Primary and secondary Storage devices By Muhammad Usman

1. Presentation on
Storage DevicesPresentation By:
 M. Usman
 Talha Shahid
 Salman khan
 Amir Khan
 Taqi Usman
 Gohar Usman
 Muneeb Bilal
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2. Storage Devices:
 A storage device is any
computing hardware that is
used for storing data files
and information.
 It can hold and store the
information both temporarily
and permanently, and can
external or internal to a
computer.
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3. Types of Storage Devices:
1. Primary storage devices :
 Generally smaller in size
 Temporarily stores data
 Fastest access data speed
2. Secondary storage devices:
 Large storage capacity
 Store data permanently
 They can be both internal and external to the computer
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4.  Primary Storage Devices:
 Primary storage, also known as main
storage or memory, is the area in a computer
in which data is stored for quick access by
the computer's processor.
 Typically, Primary storage devices have an
instance of all the data and applications
currently in use or being processed.
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5. Types of Primary Storage Devices:
There are Two main types of
Primary Storage Devices.
 RAM (Random Access
Memory)
 ROM (Read Only Memory)
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6. 1. RAM (Random Access Memory)
 Computers store data temporary in
the RAM. It is also known as Main
Memory & Random Access Memory.
 These could be operating instructions,
loose data or content from programs
that are running. When the computer
is switched off, all the data is cleared
from the RAM. So it is known as
Volatile Memory.
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7. 2. ROM (Read only Memory)
 When a computer is first switched on,
it needs to load up the BIOS (Basic
Input/output System) and basic
instructions for the hardware. These
instructions are stored in ROM (Read
Only Memory).
 ROM contains the programming that
allows your computer to be “Booted
Up”.
 This type of memory is called Non-
Volatile because it retains the data.
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8.  Secondary Storage Devices:
 Secondary Storage, is a Non-
Volatile Memory (does not lose
stored data when the device is
powered down) that is not
directly accessible by the CPU,
because it is not accessed via
the input/output channels.
 It is use to store Permanent
Data.
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9. Types of Secondary Storage Devices:
There are Three main types of Secondary
Storage Devices.
 Magnetic Storage Devices
 Optical Storage Devices
 Solid-State Storage Devices
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10. 1. Magnetic Storage Devices:
Magnetic storage is the storage of
data on a magnetized medium.
There are Three main types of
Magnetic Storage Devices.
 Hard Disk
 Floppy Disk
 Magnetic Tape
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11. Hard Disk Drive:
• Hard disk drive is a
data storage device
that uses magnetic
storage to stored data
magnetically onto the
tracks on the disk.
• The Hard Drive reads
& writes the data to the
Hard Disk.
• The platters are used
to stored the data
and these data is
access by using a
magnetic head
• A platter is a hard
disk coated with a
magnetic material.
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12. Hard Disk Drive:
 Uses
 Stores all types of media
 Stores your data files
 Advantages
 Large storage capacity up to 10 TB.
 Stored items are not lost when the computer is switched off.
 Usually fixed inside the computer and not portable.
 Disadvantages
 Slower than RAM & ROM.
 If the hard disk crashes the computer will not work & you have lost
your work!!!
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13. External Hard Drive:
 An External hard drive is a portable
storage device that can be attached to a
computer through a USB cables.
 It is usually used to store media that a
user needs to be portable, for backups,
and when the internal hard drive of the
computer is full memory capacity.
 These devices have a high storage
capacity compared to flash drives.
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14. Floppy Disk:
Floppy disk is also called Diskette.
It consists of a thin plastic disk coated
with magnetic material.
 Uses
 To keep personal data
 Keep extra copies of data
 Advantages
 Can be carried with you
 Disadvantages
 Limited capacity (typically 1.44 Mb)
 Unlikely to store your ICT coursework on one
disk
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15. Magnetic Tape Storage Devices:
 Magnetic tape is an oldest storage
media to store large amount of data
permanently.
 Modern magnetic tape is most commonly
packaged in Cassettes.
