EET 450 – Advanced DigitalInterface InfoInterface SpeedOther Interface TechnologiesOther InterfacesSlide 6Slide 7Slide 8Electro-mechanicalCharacteristicsPowerPoint PresentationSlide 12HeadsHead actuatorOther characteristicsGeometryPhysical FormatSlide 18File SystemCapacity LimitsPerformanceSpecial DrivesAlternate TechInstallationSlide 25EET 450 – Advanced DigitalChapter 10 Hard Disk DrivesInterface InfoUltra2 SCSIInterface SpeedOther Interface TechnologiesSCSIFast SCSIUltra SCSIWide Ultra SCSIUltra2 SCSIWide Ultra2 SCSIUltra3 SCSIOther InterfacesFibre Channel – Arbitrated Loop (FC-AL)100MB/secUp to 127 devices up to 10km apartAllows hot swappingCan be dual ported for up to 200 MB/secOther InterfacesSerial Storage Architecture128 devicesUp to 10km apartThroughput up to 160 MB/secData rates of 90 MB/s in non-RAID and 85MB/s in Raid modeOther InterfacesAdvanced Technology Attachment (ATA)AKA Ultra DMA or IDEOther InterfacesCompactFlash/CF+ Type IIUp to 4 Mb and aboveIBM has a new Microdrive Technology (1” disk) with capacity up to 340 Mb (7x CF)Electro-mechanicalCombination of electronics and a mechanical systemMechanical section provides ROTATION of media and STEPPING of head.Rotation is constant3600 rpm original (synchronous)Current 5400 or 7200 rpmCharacteristicsLatencyTime delay from R/W command until head is positionedIn millisecondsData Transfer RateTransfer of data from HD to computer interfaceIn megabytes per secondPlattersThe number of physical media disks inside the HDSubstrate – normally aluminum now•Rigid base for magnetic coatingArea DensityAmount of data packed into an area of diskMegabits per square inchMagnetic coatingOxide Media – iron oxideThin Film Contamination causes ‘bad spots’Read/Write headsFly above the surface of the magnetic media10-12 micro-inches originallyNow 5 micro-inchesHeadsContact headsInductive heads (gap)Magneto-resistive heads (read only)Write pre-compensationChanges strength of field due to greater density toward hubHead actuatorBand steppingOriginal – crude Servo-voice coilDual actuatorUses multiple head advantageOther characteristicsLanding ZoneCrash zonePark/lockHold head during movement of drive itselfThermal compensationGeometryTracksCylindersSectorsPhysical FormatSector IDSector interleaveLatency due to rotationCylinder skewingAddressingCyl/head/sector give absolute addressPhysical FormatCHS addressingLimited by design – 1024 cylinders, 255 heads, 63 sectorsSector TranslationLogical Block addressingDoesn’t follow CHS Sector remappingLock out bad sectorFile SystemFile Allocation TableFATClusters•See tables 10.1 and 10.2 capacity versus cluster size•Smallest chunk of drive usedCompressionNTFS – New Technology File System (NT)Capacity Limitstable 10.3Limit Bytes cause10 Mb10,485,760Hardware design16 Mb16,777,21612-bit FAT32 Mb33,554,432# of FAT entries128 Mb134,217,7282KB cluster size528 Mb528,482,304ATA vs BIOS2 Gb2,147,483,64816-bit FAT8 Gb8,589,934,59224-bit LBA addrPerformanceAccess timeTime to get to dataData Transfer RateDisk CachingSpecial DrivesAV DrivesCartridge drivesSyQuestBernoulliJazzAlternate TechMagneto-OpticalPhase Change DisksInstallationPhysicalMounting locationPowerSetup & OperationBIOSLow-Level