computer Hardware
Computer hardware
Computer
hardware (usually simply called hardware
when a computing context is implicit) is the collection of physical elements
that constitutes a computer system. Computer hardware is the physical parts or
components of a computer, such as
the monitor, mouse,keyboard, computer data
storage, hard disk drive (HDD), graphic cards, sound cards, memory, motherboard, and so
on, all of which are physical objects that are tangible.[1] In contrast, software is instructions that can be stored and run by hardware. Software
is any set of machine-readable instructions that directs a computer's processor
to perform specific operations. A combination of hardware and software forms a
usable computing system.[2]
The basics components of computer hardware:
1.
Input device
2.
Output device
3.
Processing device
4.
Storage device
5.
Communication device
INPUT
DEVICE
A common computer input
device, akeyboard.
A user presses a key which transfers information to a computer.
In computing,
an input device is a peripheral (piece
of computer hardware equipment)
used to provide data and control signals to aninformation
processing system such as a computer or information appliance. Examples of input devices include keyboards, mice, scanners,digital cameras and joysticks.
Many input devices can be classified according to:
• whether the input is
discrete (e.g. key presses) or continuous (e.g. a mouse's position, though
digitized into a discrete quantity, is fast enough to be considered continuous)
• the number of degrees of
freedom involved (e.g. two-dimensional traditional mice, or three-dimensional
navigators designed for CADapplications)
Pointing
devices, which are input devices used to specify a position in space, can
further be classified according to:
Whether
the input is direct or indirect. With direct input, the input space coincides
with the display space, i.e. pointing is done in the space where visual
feedback or the pointer appears. Touchscreens and light pens involve
direct input. Examples involving indirect input include the mouse
EXAMPLE
OF INPUT DEVICE
1. MOUSE
OUTPUT
DEVICE
Some
types of output are text, graphics, tactile,[4] audio,
and video.
Text consists of characters (letters, numbers, punctuation marks, or any other
symbol requiring one byte of computer storage space) that are used to create
words, sentences, and paragraphs. Graphics are digital representations of
nontext information such as drawings, charts, photographs, and animation (a
series of still images in rapid sequence that gives the illusion of motion).
Tactile output such as raised line drawings may be useful for some individuals
who are blind. Audio is music, speech, or any other sound. Video consists of
images played back at speeds to provide the appearance of full motion.[3] Graphics (Visual)[edit]
computer.
They don't have any physical size until they are displayed on a screen or
printed on paper. Until that point, they are just a collection of numbers on
the computer's hard drive that describe the individual elements of a picture
and how they are arranged.[5] Some computers come with built-in graphics capability.
Others need a device, called a graphics card or
graphics adapter board, that has to be added.[6] Unless a computer has graphics capability built into the motherboard,
that translation takes place on the graphics card.[7] Depending on whether the image resolution is fixed, it may be of vectoror raster type.
Without qualifications, the term "digital image" usually refers to
raster images also called bitmap images. Raster images that are composed of
pixels and is suited for photo-realistic images. Vector images which are
composed of lines and co-ordinates rather than dots and is more suited to line
art, graphs or fonts.[5] To make a 3-D image, the graphics card first creates a wire frame out of
straight lines. Then, it rasterizes the image (fills in the remaining pixels).
It also adds lighting, texture and color.[7]
Haptic
technology, or haptics, is a tactile
feedback
technology which takes advantage of the sense of touch by applying forces,
vibrations, or
motions to the user.[8] Severalprinters and
wax jet printers have the capability of producing raised line drawings. There
are also handheld devices that use an array of vibrating pins to present a
tactile outline of the characters or text under the viewing window of the
device.[4]
Speech
output systems can be used to read screen text to computer users. Special
software programs called screen readers attempt
to identify and interpret what is being displayed on the screen[9] and speech synthesizers convert data to vocalized sounds or text.[6] also it is use to produce music,speech or other sounds
These
examples of output devices also include input/output devices.[10][11] Printers and visual displays are the most common type of output device
for interfacing to people, but voice is becoming increasingly available.[12]
PROCESSING
DEVICE
When a computer receives
data from an input device, the data must go through an intermediate stage before
it can be sent to an output device, like a monitor, printer, or speakers.
A processing device is any device in a computer that handles this
intermediate stage, being responsible for controlling the storage and retrieval
of data.
Some of the most common
processing devices in a computer include the following:
Computers come in all types and sizes. There are primarily
two main sizes of computers. They are:
• Portable
• Desktop
The portable computer comes in various sizes and are
referred to as laptops, notebooks, and hand-held computers. These generally
denote different sizes, the laptop being the largest, and the hand-held is the
smallest size. This document will mainly talk about the desktop computer
although portable computer issues are also discussed in various areas.
Computer Components:
Computers are made of the following basic components:
1.
Case with
hardware inside:
1.
Power
Supply - The power supply comes with the case, but this component
is mentioned separately since there are various types of power supplies. The
one you should get depends on the requirements of your system. This will be
discussed in more detail later
2.
Motherboard - This is
where the core components of your computer reside which are listed below. Also
the support cards for video, sound, networking and more are mounted into this
board.
