Memory and physical storage

  • View

  • Download

Embed Size (px)


Memory and physical storage. Unit objective: Identify memory characteristics and install storage devices. Topic A. Topic A: Memory Topic B: Storage devices. Memory. RAM: random access memory Working area for data during processing Need sufficient RAM for Performance Software support - PowerPoint PPT Presentation

Text of Memory and physical storage

  • Memory and physical storageUnit objective:Identify memory characteristics and install storage devices

  • Topic ATopic A: MemoryTopic B: Storage devices

  • MemoryRAM: random access memoryWorking area for data during processingNeed sufficient RAM forPerformanceSoftware supportQuality of RAM is important

  • Measuring memoryCellsStore a single bit of data0 or 1Represents on/off or yes/no Measurement units BitNibble = 4 bitsByte = 8 bitsWord = based on CPU32-bit processor: 32-bit word64-bit processor: 64-bit word

  • Larger memory unitsByte (B) = 8 bitsKilobyte (KB) = 1024 bytes = 210 bytesMegabyte (MB) = 1024 KB = 220 bytesGigabyte (GB) = 1024 MB = 230 bytesTerabyte (TB) = 1024 GB = 240 bytes

  • Memory typesClassify memory as:Volatile vs. non-volatileStatic vs. dynamicAsynchronous vs. synchronous

  • Volatile vs. non-volatile memoryVolatile: Loses contents without powerNon-volatile: Keeps contents without power

    RAMVolatileRandom access memoryCMOSVolatileComplementary metal oxide semiconductorROMNon-volatileRead-only memoryPROMNon-volatileProgrammable read-only memoryEPROMNon-volatileErasable programmable read-only memoryEEPROMNon-volatileElectronically erasable programmable read-only memoryFlashNon-volatile

  • Dynamic vs. static memoryDynamic (DRAM)Must be continually refreshedInexpensivePhysically small chipsStatic (SRAM)Refreshing not requiredMore expensiveLargerFasterTypical usesMain system memory: DRAMCache memory and CMOS: SRAM

  • Asynchronous vs. synchronousAsynchronousNot synchronized to system clockConsistent time to access and read dataSynchronousSynchronized to system clockAccesses data and returns in one or more clock cyclesSDRAM faster than ADRAM

  • Memory access typescontinued

    DRAMDynamic RAMOlder technologyFPMFast Page ModeImproved over DRAMVRAMVideo RAMDual port, optimized for videoEDOExtended Data OutImproved over FPMBEDOBurst Extended Data OutAdds pipelining to EDOSDR SDRAMSynchronous DRAMInterleaving permits overlapped requestsDRDRAMDirect Rambus DRAM16-bit memory bus and two transfers per clock cycle

  • Memory access types, continued

    DDR SDRAMDouble Data RateDouble transfer rate of SDR SDRAM with two transfers per clock cycleDDR2 SDRAMDouble Data Rate 2Double transfer rate of DDR SDRAM with four transfers per clock cycleDDR3 SDRAMDouble Data Rate 3Double transfer rate of DDR2 SDRAM with eight transfers per clock cycle

  • Access timeLatencyMemory speedNanoseconds vs. megahertzOverall speedDoesnt include latencyBandwidth

  • PackagingEarly PCs used individual DRAM chipscontinued

  • Packaging, continuedPackageSmall circuit boardMore commonly called a moduleInstalled in slotModule containsMemory chipsConnecting wiresSupport chipsPins or edge contacts

  • Single- and double-sided modulesEarly DRAM had chips on just one sideDouble memory by placing chips on both sidesDouble-sided modules have two rows of pins at bottomPins on front arent connected to pins on backNumber of chips no longer has a 1:1 chip-to-bit limit

  • Package typesSIMM 30-pin ADRAMSIMM 72-pin ADRAMDIMM 100-pin printer SDRAM DIMM 168-pin SDR SDRAMDIMM 184-pin DDR SDRAMDIMM 240-pin DDR2DDR3continued

  • Package types, continuedRIMM184-pin 16-bit232-pin 32--bitMicroDIMM 144-pinSODIMM 144-pin SDR SDRAMSODIMM 200-pinDDRDDR2SODIMM 204-pin DDR3 SDRAM

