Secondary Storage Devices

Storage devices

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Store software programs and keep permanent records of work.

When working on computer, RAM holds current work and currently active software program

RAM only temporary and information discarded when you turn off computer’s power

Must save work permanently to storage device before quitting software program or turning off power

Storage device used depends on amount of storage required and speed of data retrievalHard disk drives used most often due to speed and storage capacities

Data transfer rate slower on CD but can store large amounts of data to be retrieved quickly

Tape drives slower at storing and retrieving but can store large amounts of data in compact and economical form

Examples of Storage Devices

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Hard discCD – Compact DiscDVD – Digital Versatile DiscBlu-Ray Disc (BD)Floppy DiscZip discPen driveMemory cardsTapes

Hard Disc

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A magnetic disk on which you can store computer data and programs.

Hard disks hold more data and are faster than any other storage device.

A hard disk, for example, can store anywhere from 10 to more than 1500 gigabytes.

Compact Disc

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A Compact Disc (CD) is an optical disc used to store digital data, originally developed for storing digital audio.

Storage capacity of a CD: 700 MB

DVDDVD

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DVD (also known as "Digital Versatile Disc" or "Digital Video Disc") is a popular optical disc storage media format. Its main uses are video and data storage. Most DVDs are of the same dimensions as compact discs (CDs) but store more than six times as much data. Storage capacity as from 4.7 GB

Floppy Disc

02/01/15

A soft magnetic disk. It is called floppy because it flops if you wave it (at least, the 5¼-inch variety does). Unlike most hard disks, floppy disks (often called floppies or diskettes) are portable, because you can remove them from a disk drive. Disk drives for floppy disks are called floppy drives. Floppy disks are slower to access than hard disks and have less storage capacity, but they are much less expensive. And most importantly, they are portable.

Storage Capacity of a FD : 1.44 MB

Blu-ray Disc

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Blu-ray Disc (also known as Blu-ray or BD) is an optical disc storage medium. Its main uses are high-definition video and data storage. The disc has the same physical dimensions as standard DVDs and CDs.

Storage Capacity of a BD disc:Single layer: 25 GBDual layer: 50 GB

Zip Discs

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Looks similar to floppy driveDisk used can hold between 100Mb and 250Mb of data

Relatively inexpensiveNewer zip systems not compatible with original 100Mb devices

Pen Drive

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A USB pen drive or flash drive consists of a NAND-type flash memory data storage device integrated with a USB (universal serial bus) interface. USB flash drives are typically removable and rewritable, much smaller than a floppy disk (1 to 4 inches or 2.5 to 10 cm), and weigh less than 2 ounces (56 g). Storage capacities typically range from 64 MB to 64 GB with steady improvements in size and price per gigabyte. Some allow 1 million write or erase cycles and have 10-year data retention, connected by USB.

Memory Card

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A memory card or flash memory card is a solid-state electronic flash memory data storage device used with digital cameras, handheld and Mobile computers, telephones, music players, video game consoles, and other electronics. They offer high re-record-ability, power-free storage, small form factor, and rugged environmental specifications.

Capacity from 1 MB to 32 GB or more

Magnetic Tapes

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Also known as tape streamerUses cartridge with magnetic tape for storing

informationUsed generally when backup of large amount of

data neededUse number of different formats and size of tapes

can range from 250Mb to over 80GbNewer tape drives use Digital Audio Tape (DAT)

formatSmaller and faster than traditional tape drivesCan take large size tapes and transfer data from

computer to tape at speeds that exceed 7.2Gb per hour

Storage devices

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Device Max Capacity Access type Access time

Hard Disc 1500 GB Direct Access Rapid

Blu-Ray 25 GB (SL) Direct Access Rapid

DVD 4.7 GB (SL) Direct Access Rapid

CD 700 MB Direct Access Rapid

Floppy 1.44 MB Direct Access Slow

Tape 1000 GB Serial access Slow

Pendrive 64 GB Direct Access Rapid

Memory Cards

32 GB Direct Access Rapid