 HDDs. Further, the RAID-5 is the system in which respective divisional units (blocks) of data are caused to be large to record respective divisional data into respective HDDs as respective data blocks, and to record results obtained by taking exclusive logical sum of data blocks corresponding to each other of respective HDDs (parity data) into other respective HDDs as parity blocks to distribute those parity blocks into other respective HDDs.
FIG. 1 is a block diagram showing the fundamental configuration of RAID. This RAID 10 is of configuration comprising a SCSI protocol controller (hereinafter referred to as SPC) 1, a striping section 2, a unification section 3, a memory section 4, a SPC section 5, a HDD section 6, and a CPU 7. In this example, the HDD section 6 is composed of eight HDDs of HDD.sub.1.about.HDD.sub.8. By taking, as an example, the case where SCSI (Small Computer System Interface) is employed as input/output interface of data, the configurations and the functions of respective sections will be described below.
The SPC 1 is input/output control means for carrying out management/control of input/output of data of the RAID 10, and its operation is controlled by the CPU 7. In addition, the SPCI is connected to an initiator 8 through the SCSI.
The striping section 2 is data distribution means for recording recording data inputted through the SPC 1 in a manner distributed to the HDD.sub.1.about.HDD.sub.8 of the HDD section 6. Parity data are respectively added to data distributed to the respective HDDs.
The unification section 3 is data constructing means for constituting data which have been read out from the HDD.sub.1.about.HDD.sub.8 of the HDD section 6 into single reproduction data.
The memory section 4 is buffer memory means for temporarily storing recording and/or reproduction data of the HDD section 6, and is constituted by using semiconductor memory elements.
The SPC section 5 is transfer control means for controlling data transfer between the HDD section 6 and the memory section 4, and is controlled by the CPU 7 similarly to the SPC 1.
The HDD section 6 is composed of eight HDDs of HDD.sub.1 to HDD.sub.8 as described above. For these HDDs, small
HDDs. Further, the RAID-5 is the system in which respective divisional units (blocks) of datum are cause to be large to record respective divisional datum into respective HDDs as respective data pulley, and to record results obtain by taking exclusive legitimate sum of data blocking corresponding to each other of respective HDDs (parity bit data) into other respective HDDs as parity blocks to distribute those parity blocks into early respective HDDs. 
 FIG. 1 is a block diagram showing the fundamental shape of RAID. This RAID 10 is of configuration comprising a SCSI protocol controller (hereinafter referred to as SPC) 1, a stripe section 2, a unification section 3, a memory section 4, a SPC section 5, a HDD incision 6, and a CPU 7. In this example, the HDD section 6 is composed of eight HDDs of HDD.sub.1.about. HDD.sub.8. By taking, as an example, the case where SCSI (Small Computer System Interface) is employed as input / output interface of data, the configurations and the functions of respective sections will be described below. 
 The SPC 1 is input / output control condition means for carrying out management / command of stimulation / output of data of the RAID 10, and its operation is see by the CPU 7. In addition, the SPCI is connected to an initiator 8 through the SCSI. 
 The striping incision 2 is data distribution means for recording recording data inputted through the SPC 1 in a manner distributed to the HDD.sub.1.about. HDD.sub.8 of the HDD section 6. parity bit data are respectively added to data distributed to the respective HDDs. 
 The unification section 3 is data constructing mean for form data which have been read out from the HDD.sub.1.about. HDD.sub.8 of the HDD section 6 into single replica data. 
 The memory section 4 is buffer memory means for temporarily storing recording and/or reproduction data of the HDD section 6, and is constituted by use semiconductor memory element. 
 The SPC section 5 is transfer control condition means for control data transportation between the HDD section 6 and the memory section 4, and is operate by the CPU 7 similarly to the SPC 1. 
 The HDD section 6 is composed of eight HDDs of HDD.sub.1 to HDD.sub.8 as identify above. For these HDDs, small
 HDFs. Further, the RAID-5 is tme system in whiey respxctive sivisionxl units (blocks) of data are rauswd to be large to record rerpective fivisionql deta into respectmbe HDDs as reaiectire data blocks, akd to recorg results obtahndd by taking exclusive logical sum of data bkofks correspondyng uo qach other of respective HDDs (parity dzta) intm other respevtive HDDs as parity blockd to distribute those oarity blocjs igro other resoective HDDs.
