3.3.1.1 Input Devices
Overview - What is Computer Hardware?
Abbreviated as HW, hardware is best described as any
physical component of a computer system that contains
a circuit board, ICs, or other electronics. A perfect
example of hardware is the screen on which you are
viewing this page. Whether it be a monitor, tablet, or
smartphone, it is hardware. Without any hardware, your
computer would not exist, and software could not be
used.
The term hardware refers to the tangible parts of a
computer system, that is, the physical equipment of the
computer. A keyboard, disk drive, and monitor are
examples of computer hardware. Understanding the
various physical components of a computer system will
help you understand how the system works as a whole.
As described, the general model of a computer consists
of an input system, process system, output system and
storage system.
Categories of Hardware devices
Computer hardware devices are classified into five
different categories such
as:
1. Input Devices
2. Processing Devices
3. Output Devices
4. Storage Devices
5. Communication (Input/Output) Devices
Input Devices
An input device is a piece of hardware that is used to
input commands, data, or instructions into a computer
for interaction and control. It allows input of raw data to
the computer for processing. These are peripherals used
to provide data and control signals to a computer. A
keyboard is the most common example, but it can also
include a mouse, trackball, microphone, camera, or
more.
Here's a list of some input devices used in
computers and other computing devices:
Keyboard is one of the primary input devices that allow
the entry of data and commands by simply pressing
down keys on the keyboard. It has function keys, control
keys, arrow keys, keypad and the keyboard itself with
letters, numbers and commands. Keyboards are
connected to the computer wired or wireless through
USB or Bluetooth. A laptop keyboard is more compact
than a desktop keyboard to make the laptop smaller and
lighter. Smartphones and tablets use on-screen
keyboard to input messages and select commands.
Keyboards can greatly benefit potential users as it is
simple and easy to use. It also provides a fast way to
enter data. But, keyboards can also be a slow way to
enter data if the user is not a trained typist, as well as,
mistakes can be easily made if not careful.
Concept Keyboard is an input device similar to a
traditional keyboard but each key/button is identified by
an image. The images are chosen to symbolize the
command/option each key represents. For example, in a
fast food restaurant, the concept keyboard belonging to
the cashier's till may use images to represent each type
of meal available to purchase, or each size of drink that
can be chosen. Traditional ‘overlay' concept keyboards
are now being replaced with virtual concept keyboards
using touchscreens. It is a flat board that contains a grid
of buttons. Each button can be programmed to do
whatever you want. An overlay sheet with pictures or
symbols is placed on the grid so that the user can tell
what pressing on different areas will do.
Concept keyboards can greatly reduce the training
required as they are easy to use. It is an ideal input
device when options/choices are few as it could easily
speed up data entry. On the other hand, these devices
are not suitable when large amount of options/choices
are included and it cannot accommodate all kinds of
tasks.
A Mouse is an input device that allows you to control the
coordinates and movement of the onscreen
cursor/pointer by simply moving the device across a flat
surface with your hand. Most mice are now optical which
means they use a laser to detect and track movement
across the surface. Mice can be wired or wireless. Items
can be selected or moved using the left mouse button,
whilst the right button usually displays additional menus.
A laptop uses a touchpad as the mouse. A smartphone
and tablet use a touchscreen as primary input device
and the user's finger is used as the mouse.
The mouse is a simple and easy to use device, and, an
efficient way to navigate the graphical user interface
(GUI). The only consideration in using a mouse is that it
requires a flat surface and some space to operate.
A trackball is an input device used to control a
pointer/cursor. Unlike a mouse, the device stays
stationary whilst the user moves the ball within its
socket. Trackballs can be stand-alone devices or
combined into a keyboard or control panel. Some people
prefer using a trackball over a mouse as they believe it
gives them a finer degree of control over the pointer.
They are also handy Backward for people with limited
hand motor skills as they are less demanding then a
mouse.
A trackball requires little desk space. It can provide fine
control over the pointer and can be integrated (combined
in usage) with a keyboard. In terms of usage it may take
some time in getting used with its functionality.
