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 Define the term hardware
Computer hardware is the collection of physical parts of a computer system. This includes the
computer case, monitor, keyboard, and mouse. It also includes all the parts inside the computer
case, such as the hard disk drive, motherboard, video card, and many others. Computer hardware
is what you can physically touch.
 Evaluate internal hardware devices (including: central processing unit (CPU), motherboard,
random access memory (RAM), read only memory (ROM), graphics card, sound card, hard disk
drive (HDD), solid state drive (SSD))
CPU
Alternately referred to as a processor, central processor,
or microprocessor, the CPU is the Central Processing Unit of the computer.
A computer's CPU handles all instructions it receives
from hardware and software running on the computer.
Components of the CPU
In the CPU, the primary components are the ALU (Arithmetic Logic Unit)
that performs mathematical, logical, and decision operations and
the CU (Control Unit) that directs all of the processors operations.
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Motherboard
A motherboard is one of the most essential parts of a computer system. It holds together many
of the crucial components of a computer, including the central processing unit (CPU), memory
and connectors for input and output devices. The base of a motherboard consists of a very firm
sheet of non-conductive material, typically some sort of rigid plastic. Thin layers of copper or
aluminum foil, referred to as traces, are printed onto this sheet. These traces are very narrow
and form the circuits between the various components. In addition to circuits, a motherboard
contains a number of sockets and slots to connect the other components.
Parts of a Motherboard
If you were to open up your computer and take out the motherboard, you would probably get
pretty confused about all the different parts. Depending on the make and model of your
computer, it might look something like the picture below.
To understand how computers work you don't need to know every single part of the
motherboard. However, it is good to know some of the most important parts and how the
motherboard connects the various parts of a computer system together. Some of the typical
parts are described below - they are also labeled in the next photograph:
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A CPU socket - the actual CPU is directly soldered onto this socket. Since high speed CPUs
generate a lot of heat, there are heat sinks and mounting points for fans right next to the
CPU socket.
A power connector to distribute power to the CPU and other components.
Slots for the system's main memory, typically in the form of DRAM chips.
A chip forms an interface between the CPU, the main memory and other components. On
many types of motherboards this is referred to as the Northbridge. This chip also contains
a large heat sink.
A second chip controls the input and output (I/O) functions. It is not connected directly
to the CPU but to the Northbridge. This I/O controller is referred to as the Southbridge.
The Northbridge and Southbridge combined are referred to as the chipset.
Several connectors, which provide the physical interface between input and output
devices and the motherboard. The Southbridge handles these connections.
Slots for one or more hard drives to store files. The most common types of connections
are Integrated Drive Electronics (IDE) and Serial Advanced Technology Attachment
(SATA).
A Read-only memory (ROM) chip, which contains the firmware, or startup instructions for
the computer system. This is also called the BIOS.
A slot for a video or graphics card. There are a number of different types of slots, including
Accelerated Graphics Port (AGP) and Peripheral Component Interconnect Express (PCIe).
Additional slots to connect hardware in the form of Peripheral Component Interconnect
(PCI) slots.
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RAM
Alternatively referred to as main memory, primary memory, or system memory,Random Access
Memory (RAM) is a hardware device that allows information to be stored and retrieved on a
computer. RAM is usually associated with DRAM, which is a type of memory module. Because
information is accessed randomly instead of sequentially like it is on a CD or hard drive, the
computer can access the data much faster. However, unlike ROM or the hard drive, RAM is
a volatile memory and requires power to keep the data accessible. If the computer is turned off,
all data contained in RAM is lost.
Random access memory (RAM) is the best known form of computer memory. RAM is considered
"random access" because you can access any memory cell directly if you know the row and
column that intersect at that cell.
ROM
Short for Read-Only Memory, ROM is
a storage medium that is used with computers
and other electronic devices. As the name
indicates, data stored in ROM may only be
read. It is either modified with extreme
difficulty or not at all. ROM is mostly used
for firmware updates. A simple example of
ROM is the cartridge used with video
game consoles, which allows one system to
run multiple games. Another example of ROM
is EEPROM, which is a programmable ROM used for the computer BIOS, as shown in the picture
Graphics Card
The graphics card in your office PC converts video data into electronic signals and sends them to
your monitor. The monitor accepts the graphics card signals and turns them into colorful images.
The process happens fast enough to handle videos, games and other media. All standard desktop
and notebook computers have some form of graphics card.
A graphics card is the component in your computer that handles generating the signals that are
sent to the monitor or "graphics". It is responsible for generating all the text and pictures that
are displayed on your screen. It is called a "card" because most PCs will have a physical card
that is inserted in a PCI slot on the motherboard. Some motherboards have built-in graphics
cards with is something of a misnomer since it is built in as part of the motherboard and no
longer a separate "card".
2D, or two dimensional graphics are the kind of graphics displayed when you use a web
browser, check email or work on a spreadsheet. For 2D graphics the major factors are
resolution and refresh rate.
Resolution determines how many little dots are used to draw the image on the screen. For
example, 640x480 means that the whole screen is drawn using 307,200 little dots in 640
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columns and 480 rows. The more dots that are used, the finer the detail. Thus, higher
resolutions provide for great detail and image quality.
Another factor is color depth. You may see it expressed as a third parameter such as
640x480x256. This means 640 columns x 480 rows x 256 colors. Color depth is usually a number
that is 2 raised to the power of a multiple of 8 up to 32. i.e. 2^8, 2^16, 2^24 or 2^32... or 256,
65,536, 16M or 4G colors. Obviously, the more colors the great the detail again.
Sound Card
Definition
Most of your music collection is probably in digital format, either on CDs or as files on your
computer. In order to be able to listen to your music, a sound card converts digital data to analog
sound waves you can hear. The output signal is then connected to a headphone or set of
speakers. You can also use a sound card to record audio with a microphone.
Sound Card Features and Functions
The motherboard on most computer systems has an integrated sound card, which is often
sufficient for many users. However, to get higher quality sound you can upgrade to a separate
sound card, which uses better and more expensive components.
Audio files on a computer consist
of digital data just like any other
file on a computer. Sounds we can
hear consist of waves that travel
through the air - sounds are
analog. The primary function of a
sound card is to translate between
digital and analog information, just
like a video card. Sound cards
typically
have
four
major
components:
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The digital-to-analog converter (DAC), which makes it possible to convert digital data to
analog sound
The analog-to-digital converter (ADC), which makes it possible to make digital recordings
from analog sound inputs
An interface to connect to the motherboard, typically using Peripheral Component
Interconnect (PCI)
Input and output connectors so you can plug in headphones, speakers or a microphone many computer systems have speakers and microphone built-in, but connectors allow
you to use higher quality external devices to play or record sound
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On some sound cards, the two types of converters are integrated into CODEC a single
coder/decoder chip. Some sound cards also have a digital signal processor (DSP), a built-in
processing unit. The DSP takes some of the load of the central processing unit (CPU) to convert
between digital and analog. Similarly, some sound cards have their own memory. Sound cards
without a DSP or memory will use the motherboard's CPU and memory.
Uses of a computer sound card
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Games
Audio CDs and listening to music
Watch movies
Audio conferencing
Creating and playing Midi
Educational software
Business presentations
Record dictations
Voice recognition
Hard drive
A hard disk drive (sometimes abbreviated
as hard drive, HD, or HDD) is a non-volatile
memory
hardware
device
that
permanently stores and retrieves
information. There are many variations,
but their sizes are generally 3.5" and 2.5"
for desktop and laptop computers
respectively. A hard drive consists of one
or more platters to which data is written
using a magnetic head, all inside of an airsealed casing. Internal hard disks reside in
a
drive
bay,
connect
to
the motherboard using an ATA, SCSI,
or SATA cable, and are powered by a
connection to the PSU (power supply unit).
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A hard drive can be used to store just about any type of data, including pictures, music,
videos, and text documents. Computers have a hard drive and use it to store files for the
operating and software that run on the computer, as well as files created or downloaded
to the computer by a user.
The amount of data a hard drive can store depends on the storage space of the hard drive.
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Older hard drives had a storage size of several hundred megabytes (MB) to