 Advantage:
 It is small in size.
 It is cheap.
 It can store lots of data.
 Disadvantage:
 Accessing data is very slow.
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16. 2. Optical Storage Devices:
Optical Storage Devices are discs
coated with a reflective metal on
which data is record using laser
technology.
The data on the storage medium is
read by the laser beam off the
surface of the medium.
 Types of Optical devices:
 Compact Disc (CD)
 Digital Versatile Disc (DVD)
 Blu-Ray Disc (BD)
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17. Compact Disc( CD ):
Compact Disc is a digital optical disc data
storage forma
 The average CD allows for up to 700 MB of
data storage. Digital bits are stored as pits
on the reflective material in the disc. A red
wavelength laser detects these pits and
converts them to a digital signal.
 Three basic types.
 Read only: CD-ROM
 Write once: CD-R
 Rewriteable: CD-RW
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Compact Disc is a digital optical disc data
storage format.
 The average CD allows for up to 700 MB of
data storage. Digital bits are stored as pits
on the reflective material in the disc. A red
wavelength laser detects these pits and
converts them to a digital signal.
 Three basic types.
 Read only: CD-ROM
 Write once: CD-R
 Rewriteable: CD-RW

18. CD-ROM (Read Only Memory):
 CD-ROM is a optical compact disc which contains
data. Computers can read CD-ROMs, but cannot
write to CD-ROMs, which are not writable or
erasable.
 Advantages
 Data cannot be erased
 Portable
 Much larger capacity than floppy disks (about
700Mb)
 Disadvantages
 Can’t write data to a CD Rom
 Data access can be slower than a hard drive.
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19. Digital Versatile Disc (DVD):
 A Digital Versatile Disc (DVD) is an
optical disc storage medium similar to
a compact disc, but has a larger
storage capacity.
 The DVDs allows data storage for up
to 4.7 GB to 9.4 GB.
 DVDs used a Red wavelength laser
to read data, much like CDs.
 Storing high quality audio & video.
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20. Types of DVD:
There are Three main types of DVD.
 DVD-ROM:
Read Only Memory DVDs can be only read data but not written or erased.
 DVD-R:
Blank Recordable DVD discs can be recorded once using a DVD recorder
and then function as a DVD-ROM.
 DVD-RW:
Rewritable DVDs (DVD-RW, DVD+RW) can be recorded and erased many
times.
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21. Blu-Ray Disc ( BD ):
 Blu-Ray is the new and more
expansive DVD format.
 It provides higher capacity and better
quality than DVD, especially for High-
Definition video.
 A Blu-Ray disc can hold up to 25 GB
to 50 GB of data
 Blu-Ray used a Blue wavelength laser
to read data.
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22. 3. Solid-State Storage Devices:
 Solid-State Storage is a type of non-
volatile computer storage that store data
Electronically instead of magnetically or
optical.
 Solid-State Devices have no moving
mechanical parts.
 SSD operates much faster than other
storage devices, because SSD have no
need to move a head or sensor to find
data or convert it from magnetic or
optical form into electronic form.
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23. Difference b/w HDD & SSD:
 SSD stores data Electronically on
Microchips and contains No moving
parts. Meanwhile,
 A HDD records data Magnetically on
a Storage Platter by moving a
mechanical Arm with a read/write
Head over a spinning platter.
 SSD is faster than HDD.
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24. Flash Memory:
 Flash Memory is a special types of
memory chip that combines the best
features of RAM & ROM.
 It is used for storage and for transferring
data between a digital devices.
 Flash Memory is a non-volatile.
 It is commonly used in Digital Cameras,
Multimedia Players, USB & Cell Phones.
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25. USB Storage Device:
 A USB flash drive -- also known as a
USB stick, or pen drive -- is a Plug-and-
Play portable storage device that uses
flash memory and used for store &
transferring data.
 It is lightweight enough to attach to a
keychain.
 USB Drives now come in capacities
ranging between up to 8 GB to 2 TB.
 Easy to transfer data from one place to
another.
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