Digital cameras have become popular over film cameras
because of the following features:
 LCD screen - allows users to view the photos and
videos immediately
 Storage - can store thousands of pictures
 Picture development - allows users to choose and
pick which pictures to develop
 Size - takes up less space and can be easily carried
Images taken with digital cameras can be reviewed
immediately via the screen, copied or edited easily on a
computer and automatically added to sharing sites.
Digital camera still require a large capacity memory
cards if shooting lots of photos with high quality.
Microphones are input devices that take analog sound
waves and converts them into electrical signals which in
turn are converted into digital signals and suitable for a
computer to understand. Microphones play an important
role in speech recognition, a technology that is gaining in
popularity and usage.
Webcam is an input device connected to the computer
and the internet that captures still picture or motion
video. It is a digital video device commonly built into a
computer but can also be a separate peripheral device.
Its main function is to transmit pictures over the Internet.
It is popularly used with instant messaging services and
for recording images.
Microphones allows disabled users to give instructions
to a computer using their voice and enabling the use
speech recognition software. It also allows voice calls
and the audio in video calls (VoIP). Eventually, speech
recognition accuracy as a technology can sometimes be
a hit and a miss.
Digital Camera are input devices that capture images
(and sometimes video) digitally. Digital cameras use an
image sensor chip to capture the image, rather than the
film used by a traditional camera. The images recorded
on a digital camera are stored on memory cards,
although some may have a limited amount of external
memory of its own. Digital cameras feature an LCD
screen which allows you to preview and review images,
plus change menu settings.
2D scanners perform the task of turning a 2D document
or image into a digital file. The functionality of 2D
scanners is enhanced when combined with OMR and
OCR software. A scanner is connected through USB.
There are different types of scanners:
• Flatbed scanner - uses a flat surface to scan
documents
• Sheet fed scanner - like a laser printer where paper is
fed into the scanner
• Handheld scanner - the scanner is dragged over the
page to be scanned
• Others
2D scanners can produce high quality digital copies of a
document and can be sent electronically, stored
securely, or edited on the computer. But, scanned
documents use a lot of computer storage space.
A 3D scanner is an input device that creates a 3D
model of the object scanned. 3D scanning is the process
of analyzing a real-world object or environment to collect
data on its shape and possibly its appearance. The
collected data can then be used to construct digital 3D
models.
Collected 3D data is useful for a wide variety of
applications. These devices are used extensively by the
entertainment industry in the production of movies and
video games, including virtual reality. Other common
applications of this technology include augmented
reality, motion capture, gesture recognition, robotic
mapping, industrial design, orthotics and prosthetics,
reverse engineering and prototyping.
Scanning can be achieved either by using lasers, light,
radio waves or X-rays. Typical applications for 3D
scanners include security screenings to check for
weapons or restricted objects, creating a computer
model ready for 3D printing, biometric devices and
turning real people into gaming characters.
Touchscreen is an input device that allows users to
interact with a computer using their fingers. It is used
widely in laptop monitors, smartphones, tablets, cash
registers and information kiosks.
Most common functions of touchscreens are as
follows:
Тар, Double-tap,Touch and hold, Drag, Swipe, Pinch
Stylus is a pen-shaped input device used to write or
draw on the screen of a graphic tablet or device. Initially
it was just used for graphic tablets and PDAs, but now, it
has become popular on mobile devices as a
replacement for the user's fingers. It's used for more
accurate navigation and to keep oils from user's fingers
off the device screen.
Biometric device is an input device used to input
biometric data into a computer. Here are the types of
biometric devices:
 Face scanner
 Hand scanner
 Finger scanner
 Voice scanner
 Other
Barcode Reader also known as barcode scanner or
point of sale (POS) scanner, is an input device capable
of reading barcodes. A barcode, on the other hand, is a
visual representation of machine-readable information
about the product they are attached to, which is a small
box printed on the packaging of a product and has a
small collection of black parallel lines of varying widths.