several gigabytes (GB). Newer hard drives have a storage size of several hundred
gigabytes to several terabytes. Each year, new and improved technology allows for
increasing hard drive storage sizes.
How is data read and stored on a hard drive?
Data sent to and read from the hard drive is interpreted by the disk controller, which tells the
hard drive what to do and how to move the components within the drive. When the operating
system needs to read or write information, it examines the hard drive's File Allocation Table
(FAT) to determine file location and available write areas. Once they have been determined, the
disk controller instructs the actuator to move the read/write arm and align the read/write head.
Because files are often scattered throughout the platter, the head needs to move to different
locations to access all information.
All information stored on a traditional hard drive, like the above example, is done magnetically.
After completing the above steps, if the computer needs to read information from the hard drive,
it would read the magnetic polarities on the platter. One side of the magnetic polarity is 0, and
the other is 1. Reading this as binary data, the computer can understand what the data is on the
platter. For the computer to write information to the platter, the read/write head aligns the
magnetic polarities, writing 0's and 1's that can be read later.
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HDD and SSD explained
The traditional spinning hard drive (HDD) is the basic nonvolatile storage on a computer.
That is, it doesn't "go away" like the data on the system memory when you turn the
system off. Hard drives are essentially metal platters with a magnetic coating. That
coating stores your data, whether that data consists of weather reports from the last
century, a high-definition copy of the Star Wars trilogy, or your digital music collection.
A read/write head on an arm accesses the data while the platters are spinning in a hard
drive enclosure.
An SSD does much the same job functionally (e.g., saving your data while the system is
off, booting your system, etc.) as an HDD, but instead of a magnetic coating on top of
platters, the data is stored on interconnected flash memory chips that retain the data
even when there's no power present. The chips can either be permanently installed on
the system's motherboard (like on some small laptops and ultrabooks), on a PCI/PCIe
card (in some high-end workstations), or in a box that's sized, shaped, and wired to slot
in for a laptop or desktop's hard drive (common on everything else). These flash memory
chips differ from the flash memory in USB thumb drives in the type and speed of the
memory. That's the subject of a totally separate technical treatise, but suf fice it to say
that the flash memory in SSDs is faster and more reliable than the flash memory in USB
thumb drives. SSDs are consequently more expensive than USB thumb drives for the
same capacities.
Advantages and Disadvantages
Both SSDs and HDDs do the same job: They boot your system, store your applications,
and store your personal files. But each type of storage has its own unique feature set.
The question is, what's the difference, and why would a user get one over the other? We
break it down:
Price: To put it bluntly, SSDs are more expensive than HDDs in terms of dollar per GB.
For the same capacity and form factor 1TB internal 2.5-inch drive, you'll pay about $60
to $75 for an HDD, but as of this writing, an SSD doubles that to $130 to $150. That
translates into 7 cents per gigabyte for the HDD and 14 cents per gigabyte for the SSD.
Since HDDs are older, more established technologies, they will remain less expensive for
the near future. Those extra hundreds may push your system price over budget.
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Maximum and Common Capacity: As seen above, SSD units top out at 4TB, but
those are still very rare and expensive. You're more likely to find 500GB to 1TB units as
primary drives in systems. While 500GB is
considered a "base" hard drive in 2015,
pricing concerns can push that down to
128GB for lower-priced SSD-based
systems. Multimedia users will require
even more, with 1TB to 4TB drives as
common in high-end systems. Basically,
the more storage capacity, the more stuff
(photos, music, videos, etc.) you can hold on your PC. While the (Internet) cloud may be
a good place to share these files among your phone, tablet, and PC, local storage is less
expensive, and you only have to buy it once.
Speed: This is where SSDs shine. An SSD-equipped PC will boot in seconds, certainly
under a minute. A hard drive requires time to speed up to operating specs, and will
continue to be slower than an SSD during normal use. A PC or Mac with an SSD boots
faster, launches apps faster, and has faster overall performance. Witness the higher
PCMark benchmark scores on laptops and desktops with SSDs, plus the much higher
scores and transfer times for external SSDs versus HDDs. Whether it's for fun, school, or
business, the extra speed may be the difference between finishing on time or f ailing.
Fragmentation: Because of their rotary recording surfaces, HDD surfaces work best
with larger files that are laid down in contiguous blocks. That way, the drive head can
start and end its read in one continuous motion. When hard drives start to fil l up, large
files can become scattered around the disk platter, which is otherwise known as
fragmentation. While read/write algorithms have improved to the point that the effect
is minimized, the fact of the matter is that HDDs can become fragmented, while SSDs
don't care where the data is stored on its chips, since there's no physical read head.
Thus, SSDs are inherently faster.
Durability: An SSD has no moving parts, so it is more likely to keep your data safe in
the event that you drop your laptop bag or your system is shaken about by an
earthquake while it's operating. Most hard drives park their read/write heads when the
system is off, but they are flying over the drive platter at hundreds of miles an hour
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when they are in operation. Besides, even parking brakes have limits. If you're rough on
your equipment, an SSD is recommended.
Availability: Hard drives are simply more plentiful. Look at the product lists from
Western Digital, Toshiba, Seagate, Samsung, and Hitachi, and you'll see many more HDD
models than SSDs. For PCs and Macs, internal HDDs won't be going away completely, at
least for the next couple of years. You'll also see many more HDD choices than SSDs
from different manufacturers for the same capacities. SSD model lines are growing in
number, but HDDs are still in the majority for storage devices in PCs.
Form Factors: Because HDDs rely on spinning platters, there is a limit to how small
they can be manufactured. There was an initiative
to make smaller 1.8-inch spinning hard drives, but
that's stalled at about 320GB, since the tablet and
smartphone manufacturers have settled on flash
memory for their primary storage. SSDs have no
such limitation, so they can continue to shrink as
time goes on. SSDs are available in 2.5-inch laptop
drive-sized boxes, but that's only for convenience. As laptops become slimmer and
tablets take over as primary Web-surfing platforms, you'll start to see the adoption of
SSDs skyrocket.
Noise: Even the quietest HDD will emit a bit of noise when it is in use from the drive
spinning or the read arm moving back and forth, particularly if it's in a system that's
been banged about or in an all-metal system where it's been shoddily installed. Faster
hard drives will make more noise than slower ones. SSDs make virtually no noise at all,
since they're non-mechanical.
Overall: HDDs win on price, capacity, and availability. SSDs work best if speed,
ruggedness, form factor, noise, or fragmentation (technically part of speed) are
important factors to you. If it weren't for the price and capacity issues, SSDs would be
the winner hands down.
As far as longevity goes, while it is true that SSDs wear out over time (each cell in a flash
memory bank has a limited number of times it can be written and erased), thanks to
TRIM command technology built into SSDs that dynamically optimizes these read/w rite
cycles, you're more likely to discard the system for obsolescence before you start
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running into read/write errors. The possible exceptions are high -end multimedia users
like video editors who read and write data constantly, but those users will need t he
larger capacities of hard drives anyway. Hard drives will eventually wear out from
constant use as well, since they use physical recording methods. Longevity is a wash
when it's separated from travel and ruggedness concerns.
Cloud Storage
Cloud Storage is a service where data is remotely maintained, managed, and backed up. The
service allows the users to store files online, so that they can access them from any location via
the Internet. According to a recent survey conducted with more than 800 business decision
makers and users worldwide, the number of organizations gaining competitive advantage
through high cloud adoption has almost doubled in the last few years and by 2017, the public
cloud services market is predicted to exceed $244 billion. Now, let’s look into some of the
advantages and disadvantages of Cloud Storage.
Advantages of Cloud Storage
1. Usability: All cloud storage services reviewed in this topic have desktop folders for Mac’s and
PC’s. This allows users to drag and drop files between the cloud storage and their local storage.
2. Bandwidth: You can avoid emailing files to individuals and instead send a web link to
recipients through your email.
3. Accessibility: Stored files can be accessed from anywhere via Internet connection.
4. Disaster Recovery: It is highly recommended that businesses have an emergency backup
plan ready in the case of an emergency. Cloud storage can be used as a back‐up plan by
businesses by providing a second copy of important files. These files are stored at a remote
location and can be accessed through an internet connection.
5. Cost Savings: Businesses and organizations can often reduce annual operating costs by using
cloud storage; cloud storage costs about 3 cents per gigabyte to store data internally. Users can
see additional cost savings because it does not require internal power to store information
remotely.
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Disadvantages of Cloud Storage