  • 30 pin SIMM

  • 72 pin simm

  • 168 pin dimm

  • 184 pin ddr

  • 240 pin ddr2

  • Ddr and ddr2 difference

  • 240 pin Ddr3

  • RIMM

  • sodimm

  • Modules and chipsPC100 and PC133 use SDRAMPC1600, PC2100, PC2700, and PC3200 use DDR SDRAMPC2-3200, PC2-4200, PC2-5300, PC2-6400, and PC28500 use DDR2 SDRAMPC3-6400, PC3-8500, PC3-10600, PC3-12800, PC3-14900, and PC-17000 use DDR3 SDRAM

  • Memory error recoveryParity Detects an errorEvenOddMarkSpaceECC Detects and corrects an errorDesktop memory No parity or ECCServer memory Often includes parity or ECC

  • Parity9 chips,supports parity8 chips,no parity

  • Topic BTopic A: MemoryTopic B: Storage devices

  • CDsRecordable CDsCD drivesCD drive speeds

  • DVDsDVD mediaDVD storage capacities

  • Blu-Ray discsBlu-Ray disc specificationsRecordable Blu-Ray

  • Optical drive installationConnectorsDrivers

  • Using optical drivesCD softwarePlaying DVD and Blu-Ray discs

  • Hard disk drivesComponentsSolid-state drives (SSDs)

  • Hard disk installationChassisCables and connectorsPower cable

  • Fault toleranceEnsure continued operationsRAIDRAID 0RAID 1RAID 5RAID 01RAID 10RAID considerationsLevel-specific considerations

  • RAID levelsRAID level 0Striping with no other redundancy featuresRAID level 1 (Mirroring)Simple disk mirroring


  • RAIDRedundant Array of Independent DisksPreviously Inexpensive disksRAID 1, 3 and 5 are most commonSee

  • RAID levels, continuedRAID level 1 different typeDisk duplexing (simple disk mirroring again but each disk on a separate controller)


  • RAID levels, continuedRAID level 2 (Stripping)Data is striped across all disks in the array disk wear is limited and stripping allows for reconstruction if a drive fails

  • RAID levels, continuedRAID level 3 (Disk Stripping)Uses disk striping Stores error-correcting informationInformation written to only one disk in the arrayIf disk fails, array cannot rebuild its contentscontinued

  • RAID levels, continuedRAID level 4Stripes data and stores error-correcting information on all drivesCan perform checksum verification RAID level 5Combines the best features of RAIDStripingError correctionChecksum verification

  • Windows OS software RAID does not support RAID 2 through to 4

  • Choosing a RAID levelBoot and system files can be placed on disks configured for RAID level 1, but not for RAID level 5RAID level 1 uses two hard disks; RAID level 5 uses 332 disks RAID level 1 is more expensive to implement than RAID level 5RAID level 5 requires more memory than RAID level 1

  • Reading from disk is faster than write access in both RAID level 1 and RAID level 5RAID 5 has faster read access than RAID level 1

  • Striped volumeReduces the wear on multiple disk drives by equally spreading the loadIncreases disk performance compared to other methods of configuring dynamic disk volumes

  • Mirrored volumeCreates a copy of data on a backup diskOne of the most guaranteed forms of disk fault tolerance Time to write information is doubled If 3 or more volumes are mirrored or duplexed, RAID 1 is more expensive than other RAID levels Cant be striped Requires two dynamic disks Well suited when data is mission-critical

  • RAID 5Provides better fault tolerance than a striped volume Uses disk space more efficiently than a RAID 1 volume RAID 5 with parity can reconstruct lost data on any diskRequires minimum of three diskscontinued

  • RAID 5, continuedPerformance isnt as fast as striped volumeReading is as fastGood choice for mission-critical data Parity information based on formula 1/n n = number of physical disks in volume

  • Software and hardware RAIDSoftware RAID implements fault tolerance through the computers OSHardware RAID is implemented through the server hardware and is independent of the OSMany manufacturers implement hardware RAID on the adapter Chip on the adapterBattery backupHardware RAID more expensive

  • Hardware RAID advantagesFaster read and write responseAbility to place boot and system files on disks with different RAID levelsAbility to hot-swap a failed disk More setup options to retrieve damaged data and to combine different RAID levels within one array

  • Media cardsSDxDSmartMediaCompactFlashMemory stick

  • Floppy disk storageForm factorsCapacitiesIdentifying capacitiesWrite protection

  • Floppy drive installationCableConnectorsMotherboard connector

  • Tape drivesHard drive backupsOffsite storageBurst modeSequential accessCompression

  • Unit summaryIdentified memory characteristics and installed storage devices