Secondary storage devices are used to permanently store files and data when the computer is turned off. Common secondary storage devices include hard disk drives, CDs, DVDs, Blu-Ray discs, floppy disks, zip discs, pen drives, memory cards, and magnetic tapes. Hard disk drives are most often used due to their high storage capacities and fast access times, while tape drives can store large amounts of data compactly but have slower access speeds.

1. Secondary Storage Devices

2. 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

3. Storage device used depends on amount
of storage required and speed of data
retrieval
Hard 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

4. Examples of Storage Devices
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Hard disc
CD – Compact Disc
DVD – Digital Versatile Disc
Blu-Ray Disc (BD)
Floppy Disc
Zip disc
Pen drive
Memory cards
Tapes

5. 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.

6. 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

7. 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

8. Floppy Disc
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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

9. 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 GB
Dual layer: 50 GB

10. Zip Discs
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Looks similar to floppy drive
Disk used can hold between
100Mb and 250Mb of data
Relatively inexpensive
Newer zip systems not compatible
with original 100Mb devices

11. 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 GBwith
steady improvements in size and price per gigabyte.
Some allow 1 million write or erase cyclesand have 10-
year data retention,connected by USB.

12. 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

13. Magnetic Tapes
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Also known as tape streamer
Uses cartridge with magnetic tape for storing
information
Used generally when backup of large amount of
data needed
Use number of different formats and size of tapes
can range from 250Mb to over 80Gb
Newer tape drives use Digital Audio Tape (DAT)
format
Smaller and faster than traditional tape drives
Can take large size tapes and transfer data from
computer to tape at speeds that exceed 7.2Gb
per hour

14. 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