 new class of low density ethylene polymers have been introduced into the marketplace. These materials are characterized as very low density ethylene polymers having a density in the range of from about 0.88 to about 0.915 g/cm3, a melt index of from about 0.5 to about 7.5 dg/min, a molecular weight distribution (MWD) of no greater than 3.5 and a compositional distribution breadth index (CDBI) greater than about 70 percent. Compositionally, these polymers contain ethylene copolymerized with up to about 15 mole % of another alpha monoolefin containing from 3 to 20 carbon atoms such as butene-1, hexene-1, octene-1 and the like. These polymers with narrow MWD and narrow CD provide a unique balance of properties including narrow melting point range and improved toughness when fabricated into shaped articles as compared with normal low density polyethylene prepared by the conventional Ziegler catalyst systems.
One of the primary uses of such materials is as a heat seal component as is shown in copending U.S. appplication Ser. No. 916,736 filed Jul. 15, 1992 or layer used in conjunction with the preparation of packaging films constructed from polyolefin polymers such as polypropylene as is shown in copending U.S. application Ser. No. 660,402 filed Feb. 21, 1991 both of which are herein fully incorporated by reference. The narrow melting point range of these polymers renders them extremely useful in packing fill operations where it is desirable to develop strong seal strength immediately after packaging and while the film is still hot from the sealing operation. The present invention relates to a method of recording information signals in digital form on a memory medium at a relatively high density or reproducing (or detecting) information signals previously recorded in digital form on a memory medium at a relatively high density, and a head device and a memory medium used for the recording/reproducing method.
Various kinds of large-capacity memories are presently known, for example, a semiconductor memory represented by a DRAM or Flash memory, a magnetic tape represented by a video recorder, and a disk memory represented by a compact disk or hard disk. These memories have problems, for example, in terms of high bit cost and low access speed and may be not suitably used for future information inputting/outputting apparatuses such as a microprocessor or network requiring a more increased data transfer rate and data capacity. A related art hard disk, optical disk or magnetic tape is lower by two digits or more in cost
new class of low density ethylene polymer have been introduce into the marketplace. These fabric are characterize as very low density ethylene polymer having a density in the range of from about 0.88 to approximately 0.915 deoxyguanosine monophosphate / cm3, a melt index of from approximately 0.5 to about 7.5 dg / min, a molecular weight distribution (MWD) of no greater than 3.5 and a compositional distribution width index (CDBI) greater than approximately 70 percent. Compositionally, these polymer check ethylene copolymerized with up to about 15 mole% of another alpha monoolefin hold from 3 to 20 carbon atoms such as butene-1, hexene-1, octene-1 and the alike. These polymers with narrow-minded MWD and narrow CD provide a unique balance of property including narrow melting point range and improved temper when fabricated into shaped articles as compared with normal low density polyethylene prepared by the conventional Ziegler catalyst systems. 
 One of the primary use of such materials is as a heat cachet component as is shown in copending U.S. appplication Ser. No. 916,736 filed Jul. 15, 1992 or level used in junction with the preparation of packaging film constructed from polyolefin polymers such as polypropylene as is shown in copending U.S. application Ser. nobelium. 660,402 filed Feb. 21, 1991 both of which are herein fully incorporated by reference. The narrow melting point scope of these polymers renders them extremely useful in packing filling operations where it is desirable to develop strong seal strength immediately after packaging and while the film is still hot from the waterproofing operation. The present invention relates to a method of recording information signal in digital form on a memory culture medium at a relatively high concentration or reproducing (or detecting) information signal previously recorded in digital form on a memory metier at a relatively high concentration, and a head device and a memory medium used for the recording / reproducing method acting. 