1. Usability: Be careful when using drag/drop to move a document into the cloud storage
folder. This will permanently move your document from its original folder to the cloud storage
location. Do a copy and paste instead of drag/drop if you want to retain the document’s original
location in addition to moving a copy onto the cloud storage folder.
2. Bandwidth: Several cloud storage services have a specific bandwidth allowance. If an
organization surpasses the given allowance, the additional charges could be significant.
However, some providers allow unlimited bandwidth. This is a factor that companies should
consider when looking at a cloud storage provider.
3. Accessibility: If you have no internet connection, you have no access to your data.
4. Data Security: There are concerns with the safety and privacy of important data stored
remotely. The possibility of private data commingling with other organizations makes some
businesses uneasy. If you want to know more about those issues that govern data security and
privacy, here is an interesting article on the recent privacy debates.
5. Software: If you want to be able to manipulate your files locally through multiple devices,
you’ll need to download the service on all devices.
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Hardware & Input/output Devices
Keyboard
Keyboard is the most common and very popular input
device which helps in inputting data to the computer.
The layout of the keyboard is like that of traditional
typewriter, although there are some additional keys
provided for performing additional functions.
Keyboards are of two sizes 84 keys or 101/102 keys,
but now keyboards with 104 keys or 108 keys are also
available for Windows and Internet.
The keys on the keyboard are as follows:
Sr.No
Keys
Description
1
Typing Keys
These keys include the letter keys (A-Z) and digit keys (0-9)
which generally give same layout as that of typewriters.
2
Numeric Keypad
It is used to enter numeric data or cursor movement.
Generally, it consists of a set of 17 keys that are laid out in
the same configuration used by most adding machines
and calculators.
3
Function Keys
The twelve function keys are present on the keyboard
which are arranged in a row at the top of the keyboard.
Each function key has unique meaning and is used for
some specific purpose.
4
Control keys
These keys provide cursor and screen control. It includes
four directional arrow keys. Control keys also include
Home, End, Insert, Delete, Page Up, Page Down,
Control(Ctrl), Alternate(Alt), Escape(Esc).
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5
Special Purpose Keys
Keyboard also contains some special purpose keys such as
Enter, Shift, Caps Lock, Num Lock, Space bar, Tab, and
Print Screen.
Advantages/Disadvantages of using a Keyboard:
Advantages
Disadvantages
People are used to using keyboards to enter
data, they need very little training
If you can't touch type, it can be time
consuming to enter data
A skilled typist can enter data very quickly
Keyboards are not suitable for creating
diagrams
Specialist keyboards are available e.g.
ergonomic, gaming keyboards
Disabled people often find keyboards
difficult to use.
Excessive use can lead to health problems
such as repetitive strain injury (R.S.I.)
Mouse
Mouse is most popular pointing device. It is a very famous
cursor-control device having a small palm size box with a
round ball at its base which senses the movement of mouse
and sends corresponding signals to CPU when the mouse
buttons are pressed.
Generally it has two buttons called left and right button and
a wheel is present between the buttons. Mouse can be used to control the position of cursor
on screen, but it cannot be used to enter text into the computer.
Advantages
Disadvantages
Faster to select icons and options when compared to
a keyboard.
People with wrist and hand problems (like RSI) can
find mice painful to use.
Very easy to move a pointer around a screen and to
Ball mice can pick up dirt which will affect the
navigate through documents.
accuracy of pointer movement.
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Mice are small and do not take up much space
Mice need a flat surface in order to work properly
For example - they would be difficult to use on train
unless you had a flat table to rest
Joystick
Joystick is also a pointing device which is used to move cursor position on a
monitor screen. It is a stick having a spherical ball at its both lower and
upper ends. The lower spherical ball moves in a socket. The joystick can be
moved in all four directions.
The function of joystick is similar to that of a mouse. It is mainly used in Computer Aided
Designing(CAD) and playing computer games.
Advantages
Disadvantages
Easier to control an on-screen curser or move an ingame character than it is when using a keyboard
Not as easy to control an on-screen curser when
compared to using a mouse.
Very simple to get used to.
People with hand/wrist issues (like RSI) can find them
painful to use..
Anyone can just pick one up and use it!
Can be used by disabled people. Joysticks can be
operated by hands or even feet.
Difficult (but not impossible) to enter text.
For example: some games allow you to select
individual letters using the joystick in order to spell
out your name when entering a high score.
For example - they would be difficult to use on train
unless you had a flat table to rest
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Light Pen
Light pen is a pointing device which is similar to a pen. It is
used to select a displayed menu item or draw pictures on the
monitor screen. It consists of a photocell and an optical
system placed in a small tube. When the tip of a light pen is
moved over the monitor screen and pen button is pressed, its
photocell sensing element detects the screen location and
sends the corresponding signal to the CPU.
Track Ball
Track ball is an input device that is mostly used in
notebook or laptop computer, instead of a mouse.
This is a ball which is half inserted and by moving
fingers on ball, pointer can be moved. Since the
whole device is not moved, a track ball requires
less space than a mouse. A track ball comes in
various shapes like a ball, a button and a square.
Scanner
Scanner is an input device which works more like a
photocopy machine. It is used when some
information is available on a paper and it is to be
transferred to the hard disc of the computer for
further manipulation. Scanner captures images
from the source which are then converted into the
digital form that can be stored on the disc. These
images can be edited before they are printed.
Advantages
Disadvantages
Very fast to enter hard copies into the computer
(compared to retyping with a keyboard).
Scanned images are usually of lesser quality than the
original document.
Very easy to scan and store documents and images
Scanned images can take up a lot of disk space
into the computer.
(especially if you scan them at a high resolution).
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Digital copies of the stored data can easily be
duplicated and backed up.
Old photo's that may be damaged can be scanned
into the computer then repaired using Graphics
Editing Software.
Digitizer
Digitizer is an input device which converts
analog information into digital form. Digitizer
can convert a signal from the television or
camera into a series of numbers that could be
stored in a computer. They can be used by
the computer to create a picture of whatever
the camera had been pointed at. Digitizer is
also known as Tablet or Graphics Tablet
because it converts graphics and
pictorial data into binary inputs. A graphic tablet as digitizer is used for doing fine works of
drawing and image manipulation applications.
Microphone
Microphone is an input device to input sound that is then stored
in digital form. The microphone is used for
various applications like adding sound to a multimedia
presentation or for mixing music.
Used to input sounds/speech for use in a range of applications. For example:
Narration (spoken words) in presentations or in web sites
Voice-over's in movies
Speaking over the Internet using VoIP (Voice over Internet Protocol)
An example of this would be using Skype to hold an online conversation
Conducting videoconferencing (e.g. business meetings online).
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Advantages
Disadvantages
Faster to read in text than to type it in using a
Sound files can take up a lot of computer storage
keyboard .
space.
Means that word processors can be used by people
Speaking words into a word processor is not as
who cannot use their hands. Words are simply
spoken into the software instead of typed.
accurate as typing. This means that mistakes are
common with words that sound the same but have
different meanings.
For example: 'see' and 'sea'.
Makes driving safer because people do not need to
take their hands off the steering wheel in order to
use their mobile phone.
Background noise can interfere with voice
recognition systems.
Microphones are very cheap to buy.
Magnetic Ink Card Reader (MICR)
MICR input device is generally used in banks because of a large
number of cheques to be processed every day. The bank's code
number and cheque number are printed on the cheques with a
special type of ink that contains particles of magnetic material
that are machine readable. This reading process is called
Magnetic Ink Character Recognition (MICR). The main
advantages of MICR is that it is fast and less error prone.
Optical Character Reader (OCR)
OCR is an input device used to read a printed text. OCR
scans text optically character by character, converts them
into a machine readable code and stores the text on the
system memory.
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Bar Code Readers
Bar Code Reader is a device used for
reading bar coded data (data in form of
light and dark lines). Bar coded data is
generally used in labelling goods,
numbering the books etc. It may be a
hand held scanner or may be
embedded in a stationary scanner. Bar
Code Reader scans a bar code image,
converts it into an alphanumeric value
which is then fed to the computer to which bar code reader is connected.
Optical Mark Reader (OMR)
OMR is a special type of optical scanner used to recognize the type of mark made by pen or
pencil. It is used where one out of a few alternatives is to be selected and marked. It is
specially used for checking the answer sheets of examinations having multiple choice
questions.
Digital Cameras


