Lecture 12

CSC 101Introduction to Computing

Lecture 15

Dr. Iftikhar Azim Niazianiaz@comsats.edu.pk1##1Last Lecture Summary IHard Disk ControllersSATAEIDESCSI and SASExternal and Removable Hard disksRAID and Online StorageZip DiskTape Drive2#2Last Lecture Summary IIOptical DiscsHow a Laser Reads DataCD-ROM, CD-R, CD-RW, PhotoCD, Archive CDDVD ROM, DVR+/-R, DVD-RW, DVD-RAMDrive speed and Writing timeCare of Optical Discs3#Solid State Storage DevicesData is stored physically using switchesuses integrated circuit assemblies as memory to store data persistently.No magnets or laserVery fast data transfer

4#Solid State Storage DevicesByte for byte, standard magnetic or optical storage is less expensive and more reliable than solid-state storageMemory devices can move data in much less time than any mechanical storage devicesolid-state devices have no moving parts andstore data electronically (the way it is used by the CPU).Unlike standard devices, solid-state devices do not need to move ahead or sensor to find data or to convert it from magnetic or optical form into electronic form.5#Solid State DriveA storage device that typically uses flash memory to store data, instructions, and informationAvailable form factors of 3.5in, 2.5 in, and 1.8 inUsed in all types of computers including servers, desktop computers, and mobile computersportable media players and digital video camerasStorage capacities range from 16 GB to 256 GB and more

#Solid State DrivesSolid State Drives (SSDs) have several advantages over magnetic hard disks:

#SSD vs HDD

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#Flash Memory StorageType of nonvolatile memory that can be erased electronically and rewritten.Long term updateable storageContains no moving parts makes themmore durable and shock resistantthan magnetic hard disks or optical discs.Found in cameras and USB drivesCombination of RAM and ROM

10#Flash Memory StorageA memory card is a removable flash memory device that you insert and remove from a slot in a computer, mobile device, or card reader/writer

#Flash Memory Storage

#Flash Memory Storage

#Compact Flashused in portable electronic devicesType I (3.3 mm thick) and the thicker Type II (CF2) cards (5 mm thick)2 MB to 128 GBCompact Flash IDE (ATA) speed is usually specified in "x" ratings, e.g. 8x, 20x, 133x133x rating means transfer speed of: 133 * 150 KByte/s = 19,950 KByte/s ~ 20 MBps

#Smart Mediaa flash memory card standard owned by Toshibacapacities ranging from 2 MB to 128 MB. Data transfer rate: 2MB/s1,000,000 write cycles10 year storage time without powerNo longer manufactured.

#Multi Media Card (MMC)About the size of a postage stampused mostly for a portable deviceSizes up to and including 128 GBMMC, RS-MMC, MMCplus, MMCmobileData transferMMC20MbpsRS-MMC20MbpsMMC mobile20 MbpsMMC Plus416Mbpsmore or less superseded by SD (Secure Digital) card,

#MMC Micromicro-size version of MMCeven smaller and thinner than RS-MMCbackward compatible with MMC, and can be used in full-size MMC and SD slots with a mechanical adapterStorage capacity 16 MB - 2 GBData transfer speedRead Upto 10MBps 66XWrite upto 7 MBps 4X

#SD CardsCapacitySDSC (SD): 1 MB to 2 GB, SDHC: 4 GB to 32 GBSDXC: 32 GB to 2 TBDimensionStandard: 32242.1 mmMini: 21.5201.4 mmMicro: 15111.0 mmSpeed Class Rating2 10 MBps

#Memory StickFlash Memory CardCapacity 4 MB to 256 GB (Maximum theoretical size: 2TB)Different VariantsMemory Stick SelectMemory Stick PRO andDuoMemory Stick PRO-HG DuoMemory Stick Micro (M2)Data Transfer Speed upto 60 MBps

#xD Picture CardxD stands for Extreme Digitalused mainly in older digital camerasCapacity Maximum 512 MiB (original)maximum 2 GiB (Type M/M+, Type H)Dimensions 20 mm 25 mm 1.78 mmData Transfer RateReadup to 6 MBpsWriteup to 4 MBps

#USB Flash DrivePlug into a USB port on a computer or mobile deviceStorage capacities up to 100 GBData transfer rates of about 12 MBpsSome USB flash drives include fingerprint readers, restricting access to authenticated users

#Flash Drive AdvantagesUse little powerHave no fragile moving parts, andFor most capacities are small and lightData stored on flash drives is impervious tomechanical shock, magnetic fields, scratches and dustStore data densely compared to many removable media#PC CardsAdds capabilities to computerCredit-card sized device commonly used in notebook computersReplaced by Express card

#ExpressCard ModuleRemovable device that fits in an Express Card slotAbout 75 mm long and 34 mm wide or L-shaped with a width of 54 mmDeveloped by the PCMCIACommonly used in notebook computers

#Smart CardsStores data on microprocessor embedded in small cardInput, process, output and storage capabilitiesCommunicates with external services via card-reading devices, such as ticket readers, ATMs

#Smart CardsCredit cards with a chipChip stores dataEventually may be used for cashHotels use for electronic keys