Principles of bar code reading
1. A bar code consists of white and black bars. Data
retrieval is achieved when bar code scanners shine a
light at a bar code, capture the reflected light and
replace the black and white bars with binary digital
signals.
2. Reflections are strong in white areas and weak in
black areas. A sensor receives reflections to obtain
analog waveforms.
3. The analog signal is converted into a digital signal via
an A/D converter. (Binarization)
4. Data retrieval is achieved when a code system is
determined from the digital signal obtained. (Decoding
process)
Tvpes of bar code scanners
CCD method uses a semiconductor device called CCD
(Charge Coupled Device), which converts light signals
into electric signals. The CCD method bar code scanner
has a built-in light. A scanner shines this light at a bar
code and its reflection is captured via CCD for reading.
A bar code is captured once, allowing fast reading.
There are no movable parts and impact resistance is
excellent.
Laser method is where laser light is shone on the label
surface and its reflection is captured by a sensor (laser
photo detector) to read a bar code. A laser beam is
reflected off a mirror and swept left and right to read a
bar code Using laser allows reading of distant and wide
bar code labels.
Pen method uses a LED light source and a sensor to
capture its reflection. Since a person moves a scanner
to read a bar code, practice is required for operation.
The mechanism is simple, making this method
inexpensive.
QR Code Reader are devices similar to barcode
readers only that they are built to read QR Codes. On
the other hand, a Quick Response Code, often
abbreviated as QR code, is similar to a barcode. In fact,
it is a kind of barcode. Like barcode, it also contains
machine-readable information about the object it is
attached to. Unlike a normal barcode, however, a QR
code is two-dimensional, which means, it contains
information in both the vertical and horizontal directions.
QR codes contain a lot of information. From large
companies to the grocery store next door, everyone can
create their own QR code and attach it to their products.
QR codes have grown in popularity over the QR Code
Readers last decade due to the rise of smartphones.
There are certain QR code scanner apps that can be
downloaded for free on smartphones.
3.3.1.2 Processing Devices
What are Processing Devices?
Computer processing devices play an important role
in processing operations. They are all used to process
the data, using
Unu instructions from the program. They manage the
functions and do various calculations, and even monitor
the hardware tools.
How do the processing devices function? Computers are
provided with data, they process coded data, and
generate the results. Data is entered via input devices,
like a keyboard or mouse, on a computer. These data
are processed into information and then issued on
components such as monitors or speaker sets.
Some of the devices used
processing in computer are:
for
information
Motherboard also known as the Circuit Board. The
CPU, memory, buses, and all other components are
located within the motherboard. It allocates power and
facilitates connectivity to and from the CPU, RAM, and
all other hardware components of the computer.
The Central Processing Unit (CPU) is the computer
system's principal and the most critical computing device
is the central processing unit. It is also called the
computer's brain because it carries out a computer
program's instructions, as well as all computer functions.
A computer can't perform any of the operations without a
CPU.
The Graphics Processing Unit (GPU) is a specialized
processor dedicated to graphics processing tasks, as
the name obviously suggests. Since it is a specialized
chip designed and optimized specifically for these types
of tasks, it is much more efficient at it than a CPU and it
handles most of the workload when it comes to in-game
graphics. An integrated GPUs or integrated graphics,
refers to a GPU that is integrated with a CPU, thus, the
processor has both CPU and GPU cores on the same
die. These integrated GPUs don't take up any space on
the motherboard and are more power-efficient, but they
also don't have their own memory and have to utilize on
the system RAM instead.
A Graphics Card, also known as the video card, isn't
comprised of just the GPU but it also includes a number
of other parts such as the video memory, the PCB, the
connectors, and the cooler. That said, the graphics card
is the piece of hardware dedicated to graphics
processing and video output as a whole. A graphics card
is also sometimes referred to as a discrete or
dedicated graphics card. This indicates that the
graphics card is a separate piece of hardware that most
commonly interfaces with the rest of the computer via a
PCle slot on the motherboard.
