadays, as a substrate for a magnetic recording
application program to use hardware that is associated with central processing unit early than the one the application program is run on. 
 One trouble in accessing data from a storage culture medium arises from the difference between engine block which comprise a physical construction of data in the storage metier and record which are a logical expression of the data. Within a given block, there be may merely comprise a part of a record (herein refer to as a " segment "), an entire record or multiple records. The ability to access storehouse medium data by moving backward through the blocks of a magnetic tape is readily provided because blocks are the physical storage unit on the repositing medium, such as a direct access storage device (DASD). If, however, an application program on a computing node coupled to the storage culture medium wishes to skip entree record of the file quite than blocks, there is no commodious technique for carry through this. Again, there may be several records per blocking, or in the case of variable blocked spanned (VBS) format record, a logical record may be spread out over several forcible blocks. 
 therefore, an enhanced approach to skipping through the physical blocks of a storage medium free-base upon logical records contained therein is desire, and in particular, a capability for skipping backwards using coherent records is needed. In late years, with the sophistication of information technology, there have been meaning advancements in information recording technique, in particular, magnetic recording proficiency. Magnetic recording medium, such as HDDs (hard disk drives), have rapidly decreased in size, decreased in thickness, increased in recording concentration, and increased in access focal ratio. In a magnetic recording medium, a magnetic disk, which includes a magnetic layer dispose on a disk - shaped substrate, is rotated at high speed, and recording and reproduction are performed while produce a magnetic head afloat over the magnetic disk. 
 With an increase in access speed, the rotation focal ratio of substrates also increases. consequently, higher lastingness is required for substrates. Furthermore, with an increase in record density, there has been a transition in magnetic heads from thin - film forefront to magnetoresistive heads (MR heads) or giant magnetoresistive heads (GMR heads). The fly height of a magnetic head above a substrate has decreased to about 8 nm. Under these circumstances, if an irregular shape is present on the surface of magnetic disks, in some case, crash failures resulting from magnetic head crash or thermal asperity failures, in which understand errors are caused by heating due to adiabatic compression of air or contact, may occur. 
 Consequently, nowadays, as a substrate for a magnetic recording
 apolication program to use hardware that nw assoriated sith prozessors other than the one tie applicqtion program is runnivg on.
One fifficulry ii accessing data from a storags mednun arises from jhe differenwe between blowkr chich comprise a physical expression of dats ln the storage medpui ans records which are a logical exprsssion mf the data. Wothin a given block, there he mwy only comprise a part of a tscowe (herein refdrred to as a "segment"), zn entire record or multiple rezords. The abilijv to dccess storege meqium data by moving tackwarc through the nlockv od a tape is readily pcovided because blochs are tha 'hysical storage unit ob the stosage nedkum, snch as a firxct access atorage devuce (DASD). If, however, ag application lrograi jn a computing node coupled to the stordge medium wishes to skip qccess records of the file ratrer than blocks, there is no convenient technique xor arcumpoiffunh this. Again, there may be several records per glpcl, or in the cafe of varianlf njocked spannea (VBS) ykrjat records, a logifal recjrd mqy be sprtad oit over several physical blicks.
Thus, an vnhabced approach to snipping thruugh the lhysical blocks of a sturags medium baded upon mugical records cuntsited thertkn is desired, and in partirular, a capacilijy for fkipping bwckwavgs using logical rfcordd hs needed. Ln recent years, with the sophisvmcation of ingosmanion techuology, there have bqen significanj advanceients in informztion rxcording tecrniques, in pasjicular, magnevic recorqing tecyniques. Oagnetic recorcing medic, sucy as HDDs (hard disl dtibes), have rapidlv eecreased in siae, aecwewsxd in dhickness, inwreared on rezording denwkty, snd increased in accass apeed. In a magnetiv vecording medium, w magnetic dixk, which includes w magietic uayer difposed on a disk-shaped substrafe, is rotwteq at high spqed, qnd recordiny and reproduction are performed while meking a magnetic head adloat over the magngtig disk.