26#Smart Card Technology

27#Storage Devices Comparison

28#Other Type of Storage#Magnetic StripA magnetic stripe card contains a magnetic stripe that stores informationA smart card stores data on a thin microprocessor embedded in the card

#Microfilm and MicroficheImages recorded using computer output microfilm recorderStore microscopic images of documents on roll or sheet of film

Microfilm 100- to215-foot roll of filmMicrofiche small sheet of film, usually 4 6#Microfilm Advantagesgreatly reduce the amount of paper firms must handlelongest life of any storage media andinexpensive

#Media Life Expectancies

#Enterprise Storage DevicesEnterprise storage stores huge volumes of data and information for large businessesUses special hardware for heavy use, maximum availability, and maximum efficiency

#Cloud StorageCloud storage is an Internet service that provides storage to computer users

#Cloud Storage

#Cloud StorageUsers subscribe to cloud storage for a variety of reasons:37#37Teaching tipBit size tends to confuse students. A simple example clarifies the importance of bit size. Consider two equal computers, one has a 32-bit processor, the other a 64 bit processor. With all other items equal, the 64-bit processor will handle twice the data the 32 bit processor handles. This is like driving a car at 55 Mph then doubling it to 110 Mph.Drive PerformanceAverage Access TimeData Transfer Rate

#Average Access TimeAlso known as seek timeTime to find desired dataMeasured in millisecondsDepends on two factorsRPMTime to access a trackHard drive between 6 and 12 msCD between 80 and 800 ms#39Teaching tipTo provide contrast, present the speed of memory as measured in the nanoseconds, or billionth of a second. Then discuss virtual RAM as defined earlier in the text. More RAM, less virtual RAM makes a faster machine. Data Transfer RateHow fast data can be readMeasured in Bps or bpsHard drive ranges from 15 to 160 MBpsCD ROMS depend on X factor24x CD transfers 24 x 150 KBpsFloppy disks transfer at 45 KBps

#40Insider informationMost hard disks do not list the time to access a track. This is a good topic to tread lightly with. Optimizing PerformancePCs performance can slow downDisk optimizationHandled by operating system toolRoutine disk maintenanceOptimization should be run monthly#Maintaining Hard DisksManufacturer give guarantee for 3-5 yearsregularly should perform preventive maintenance such as defragmenting or scanning the disk for errorsDisk Clean up removes unused files from a hard disk so that the computer does not have to spend time searching through and accessing unneeded files, and Disk Defragmenter reorganizes the data on a hard disk so that the data can be accessed more quickly#Disk Clean UpClean up unnecessary filesDelete temp filesUninstall unused programsDelete obsolete data filesFiles should be cleaned weekly#43Teaching tipFigure 6B.3 on page 249 shows the disk cleanup utility for Windows XP. Disk Cleanupby removing any programs and data that are not requiredfor the computer.

#Scan a disk for ErrorsBad spots on the mediaFind and fix the errorMove data to a good spotMark the spot as badDisks should be scanned monthly#Checking Disk ErrorsTo do a complete scan of the disk and correct any errors that are foundPlace a checkmark in the Scan for and attempt recovery of bad sectors check box, andthen click the Start button.

#DefragmentationDefragment a diskFiles fragment when resavedFragmented files load slowerDefragment puts the fragments togetherDisks should be defragged monthly#47Insider informationWindows 9x required the screen saver to be disabled before running scan or defrag. Failing to disable the screen saver could lead to catastrophic data loss! DefragmentationWhich combines all files so that no files are stored in a noncontiguous mannerThe defragmentation process can consume more than one hour in some cases. You can cancel the operation at any time by clicking the Stop operation button in the Disk Defragmenter window

#Defragment

#File CompressionShrinks the size of a fileTakes up less space on diskReduce a disks performanceWill increase disk capacityPKZip, WinZip and WinRAR#50Teaching tipMP3s are created using compression. If a audio song is recorded on a hard drive, the required storage is about 1 MB per second. When the MP3 compression is applied, the size is reduced to about 1 MB per minute.

Windows XP provides several compression routines. It provides for .zip file compression and archive creation. Zip archives can be accessed like normal folders. Folders can be compressed to shrink the contents. Finally, the entire disk can be compressed .File Compression

763 KBon diskCompressed157 KB#Putting it All Togetherw#Putting it All Togetherw#Summary ISolid State DevicesFlash Memory StorageCompact Flash (CF)Secure Digital (SD)MicroSDSecure Digital High Capacity (SDHC)MicroSDHCxD Picture CardMemory StickMemory Stick Micro (M2)PC Card Express CardSmart CardMagnetic Strip and Microfilm

54#54Summary IIEnterprise Storage DevicesCloud StorageDrive PerformanceAverage Access timeData Transfer RateOptimizing PerformanceDisk Clean UPCheck Disk for ErrorsDefragmentationFile Compression

55#55Recommended Websiteshttps://en.wikipedia.org/wiki/Solid_state_driveshttps://en.wikipedia.org/wiki/Memory_cardhttps://en.wikipedia.org/wiki/Comparison_of_memory_cardshttps://en.wikipedia.org/wiki/Cloud_storagehttps://en.wikipedia.org/wiki/Defragmentationhttps://en.wikipedia.org/wiki/Disk_cleanuphttps://en.wikipedia.org/wiki/CHKDSK

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