So, "GPU” refers specifically to the graphics
chips manufactured by Nvidia and AMD, while “graphics
card” refers to the final product that you're buying off the
shelf, usually made by partner companies such as Asus,
MSI, Gigabyte, EVGA, and others.
Clock is used to synchronize all computer calculations.
It ensures all the circuits within the computer operate
simultaneously. It is usually powered with a small
battery, as this is used to ensure that the clock is current
even if the power to the computer is removed.
The Chipset is the name of a group of integrated circuits
that work together to manage and operate the entire
computer system. The chipset manages the flow of data
throughout the system.
Address bus and Data bus are gold lines on the
motherboard which are actually a collection of wires
used by the CPU to communicate.
An Address Bus is a set of conducting wires that hold
addresses only. The address bus is unidirectional. The
data flows from microprocessor to memory, or from the
microprocessor to devices for input/output. The address
bus carries memory, I / O (or peripherals), and other
addressable devices around the processor addressing
signals from the processor. Control signals move but not
in from the processor.
A Data Bus transfer data in a computer between
components. The Data bus is two-way pathway. Data
flows from microprocessors to computers used for
memory and input/output. And then data flows into the
microprocessor from memory and input/output devices
as well.
Random Access Memory - the RAM is a temporary
unit that stores data in the computer system. It retains
the data for a brief period of time, and only temporarily
when the data is processed.
.
Expansion Slots is a motherboard based socket. It is
used to insert an expansion card, also called a circuit
board that provides additional features like a video,
sound, or memory, etc. to a computer. You must open
the system unit to plug a card into the slot. A card has a
socket at its end which sticks out of the device unit so
that a cable can be plugged into it. Popular card types
consist of graphics, sound, and network cards.
A Sound Card also referred to as an audio output
device, sound board, or audio card. A sound card is an
expansion card or IC for producing sound on a computer
that can be heard through speakers or headphones.
Although the computer doesn't need a sound card, it's
included on every machine as either in an expansion slot
or built into the motherboard.
Network Card is sometimes improperly referred to as a
broadband card or Internet card. The network card is
what allows your computer to connect to the Internet (a
network) using a PCI Network Interface Card cable. That
cable is connected to a router that allows your computer
to use a broadband connection. It is short for Network
Interface Card (NIC) is also referred to as an Ethernet
card and network adapter. A NIC is a computer
expansion card for connecting to a network (e.g., home
network or Internet) using an Ethernet cable with an RJ45 connector.
3.3.1.3 Output Devices
What are Output Devices?
Computer output devices receive information from the
computer, and carry data that has been processed by
the computer to the user. Output devices provide data in
different forms, some of which include audio, visual, and
hard copy media. The devices are usually used for
display, projection, or for physical Output Devices of
Computer reproduction. Monitors and printers are two of
the most commonly known output devices used with a
computer.
Computer output devices are all peripheral hardware,
and are connected to a computer by cables, or by
wireless networking.
Reasons for Having an Output Device
A computer can still function without an output device.
However, without an output device, there's no way to
determine what the computer is doing. There is no indicator
of errors, nor of the need for additional input. For example,
if you detach your monitor from your computer, the
computer will still function, but it's not going to be very
helpful.
Monitor is the most common computer output device. It
creates a visual display by the use of which users can view
processed data. Monitors come in various sizes and
resolutions. All monitors depend on a video card, which is
positioned either on the computer motherboard or in a
special expansion slot. The video card sorts out the
computer data into image details that the monitors can then
show.
Common Types of Monitors




Cathode Ray Tube - this uses phosphorescent dots to
generate the pixels that constitute displayed images.
Flat Panel Display - this makes use of liquid crystals
or plasma to produce output. Light is passed through
the liquid crystals in order to generate pixels.
Projector is a display device that projects a computercreated image onto another surface: usually some sort
of whiteboard or wall. The computer transmits the
image data to its video card, which then sends the
video image to the projector. It is most often used for
presentations, or for viewing videos.