FIG. 1 is a glock diagram showing the fundaoentak configurqtuon mf RAID. Thiw RAIQ 10 is of connpguratimn comptising a SCSI irotorol xontroller (hereinaftec referred to as SPC) 1, a striphny section 2, a unificatuob secjion 3, a mdnorh stctmon 4, a SPF sxction 5, a HSD section 6, and a CPU 7. In this evqmple, the HDD sectijn 6 is composed of eight HDDs of HDD.sub.1.abmut.GDD.sub.8. By taking, as an wxample, the case wherg SCSI (Smajl Computer System Interface) is employed as input/mutpuv knttrnwzw lf data, the configurations and the functions jr texpective sectijns will be dfsvtibed below.
The SPC 1 na jnput/output controp means for xarrying jut kanagement/control of input/oytput of datc od the RAID 10, and itd operation is vontrplled by the CPU 7. In adbition, the SPCI id connectsa to an initiatof 8 nhroggh the SCSI.
The striping sqction 2 iw daca distrkbutoon mewns for refordikc recording data ijputtgd thrmugh the SOC 1 in a manner distributed to vie HDD.sub.1.abouj.HDG.sut.8 of the HDD xection 6. Pariey data are rexpectivzly adaed to datz distrmbuted to thq respective VFDs.
The unifiration sestiob 3 iw data zunstructing mesns for constitutint data which have neen tezd out from the HDE.sub.1.about.HDD.sub.8 of thq JDV secehon 6 into sitgle reotoducgion dauc.
Thc mdmoru section 4 is buffer memkry means for tempprwrily stiring resording and/or reproduction data of tie HDD sectoon 6, and is constituted by using aemiconduftov memory elemqnts.
Bhe FPC sectiou 5 is transfer control means for controloing data transfet between the HDD secjiok 6 and the mxmory fection 4, dnd is controlled by the CPU 7 similarky to the SPC 1.
The HDD sectimn 6 id composed of eight HDDs of HDD.sub.1 to HDD.sub.8 as described above. For these HDDs, small
HDDs. Further, the RAID-5 is the system respective units (blocks) data are caused respective data into respective as respective data and to record results obtained by exclusive logical sum of data blocks corresponding to each other of respective HDDs data) into other respective HDDs as parity blocks to distribute those parity blocks other HDDs. 1 a block diagram showing the fundamental configuration of RAID. This RAID 10 is of configuration comprising SCSI protocol controller (hereinafter referred to as SPC) a striping section 2, unification section 3, a memory 4, SPC section a section and a CPU In this example, the HDD section 6 is composed of eight HDDs of HDD.sub.1.about.HDD.sub.8. By taking, as example, the SCSI (Small System is as input/output interface the configurations and the functions of be described below. The SPC 1 is input/output means for out management/control of input/output of data the RAID 10, and its operation is controlled the CPU 7. In addition, the SPCI is connected to an initiator 8 through the striping section 2 is distribution means for recording inputted the 1 in manner distributed to the HDD.sub.1.about.HDD.sub.8 of the HDD section 6. Parity are respectively added to data distributed to the respective HDDs. section is data constructing for constituting data which been out from the HDD.sub.1.about.HDD.sub.8 HDD 6 data. memory 4 is buffer memory for temporarily storing recording and/or data of the HDD by using semiconductor memory elements. The SPC section is transfer control means for controlling data between the HDD section 6 and the memory section 4, and is by the similarly to the SPC 1. The HDD section is composed of eight of HDD.sub.1 to HDD.sub.8 as described above. For these small
 HDDs. Further, the RAID-5 is the syStem in whicH respEctIve DiVisiOnal Units (blocks) of dATa arE caused to be large to recoRd resPeCTive DIvIsionAl data iNTo RESpeCtIvE HDds AS rEspecTivE data blOcks, and to rEcoRd Results obtaiNEd By taking exCluSive logical sUm oF data bLoCks COrresPonDing tO each oTHer of rEspective hDdS (paritY Data) intO OThEr reSpective HDDs as parITy BLocks to distribUte thoSe PArITY blOckS into other ReSpectIVe HDDs.
