Fundamental III
permits reader to recognize human
recognizable characters printed in special magnetisable ink capable of
processing with related machines.
BAR CODE
Bar codes are thick and thin black
strips to represent numbers and character. These are prices form of encoding
the detailed information. Bar code scanner or reader are used the bar coded
information. It is useful in inventory control. It is also used as information/
price tag of books and various products in departmental stores.
Video input
Photograph and full motion films can
be captured through electronics cameras or VCRs and fed to computer through add
on cards that can be plugged into an expansion slot of personal computer.
How it works? - Video signals are
received from output of electronics camera or VCR .
Personal computer equipped with add on card such as frame grabber, Video,
blaster etc. Converts graphic image and full motion video signals into digital
files through Analog to Digital Convertor (ADC )
and other circuits.
Web camera:- A webcamera is an input device. Which a web camera allows a
computer to accept input a just by focusing on an object. A camera is focused
on the input object to capture a picture of the object to transferred over
networking to a distant place of the picture the image of the can be seen on
the monitor of the distant computer connected through a network or through
internet thus, two or more persons can talk and see one another in the way.
Digitizer :- Digitizer is an input device which is
used for converting picture maps, and drawing into digital form for storage in
computer for storage in computer. Such as X and Y co-ordinates of points in a
drawing.
Digitizer
commonly used in the area computer aided go design cars, building, mechanical
device etc.
Voice/Audio Input
Voice/audio or music signal can be
stored, processed mixed further stored in the wave form. These processed files
can be heard with the help of speakers. Audio processing technique has helped a
lot to develop voice recognition system, creating, innovative musical notes,
audio-video mixing and other multimedia applications.
We may segregate the voice recognition
& music processing as under:-
Voice Recognition:- In voice recognition technique firstly various voice
patterns are stored in the form of digital files. The voice to be recognised is
fed into the computer, the computer and the relevant software analyses the
input audio pattern with the stored one. If both patterns match with each
other, the computer allows user to perform certain pre-derermined operation.
Some software also allow users to give certain voice commands that computer can
understand and follow.
Music Processing:- Music can be stored, mixed and new tunes can be
composed with the help of waveform files and innovative waveform can be created
through MIDI keyboards. Usually, a picture of
switches of tape deck appears on screen which helps user to control play,
pause, reverse fast forward, rewind etc.
Audio & Video - Graphics presentation,
animation or advertisement slides/films can be processed and prepared with the
help of sound/video card and relevant compatible software.
OUTPUT DEVICES
Such devices that
can be used for converting machine comprehensible forms into human compressible
form are said to be output devices. Usually, output devices can provides output
in printed form of text/graphics, display text/graphics, produce audible
signals or machine readable signals, which can be further, stored on storage
media or communicated to remote computer.
PRINTERS:- This is the most commonly used output device
without which enduser find himself helpless to present his work done on
computers. Your selection must be based on the job to the performed.
The following table is self explicit for
the classification of printers:
Printers
can be classified into two groups:
(a) Impact Printer
(b) Non-Impact Printer
IMPACT PRINTER
These printers
generate a mark by the impact of typeface or typefaces against paper through
inked ribbon. Mulitple copies may be obtained by using carbon paper or
carbonless chemical coated paper. Impact printer may be further classified
into following two classes :
(a) Low speed impact character printer
(b) High speed impact line printer
Low speed impact character printer
These printers print a character at a time these may be
further classified into following three sub groups:
(a) Dot Matrix printer
(b) Daisy wheel printer
(c) Golf/Type Ball Printer
Dot/Marix Printer
These are capable of printing text
and graphic images.Some dot matrix printers are equipped with multicolour
ribbons. Speed of dot matrix printers vary between 40 and 500 character per
second (cps)
Daisy Wheel printer
These are also known as letter
quality printers. These are best for text printer graphic images cannot be
printed through these printers. Its speed may vary between and 60 cps.
Golf/Type Ball Printer
These are letter quality printer but
almost obsolete now. These were equipped with plastic or metallic ball embossed
with characters. Graphic/image printing was
not possible with this printer. Its speed varied between 25 to 60
character per second.
High speed impact line printer
These printers construct a line of
output at a time. Usually its speed varies 150 to 3000 lines per minute
depending on printer device used. These are primarily used with
mini/mainframe/super computers. Some printing devices used in line printers
are:
(a) Print chain device
(b) Steel Print band device
(c) Drum or Barrel print device
Print chain device :- Printing of graphic image is not
possible with this printer.
How it works? – it consists of a
chains with character engraved on each link which composes a line of output on
paper.
Steel Print band device :-It is similar to print chain device.
How it works?- It uses a horizontal
rotating steel band with engraved characters instead of a chain that produces
output on paper.
Drum or Barrel print device
It
consists of a set of bands around the drum or barrel. This technique is also known
as fly printing The number of bands are equal to the printing position of
printer usually 132. One revolution of drum is required t print one line. Band
and barrel of characters are moving all the time is this technique.