Have pretty much replaced the old style film-based cameras.
Digital cameras store digital photographs on a memory card and these images can easily
be transferred onto a computer for viewing or editing.
 Most digital cameras have a built-in screen to allow for previewing the digital
photograph. This is useful so that the photographer can decide which images to keep
and which to delete.
 Digital camera image quality is measured in 'Megapixels'. These are the number of dots
that make up the image. Generally speaking, the higher the Megapixels, the higher the
detail quality of the image.
3 Megapixel cameras produce images made up of 3 Million pixels (dots).
24 Megapixel cameras produce images made up of 24 Million dots (8 times more detail
Uses of Digital Cameras:




Used to capture digital images for uses such as: Saving special moments (weddings,
birthdays, family snaps etc)
Gathering images for use in presentations, web pages or publications (newspapers and
magazines etc)
Easy to transfer images to a computer for editing.
For example: using Photoshop to alter brightness or contrast
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



Images can be printed easily by: Uploading to a computer and then printing
Connecting directly to a photo-printer and printing straight from the camera
(no need to upload to a computer)
Most digital cameras also allow for short, high-quality video clips to be produced.
Advantages/Disadvantages of Digital Cameras:
Advantages
Disadvantages
No film to develop. This means that producing the
photo is much quicker.
Camera user needs to have computer skills to be
able to transfer and print digital photographs.
Unwanted images can easily be deleted from the
memory card.
Not all digital cameras produce images as highquality as traditional cameras.
Because the images are digital it is easy to make
copies of them
Artistry of traditional photography is being lost.
No need to print at all because the images can be
Camera software can automatically correct 'bad
images' making photography easier to master
without as much skill.
viewed a computer screen. This saves paper and is
better for the environment.
Memory cards can store thousands of digital
photographs. Traditional photographs can take up a
lot of physical storage space.
People using traditional 'film-cameras' had to take
much more care to capture each image perfectly.
Digital images can easily be transferred using
blutooth, email attachments and mobile phones.
Digital images can be improved and edited easily
using software (sharpening the image for example)
Web Cameras (web cams)
Web cameras are similar to digital cameras in their function but they are directly connected to
a computer and do not have memory storage.
Web cameras can capture both digital images and video.
Images / video are sent directly to the computer where they can be stored and used.
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Uses of Web Cameras:







Used to conduct face-to-face conversations with friends and family online over VoIP
applications such as Skype.
A similar use is to conduct face-to-face job interviews over the Internet. This removes
the need for job applicants to travel very large distances to attend the interview.
Used to hold video-conferencing meetings over the Internet.
Can capture image and video content for presentations, web sites and even YouTube
content.
Web Cameras are sometimes used by parents to keep an eye on their children when
they are in another room.
Some people use web cams as a cheap alternative to security cameras.
Sometimes used to allow drivers to view the traffic conditions on roads.
Advantages/Disadvantages of Web Cameras:
Advantages
Disadvantages
Allow for long-distance face-to-face conversations.
This removes the need for people to travel.
The image/video quality can sometimes be poor
(low resolution).
(especially useful for elderly and disabled people to
keep in touch with family)
Video conference business meetings and job
interviews can be conducted very cheaply over long
distances.
They do not have their own storage and so must be
permanently fixed to the computing device.
(no need for expensive travel or bookings of hotel
rooms to attend the meeting or interview)
Parents can keep an eye on their children from a
different location.
Are usually in a fixed position and so cannot be easily
moved around.
Web cams can be left running constantly which
makes them useful as security devices on properties.
(as a form of security camera)
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Biometrics
When referring to computers and security, biometrics is the
identification of a person by the measurement of their biological
features. For example, a user identifying themselves to a computer or
building by their finger print or voice is considered a biometrics
identification. When compared to apassword, this type of system is much
more difficult to fake since it is unique to the person. Below is a listing of
all known biometric devices.
Other common methods of a biometrics scan are a person's face, hand, iris, and retina.
Types of biometric devices





