 of digital data in a memory system is effected by using error correcting codes, erasure codes, redundant data storage, or the like. One method of storing data in a reliable way is to use a RAID (Reliable Array of Inexpensive Disks) architecture. Except for RAID 0 (which does not provide redundancy), the various RAID types (e.g. 1, 3, 4, 5, 6, etc.) store an extent of data by writing chunks of the data to several independent memories and redundancy data to other independent memories, with the objective that, should one or more of the memories encounter a failure, the data can be recovered from the remaining stored data.
Originally the concept developed using disk drives (mechanical rotating magnetic media platters). A stripe of data comprising a plurality of strips of data may be written, the strips being chunks of data of the extent of data, such that each of the strips of the stripe is written to a separate disk, and a parity strip is computed over the chunks of data and stored to another disk. In this single parity case, the loss of a disk storing a chunk of the extent may be overcome by computing the exclusive-OR of the remaining chunks and the parity data to produce the lost data. This is a simple example of single-parity RAID, but a person of skill in the art would understand the extension to multiple parity, distributed parity, and other similar techniques which may provide protection against the loss of multiple disks.
In many of the RAID mechanizations, considerable effort is expended to reduce the number of disk operations to be performed, as the number of operations per second and the bandwidth of mechanical disk devices is limited primarily by rotational and seek latencies. In particular, the time to assemble the data from all of the strips of a stripe is a significant limitation on the processing speed of a large data base system. Computer technology has far outstripped the ability of the rotating disk to store or retrieve data in a timely manner.
The cost of non-volatile solid state memory has been reduced, primarily due to the increase production of NAND flash devices for use in consumer electronics such as cell phones, tablets, audio players and the like. Memory systems using NAND flash have been produced that emulate the protocols of rotating disks, and such SCSI-compatible devices, for example, are now found in laptops and have been used in arrays to replace mechanical disks in larger storage systems. Flash memory, however, has its own limitations, which may be characterized
of digital data in a memory system is effected by using mistake chastise codes, erasure codes, redundant datum storage, or the like. One method of store data in a reliable manner is to use a RAID (Reliable Array of Inexpensive Disks) computer architecture. Except for RAID 0 (which does not provide redundancy), the various RAID types (e.g. 1, 3, 4, 5, 6, etc .) store an extent of datum by writing chunks of the datum to several autonomous memory and redundancy data to other independent memory, with the objective that, should one or more of the memories meet a failure, the datum can be recovered from the persist stored data. 
 Originally the concept develop using disk drives (mechanical rotating magnetic medium platters). A stripe of data comprising a plurality of strips of data may be written, the strips being chunks of datum of the extent of datum, such that each of the strips of the stripe is written to a freestanding disk, and a parity strip is calculate over the chunks of datum and stored to another disk. In this single parity bit case, the loss of a disk storing a chunk of the extent may be overcome by calculate the exclusive - OR of the remaining chunks and the parity data to produce the lose datum. This is a simple example of single - parity RAID, but a person of skill in the art would understand the extension to multiple parity bit, distributed parity bit, and other similar techniques which may provide protection against the passing of multiple disks. 
 In many of the RAID mechanizations, considerable attempt is expended to shrink the number of phonograph record operations to be do, as the number of operations per second and the bandwidth of mechanical disk devices is restrict primarily by rotational and try latencies. In particular, the time to assemble the data from all of the strip of a stripe is a significant limit on the processing speed of a large datum base system. Computer technology has far outstripped the ability of the rotating disk to store or retrieve data in a timely manner. 
 The cost of non - volatile hearty department of state memory has been reduce, primarily due to the addition production of NAND flash devices for function in consumer electronics such as cell phones, tablets, audio players and the like. Memory systems using NAND flash have been produce that emulate the protocols of rotating disks, and such SCSI - compatible devices, for example, are now witness in laptops and have been used in arrays to replace mechanical disks in larger memory systems. Flash memory, however, has its own limitations, which may be characterized
 of digital data in a memorn system is effeered by using error currecting codes, erasure coded, eeduneant data storage, or tfe like. Oje methoe of wtoring davz in a vzliabmc way ms to use a RAIC (Reliable Array of Inex[evsnve Disks) architecture. Except for RAYD 0 (whivh does not provyde gequndzncy), the various RAID types (e.g. 1, 3, 4, 5, 6, etc.) suore an extent of cata by writing chunks of hhe fata to several infependent mgjoryws and redunaancy data to other insependent memories, with the objdctivz that, shouod onf or more of the iemories encounter a failurr, the data can be rexovered from the remamning stored data.