NON IMPACT PRINTERS
The printing process is done without or
with minimal impact of type faces on paper in these printers. Owing to this
peculiarity, these printers cannot produce multiple copies.
These may be further classified as :
(a)
Low speed non-impact character/page printer
(b)
Low/High Speed non-impact/page printer
Low Speed non-impact character page
printer
These printer print a character/page
at a time. The most popular technique are:
(a)
Thermal transfer technique
(b)
Ink-jet technique
(c)
Bubble-jet technique
Thermal transfer technique
These printers are also known as
solid ink printers. These can print at a speed of apx.500 cps.
Ink-jet technique
These printers are capable of colour
printing using three primary colour cyan magenta and yellow apart from black
& white printing.
Bubble jet technique
These are capable of printing at the
speed of 110 cps to 220 cps for high quality printing.
Low/High speed non-impact page
printer
These printers construct a page of
output on paper in a single cycle. Some of the most popular techniques are:
a) Thermal Transfer Technique
b)
Magnetograghy Technique
c)
Laser Technique
d)
Led Technique
Thermal Transfer Technique
This technique is similar to that of
thermal transfer technique adopted for character printer. This technique is
used for high resolution printing. It is inexpensive and quiet in operation,
speed is handicap.
Magnetography Technique
A japanese company Iwasaki Tsushinki
claimed the development of super fast speed of 115 pages per minute using
conventional toner.
Lazer/Optical Technique
Laser is abbreviated form of light Amplification
by stimulated Emission of Radiation. We have discussed about the term resolution
which refers to dots per inch (dpi).Higher the dpi, higher the resolution and
lower the dpi, lower the resolution. opatiocal/laser printer arrived in 1980's
in the market. A typical laser printer may handle A-4 size of paper and capable
to print 8 page paper per minute (ppm) to 16 ppm. Standard resolutions are
300,600,1200 dpi etc.
GRAPH PLOTTER
Graph Plotter is an output device
which is used for drawing graphics and text computer’s processor direct6ly
controls the movement of one or more pens over a paper by sending a series of
digital signals representing X,Y co-ordnates for two dinmension and X,Y and Z
co-ordinate for 3 dimension graphics. Some dot matric printers are capable for
pripnging graphics but, their quality and resolution are limited. Graphics
plotters have replaced them due to high quality and resolution. Thus higher the
resolution; finer the graphics output.
VIDEO OUTPUT
Video output is the most important
aspect without which user may find himself handicap to interact with computers.
It would be something like a blind person reading with the braile technique
without visual sense. In computer jargon Visual Display Units the (VDUs) are
termed as monitors. Most of the monitors consist of a CRT (Cathode Ray Tube),
LCD (Liquid Crystal Display) or ELD (Electro Luminescent Display) and related
circuitry for visual display of text and video graphic output.
A
light pointer appears on screen to assist a user is known as cursor. The cursor
moves automatically alongwith keyed character,
A typical monitor displays 24 or 25 lines with
80 character in each line. User can view/read a full screen or page. User may
also scroll line by line or page by page the text/graphics upwards or
downwards. Some software also provide facility of scrolling the text/ graphics
horizontally left wards or right wards.
A
basics tip to purchase a good monitor is to judge the monitor from your eyes.
Technically speaking you must be comfortable to use the monitor with industry
level specifications. Apart from size of monitor such as 9" , 12" ,
13", 14", 17" etc. other factors are resolution, dot pitch, phosphor coating etc.
It would be obvious to understand some of the terms related to monitors.
Pixel- It is a light or dark
point of tiniest patch of light that can be displayed on the screen of monitor.
Grid- A screen of monitor is
divided into columns and rows known as grid.
Resolution – Number of pixels in
a grid is known as resolution. Higher the density of pixels, higher the
resolution and lower the density of pixel, lower the resolution.
Video Memory – A part of memory
is arranged to represent characters according to grids of rows and columns on
the screen in known as video memory.
Dot pitch- Dot pitch is the vertical distance of centre of two adjacent
pixels in B&W monitor. In color monitor dot pitch is the vertical distance
between two adjacent pixels of same colour. It is measured in millimeter (mm).
Phosphor Coating- It is a
special coating on inner surface of the monitor screen, which glows at the spot
where electronic beam’s negative charged particles strike. The glowing retains
till the beam strikes and glowing vanishes as soon as beam lefts the spot. The
retention time of growing should be neither too long nor too short. Imbalanced retentively
may damage the text/graphic display.
Scanning – Scanning is the
process of electronic beam’s movement from top left of screen to the right
bottom of screen horizontally and vertically.
CATHODE RAY TUBE (CRT) BASED MONITORS
These monitor can be classified in
two classes according to display colours.
a. Monochrome Monitors
b. Colour Monitors.
Monochrome Monitor
Monochrome
monitor can only display one colour. The colour displayed by these monitors are
black & white, or one colour such as green or amber.