Face scanner - Biometric face scanners identify a person by taking measurements of a
person face. For example, the distance between the persons chin, eyes, nose, and
mouth. These types of scanners can be very secure assuming they are smart enough to
distinguish between a picture of a person and a real person.
Hand scanner - Like your finger print, the palm of your hand is also unique to you. A
biometric hand scanner will identify the person by the palm of their hand.
Finger scanner - Like the picture shown on this page a biometric finger scanner
identifies the person by their finger print. These can be a secure method of identifying a
person, however, cheap and less sophisticated finger print scanners can be duped a
number of ways. For example, in the show Myth Busters they were able to fake a finger
print using a Gummy Bear candy treat.
Retina or iris scanner - A biometric retina or iris scanner identifies a person by scanning
the iris or retina of their eyes. These scanners are more secure biometric authentication
schemes when compared to the other devices because there is no known way to
duplicate the retina or iris.
Voice scanner - Finally, a voice analysis scanner will mathematically break down a
person's voice to identify them. These scanners can help improve security but with
some less sophisticated scanners can be bypassed using a tape recording.
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Business card reader
Similar to other computer scanners, a business card
readerallows a user to scan business cards into their computer
for digital storage. Computer scanners are capable of scanning
and converting text documents to typed text by use of Optical
Character Recognition (OCR) software. Business card readers
work on a similar principle, reading the text on the business
card and converting to typed text on the computer.
Some business card readers offer the functionality of scanning a business card directly into
a Microsoft Outlook contact record. Other readers can scan to a web format, directly to a new
computer file, to a database or even to a CRM system, like SalesForce.com or Microsoft CRM.
Some business card readers are capable of connecting to PDA devices, smartphones, and tablet
computers.
Today, many people are replacing business card readers with smartphones with apps capable of
scanning and storing business card information.
Light gun
A light gun is a pointing input device that detects light
using a photodiode in the gun barrel. When the player
of the game pulls the trigger on the gun, the screen is
blanked out for a fraction of a second, which allows the
photodiode to determine where the gun is pointed.
Light guns were most widely used with early console
gaming systems such as the NES Zapper light gun, as shown in the picture. Using this gun the
player could play games where they were required to point the gun at the screen and shoot
targets, such as ducks in the popular Duck Hunt game.
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Yoke
A yoke is a hardware input device used with
computer games, such as flight simulation games,
that allow a player to fly up or down, or back or
forth by pulling or pushing the device.
The picture shows an example of a flight yoke
by Saitekand is a good example what a typical
yoke that connects to your computer.
Paddle
1. More commonly known as a game paddle or gamepad, a paddle is
an input device commonly used with games that may contain
various buttons used to steer and utilize different options in a
game. All console game systems utilize a paddle or gamepad for
control. The picture shows an example of a game paddle used
with the Atari 2600.
2. The term paddle may also be used to describe various handheld
devices that are capable of controlling a function on a computer
or electronic device.
Computer - Output Devices
Monitors
Monitors, commonly called as Visual Display Unit (VDU), are the main output device of a
computer. It forms images from tiny dots, called pixels that are arranged in a rectangular form.
The sharpness of the image depends upon the number of pixels.
There are two kinds of viewing screen used for monitors.