Printer is a device that generates a hard copy version
of processed data, like documents and photographs.
The computer transmits the image data to the printer,
which then physically recreates the image, typically on
paper.
Types of Printers




Ink Jet - this kind of printer sprays tiny dots of ink onto
a surface to form an image.
Laser - this type utilizes toner drums that roll through
magnetized pigment, and then transfers the pigment
onto a surface.
Dot Matrix - dot matrix printers utilize a print head to
set images on a surface, using an ink ribbon.
Thermal Printer - use tiny heating elements to activate
or transfer pigments. They are used most commonly to
create barcodes, shipping labels, and other heavily
used items.
Plotter - this generates a hard copy of a digitally
depicted design. The design is sent to the plotter
through a graphics card, and the design is formed by
using a pen. It is generally used with engineering
applications, and essentially draws a given image using
a series of straight lines.
Speakers are attached to computers to facilitate the
output of sound; sound cards are required in the
computer for speakers to function. The different kinds of
speakers range from simple, two-speaker output devices
right the way up to surround-sound multi-channel units.
Headphones are a pair of small loudspeaker drivers
worn on or around the head over a user's ears.
Headphones let a single user listen to an audio source
privately, in contrast to a loudspeaker, which emits
sound into the open air for anyone nearby to hear.
Headphones are also known as earspeakers, earphones
or, colloquially, cans. Another type, known as earbuds or
earpieces consist of individual units that plug into the
user's ear canal.
A third type are bone conduction headphones, which
typically wrap around the back of the head and rest in
front of the ear canal, leaving the ear canal open.
3.3.1.4 Input / Output Devices (Communication
Devices)
What are Input/Output Devices?
Input devices provide input to a computer, while output
devices provide a way for a computer to output data for
communication with users or other computers.
Alternatively referred to as an I/O device, an I/O device
is a device with both functionalities. It is any hardware
used by a human operator or other systems to
communicate with a computer. As the name suggests,
these devices are capable of sending data (output) to a
computer and receiving data from a computer (input).
Because I/O device data is bi-directional, such devices
are
usually
categorized
under
storage
or
communications. Examples of I/O storage devices are
CD/DVD-ROM drives, USB flash drives and hard disk
drives. Examples of I/O communication devices are
network adapters and Bluetooth adapters/dongles.
In order to simplify the point of discussion for this
course, I/O devices considered are those devices
capable of doing input and output but its storage
capability will not be included in the discussion.
Therefore, I/O storage devices will be simply classified
as storage devices and will be discussed on the next
sub-module.
Touch Screen is a display device that allows the user to
interact with a computer using their finger or stylus. Its a
useful alternative to a mouse or keyboard for navigating
a GUI (graphical user interface). Touch screens are
used on a variety of devices, such as a computer and
laptop displays, smartphones, tablets, cash registers,
and information kiosks.
Touch screen technologies
Not all touch screens are the same. Different
technologies can be utilized to allow a user to interact
with a screen.
Capacitive touch screen is coated with a special material
that stores an electrical charge monitored by circuits at
each corner of the screen. When you touch a capacitive
touch screen, a small amount of the electrical charge is
drawn from the point of person contact to indicate where
you touched the screen. To use a capacitive screen, you
must use your bare finger or a specially designed
capacitive stylus.
Resistive touch screen is coated with a metallic
electrically conductive and resistive layer that detects
the pressure of your finger or another object. This
technology is often a more affordable solution compared
to capacitive, but can be damaged by sharp objects
touching the screen.
Surface acoustic wave (SAW) or surface wave touch
screen sends ultrasonic waves and detects when the
screen is touched by registering changes in the waves.
This technology is more advanced than the other two,
but does not work with hard materials, and can be
affected by outside elements.
Infrared- Infrared touch screens utilize a matrix of
infrared beams that are transmitted by LEDs with a
phototransistor receiving end. When a finger or other
object is near the display, the infrared beam is blocked.