1.
Microprocessor - This is
the brain of your computer. It performs commands and instructions and controls
the operation of the computer.
2.
Memory - The RAM
in your system is mounted on the motherboard. This is memory that must be
powered on to retain its contents.
3.
Drive
controllers - The drive controllers control the interface of your
system to your hard drives. The controllers let your hard drives work by
controlling their operation. On most systems, they are included on the
motherboard, however you may add additional controllers for faster or other
types of drives.
3.
Hard disk
drive(s) - This is where your files are permanently stored on your
computer. Also, normally, your operating system is installed here.
4.
CD-ROM
drive(s) - This is normally a read only drive where files are
permanently stored. There are now read/write CD-ROM drives that use special
software to allow users to read from and write to these drives.
5.
Floppy
drive(s) - A floppy is a small disk storage device that today
typically has about 1.4 Megabytes of memory capacity.
6.
Other possible file storage devices include DVD devices,
Tape backup devices, and some others.
2.
Monitor - This
device which operates like a TV set lets the user see how the computer is
responding to their commands.
3.
Keyboard - This is
where the user enters text commands into the computer.
4.
Mouse - A point
and click interface for entering commands which works well in graphical
environments.
.
Internal Computer Hardware
Introduction
Computer Hardware is the
physical part of a computer, as distinguished from the computer software
that executes or runs on the hardware. The hardware of a computer is
infrequently changed, while software and data are modified frequently. The term
soft refers to readily created, modified, or erased. These are unlike the
physical components within the computer which are hard.
When
you think of the term computer hardware you probably think of the guts inside
your personal computer at home or the one in your classroom. However, computer
hardware does not specifically refer to personal computers. Instead, it is all
types of computer systems. Computer hardware is in embedded systems in
automobiles, microwave ovens, CD players, DVD players, and many more devices.
In 2003, only 0.2% of all microprocessors sold were for personal computers. How
many other things in your house or your classroom use computer hardware?
Inside Computer
Motherboard
The motherboard is the body or
mainframe of the computer, through which all other components interface.
It is the central circuit board making up a complex electronic system. A
motherboard provides the electrical connections by which the other components
of the system communicate. The mother board includes many components such as:
central processing unit (CPU), random access memory (RAM), firmware, and
internal and external buses.
Motherboard
Central Processing Unit
The Central Processing Unit (CPU; sometimes just called
processor) is a machine that can execute computer programs.
It is sometimes referred to as the brain of the computer.
CPU Diagram
There are four steps that nearly all CPUs use in their
operation: fetch, decode, execute, and writeback. The first step, fetch,
involves retrieving an instruction from program memory. In the decode step, the
instruction is broken up into parts that have significance to other portions of
the CPU. During the execute step various portions of the CPU, such as the arithmetic logic unit (ALU) and the floating point unit (FPU) are connected so they can
perform the desired operation. The final step, writeback, simply writes back
the results of the execute step to some form of memory.
Random Access Memory
Random
access memory (RAM) is fast-access memory that is cleared when the computer is
power-down. RAM attaches directly to the motherboard, and is used to store
programs that are currently running. RAM is a set of integrated circuits that
allow the stored data to be accessed in any order (why it is called random).
There are many different types of RAM. Distinctions between these different
types include: writable vs. read-only, static vs. dynamic, volatile vs.
non-volatile, etc.
RAM
Firmware
Firmware is loaded from the Read only memory (ROM) run
from the Basic Input-Output System (BIOS). It is a computer program that is
embedded in a hardware device, for example a microcontroller. As it name
suggests, firmware is somewhere between hardware and software. Like software,
it is a computer program which is executed by a microprocessor or a
microcontroller. But it is also tightly linked to a piece of hardware, and has
little meaning outside of it. Most devices attached to modern systems are
specialpurpose computers in their own right, running their own software. Some
of these devices store that software (“firmware”) in a ROM within the device
itself
Power Supply
The power supply as its name
might suggest is the device that supplies power to all the components in the
computer. Its case holds a transformer, voltage control, and (usually) a
cooling fan. The power supply converts about 100-120 volts of AC power to low-voltage
DC power for the internal components to use. The most common computer power
supplies are built to conform with the ATX form factor. This enables different
power supplies to be interchangable with different components inside the
computer. ATX power supplies also are designed to turn on and off using a
signal from the motherboard, and provide support for modern functions such as
standby mode.
Removable Media Devices
If your putting something in
your computer and taking it out is most likely a form of removable media. There
are many different removable media devices. The most popular are probably CD
and DVD drives which almost every computer these days has at least one of.
There are some new disc drives such as Blu-ray which can hold a much larger amount
of information then normal CDs or DVDs. One type of removable media which is
becoming less popular is floppy disk.
CD
CDs
are the most common type of removable media. They are inexpensive but also have
short life-span. There are a few different kinds of CDs. CD-ROM which stands
for Compact Disc read-only memory are popularly used to distribute computer
software although any type of data can be stored on them. CD-R is another
variation which can only be written to once but can be read many times. CD-RW
(rewritable) can be written to more than once as well as read more than once.