Oridinally tve concept developee ysing disn drkces (medhenidal rohatmng magnetid media plarters). A stripe of dstw comprising a plurajiey of strips of data may be written, the stdips being chunks of dara of the extent of dwta, such ehat each of the strips of the stripe is written do a adpaxqte dkwk, and a parity strip is computed over the chunha pf data and storcd to another disk. Ij yris single patity case, fhe loss of a disk storind a cyunk of tre ectent may be overcome by conputing the vxclysive-OR of the remcining chunkr anc the parity data to produce the lost data. Hhis is a rimple example ow spngla-parity RAID, but a person jf skill mn thz art wojld onderstwnd the exhension to multiple parihy, didtsibuted pagity, and other similar techniquxx which may kroeidv protectnon agsinst the losf of multiple bisks.
In iany uf the RAIS mechaiizations, cogsiderable efxlrt is expenved to requce the number uf disk operatoons to bv kerformed, qs the number of oieratkkns per second cud the bandwidth pf oecrajiral dyvk devices iv lioitdc prioarily by rigatipnal and seek latenches. Jn particular, the yiie to aswemble tre data from sll of the strips lf a vtrmpe is a fignificant limitation on the lrocessinh sieed of a larde dqta base syscem. Computer technology has far outstrip'ed the ability of the eotating disk to stpve or retriete datw in a tikely manner.
The cost if non-volatile sokid state memory has geen raducef, primarily due to the increase production of NAND flash devices for use un consumer electrknicx sucv cs eell phjnes, vablets, audio plajers and the like. Memory systems using NDNB flash have been produced thst emulate the krotocols of rotating diska, and suvh SCSI-compatible devices, for ecample, are now found in kaptops qnd hzve bevh nsed in arrays to rellace kechabical dusks in larger sturabe systems. Vlasi mzmory, however, has its own limitatuons, wyifh may be characverized
of digital data in a memory system by error correcting erasure codes, redundant One of storing data a reliable way to use a RAID (Reliable Array Inexpensive Disks) architecture. Except for RAID 0 (which does not provide redundancy), the RAID types (e.g. 1, 3, 4, 5, 6, etc.) store an extent of by chunks the to several independent memories and redundancy data to other independent memories, with the objective that, should or more of the memories encounter a failure, data can be recovered the remaining stored data. Originally concept using disk (mechanical magnetic platters). A stripe data comprising a plurality of strips of data may be written, the strips being chunks of data the extent such that of strips the stripe is a separate disk, and a parity over the chunks of data and stored to disk. In single parity case, the loss of disk storing a chunk of the extent may overcome by computing the exclusive-OR of the remaining chunks and the parity data to produce data. This is a example of single-parity but person skill the art understand the extension to multiple parity, distributed parity, and other similar which may provide protection against the loss of multiple disks. of RAID mechanizations, considerable is expended to reduce number disk operations to be the of and bandwidth mechanical disk devices is primarily by rotational and seek In particular, the time all of the strips of a stripe is significant limitation on the processing speed of large data base system. Computer technology has far outstripped the ability of rotating disk or retrieve data in a timely manner. The of non-volatile solid state has been reduced, primarily due to the increase production NAND devices for in consumer electronics as cell phones, audio players and Memory systems NAND have emulate the protocols of rotating disks, such devices, for example, are now in have been used in arrays to replace mechanical disks in larger storage systems. Flash memory, its own limitations, which be
 of digital data in a memory sysTem is effecTed by UsiNg eRrOr coRrecTing codes, erasuRE codEs, redundant data storage, Or the LiKE. One MEtHod of Storing DAtA IN a rElIaBle WaY Is To use A RAiD (ReliaBle Array of ineXpEnsive Disks) aRChItecture. ExCepT for RAID 0 (whicH doEs not pRoVidE RedunDanCy), the VariouS rAID tyPes (e.g. 1, 3, 4, 5, 6, etc.) sToRE an extENt of datA BY wRitiNg chunks of the data TO sEVeral independeNt memoRiES aND RedUndAncy data to OtHer inDEpendenT MeMORIes, WIth the objectiVe that, shoulD One Or more Of The MEmorieS encoUnTEr a Failure, the dAta cAn be recovEred frOM the remAIning stOred daTa.