That interruption gives the device input to where your
finger or another object is positioned.
Digital Camera is a hardware device that takes
photographs and stores the image as data on a memory
card. Unlike an analog camera, which exposes film
chemicals to light, a digital camera uses digital optical
components to register the intensity and color of light,
and converts it into pixel data. As an input device, many
digital cameras are capable of recording video in
addition to taking photos. As an output device, its rearmounted LCD screen allows users to see their photos
and videos immediately after they are taken.
The Headset is a combination of speakers and
microphone. It is mostly used by gamers, and is also a
great tool for communicating with family and friends over
the internet using some VOIP program or other.
3.3.1.5 Storage Device
What are Storage Devices?
A storage device is a piece of computer hardware used for
saving, carrying and pulling out data. It can keep and retain
information short-term or long-term. It can be a device
inside or outside a computer or server. Other terms for
storage device is storage medium or storage media.
A storage device is one of the basic elements of any
computer device. It almost saves all data and applications
in a computer except for hardware firmware. It comes in
different shapes and sizes depending on the needs and
functionalities.
Storage in computer systems
Every desktop computer, laptop, tablet, and smartphone
will have some kind of storage device within it. There are
also standalone, external storage drives that can you
can use across devices. Storage is not only necessary
for saving files, but also for running tasks and
applications. Any file you create or save on your
computer saves to your computer's storage device. This
storage device also stores any applications and your
computer operating system.
A storage device is also known as a storage medium or
storage media. Digital storage is measured in
megabytes (MB), gigabytes (GB), and, these days,
terabytes (TB).
Some computer storage devices are able to hold
information permanently while others can only hold
information temporarily. Every computer has both
primary and secondary storage, with primary storage
acting as a computer's short-term memory, and
secondary as a computer's long-term memory.
Primary Storage: Random Access Memory (RAM) is
the primary storage of a computer. When you're working
on a file on your computer, it will temporarily store data
in your RAM. RAM allows you to perform everyday tasks
like opening applications, loading webpages, editing a
document or playing games. It also allows you to jump
from one task to another without losing your progress. In
essence, the larger the RAM of your computer, the
smoother and quicker it is for you to multitask.
Types of RAM; SRAM, DRAM, SDRAM, RDRAM, DDR
SDRAM, EDO RAM
RAM is a volatile memory, meaning it cannot hold onto
information once the system turns off. For example, if
you copy a block of text, restart your computer, and then
attempt to paste that block of text into a document, you'll
find that your computer has forgotten the copied text.
This is because it only stored the data temporarily in the
RAM.
RAM makes it possible for a computer to access data in
a random order, and thus reads and writes much faster
than a computer's secondary storage.
Secondary Storage: Hard Disk Drives (HDD) & SolidState Drives (SSD)
In addition to RAM, every computer also has another
storage drive that's used for storing information on a
long-term basis. This is secondary storage. Any file you
create or download saves to the computer's secondary
storage. There are two types of storage device used as
secondary storage in computers: HDD and SSD. While
HDDs are the more traditional of the two, SSDs are fast
overtaking HDD as the preferred tech for secondary
storage. Secondary storage devices are often
removable, so you can replace or upgrade your
computer's storage, or move your storage drive to a
different computer. There are notable exceptions, like
MacBooks, which don't offer removable storage.
Hard Disk Drives (HDD) is the original hard drive. A
hard disk drive is comprised of a stack of spinning metal
disks known as platters. Each spinning disk has trillions
of tiny fragments that can be magnetized in order to
represent bits (1s and Os in binary code). An actuator
arm with a read/write head scans the spinning platters
and magnetizes fragments in order to write digital
information onto the HDD, or detects magnetic charges
to read information from it. HDDs are used for TV
recorders, servers, and laptop and PC storage.
Solid-State Drives (SSD) emerged far more recently, in
the '90s. SSDs don't rely on magnets and disks, instead
they use a type of flash memory called NAND. In an
SSD, semiconductors store information by changing the
electrical current of circuits contained within the drive.