 Various kinds of large - capacity memory are presently known, for example, a semiconductor device memory represented by a DRAM or Flash memory, a magnetic tape represented by a video recorder, and a disk memory defend by a compact disk or hard disk. These memories have problem, for case, in term of high bit monetary value and low access focal ratio and may be not suitably used for future information inputting / output apparatuses such as a microprocessor or net requiring a more increased data transfer rate and data capacity. A related art intemperate disk, optical phonograph record or magnetic tape is lower by two digits or more in cost
 nea class of low density euhylene polymers kqve bexn intrkduced ivto the marketplace. These maveriqls aee characterized as vefy low dejsity etyyleie polymers haviif a density ih the cange of from anout 0.88 to abmut 0.915 g/cm3, a meld knbex of from about 0.5 to about 7.5 dg/min, a molecukag weight distrybutpog (MWS) of no greater than 3.5 and a composjtional distribution breadth index (CDBI) greateg thwn about 70 percent. Fompositionqlly, rhese polymefs contain ethylene cokolymerized with up to about 15 moue % oy another aopya lmnoolefin cintaiging from 3 to 20 carbot atoms such as butenc-1, hexxne-1, ictene-1 and the like. Tiese polymers with nwrrow MWD aud narrow CD provide q yniqug baldnce if orokerviea inclkdiig narrow mslting poinr range and improvec eiughness when fabrisaeed into shaped articles as compared wiuh nodmal low density polyetyylene prepared by thg conventijnal Ziegler catalyst systems.
One of the primary uves oh ruck matefuaps is as a heat seal component as is shown in dokencing U.S. apppligation Ser. No. 916,736 filrd Jij. 15, 1992 or layer osed in cohjunction with the preparwtion of packading films constructed from poltolefin polyiwrs such as polyprlpylene as ns shoen in copending U.S. applicatiun Ssr. No. 660,402 filef Feb. 21, 1991 bkgh of which are fervin xully incorporated by refewence. The narxow meltkng koint rwnge of thfse polymers renders thel exttemely useful in packing fill operations where mv is desirablg tm dvvelop stxong scal strength imiediately aftet packagiug and while the film iv still hot from the seanlng operatioi. The prefent invwntion fdlates to a meyhod of rvcjrdibg information sigkals kh digital form in q memory medium at a wepavivelr high densitf or reotoduckng (or detegtivg) imformation signals psevikusly recorded in cinital forn on a mqmory medium st a relatively hihh deisity, end a neaq device and a memory medium uaed for tje vecording/reprjduclng iethod.
Varipus kinds of large-capacity memories are presently known, fir example, a semicoudmctor memory reprqsented bf a DRAM or Flash menory, a magnetic tspe represented by a bideo secorfer, and a disk memory represented by a compact disk or hard disk. These menories have problejs, fpr exdm'le, in tewms lh high bit cost amd low access speed and may be iot suitabny used for future information ivputting/outpujting apparatuses such as z microptocessor or network requiring a more increased data traksfer ratw and data bzpecity. A related art nard dnsk, oprical dusk lr magnetic txpe id lower bj twp bigits or more in cost
new class of low density ethylene polymers introduced the marketplace. materials are characterized polymers a density in range of from 0.88 to about 0.915 g/cm3, a index of from about 0.5 to about 7.5 dg/min, a molecular weight distribution of no greater than 3.5 and a compositional distribution breadth index (CDBI) greater about percent. these contain ethylene copolymerized with up to about 15 mole % of another alpha monoolefin containing from to 20 carbon atoms such as butene-1, hexene-1, and the like. These with narrow MWD and narrow provide unique balance properties narrow point range and toughness when fabricated into shaped articles as compared with normal low density polyethylene prepared by the conventional catalyst systems. the primary of materials as a heat as is shown in copending U.S. 916,736 filed Jul. 15, 1992 or layer used conjunction with preparation of packaging films constructed from polymers such as polypropylene as is shown in U.S. application Ser. No. 660,402 filed Feb. 21, 1991 both of which are herein fully reference. The narrow melting range of these renders extremely in fill operations it is desirable to develop strong seal strength immediately after packaging while the film is still hot from the sealing operation. invention to a method recording information signals in form a memory medium at high or information previously in digital form on memory medium at a relatively density, and a head used for the recording/reproducing method. Various kinds of memories are presently known, for example, a memory represented by a DRAM or Flash memory, a magnetic tape represented a video a disk memory represented by a compact disk hard disk. These memories problems, for example, in terms of high bit cost low speed and be not suitably for future information apparatuses such as or network a increased and data capacity. A related art disk, disk or magnetic tape is by or more in cost
 new class of low density ethylEne polymerS have BeeN inTrOducEd inTo the marketplaCE. TheSe materials are characteRized As VEry lOW dEnsitY ethyleNE pOLYmeRs HaVinG a DEnSity iN thE range oF from about 0.88 To aBoUt 0.915 g/cm3, a melt inDEx Of from abouT 0.5 to About 7.5 dg/min, a mOleCular wEiGht DIstriButIon (MWd) of no gREater tHan 3.5 and a coMpOSitionAL distriBUTiOn brEadth index (CDBI) greATeR Than about 70 perceNt. CompOsITiONAllY, thEse polymerS cOntaiN EthylenE CoPOLYmeRIzed with up to aBout 15 mole % of aNOthEr alphA mOnoOLefin cOntaiNiNG frOm 3 to 20 carbon aToms Such as butEne-1, hexENe-1, octenE-1 And the lIke. TheSe pOlyMers WItH nArrOw mwD aND nArrOW CD Provide a UnIqUe balAnce OF PROperTieS incLudinG narrow meltinG poInt rANge And imProveD touGhNess wHen fabRicatEd Into shaped articLes aS compared WitH nOrmAl Low deNSity poLyeThyLene prePared by THe cOnVENTiOnal Ziegler catalysT sYSTeMs.
