Computer Architecture C H A P TE R 06 CO NT EN TS 보조저장장치 6.1 자기 디스크 6.2 RAID 6.3 플래시 메모리와 SSD 6.4 광 저장장치
Computer Architecture CHAPTER 06 보조저장장치 이 장에서는 외부 기억장치에 해당하는 보조저장장치들에 대하여 설명하고 자 한다. 그들 중에서 시스템의 프로그램 처리 속도에 직접 영향을 주고 거의 모 든 컴퓨터시스템에서 가장 중요한 보조저장장치로 사용되고 있는 자기 디스크 (magnetic disk)에 대한 설명부터 시작한다. 그 다음에는 디스크의 용량과 신뢰 도를 높이기 위하여 개발된 결함-허용 디스크 배열(fault-tolerant disk array) 인 RAID의 설계 원리를 분석한다. 그리고 마지막으로, 최근 많은 컴퓨터시스 템들에서 점차 더 널리 사용되고 있는 SSD(solid state disk)와 광 기억장치 (optical memory)들의 종류와 동작 원리에 대하여 살펴보고자 한다. 6.1 자기 디스크 자기 디스크는 하드 디스크(hard disk)라고도 하며, 단순히 디스크로 부르기도 한다. 디스크는 자화될 수 있는 물질(magnetizable material)로 코팅된 플라스 틱이나 금속을 이용한 원형 평판(circular platter)으로 만들어지는데, 그 평판 위에 헤드(head)라고 불리는 전도성 코일을 통하여 표면을 자화시킴으로써 데이터를 저장하게 된다. 디스크의 표면에는 그림 6-1에서 보는 바와 같이 여러 개의 동 심원들이 존재하는데, 이 원들을 트랙(track)이라고 부른다. 데이터들은 트랙 위 에 저장되며, 헤드가 그 트랙을 지나가는 동안에 데이터가 저장되거나 인출된다. 2
06 CHAPTER magnetic field 2 1 0 6 1 a 3
Computer Architecture msec 6 1 b 6 2 block 6 2 8 4
06 CHAPTER 500 2000 32 64 2 5
Computer Architecture 6 3 CAV CAV CAV 6
06 CHAPTER 6 4 600 512 ID ID 6 4 ID SYNCH ID CRC cyclic redundancy checking 6 4 7
Computer Architecture 6 5 a spindle 8
06 CHAPTER 6 5 b 1 6 5 b 8 20 electric field 9
Computer Architecture aerodynamic foil IBM 3340 6 1 a disk controller startup time ms 10
06 CHAPTER locality 7200rpm rotations per minute 120 1 120 8 33ms 0 8 33ms 4 17ms phase 5400 7200 10000 15000rpm 20000rpm CHE01 fluid bearing 1990 SCSI 1 MByte s 4 MByte s Ultra SCSI 100 MByte s 400 MByte s disk queue 11
Computer Architecture ={1 (5400 60)} 0 5 5 5ms Ta=8ms 5 5ms (0 5KByte 100MByte s) 1ms 14 5ms 6 1IBM Hitachi HDD HGS08 Deskstar E7K1000 1000GByte 1TByte5 2 53 5 512 5400rpm 7200rpm 15000rpm 5 5ms 4 17ms 2 0ms 11ms 8 5ms 3 6ms 160GBytes 1000GBytes 450GBytes 4 10 8 2 5 4 131Gbits in 2 270Gbits in 2 183Gbits in 2 100 MBytes s 300 MBytes s 300 MBytes s 2 5 3 5 3 5 12
06 CHAPTER I O 30 CPU 1 array RAID RAID RAID 13
Computer Architecture 1956 RAMAC 14 10 5 8 PC 5 25 3 5 concurrent access round robin 16 6 6 B 1 B 2 B 3 B 4 14
06 CHAPTER B 5 6 2 10 5 IBM 33903 5 IBM 0061 CHE90 IBM 3390 70 IBM 0061 6 2 MTTF MTTF=100100 15
Computer Architecture MTTF MTTF MTTF= MTTF (6-1) 23GByte 97ft 3 320MByte 0 1ft 3 23GByte 11ft 3 3KW 11W 1KW 15MB sec 1 5MB sec 120MB sec I O 600IOs sec 55IOs sec 3900IOs sec 200 000 2 000 150 000 MTTF 250000 50000 MTTF=30000 100 MTTF 30000 100=300 3 100 2 1000 30 fault tolerance 6 6 redundant disks 16
06 CHAPTER RAID RAID error detection and correction RAID RAID 6 7 TANDEM Nonstop fault tolerant computer system mirror disk pair 6 7 RAID 1 17
Computer Architecture 6 6 RAID 1 RAID 1 6 8 18
06 CHAPTER Hamming code RAID 2 G C 6 2 C 2-1 $ G+ C (6-2) 8 G=8 C=4 50 G=16 C=5 31 6 8 4 3 RAID 2 RAID 1 log 2 RAID 2 RAID 2 RAID 3 6 9 19