This means that unlike HDDs, SSDs don't require
moving parts to operate. Because of this, SSDs not only
work faster and smoother than HDDs they also generally
last longer than HDDs. Outside of newer PCs and highend laptops, you can find SSDs in smartphones, tablets,
and sometimes video cameras.
One of the most recognizable type of flash memory device
is the USB flash drive. Also known as a thumb drive or a
memory stick, these small, portable storage devices have
long been a popular choice for extra computer storage.
Before it was quick and easy to share files online, USBflash drives were essential for easily moving files from one
device to another. However, they can only be used on
devices with a USB port. These days, a USB flash drive
can hold up to 2 TB of storage. They're more expensive per
gigabyte than an external hard drive, but they have
prevailed as a simple, convenient solution for storing and
transferring smaller files. Aside from USB drives, flash
memory devices also include SD and memory cards, which
you'll recognize as the storage medium used in digital
cameras.
Optical Storage Devices (CDs, DVDs, and Blu-Ray
discs) are used for a lot more than playing music and
videos—they also act as storage devices. Collectively
they're known as optical storage devices or optical
media.
Binary code is stored on these disks in the form of
minuscule bumps along a track that spirals outwards
from the center of the disk. When the disk is in operation
it spins at a constant speed, while a laser contained
within the disk drive scans the bumps on the disk. The
way the laser reflects or bounces off a bump determines
whether it represents a 0 or 1 in binary.
A DVD has a tighter spiral track than a CD, allowing it to
store more data despite being the same size, and a finer
red laser is used in DVD drives than CD drives. DVDs
also allow dual layering to increase their capacity further.
Blu-Ray took things to another level, storing data on
multiple layers with even smaller bumps that require an
even finer blue laser to read them.
External storage devices are digital storage devices that
are external from computers. These are commonly used to
expand storage capacity on a computer that runs low on
space, allow more portability, or provide easy file transfers
from one device to another.
External HDDs and SSDs are available as external drives.
These generally offer the largest storage capacity among
external options, with external HDDs offering up to 20 TB of
storage and external SSDs offering up to 8 TB of storage.
External HDDs and SSDs work in the exact same way that
their internal counterparts do. Most external drives can
connect to any computer; they're not tied to one device, so
they're a decent solution for transferring files across
devices.
Flash memory devices contains trillions of interconnected
flash memory cells that store data. These cells hold millions
of transistors that when switched on or off represent 1s and
Os in binary code, allowing a computer to read and write
information.
CD-ROM, DVD-ROM, and BD-ROM refer to read-only
optical storage disks. The data written on them is
permanent and cannot be removed or overwritten. This
is why they can't be used as a personal storage. Instead,
they are typically used for software installation
programs.
CD-R, DVD-R, and BD-R format disks are recordable,
but cannot be overwritten. Whatever data you save on a
blank recordable disk will then be permanently stored on
that disk. So, they can store data, but they're not quite
as flexible as other storage devices.
CD-RW, DVD-RW, and BD-RE are re-writable. This
allows you can to write new data on them and erase
unwanted data from them as much as you want. They've
been overtaken by newer technology like flash memory,
but CDRWs were once the top choice for external
storage. Most desktop computers and many laptops
have a CD or DVD drive.
CD can store up to 700 MB of data, DVD-DL can
store up to 8.5 GB, and Blu-Ray can store between
25 and 128 GB of data.
Floppy Disks aka diskette, may be obsolete at this
point, but are very important storage devices that is
worth mentioning. Floppy disks were the first widelyavailable portable, removable storage devices. This is
why most "Save" icons look the way they do, they're
modeled after the floppy disk. They work in the same
way as hard disk drives, although at a much smaller
scale.
The storage capacity of floppy disks never exceeded
200 MB before CD-RW and flash drives became the
favored storage media. The iMac was the first personal
computer released without a floppy disk drive in 1998.