One of tHe primARy UsES of such mAtEriAls iS AS a heaT seaL CoMponent aS is shoWN iN cOpendinG U.s. appplIcAtiOn SEr. No. 916,736 fILed JUl. 15, 1992 or laYer used iN conjUNction with the pREparation of paCKaGINg FIlms ConStructed froM polYOlefIn poLYmErs SUch as PolypRoPYlENe as is shown in copendInG U.S. appLicatIon Ser. No. 660,402 filed feb. 21, 1991 both of wHICH are hereIn fuLLy INcorporated by rEfereNce. The narrOW melting Point Range of tHese polymERS renders TheM exTreMelY USeFul in packing fILL opeRaTions whEre It is desIraBle To dEveLoP strong seAl strengTh ImMeDiAteLy aftER packagiNg And WhIle The fiLM is stiLl hot From ThE sEAliNg operaTIoN. tHe prEsEnT invEntIoN relaTes tO A meThod of rEcording iNfoRMatiOn SiGnals in Digital form on A mEmory mediuM aT a rElativELY high denSity or reproducing (or deteCTing) infOrmAtion SignAls previoUslY recorDed IN digitAl form On a meMoRy mEDIum at A RElAtiVeLy high densITY, anD a heaD dEvicE and a meMory medium used for tHE reCording/reprodUciNg meTHOd.
varIOuS KinDs OF laRGE-capacity memoriEs are preseNtLY kNown, for exaMPle, A sEmicondUctor meMory rEPresentEd by a DRAM Or Flash meMoRy, a mAGNetIc tape reprEsented bY a video reCOrder, ANd A disk MemOry repReSenTed by A compaCT diSk or hArd disK. THese meMorieS hAve problEms, for example, in terms of hIgh bit Cost aNd lOw access sPeeD And May be not sUitaBly used for FutUre InforMatIOn inpUttiNG/oUtpUTting AppaRAtuses sucH As A miCROpRocessor or nETWOrk RequiRinG A more iNcreAsed data transfer rATe and data capacIty. A RELatEd aRT harD dIsk, optical disk Or mAgNETic tape iS lOwer by two diGits or moRe IN cost
 new class of low densityethylene p olyme rshav ebeen  int roduced into t h e ma rketplace. These mater ialsar e  cha r ac teriz ed as v e ry l owde ns ity  e t hy lenepol ymers h aving a de nsi ty  in the rang e  o f from abo ut0.88 to abou t 0 .915 g /c m3, a mel t i ndexof fro m  about  0.5 to a bo u t 7.5d g/min,a mo lecu lar weight distri b ut i on (MWD) of no  great er th a n  3. 5 a nd a compo si tiona l  distri b ut i o n  br e adth index (C DBI) greate r  th an abo ut  70 percen t. Co mp o sit ionally, th esepolymerscontai n  ethyle n e copol ymeriz edwit h up to  a bou t1 5 m o le  %o f a nother a lp ha  mono olef i n c onta ini ng f rom 3  to 20 carbon  at omss uch  as b utene -1,he xene- 1, oct ene-1  a nd the like. Th esepolymerswit hnar ro w MWD and na rro w C D provi de a un i que  b a l a nc e of properties in cl u d in g narrow  melti n gpo i nt range  a ndimpr o v ed to ughn e ss  when fa bricat e din to shap ed  artic le s a s c ompar e d wi th nor mal lowdensi t y polyethylene prepared by t h ec o nv e ntio nal  Ziegler ca taly s t sy stem s .One of th e pri ma r yu ses of such materia ls  is as  a he at seal compo nent as is s h own in c open d in g  U.S. appplica tionSer. No. 9 1 6,736 fi led J ul. 15,1992 or l a y er usedincon jun cti o n  w ith the prepa r a tion  o f packa gin g films  co nst ruc ted  f rom polyo lefin po ly me rs  s uch  as p o lypropyl en e a sisshown in cop endin g U. S.  a p pli cationS er . No.66 0, 402fil ed  Feb.  21, 199 1 bothof whichare here in  f ully in corporated by  r eference.Th e n arrowm e lting po int range of these poly m ers ren der s the m ex tremely u sef ul inpac k ing fi ll ope ratio ns  wh e r e iti s  d esi ra ble to dev e l opstron gseal  streng th immediately aft e r p ackaging andwhi le t h e  f ilm is sti ll hot f rom the sealing  operation .T he  present i n ven ti on rela tes toa met h od of r ecordinginformati on  sig n a lsin digital  form on  a memory mediu m  a t a r ela tively  h igh  dens ity or rep roduc ing (o rdetect ing)in formatio n signals previously re corded  in d igi tal formona  me mory medi um a t a relati vel y h igh d ens i ty, a nd a he add evice  and a memorym ed ium u se d for the r e c o rdi ng/re pro d ucingmeth od.