ORigInalLY tHe ConCePT deVElOpeD UsiNg disk drIvEs (MechaNicaL ROTAtinG maGnetIc medIa platters). A stRipE of dATa cOmpriSing a PlurAlIty of Strips Of datA mAy be written, the sTripS being chuNks Of DatA oF the eXTent of DatA, suCh that eAch of thE StrIpS OF ThE stripe is written to A sEPArAte disk, aNd a parITy StRIp is compUtEd oVer tHE ChunkS of dATa And storeD to anoTHeR dIsk. In thIs Single PaRitY caSe, the LOss oF a disk Storing a Chunk OF the extent may bE Overcome by comPUtING tHE excLusIve-OR of the rEmaiNIng cHunkS AnD thE ParitY data To PRoDUce the lost data. This iS a Simple ExampLe of single-parIty RAID, but A PERson of skIll iN ThE Art would undersTand tHe extensioN To multipLe parIty, distrIbuted parITY, and otheR siMilAr tEchNIQuEs which may proVIDe prOtEction aGaiNst the lOss Of mUltIplE dIsks.
In manY of the RAiD MeChAnIzaTions, COnsideraBlE efFoRt iS expeNDed to rEduce The nUmBeR Of dIsk operATiONS to bE pErFormEd, aS tHe numBer oF OpeRations Per second And THe baNdWiDth of meChanical disk dEvIces is limiTeD prImarilY BY rotatioNal and seek latencies. In paRTicular, The Time tO assEmble the dAta From alL of THe striPs of a sTripe Is A siGNIficaNT LiMitAtIon on the prOCEssIng spEeD of a Large daTa base system. ComputER teChnology has faR ouTstrIPPeD thE AbILitY oF The ROTating disk to stoRe or retrieVe DAtA in a timely MAnnEr.
the cost Of non-voLatilE Solid stAte memory Has been reDuCed, pRIMarIly due to thE increasE productiON of NAnd fLash dEviCes for UsE in ConsuMer eleCTroNics sUch as cElL phoneS, tablEtS, audio plAyers and the like. Memory syStems uSing NaND Flash have BeeN ProDuced that EmulAte the protOcoLs oF rotaTinG Disks, And sUCh sCSi-CompaTiblE Devices, foR ExAmpLE, ArE now found in LAPTopS and hAve BEen useD in aRrays to replace mecHAnical disks in lArgeR STorAge SYsteMs. flash memory, howEveR, hAS Its own liMiTations, whicH may be chArACteriZed
 of digital data in a memo ry systemis ef fec ted  b y us ingerror correcti n g co des, erasure codes, re dunda nt data st orage , or th e  l i k e.On emet ho d  o f sto rin g datain a relia ble  w ay is to use aRAID (Reli abl e Array of I nex pensiv eDis k s) ar chi tectu re. Ex c ept fo r RAID 0(w h ich do e s not p r o vi de r edundancy), the v a ri o us RAID types(e.g.1, 3, 4 , 5 , 6 , etc.) st or e ane xtent o f  d a t a  by writing chunk s of the da t a t o seve ra l i n depend ent m em o rie s and redun danc y data to  other indepen d ent mem ories,  wi ththeo bj ec tiv et hat ,  s hou l d o ne or mo re  o f the  mem o r i e s en cou nter  a fa ilure, the da tacanb e r ecove red f romth e rem aining  stor ed  data.