Some other types of CDs which are not as popular include Super Audio CD (SACD),
Video Compact Discs (VCD), Super Video Compact Discs (SVCD), PhotoCD,
PictureCD, CD-i, and Enhanced CD.
CD-ROM Drive
There are two types of devices in a computer that use
CDs: CDROM drive and a CD writer. The CD-ROM drive used for reading a CD. The
CD writer drive can read and write a CD. CD writers are much more popular are
new computers than a CD-ROM drive. Both kinds of CD drives are called optical
disc drives because the use a laser light or electromagnetic waves to read or
write data to or from a CD.
DVD
DVDs
(digital versatile discs) are another popular optical disc storage media
format. The main uses for DVDs are video and data storage. Most DVDs are of the
same dimensions as compact discs. Just like CDs there are many different
variations. DVD-ROM has data which can only be read and not written. DVD-R and
DVD+R can be written once and then function as a DVD-ROM. DVD-RAM, DVD-RW, or
DVD+RW hold data that can be erased and re-written multiple times. DVD-Video
and DVD-Audio discs respectively refer to properly formatted and structured
video and audio content. The devices that use DVDs are very similar to the
devices that use CDs. There is a DVD-ROM drive as well as a DVD writer that
work the same way as a CD-ROM drive and CD writer. There is also a DVDRAM drive
that reads and writes to the DVD-RAM variation of DVD.
DVD
Blu-ray
Blu-ray is a newer optical disc
storage media format. Its main uses are high-definition video and data storage.
The disc has the same dimensions as a CD or DVD. The term “Blu-ray” comes from
the blue laser used to read and write to the disc. The Blu-ray discs can store
much more data then CDs or DVDs. A dual layer Blu-ray disc can store up to
50GB, almost six times thecapacity of a dual layer DVD (WOW!). Blu-ray discs
have similar devices used to read them and write to them as CDs have. A BD-ROM drive
can only read a Blu-ray disc and a BD writer can read and write a Blu-ray disc.
Floppy Disk
A floppy disk is a type of data
storage that is composed of a disk of thin, flexible(“floppy”) magnetic storage
medium encased in a square or rectangular plastic shell. Floppy disks are read
and written by a floppy disk drive. Floppy disks are a dying and being replaced
by the optical and flash drives. Many new computers do not come with floppy
drives anymore but there are a lot of older ones with floppy drives lying
around. While floppy disks are very cheap the amount of storage on them
compared to the amount of
storage for the price of flash drives makes floppy disks
unreasonable to use.
Floppy Disk
Internal Storage
Internal storage is hardware that keeps data inside the
computer for later use and remains persistent even when the computer has no
power. There are a few different types of internal storage. Hard disks are the
most popular type of internal storage. Solid-state drives have grown in
popularity slowly. A disk array controller is popular when you need more
storage then a single har disk can hold.
Hard Disk Drive
A hard disk drive (HDD) is a
non-volatile storage device which stores digitally encoded data on rapidly
rotating platters with magnetic surfaces. Just about every new computer comes
with a
hard disk these days unless it comes with a new
solid-state drive. Typical desktop hard disk drives store between 120 and
400GB, rotate at 7,200 rpm, and have a madia transfer rate of 1 Gbit/s or
higher. Hard disk drives are accessed over one of a number of bus types,
including parallel ATA(also called IDE), Serial ATA (SATA), SCSI, Serial
Attached SCSI, and Fibre Channel.
Hard Drive
Solid-State Drive
A solid-state drive (SSD) is a
data storage device that uses solidstate memory to store persistent data. An
SSD emulates a hard disk drive, thus easily replacing it in any application.
SSDs have begun to appear in laptops because they can be smaller than HDDs.
SSDs are currently more expensive per unit of capacity than HDDs which is why
they have not caught on so quickly.
Disk Array Controller
A disk array controller is a
device which manage the physical disk drives and presents them to the computer
as logical units. It almost always implements hardware RAID. RAID (Redundant
Array
of Independent Drives) is a
technology that employs the simultaneous use of two or more hard disk drives to
achieve greater levels of performance, reliability, and/or larger data volume
sizes. A disk array controller also provides additional disk cache.
A
portable communications device is a hand-held or wearable device.
For example, the walkie-talkie is
a device that is hand-held when in use, and wearable when not in use. Portable
telephones (cellular
telephones) are also carried, or worn, on a belt, or in a pocket.
Portable
devices have also become usable when worn. For example, most walkie talkies
come with a voice operated
transmit capability so that they will work hands-free, when used with a wearable
microphone. Many telephones such as the Motorola Star
Tac also feature an earpiece that allows the phone to be worn and used
hands-free. The Star Tac was the first wearable cellular telephone, in the
sense that it was the first that could be used while being worn.[citation needed]
Portable
computers
are computers that can be hand-held, used on a lap, or worn in a pocket, belt,
or the like, such as Personal
digital assistants (PDAs). PDAs are almost always worn (pocket or belt) when not in use,
but some are also usable when worn (e.g. with eyeglassbased displays as well as
electric seeing aids such as eyetap devices).
• Portable: hand-held or wearable;