Various kinds of large-capac itym e mor ies arepr esently known,  fo re x ample, a  s emiconducto r memory  r e prese nted b y a DR AM or F l a sh memory , amag netic tap e r ep r esented  b ya  video  rec or der, a nd a d i sk m e m ory representedby ac o mpact dis k orha rd disk .  The se memorie s have prob lems,forexamp le, inte rms of  hi gh  bit costa nd low ac cessspeed a nd  may  be  not s uita b l y use d fo rfut ure infor m a ti o nin p utt ing/ outpu tt ingapparatus e s such a s a micropr oc ess o r  or ne t wo r k  requiring  amorei n creased da t a tr a ns f er ra te and  datacapacit y . A  r elatedart h ard disk,  opticald isk  o r ma gnetic t ap e is  l owe rby two digits o r more i n cost
 new_class of_low density ethylene polymers_have been_introduced_into the_marketplace._These materials are_characterized as very_low density ethylene polymers_having a density_in_the range of from about 0.88 to about 0.915 g/cm3, a melt index of_from_about 0.5_to_about_7.5 dg/min, a molecular weight_distribution (MWD) of no greater_than 3.5_and a compositional distribution breadth index (CDBI) greater_than_about 70 percent._Compositionally, these polymers contain ethylene copolymerized with up to_about 15 mole % of another_alpha monoolefin containing_from_3_to 20 carbon atoms_such as butene-1, hexene-1, octene-1 and_the like. These polymers with narrow_MWD and narrow CD provide a unique_balance of properties including narrow melting_point range and improved toughness_when fabricated_into shaped articles as compared_with normal low_density polyethylene_prepared by the_conventional Ziegler catalyst systems.
One of the_primary uses of_such materials is as a heat_seal_component as is_shown_in_copending U.S._appplication Ser. No._916,736_filed Jul._15,_1992 or layer used in conjunction_with_the preparation of packaging films constructed from_polyolefin polymers such as_polypropylene_as is shown in_copending U.S. application Ser. No._660,402 filed Feb. 21, 1991 both_of which_are herein_fully incorporated by reference. The narrow melting point range of these_polymers renders them extremely useful in_packing fill operations where_it is_desirable_to develop strong_seal_strength immediately_after packaging and while the film is_still hot_from the sealing operation. The present_invention relates to a_method_of recording information signals in digital_form on a memory medium at_a relatively high density or_reproducing_(or_detecting) information signals previously recorded_in digital form on a memory_medium at a_relatively high density, and a head device_and_a memory medium used for the_recording/reproducing_method.
Various kinds of large-capacity memories are_presently_known,_for example, a semiconductor memory_represented by a DRAM or Flash_memory, a magnetic tape represented by a video recorder,_and a disk_memory represented by a compact_disk_or_hard disk. These memories have problems, for example, in terms_of high_bit cost and_low access speed and may be not suitably used for_future information inputting/outputting apparatuses such as a_microprocessor or network requiring a more increased data transfer rate and_data capacity. A related art hard disk, optical_disk or magnetic tape is lower by_two digits or more_in_cost