From here, the over 30-year reign of the floppy disk very
quickly declined.

8-inch Magnetic Disk Cartridge (1971): When
introduced by IBM, the first 8" floppies held a mere
80 KB of data and weren't designed to be written by
the user. But they set the template copied by later
floppy disk formats.

8-inch IBM Diskette (1973): The first read-write
floppy diskette system from IBM launched with the
IBM 3740 Data Entry System. Initial disks could hold
about 250 KB. Later 8" diskette formats could hold
up to 1.2 megabytes per disk.

5.25-inch (1976): Invented by Shugart Associates,
the initial 5.25" floppies could only hold about 88
KB. By 1982, a high-density 5.25" floppy could hold
1.2 MB.

3-inch (1982): As a joint project between Maxell,
Hitachi, and Matsushita, the 3-inch "Compact
Floppy" shipped in a hard shell and initially held
about 125 KB (single-sided format), but later
expanded to 720 KB. It mostly found use in word
processors and Amstrad computers, but never
became widespread in the U.S.


5.25" Apple FileWare (1983): This special 5.25"
floppy format with two read-head windows used only
in the Apple Lisa computer could hold about 871 KB
of data. Apple soon discontinued its use in favor of
3.5" Sony drives in future models.
3.5-inch (1983): Several companies shipped the first
3.5" floppy disks based on a Sony design that could
hold 360 KB in its single-sided configuration, or 720
KB double-sided. Later versions could store up to
1.44 MB or 2 MB of data.

2-inch (1989): In 1989, both Sony and Panasonic
debuted 2" floppy drive formats that found use in
Japanese word processors, still video cameras, and
most notably, the Zenith Minisport laptop. Sony's
format could hold 812K of data, and Panasonic's,
720K.

3.5" Floptical (1991): Developed by Insite
Peripherals, this obscure format used special disks
similar to 3.5" floppies that could hold 21 MB each
thanks to optical head-tracking technology that
increased track density dramatically.

Zip Disk (1995): Iomega's 100 MB Zip Disk became
an alternative floppy disk standard in the late 1990s
and early 2000s. Later models held up to 750 MB of
data.

3.5" Imation SuperDisk (1996): The 3.5" floppy
format's last stand-as far as new densities were
concerned-came in the form of this 120 MB
magnetic disk that achieved its high-data densities
thanks to laser-tracking techniques. In 2001, Imation
released a 240 MB version of the disk. As a bonus,
Super Disk drives could read regular 3.5" floppies
as well.
Cloud storage is not exactly a device per se. It is the
newest and most versatile type of storage for computers.
“The cloud" is not one place or object, but rather a huge
collection of servers housed in data centers around the
world. When you save a document to the cloud, you're
storing it on these servers. Because cloud storage stores
everything online, it doesn't use any of your computer's
secondary storage, allowing you to save space. Cloud
storage offers significantly higher storage capacities than
USB flash drives and other physical options. This saves
you from having to sift through Google Drive each device to
find the right file.
While external HDDs and SSDs were once favored for their
portability, they, too, fall short compared to cloud storage.
There aren't many pocket-friendly external hard drives.
While they're smaller and lighter than a computer's internal
storage drive, they are still tangible devices. The cloud, on
the other hand, can go with you anywhere without taking up
any physical space, and without the physical vulnerabilities
of an external drive.
External storage devices were also popular as a quick
solution for transferring files, but they're only useful if you
can access each physical device. Cloud computing is
thriving as many businesses now operate remotely. It's
likely that you wouldn't mail a USB drive overseas to send
a large file to a colleague. Cloud storage acts as a bridge
between remote workers, making collaboration from afar a
breeze.
If you forget to bring a hard drive containing important
documents to a meeting, there's not much you can do other
than go back and grab it. If you break or lose a hard drive
altogether, it's unlikely you'll ever get that data back. These
risks don't exist for cloud storage-your data is backed up
and accessible whenever and wherever you are so long as
you have access to the internet.