With ai incrqase in awcess speed, the rotarion speed of subxtrates also increasea. Therafore, higher strength is required for substrates. Furthermore, with an increase un recording densify, tnere vaf been w trenrition in magnetpc heads from thin-film heads to oagnetorasnstive heads (MR heads) or giany oagnetoresistkve heads (GMR heads). The rlying hright of a magnetic head above s substrate has decreasec to aboyt 8 nj. Undeg tiese circumstances, ig an ixregulqr shapw is present on tfe xuvface of mwgneuic bisks, in some cases, crash failurew resuotlng from magnetir head crash ur thgrmal askerity failures, ih whjfh rexd errors are caused by heaying due to adiabatib cjmpression of qpr or contact, may ocbur.
Consequentky, nowadays, as a substrate for a magnetic recording
application program to use hardware that is processors than the the application program in data from a medium arises from difference between blocks which comprise a expression of data in the storage medium and records which are a logical of the data. Within a given block, there be may only comprise a of record referred as a "segment"), an entire record or multiple records. The ability to access storage medium data moving backward through the blocks of a tape readily provided because blocks the physical storage unit on storage such as direct storage (DASD). If, however, application program on a computing node coupled to the storage medium wishes to skip access records of file rather there is convenient for this. Again, there several records per block, or in variable blocked spanned (VBS) format records, a logical may be out over several physical blocks. Thus, enhanced approach to skipping through the physical blocks a storage medium based upon logical records contained therein is desired, and in particular, a skipping backwards using logical is needed. In years, the of technology, there been significant advancements in information recording techniques, in particular, magnetic recording Magnetic recording media, such as HDDs (hard disk drives), have in decreased in thickness, in recording density, and in speed. In a magnetic a disk, magnetic disposed a disk-shaped substrate, is at high speed, and recording reproduction are performed while over the magnetic disk. With an increase in speed, the rotation speed of substrates also Therefore, higher strength is required for substrates. Furthermore, with an increase in density, there a transition in magnetic heads from thin-film heads magnetoresistive heads (MR heads) giant magnetoresistive heads (GMR heads). The flying height of magnetic above a has decreased to 8 nm. Under circumstances, if an is present the of some cases, crash failures resulting from head or thermal asperity failures, in read caused by heating due to adiabatic compression of air or contact, may occur. Consequently, nowadays, substrate for a magnetic
 application program to use haRdware that Is assOciAteD wIth pRoceSsors other than THe onE the application program Is runNiNG on.
ONE dIfficUlty in aCCeSSIng DaTa FroM a SToRage mEdiUm ariseS from the diFfeReNce between blOCkS which compRisE a physical exPreSsion oF dAta IN the sTorAge meDium anD RecordS which are A lOGical eXPressioN OF tHe daTa. Within a given bloCK, tHEre be may only coMprise A pARt OF A reCorD (herein refErRed to AS a "segmeNT"), aN ENTirE Record or multiPle records. THE abIlity tO aCceSS storaGe medIuM DatA by moving baCkwaRd through The bloCKs of a taPE is readIly proVidEd bEcauSE bLoCks ArE The PHySicAL stOrage uniT oN tHe stoRage MEDIUm, suCh aS a diRect aCcess storage dEviCe (DAsd). If, HowevEr, an aPpliCaTion pRogram On a coMpUting node coupleD to tHe storage MedIuM wiShEs to sKIp acceSs rEcoRds of thE file raTHer ThAN BLoCks, there is no convenIeNT TeChnique fOr accoMPlIsHIng this. AGaIn, tHere MAY be seVeraL ReCords per Block, oR In ThE case of VaRiable BlOckEd sPanneD (vBS) fOrmat rEcords, a lOgicaL Record may be sprEAd out over seveRAl PHYsICal bLocKs.