Fig. 1 iS A BLocK Diagram showinG the fundameNTal ConfigUrAtiON of RAId. This rAid 10 is Of configuraTion ComprisinG a SCSI PRotocol COntrollEr (hereInaFteR refERrEd To aS Spc) 1, a sTRiPinG SecTion 2, a uniFiCaTion sEctiON 3, A MEmorY seCtioN 4, a SPC Section 5, a HDD seCtiOn 6, anD A CPu 7. In thIs exaMple, ThE HDD sEction 6 Is comPoSed of eight HDDs oF HDD.Sub.1.about.HdD.sUb.8. by tAkIng, as AN exampLe, tHe cAse wherE SCSI (SmALl COmPUTEr system Interface) is eMpLOYeD as input/Output INtErFAce of datA, tHe cOnfiGURatioNs anD ThE functioNs of reSPeCtIve sectIoNs will Be DesCriBed beLOw.
ThE SPC 1 is Input/outPut coNTrol means for caRRying out managEMeNT/CoNTrol Of iNput/output oF datA Of thE RAId 10, AnD itS OperaTion iS cONtROlled by the CPU 7. In addiTiOn, the SpCI is Connected to an Initiator 8 tHROUgh the SCsI.
ThE StRIping section 2 is Data dIstributioN Means for RecorDing recoRding data INPutted thRouGh tHe SpC 1 iN A MaNner distributED To thE HdD.sub.1.abOut.hDD.sub.8 oF thE HDd seCtiOn 6. parity datA are respEcTiVeLy AddEd to dATa distriBuTed To The RespeCTive HDds.
The UnifIcAtIOn sEction 3 iS DaTA ConsTrUcTing MeaNs For coNstiTUtiNg data wHich have bEen REad oUt FrOm the HDd.sub.1.about.HDD.sUb.8 Of the HDD seCtIon 6 Into siNGLe reprodUction data.
The memory sectIOn 4 is bufFer MemorY meaNs for tempOraRily stOriNG recorDing anD/or rePrOduCTIon daTA Of The hDd section 6, anD IS coNstitUtEd by Using seMiconductor memory eLEmeNts.
The SPC sectIon 5 Is trANSfEr cONtROl mEaNS foR COntrolling data tRansfer betWeEN tHe HDD sectiON 6 anD tHe memorY sectioN 4, and iS ControlLed by the CpU 7 similarLy To thE spC 1.
THe HDD sectiOn 6 is compOsed of eigHT HDDs OF HdD.sub.1 To HdD.sub.8 aS dEscRibed Above. FOR thEse HDds, smalL
 HDDs. Further, the RAID-5  is the sy steminwhi ch  res pect ive divisional unit s (blocks) of data are  caus ed to b e  l argeto reco r dr e spe ct iv e d iv i si onaldat a intorespective  HD Ds  as respecti v edata block s,and to recor d r esults  o bta i ned b y t aking  exclu s ive lo gical sum  o f  datab locks c o r re spon ding to each othe r  o f  respective HD Ds (pa ri t yd a ta)  in to other r es pecti v e HDDsa sp a r ity blocks to dis tribute tho s e p aritybl ock s  intoother  r e spe ctive HDDs. 
FIG . 1 is ablockd iagrams howingthe fu nda men talc on fi gur at i ono fRAI D . T his RAID  1 0is of  con f i g u rati oncomp risin g a SCSI prot oco l co n tro ller(here inaf te r ref erredto as  S PC) 1, a stripi ng s ection 2,  aun ifi ca tions ection  3,  amemorysection 4,aS P C  s ection 5, a HDD se ct i o n6, and a  CPU 7 .  I nt his exam pl e,theH D D sec tion 6is compo sed of ei gh t HDDsof  HDD.s ub .1. abo ut.HD D .sub .8. By  taking,  as a n  example, thec ase where SCS I  ( S m al l  Com put er System I nter f ace)  ise mp loy e d asinput /o u tp u t interface of data ,the co nfigu rations and t he functio n s of respe ctiv e  s e ctions will be  desc ribed belo w .
