Primary storage, also known as main memory or RAM, is the area where data is stored temporarily for quick access by the CPU. Secondary storage refers to external storage devices like hard disks that retain data even when powered off. Secondary storage is needed because it has large capacity for storing operating systems and files, and is non-volatile unlike primary storage. Hard disks are an example of secondary storage - they are non-volatile, have large capacity, and use magnetic disks and heads to store and retrieve digital data.

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4. Primary Storage, also known as
main storage or memory, is the main
area in a computer in which data
is stored for quick access by the
computer's processor. ... Primary
storage is fast and expensive as
compared to secondary storage.

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Secondary storage refers
to storage devices and media that
are not constantly accessible by a
computer system. Examples
include external hard drives,
portable flash drives, CDs, and
DVDs. ... Because secondary
storage technology is not always
connected to the computer.

6. ▪ Secondary
storage needed because it is
non-volatile, meaning it retains
its contents without the need for
a power supply. It also has the
large storage capacity needed to
store the operating system and
all the programs and
files needed by a modern
computer system.
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Characteri
stics of
Secondary
Storage
non-
volatile.
cheap
in cost.
Example:
Hard disk,
Floppy
disk etc.
large
capacity.
slower
than
primary
memory
cannot
directly
access by
the
computer
processor.

7. A hard disk drive (HDD), hard disk, hard drive, or
fixed disk is an electro-mechanical data storage
device that uses magnetic storage to store and
retrieve digital data using one or more rigid rapidly
rotating platters coated with magnetic material. Hard
Disk, also called Hard Disk Drive (HDD), is a non-
volatile memory hardware device. ... Hard Disk uses
magnetic storage to store and retrieve digital
information. That is why it is also called Electro-
mechanical data storage device. The hard
disk consists of one or more circular rotating disks to
store the data.
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8. On hard disks, the data are stored on the disk in
thin, concentric bands called tracks.
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A hard disk drive platter is the circular disk on
which magnetic data is stored in a hard disk drive
In computer disk storage, a sector is a subdivision
of a track on a magnetic disk or optical disc.

9. A cylinder is any set of all of tracks of equal diameter in a hard disk drive (HDD). It
can be visualized as a single, imaginary, circle that cuts through all of the platters
(and both sides of each platter) in the drive
Disk read/write heads are the small parts of a
disk drive which move above the disk platter and
transform the platter's magnetic field into
electrical current or, vice versa, transform
electrical current into magnetic field.
A head crash is a hard-disk failure that occurs
when a read–write head of a hard disk drive
comes in contact with its rotating platter,
resulting in permanent and usually irreparable
damage to the magnetic media on the platter
surface

10. An internal hard drive is the primary storage
device located inside a computer system. It
usually contains pre-installed software
applications, the operating system and other
files. Most desktop computers have several
internal hard drives, allowing them to provide
greater data storage. On the other hand, laptop
computers can only accommodate one internal
hard drive, forcing the user to add an external
storage device to store data that exceeds the
laptop’s internal capacity..

11. An external hard disk is just a hard disk
drive (HDD) or solid-state drive (SSD)
that needs to be connected to the
computer rather than being inside the
computer. ... External hard drives have
different storage capacities, but they
can be connected to the computer via
USB, FireWire, or wirelessly.

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A disk cache is a software utility
that works by reserving a section
of memory where it keeps a copy
of information that previously read
from your disks. The next time your
computer needs that same
information, the data can be
accessed directly from the cache,
bypassing the slower disk.

13. RAID is an acronym that stands
for Redundant Array of Inexpensive Disks
or Redundant Array of Independent
Disks. RAID is a term used in computing.
With RAID, several hard disks are made into
one logical disk. he most
common types are RAID 0 (striping), RAID 1
(mirroring) and its variants, RAID 5
(distributed parity), and RAID 6 (dual
parity).

14. File compression is a
data compression method in
which the logical size of
a file is reduced to save disk
space for easier and faster
transmission over a network
or the Internet.
Uncompressing (or decompressing)
is the act of expanding a
compression file back into its original
form.

15. CONCEPT CHECK

16. A solid-state drive (SSD) is a solid-state storage device that uses
integrated circuit assemblies to store data persistently, typically
using flash memory, and functioning as secondary storage in the
hierarchy of computer storage
These are compact so that they can be transported on a key ring.
A USB flash is a data storage device that includes flash memory
with an integrated USB interface. It is typically removable,
rewritable and much smaller than an optical devices.
Small Solid State Cards . Widely used in portable devices Ex –
Laptops, Smartphones ,etc. It also used to store images captured
from digital cameras and transfer to desktop.

17. CONCEPT CHECK

18. An optical disc is any computer disc that uses optical storage techniques
and technology to read and write data. It is a computer storage disc that
stores data digitally and uses laser beams (transmitted from a laser head
mounted on an optical disk drive) to read and write data.
CDs are circular discs that are 4.75 in (12 cm) in
diameter. The CD standard was proposed by Sony
and Philips in 1980 and the technology was
introduced to the U.S. market in 1983. CDs can hold
up to 700 MB of data or 80 minutes of audio.

19. BDs provide the highest capacity of data storage of any
consumer level optical disc available today. Blu-ray
discs can store up to 25GB of data on a single
layer disc or up to 50 GB on a dual layer disc.
DVD is a digital optical disc storage format invented
and developed in 1995 and released in late 1996. The
medium can store any kind of digital data and is
widely used for software and other computer files as
well as video programs watched using DVD players.

20. An optical disc that can be re-recorded many times. CD and
DVD media are typically used by consumers and small business,
while magneto-optic, UDO and WORM media are used in the
enterprise.
In computer storage media, WORM (write once, read many) is a
data storage technology that allows information to
be written to a disc a single time and prevents the drive from
erasing the data.
ROM read-only optical media Optical storage media that cannot
be written by the user but that carry data imprinted during
manufacture, usually by pressing from a master disk.

21. CONCEPT CHECK

22. Cloud storage is a cloud computing model in which data is stored on remote
servers accessed from the internet, or "cloud." It is maintained, operated and
managed by a cloud storage service provider on a storage servers that are built on
virtualization techniques
Maintenance
Hardware
Upgrades
File sharing and
Collaboration
Access Speed
File Security
Advantages
Disadvantages

23. Cloud Computing is the use of hardware and software to deliver a
service over a network (typically the Internet). With cloud computing,
users can access files and use applications from any device that can
access the Internet. An example of a Cloud Computing provider is
Google's Gmail..

24. CONCEPT CHECK

25. Mass storage devices are
those devices on your system
available for storing large amounts of
data. Your system can support any
combination of physical mass
storage devices including hard disks,
tape drives, CD-ROM, and
WORM devices.
Enterprise Storage System is a
centralized repository for business
information that provides common
data management and protection, as
well as data sharing functions,
through connections to numerous
computer systems.

26. RAID is a data storage virtualization technology that combines multiple physical
disk drive components into one or more logical units for the purposes of data
redundancy, performance improvement, or both.
Network-attached storage is a file-level computer data storage server connected to
a computer network providing data access to a heterogeneous group of clients.
NAS is specialized for serving files either by its hardware, software, or configuration.
a device which controls access to separately stored files, as part of a multi-user
system.
Cloud storage is a model of computer data storage in which the digital data is
stored in logical pools. The physical storage spans multiple servers, and the physical
environment is typically owned and managed by a hosting company

27. A storage area network (SAN) is a dedicated high-speed network or subnetwork
that interconnects and presents shared pools of storage devices to multiple
servers. A SAN moves storage resources off the common user network and
reorganizes them into an independent, high-performance network.

28. CONCEPT CHECK

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