Computer Architecture 6 9 b 1 b 2 b 3 b 4 p p = b 5b 5b 5b (6-3) 1 2 3 4 RAID b 2 6 4exclusive OR b = p5b 5b 5b (6-4) 2 1 3 4 1001 p=0 6 4 b 2 =0 1 0 20
06 CHAPTER 1=0 RAID 3 RAID 3 6 6 6 10 B1 B2 B3 B4 P 1 4 RAID 2 RAID 3 21
Computer Architecture RAID 4 B2 B2 P 6 5 exclusive OR Pl = B15B2l 5B35B4 (6-5) B1 B3 B4 B1 B3 B4 8 7 CHE93 6 5 B2 B2 B2 6 6 B2 B2=0 Pl = B15B2l 5B35B45( B25B2) = ( B15B25B35B4) 5B25B2l (6-6) = P5B25B2l 22
06 CHAPTER exclusive OR RAID 5 RAID 5 RAID 4 6 11 RAID 4 B 1 B 2 B 3 B 4 P 1 4 B 5 B 6 B 7 B 8 P 5 8 P 21 24 round robin 6 11B 1 B 7 B 1 B 7 23
Computer Architecture G G 1 2 LEE93 RAID RAID 1 RAID 5 RAID 1 RAID 5 RAID 1 RAID 5 large write small write RAID 1 RAID 5 RAID 5 24
06 CHAPTER DRAM CPU CPU OS booting SSD EEPROM 25
Computer Architecture RAID SSD SSD SSD EPROM EEPROM memory cell EEPROM NMOS 6 12 a drainsource gate NMOS 6 12 b control gate float gate SiO 2 26
06 CHAPTER electron empty V g GND V d N- p-well a b NMOS V d GND V g Nelectron 12V V g electric field N tunneling effect tunnel injection p p well V P 27
Computer Architecture N tunnel release 1 0 1 GND N GND V g V d p-well a V g GND V d p-well b 28
06 CHAPTER 2V V g 6 13 a p hole N ON 1 6 13 b 0 N OFF 0 NOR NAND NOR 6 14 a V cc bit line BL word line WL 0 5V OFF5V 1 ON 0V 1 0V NOR NOR sense amplifier 1 29
Computer Architecture NOR BL BL WL0 WL0 WL1 WL1 WL2 WL2 WL n-2 WL n-2 WL n-1 GND WL n-1 GND a NOR b NAND NAND 6 14 b GND NAND 1 ONthreshold voltage V th 3V 30
06 CHAPTER 0V th = 1V V g 1V ON WL 5V V g =5V ON 0V V g 0V 1Vth= 3V V g >V th ON 0V 1 0V th = 1V V g <V th OFF 5V0 5V 1 NAND NAND NOR NAND6 14 b NOR NOR PC BIOS PDA OS 31
Computer Architecture SSD NAND NAND 512 2K 4K NAND 1Gbit 6 151Gbit y 1024 6464 1024 x 2048 z 82KByte 6 15 NAND 6 14 b 64 2048 page select decoder 2048 6 1536 z 8 2048 8 page register 32
06 CHAPTER NOR BL0 BL1 BL2046 BL2047 WL0 WL1 WL2 WL36 WL62 WL63 6 15 2048 8 64 1024 =1Gbit=128MByte ECC error correction code 64 ECC 2K 64 128K 4K 32 64 128 2KByte 4KByte 16KByte 64KByte 33
Computer Architecture NAND USB universal serial bus SSD SLC Single Level Chip MLC Multi Level Chip 00 01 10 11 6 16 6 12 b SLC MLC SLC 0 1 MLC 0 a SLC 1 00 01 b MLC 10 11 34
06 CHAPTER TLC Triple Level Chip 8 000 111 8 SLC 0 1 MLC TLC 2 3 6 3 1 2 3 25 50 75 200 300 600 900 900 1 300 1 5ms 3ms 4 5ms 100 000 3 000 10 000 1 000 NAND HDD HDD 35
Computer Architecture 6 17 Intel SSD DC S3700 PCB Printed Circuit BoardSTO12 8 RAID SSD DRAM SATA PCIe HDD OS HDD SSD SSD 36
06 CHAPTER middlewareftl HDD SSD HDD 6 18 FTL mapping SSD SSD Program Erase cycle MLC TLC 37
Computer Architecture FTL SSD SSD garbage SSD SSD Intel DC S3500 SSD 120GByte 128GByte 8GByte 840250GByte MZ 7TD250B 6GByte 38