Cathode-Ray Tube (CRT)

Flat- Panel Display
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Cathode-Ray Tube (CRT) Monitor
The CRT display is made up of small picture elements called
pixels. The smaller the pixels, the better the image clarity, or
resolution. It takes more than one illuminated pixel to form
whole character, such as the letter ‘e’ in the word help.
A finite number of characters can be displayed on a screen at
once. The screen can be divided into a series of character
boxes - fixed location on the screen where a standard
character can be placed. Most screens are capable of
displaying 80 characters of data horizontally and 25 lines vertically. There are some
disadvantages of CRT:

Large in Size

High power consumption
Flat-Panel Display Monitor
The flat-panel display refers to a class of video devices that
have reduced volume, weight and power requirement in
comparison to the CRT. You can hang them on walls or wear
them on your wrists. Current uses of flat-panel displays
include calculators, video games, monitors, laptop computer,
graphics display.
The flat-panel display is divided into two categories:

Emissive Displays - The emissive displays are devices
that convert electrical energy into light. Example are
plasma panel and LED(Light-Emitting Diodes).

Non-Emissive Displays - The Non-emissive displays use optical effects to convert sunlight
or light from some other source into graphics patterns. Example is LCD(Liquid-Crystal
Device)
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Printers
Printer is an output device, which is used to print information on paper.
There are two types of printers:

Impact Printers

Non-Impact Printers
Impact Printers
The impact printers print the characters by striking them on the ribbon which is then pressed
on the paper.
Characteristics of Impact Printers are the following:




Very low consumable costs
Very noisy
Useful for bulk printing due to low cost
There is physical contact with the paper to produce an image
These printers are of two types

Character printers

Line printers
Character Printers
Character printers are the printers which print one character at a time.
These are further divided into two types:

Dot Matrix Printer(DMP)

Daisy Wheel
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DOT MATRIX PRINTER
In the market one of the most popular printers is Dot
Matrix Printer. These printers are popular because of
their ease of printing and economical price. Each
character printed is in form of pattern of dots and head
consists of a Matrix of Pins of size (5*7, 7*9, 9*7 or 9*9)
which come out to form a character that is why it is
called Dot Matrix Printer.

Dot matrix printers are still used in
environments where print speed and noise is not an
issue (like in car garages and factories).

These printers work by using a set of pins to
press an inked ribbon against paper.

When the pin/ribbon hits the paper a
printed dot is left behind.

The dots can be arranged to form basic text
and images.
Uses of Dot Matrix Printers:
 Dot matrix printers are very robust and can be used in noisy and dirty environments
(like garages and warehouses).
 Can make ‘Carbon Copies’ of a document using special ‘Carbon Paper’ underneath
normal printer paper.
Advantages
Disadvantages
Work just fine in dusty and dirty environments
Very noisy so not suitable for an office environment
where laser or inkjet printers could easily be
damaged.
Carbon copies can be produced using carbonated
paper.
Very slow to print (slowest of all the types of printers)
Very cheap to buy and maintain.
Very poor print quality
(Inked ribbons are very cheap)
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Good for continuous printing.
(e.g. long print jobs like wage slips)
Cheaper to run than inkjets (low cost per page).
Line Printers
Line printers are the printers which print one line at a time.
Non-impact Printers
Non-impact printers print the characters without using ribbon. These printers print a complete
page at a time so they are also called as Page Printers.
These printers are of two types

Laser Printers

Inkjet Printers
Characteristics of Non-impact Printers

Faster than impact printers.