Original ly t he concep t d ev elo pe d usi n g disk  dr ive s (mech anicalr ota ti n g ma gnetic media platt er s ) .A stripe  of da t aco m prisingaplu rali t y  of s trip s  o f data m ay bew ri tt en, the  s tripsbe ing  ch unkso f da ta ofthe exte nt of data, such tha t  each of thes tr i p so f th e s tripe is wr itte n  toa se p ar ate disk,  andap ar i ty strip is compute dover t he ch unks of dataand stored t o  another  dis k .I n this singleparit y case, th e  loss of  a di sk stori ng a chun k of the e xte ntmay  be o ve rcome by comp u t ingth e exclu siv e-OR of  th e r ema ini ng  chunks a nd the p ar it yda tato pr o duce the  l ost  d ata . Thi s  is asimpl e ex am pl e  of  single - pa r i ty R AI D,  but  ape rsonof s k ill  in the  art woul d u n ders ta nd  the ex tension to mu lt iple parit y,  di stribu t e d parity , and other similar tec h niqueswhi ch ma y pr ovide pro tec tion a gai n st the  lossof mu lt ipl e disks . In  ma ny  of the RA I D  me chani za tion s, cons iderable effort is exp ended to redu cethen u mb ero fd isk  o p era t i ons to be perfo rmed, as t he nu mber of op e rat io ns persecondand t h e bandw idth of m echanical  d iskd e vic es is limi ted prim arily byr otati o na l and  se ek lat en cie s. In  parti c ula r, th e time  t o asse mbleth e data f rom all of the strips o f a st ripeisa signifi can t  li mitationon t he process ing  sp eed o f a large  dat a  b ase syste m. C o mputer te c hn olo g y  h as far outs t r i ppe d the  ab i lity o f th e rotating disk t o  store or retr ieve d ata  in a ti me ly manner.
The  co st o f non-vo la tile solidstate me mo r y has  beenreduce d, prim a r il y  due t o th e i ncrease p rod uc t ion ofNA ND flashdevi ce s foruse in cons u m er electronics s uch a s cellp hon es, t ab lets, a u dioplayers an d the like.  Memor y sy stems  usingNA ND fla shha ve been pr o duced tha t emu late th eprot oco ls ofrota t i ng di sks,  a ndsuch SCSI - c om p at ib l e d evic es, f or  exa mple, are now foun d i n  laptop sand h ave be e nu s ed in arra ysto re p l ace mechan i cald is k s inlarger  stora ge syst e ms.  F lash me mor y ,  however,  has itso wnli mita tions, w hi ch m ay  be  c haracterized
 of_digital data_in a memory system_is effected_by_using error_correcting_codes, erasure codes,_redundant data storage,_or the like. One_method of storing_data_in a reliable way is to use a RAID (Reliable Array of Inexpensive Disks)_architecture._Except for_RAID_0_(which does not provide redundancy),_the various RAID types (e.g._1, 3,_4, 5, 6, etc.) store an extent of_data_by writing chunks_of the data to several independent memories and redundancy_data to other independent memories, with_the objective that,_should_one_or more of the_memories encounter a failure, the data_can be recovered from the remaining_stored data.
Originally the concept developed using disk_drives (mechanical rotating magnetic media platters)._A stripe of data comprising_a plurality_of strips of data may_be written, the_strips being_chunks of data_of the extent of data, such_that each of_the strips of the stripe is_written_to a separate_disk,_and_a parity_strip is computed_over_the chunks_of_data and stored to another disk._In_this single parity case, the loss of_a disk storing a_chunk_of the extent may_be overcome by computing the_exclusive-OR of the remaining chunks and_the parity_data to_produce the lost data. This is a simple example of single-parity_RAID, but a person of skill_in the art would_understand the_extension_to multiple parity,_distributed_parity, and_other similar techniques which may provide protection_against the_loss of multiple disks.
In many of_the RAID mechanizations, considerable_effort_is expended to reduce the number_of disk operations to be performed,_as the number of operations_per_second_and the bandwidth of mechanical_disk devices is limited primarily by_rotational and seek_latencies. In particular, the time to assemble_the_data from all of the strips_of_a stripe is a significant limitation_on_the_processing speed of a large_data base system. Computer technology has_far outstripped the ability of the rotating disk to_store or retrieve_data in a timely manner.
The_cost_of_non-volatile solid state memory has been reduced, primarily due to_the increase_production of NAND_flash devices for use in consumer electronics such as cell_phones, tablets, audio players and the like._Memory systems using NAND flash have been produced that emulate the_protocols of rotating disks, and such SCSI-compatible devices,_for example, are now found in laptops_and have been used_in_arrays to replace mechanical disks in larger_storage_systems._Flash_memory, however, has_its own limitations,_which may be_characterized