06 CHAPTER compact disk CD1983 CD 60 non erasable disk CD ROM CD R RW DVD HD BD CD CD ROM error correction device polycarbonate pit high intensity die CD ROM lacquer CD ROM 39
Computer Architecture 0 1 optical sensor 6 19 CD ROM CLV CAV 6 19 CD ROM 1 6 micron 1 6 10 6 CD ROM 32 55mm 32 550 40
06 CHAPTER 20 344 5 27km CD ROM 1 2m sec 4392 73 2 CD ROM 0 15 Mbytes sec CD ROM 774 57Mbyte 530 3 5 rpm CD ROM CD ROM 0 15 Mbytes sec 1 1X rating 41
Computer Architecture 2 2X 0 3 Mbytes sec 12 1 8 Mbytes sec 20 CLV CAV 48 1 8 Mbytes sec 7 2 Mbytes sec 4 5 Mbytes sec CD ROM 6 20 0 1 10 0 4 ID mode MIN SEC SECTOR 0 12048 ECC 2 ECC 2336 2048 288 2 42
06 CHAPTER 6 19 60 MIN 03 SEC 74 SECTOR 60 MIN 3 SEC 74 60 03 74 6 20 ID MIN SEC SECTOR CD ROM CD ROM CD ROM 0 5 CD ROM CD R 43
Computer Architecture 6 21 a CD R CD R organic photoconductive dye layer CD Rrecorder pit 1 0 6 21 b 0 1 6 22 CD R PCA Power Calibration Area recording 44
06 CHAPTER Power Calibration Error PMA Programmable Memory Area TOC table of contents Lead In 6 22 Program Area Lead Out CD 1000 CD RW CD R phase change silver indium antimony 45
Computer Architecture tellurium crystal phase amorphous phase CD RW 0 1 CD RW 0 1 CD RW CD ROM 0 1 1 0 DVD DVD 46
06 CHAPTER DVD VCR CD ROM DVD DVD CD 120mm 4 75 CD DVD1 2mm CD 0 6mmCD DVDCD 6 23 DVD DVD tray CPU IDE SCSI spindle motor tracking motor 47
Computer Architecture light sensor guide DVD CLV DVD DVD single layer double layer 6 24 single side single layer4 7GByte MPEG 2 3 4 135 CD ROM 48
06 CHAPTER 9 4GByte 8 5GByte 17GByte DVD CD ROM DVD CD ROM 0 83nm DVD 0 4nm CD ROM 1 6nm DVD 0 74nm DVD CD ROM CD ROM High Definition HD DVD 4 7GByteBD HD 25GByte BD 405nm wavelength blue violet laser BD 720nm CD ROM 650nm DVD blue e Blu ray nm 49
Computer Architecture BD BD CD DVD 120mm 1 2mm BD cover layer 6 25a BD b DVD c CD substrate record layer BD DVD 405nm 0 1mm NA numerical aperture q 50
06 CHAPTER 0 85 0 15nm 0 32nm 6 25 b c DVD CD 0 6mm 1 2mm NA 6 26 a BD 0 1 0 0 0 6 26 b a DVD BD a BD b DVD BD DVD 6 4 CD ROM DVD BD 51
Computer Architecture 120mm 120mm 120mm 1 2mm 1 2mm 1 2mm 2 0 6mm 2 2 0 6mm 2 720nm Infared 650nm Red 405nm blue 0 8mm 0 4mm 0 15mm 1 6mm 0 74mm 0 32mm 0 41Gbits inch 2 2 77Gbits inch 2 14 73Gbits inch 2 layer 680MByte 4 7GByte 8 5GByte 25GByte 50GByte KBytes sec 153 6 176 4 1 103 4 608 52
06 CHAPTER RAID 36ms 16 6ms 8 33ms 4 17ms 200 250 400 1600 53
Computer Architecture RAID 1 RAID 2 RAID 3 RAID 5 N AND EEPROM NOR NAND AND EEPROM NOR NAND EEPROM SSD 54
06 CHAPTER 2 4 8 16 200 2400 2400 CD ROM BD R BD RE BD RW BD ROM 55
Computer Architecture 1MByte 2 5400rpmms = 2400 = 32 = 512 = 0 012ms = 7200rpm = 4 MBytes sec 1 MByte 2 1250450 ms 3 ms 4 6 56
06 CHAPTER 57
Computer Architecture 58