They are not noisy.

High quality.

Support many fonts and different character size.
Laser Printers
These are non-impact page printers. They use laser lights to
produce the dots needed to form the characters to be printed
on a page.
Uses of Laser Printers:
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



Very useful for printing where noise levels
need to be kept low (Like in an office where
people need to concentrate or use telephones
etc).
Good at producing high quality printouts very
fast.
Good for environments where high volume of
printing is required (lots of printouts).
This is because they have a low printing cost
per page.
Advantages
Disadvantages
Very fast at printing documents.
Environmentally unfriendly (produce ozone).
They also use more power than inkjets.
Toner cartridges last a long time and don't need to
be replaced often.
Laser printers are more expensive to buy (but cheap
to run).
Laser printers can handle high volumes of printing.
Colour laser printers are much more expensive to
Very quiet when printing.
buy and run than inkjets.
Very high quality printouts.
Reliable - don't breakdown as easily as inkjet printers.
Cheaper to run than inkjets (low cost per page).
They are larger in size compared to other types of
printers.
Inkjet Printers
Inkjet printers are non-impact character printers based on a
relatively new technology. They print characters by spraying
small drops of ink onto paper. Inkjet printers produce high
quality output with presentable features.
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They make less noise because no hammering is done and these have many styles of printing
modes available. Colour printing is also possible. Some models of Inkjet printers can produce
multiple copies of printing also. Inkjet
printers work by spraying ink onto a
page of paper.
The ink is held in 'ink cartridges' and
there are 4 different colours - black,
cyan, magenta and yellow.
Uses of Inkjet Printers:



Good where few printouts are
needed (low volume).
Ideal for single-page, very high
quality printing. (Photo quality images).
Often used to print photographs.
Advantages
Disadvantages
Output is very high quality (Especially good for colour
Slow printing rates, especially if several copies are
photograph printing).
needed.
Much cheaper to buy than laser printers.
Ink cartridges don’t last long and so are not suitable
for large print jobs.
Smaller than laser printers so take up less space.
They can be expensive to run as new ink cartridges
are not cheap to buy.
Do not produce ozone or other harmful compounds.
Very quiet whilst printing.
Printouts can easily smudge if document is not left to
dry properly.
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Plotter
Information:





There are 2 different types of plotters --- drum
and flatbed.
Produce hard copies but are capable of printing
on very large pieces of paper (e.g. 3 foot wide
by 10 foot long).
The print quality of plotters in very high.
Plotters can also produce very large and
accurate documents such as blueprints (plans)
for buildings
Plotters draw images on the page using colored
pens which are moved around the paper by a
computer.
Uses of Plotters:




Used to produce large, accurate drawings. Some
examples are listed below: Blueprints of
buildings (plans/designs)
Maps
Giant posters and adverts (like those we see on
billboards).
Pens can be replaced with cutting tools to
produce large signs.
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Advantages
Disadvantages
They can produce much larger printouts than other
Their print times are very slow.
printers.
The print quality is extremely high.
Plotters can also 'cut out' designs for use in sign
making.
Speakers
Information:




Many everyday uses of a computer require the
user to listen to different types of sounds. For
example: Listening to a music album
Watching a movie.
Browsing videos on YouTube
Multimedia encyclopedias.
Speakers are analogue and cannot output digital
'computerised' sounds.
Digital data from the computer must first be
converted into analogue sound using a sound card.
The analogue sound can then be output via the
speakers and we can listen to it.
Uses of Speakers:



Used to output sound from multimedia
presentations (like famous speeches etc).
Used in home entertainment (surround sound
etc).
Can be used by blind people to listen to words
on the screen instead of reading .
Note:
 Special software called 'screen readers' are
also needed in order to convert the printed
words into sound.

Can be used to play downloaded music files.
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Advantages
Disadvantages
Everyone in the room can hear the sound.
Output from speakers can disturb people trying to
work.
They can help blind people use a computer because
text can be turned into sound.
High quality speakers can be expensive.
Multimedia Projectors
Information:




These project whatever appears on a
computer monitor onto a very large
screen so that large numbers of people
can view it.
Multimedia Projectors are usually
controlled using a remote control.
The remote control makes it possible
to direct the presentations without the
need to be at the computer.
Multimedia projectors are often hung
from the roof on special brackets.
Uses of Multimedia Projectors:

Can be used for training presentations
to allow the whole audience to see
images from a single computer.
 Also used for large scale advertising of
new products.
For example: the famous Apple Technology
Innovations presentations with Steve Jobs
 Home cinema systems where images
from DVD’s or televisions are projected
to a large screen.
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Advantages
Disadvantages
Many people to clearly view the same presentation.
Lower image quality compared to a computer
screen.
Enhance the viewers experience.
Very expensive to buy.
For example: watching movies on a large screen is
better than a small TV screen.
Cooling fans in the projector are noisy.
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