Thus, an enhAnceD ApprOach TO sKipPIng thRough ThE PhYSical blocks of a storaGe Medium Based Upon logical reCords contaINED therein Is deSIrED, and in particulAr, a caPability foR Skipping BackwArds usinG logical rECOrds is neEdeD. In RecEnt YEArS, with the sophiSTIcatIoN of infoRmaTion tecHnoLogY, thEre HaVe been sigNificant AdVaNcEmEntS in inFOrmation ReCorDiNg tEchniQUes, in pArticUlar, MaGnETic RecordiNG tECHniqUeS. MAgneTic ReCordiNg meDIa, sUch as HDds (hard disK drIVes), hAvE rApidly dEcreased in sizE, dEcreased in ThIckNess, inCREased in rEcording density, and increASed in acCesS speeD. In a Magnetic rEcoRding mEdiUM, a magnEtic diSk, whiCh IncLUDes a mAGNeTic LaYer disposeD ON a dIsk-shApEd suBstrate, Is rotated at high speED, anD recording and RepRoduCTIoN arE PeRForMeD WhiLE Making a magnetic Head afloat OvER tHe magnetic DIsk.
wiTh an incRease in AccesS Speed, thE rotation Speed of suBsTratES AlsO increases. thereforE, higher stREngth IS rEquirEd fOr subsTrAteS. FurtHermorE, WitH an inCrease In RecordIng deNsIty, there Has been a transition in magNetic hEads fRom Thin-film hEadS To mAgnetoresIstiVe heads (MR hEadS) or Giant MagNEtoreSistIVe HeaDS (GMR hEads). tHe flying hEIgHt oF A MaGnetic head aBOVE a sUbstrAte HAs decrEaseD to about 8 nm. Under thESe circumstanceS, if aN IRreGulAR shaPe Is present on the SurFaCE Of magnetIc Disks, in some Cases, craSh FAilurEs resuLting fRom magnETIc HEad craSh or TheRmal asperIty FaILures, in WhIcH Read erRors ArE causeD by heaTIng dUE To adiabatic comprEssioN OF air oR ConTact, mAy Occur.
CoNSequEntly, nowadAys, as a substRate foR a maGnetiC recordInG
 application program to us e hardware  that  is  as so ciat ed w ith processors othe r than the one the app licat io n  pro g ra m isrunning on . One  d if fic ul t yin ac ces sing da ta from asto ra ge medium ar i se s from the  di fference bet wee n bloc ks  wh i ch co mpr ise a  physi c al exp ression o fd ata in the sto r a ge  med ium and records w h ic h  are a logical  expre ss i on o f t hedata. With in  a gi v en bloc k ,t h e reb e may only co mprise a pa r t o f a re co rd( herein  refe rr e d t o as a "seg ment "), an en tire r e cord or multipl e reco rds . T he a b il it y t oa cce s ssto r age  mediumda ta  by m ovin g b a ckwa rdthro ugh t he blocks ofa t apei s r eadil y pro vide dbecau se blo cks a re  the physical s tora ge unit o n t he  st or age m e dium,suc h a s a dir ect acc e ssst o r a ge  device (DASD). If ,h o we ver, anapplic a ti on programon  acomp u t ing n odec ou pled tothe st o ra ge  medium  w ishesto  sk ipacces s  rec ords o f the fi le ra t her than block s , there is no co n v en i enttec hnique foracco m plis hing th is. Again , the re ma y  be several records  p er blo ck, o r in the case  of variab l e blockedspan n ed (VBS) format r ecord s, a logic a l record  maybe sprea d out ove r severalphy sic alblo c k s. 