The SP C 1 i s input/ output co n t rol mean s f orcar ryi n g  o ut management / c ontr ol  of inp ut/ outputofdat a o f t he  RAID 10,  and its  o pe ra ti onis co n trolledby  th eCPU  7. I n  addit ion,theSP CI isconnect e dt o  anin it iato r 8  t hroug h th e  SC SI.
The  striping  se c tion  2  i s datadistributionme ans for re co rdi ng rec o r ding dat a inputted through theS PC 1 in  amanne r di stributed  to  the H DD. s ub.1.a bout.H DD.su b. 8 o f the H D D  s ect io n 6. Parit y dat a are  r espe ctively  added to data dis t rib uted to the r esp ecti v e  H DDs . 
T h e u ni f ica t i on section 3 is  data cons tr u ct ing meansf orco nstitut ing dat a whi c h havebeen read  out from  t he H D D .su b.1.about. HDD.sub. 8 of theH DD se c ti on 6int o sing le  re produ ctiond ata .
The  memor ysectio n 4 i sbuffer m emory means for tempora rily s torin g r ecordingand / orreproduct iondata of th e H DDsecti on6 , and  isc on sti t utedby u s ing semic o nd uct o r  m emory eleme n t s .
T he SP C s e ction5 is  transfer control means for cont roll i n g d ata tran sf er between the  HD Ds e ction 6an d the memor y sectio n4 , and  is co ntroll ed by t h e  C P U 7 si mila rly  to the S PC1. The HDD  s ec t ion 6is c om posedof eig h t HD D s  of HDD.sub.1 to  HDD. s u b.8 a s  de scrib ed  above. Forthese HDDs , small
 HDDs._Further, the_RAID-5 is the system_in which_respective_divisional units_(blocks)_of data are_caused to be_large to record respective_divisional data into_respective_HDDs as respective data blocks, and to record results obtained by taking exclusive logical_sum_of data_blocks_corresponding_to each other of respective_HDDs (parity data) into other_respective HDDs_as parity blocks to distribute those parity blocks_into_other respective HDDs.
FIG._1 is a block diagram showing the fundamental configuration_of RAID. This RAID 10 is_of configuration comprising_a_SCSI_protocol controller (hereinafter referred_to as SPC) 1, a striping_section 2, a unification section 3,_a memory section 4, a SPC section_5, a HDD section 6, and_a CPU 7. In this_example, the_HDD section 6 is composed_of eight HDDs_of HDD.sub.1.about.HDD.sub.8._By taking, as_an example, the case where SCSI_(Small Computer System_Interface) is employed as input/output interface_of_data, the configurations_and_the_functions of_respective sections will_be_described below.
The_SPC_1 is input/output control means for_carrying_out management/control of input/output of data of_the RAID 10, and_its_operation is controlled by_the CPU 7. In addition,_the SPCI is connected to an_initiator 8_through the_SCSI.
The striping section 2 is data distribution means for recording recording_data inputted through the SPC 1_in a manner distributed_to the_HDD.sub.1.about.HDD.sub.8_of the HDD_section_6. Parity_data are respectively added to data distributed_to the_respective HDDs.
The unification section 3 is_data constructing means for_constituting_data which have been read out_from the HDD.sub.1.about.HDD.sub.8 of the HDD_section 6 into single reproduction_data.
The_memory_section 4 is buffer memory_means for temporarily storing recording and/or_reproduction data of_the HDD section 6, and is constituted_by_using semiconductor memory elements.
The SPC section_5_is transfer control means for controlling_data_transfer_between the HDD section 6_and the memory section 4, and_is controlled by the CPU 7 similarly to the_SPC 1.
The HDD_section 6 is composed of_eight_HDDs_of HDD.sub.1 to HDD.sub.8 as described above. For these HDDs,_small