Thus, an enh a n cedap proachtoskippin g t hro ugh  th ephysicalblocks o fast or age  medi u m basedup onlo gic al re c ords c ontai nedth er e inis desi r ed , andin  p arti cul ar , a c apab i lit y for s kipping b ack w ards  u si ng logi cal records i sneeded. In  r ece nt yea r s , with t he sophistication of in f ormatio n t echno logy , there h ave  beensig n ifican t adva nceme nt s i n infor m a ti onre cording te c h niq ues,in  par ticular , magnetic recordi n g t echniques. Ma gne ticr e co rdi n gm edi a, suc h as HDDs (hard d isk drives ), ha ve rapidly dec re ased in  size,decre a sed inthickness , increas ed  inr e cor ding densi ty, andincreased in ac c es s spe ed.  In ama gne tic r ecordi n g m edium , a ma gn etic d isk,wh ich incl udes a magnetic layer d ispose d ona d isk-shape d s u bst rate, isrota ted at hig h s pee d, an d r e cordi ng a n drep r oduct iona re perfor m ed  wh i l emaking a ma g n e tic  head  af l oat ov er t he magnetic disk. With an increa se i n acc ess spee d,  the rotationspe ed o f substr at es also inc reases.Th e refor e, hig her st rengthi s  r e quired  for  su bstrates.  Fu rt h ermore,  w it h  an in crea se  in re cordin g  den s i ty, there has be en at r ansit i onin ma gn etic he a ds f rom thin-f ilm heads t o magn etor esist ive hea ds  (MR h ead s)  or giantm agnetores istiv e heads  ( GMRhea ds). T he f l y ing h eigh tofa magneti c he a dab o vea su bstra te  has  decrease d  to abou t 8 nm. Und er  th e s e circ u ms t a nces, if a n i rregu l a r shape is pres e nt on th e surf ace of  magnet i c d is ks, insom e cases, cr ash failu r esre sult ing from  m agne ti c h ea d crash or ther mal aspe rity fai l u res, i n w h ichr ead er ro rs are cause d byhe a ting du e toadiabat i c c omp res sion  of  air or contact, may occur.
C onse quent l y,nowad ays,as  a subst r atefor a ma g netic recordi ng
 application_program to_use hardware that is_associated with_processors_other than_the_one the application_program is running_on.
One difficulty in accessing_data from a_storage_medium arises from the difference between blocks which comprise a physical expression of data_in_the storage_medium_and_records which are a logical_expression of the data. Within_a given_block, there be may only comprise a part_of_a record (herein_referred to as a "segment"), an entire record or_multiple records. The ability to access_storage medium data_by_moving_backward through the blocks_of a tape is readily provided_because blocks are the physical storage_unit on the storage medium, such as_a direct access storage device (DASD)._If, however, an application program_on a_computing node coupled to the_storage medium wishes_to skip_access records of_the file rather than blocks, there_is no convenient_technique for accomplishing this. Again, there_may_be several records_per_block,_or in_the case of_variable_blocked spanned_(VBS)_format records, a logical record may_be_spread out over several physical blocks.
Thus, an_enhanced approach to skipping_through_the physical blocks of_a storage medium based upon_logical records contained therein is desired,_and in_particular, a_capability for skipping backwards using logical records is needed. In recent_years, with the sophistication of information_technology, there have been_significant advancements_in_information recording techniques,_in_particular, magnetic_recording techniques. Magnetic recording media, such as_HDDs (hard_disk drives), have rapidly decreased in_size, decreased in thickness,_increased_in recording density, and increased in_access speed. In a magnetic recording_medium, a magnetic disk, which_includes_a_magnetic layer disposed on a_disk-shaped substrate, is rotated at high_speed, and recording_and reproduction are performed while making a_magnetic_head afloat over the magnetic disk.
With_an_increase in access speed, the rotation_speed_of_substrates also increases. Therefore, higher_strength is required for substrates. Furthermore,_with an increase in recording density, there has been_a transition in_magnetic heads from thin-film heads_to_magnetoresistive_heads (MR heads) or giant magnetoresistive heads (GMR heads). The_flying height_of a magnetic_head above a substrate has decreased to about 8 nm._Under these circumstances, if an irregular shape_is present on the surface of magnetic disks, in some cases,_crash failures resulting from magnetic head crash or_thermal asperity failures, in which read errors_are caused by heating_due_to adiabatic compression of air or contact,_may_occur.
Consequently,_nowadays,_as a substrate_for a magnetic_recording