How it works? – It consists of CRT
which is a vacuum tube having an electronic gun, a yoke and phosphor coated
screen. Video signals received from peripheral controller or adoptor circuits
of computer’s CPU is passed to CRT through relevant circuits of monitor which
controls darkness brightness, contrast, colour, shades and other fine tuning
controls. While scanning process text and graphics images are formed by turning
on or off the electron beam.
Colour Monitor
Colour
monitor can be further classified as under:
a. Analog Monitors
b. Digital or TTL (Transistor to
Transistor Logic) Monitors
Analog Monitor
Its
function is similar to that of TV monitor capable of displaying variable
degrees of brightness and shades. The pixel in this monitor is either
completely on or completely brightness and shades. The pixel in this monitor is
either completely on or completely off.
Digital or TTL
Monitor
In
this monitor a fixed low voltage is being applied for pixel in either off or an
state. It means that when on a signified higher voltage is applied whereas in off
condition a fixed low voltage is applied.
Sometimes
colour monitor are also classified in two types, composite colours & RGB
type monitors. Composite color monitors produce image similar to TV, whereas,
RGB type monitors separate colour signals and produce sharp images than
composite colour monitors.
What is an adaptor?
An
adaptor is a Printed Circuit Board (PCB) fixed in an appropriate expansion slot
on mother board of PC. It receives digital signals from the CPU, converts them
into analog signals, sends them to the monitor’s PCB for controlling intensity,
colours, beams to create desired shades, size of text etc. Basically, any
adaptor consist of two components video controller chip and display memory
chip. Most of the monitors are named on the names of relative adaptors.
Various
most popular Graphics Adaptor circuit used to translate computer signals into
graphic signals are as under:
Monochrome Display Adaptor (MDA)
It
displays single colour e.g Green, amber or white against a dark background.
HGA (Hercules Graphic Adaptor)
A typical HGA provides 720 X 348
pixel resolution with no colours. It is named on its manufactured Hercules Computer
Technologies.
CGA (Colour Graphic
Adaptor)
A
typical CGA provides 320 x 200 pixel resolution and 16 colour palette.
EGA (Enhanced Graphic
Adaptor)
A
typical EGA provides 640 x 350 pixel resolution and 16 colour palette.
VGA (Video Graphic Array)
A
typical VGA provides 640 x 480 pixel resolution & 256 colour palette.
Super VGA
It
is a least expensive way to upgrade the performance of VGA by putting SVGA card
into appropriate expansion slot which can increase 2,62,000 to several million
colours which further depends on video RAM with resolution mentioned above in
VGA or beyond.
Flat Panel Display Devices (FPDD).
Flat panel Display devices are
gaining popularity due to its light weight, compact design and low power
consumption. These are most popular display devices for portable computers e.g
note book PC. Laptop PC, hand held/Palm top PCs etc.
FPDD uses any of the following
techniques.
a. Liquid Crystal Display(LCD)
b. Electro Luminescent Display(ELD)
c. Gas Plasma Display(GPD)
Liquid Crystal display (LCD)
In
this technique a liquid filled display surface us used which creates
images/text using ambient light when electrically charged.
Electro Luminescent Display (ELD)
In this technique light is produced
on a sensitive surface through the application of electric current.
Gas Plasma Display (GPD)
In this technique an inert gas usually mixture
of neon and organ is trapped between flat glass plates and a grid of electrodes
permit the turning ‘on’ and ‘off’ of pixels. These monitors are least portable
than others.
MASS STORAGE DEVICES/SECONDARY MEMORY
You have studied about various types
of input and output devices needed to store data. Mass Storage Devices (MSDs)
are necessary to store computer programs, software and mass data. The term mass
storage means the quality of data larger than the amount that can be stored in
computer’s memory at any one instance.
There are further types divided into
mass storage devices.
1.
Hard disk Drives (HDD)
Disk drives are known by various
names such as fixed disk, rigid disk, Winchester (code name for the IBM project
that developed this product) disk, hard disk drive etc. and come various sizes
e.g 15", 8", 9", 5'-1/4", 3'-1/2" etc. Here, size
refers to the diameter of a set of rigid aluminum platters coated with magnetic
oxide and read/write heads assembly in a sealed unit. These hard disks are
being used in almost all computers from portable to mini/mainframe computer as
single/double floppy drive based systems became obsolete now days. Hard disks
are about 20 times faster than floppy disks with a capacity to store and f
Offer access to hundreds of data
files/programs. Also it can provide faster access to large amounts of data
files/programs. Also it can provide faster access to larger amounts of data
with a single move of the access arm. The major disadvantage is that it is
shock sensitive and it must be backed up regularly.
Hard
disk drives can be either fixed in the system unit or can be used as an
external storage device making them portable. Various important part of the
hard disk are as under:
There are three types of HDD.
1. Zip/Bernoulli Disks
2. Disk Packs
3. Winchester
Zip/Bernoulli Disk:- In this hard disk, a single hard disk
platter is encored in a plastic cartridge. A commonly in a used zip disk is of
3-1/2 inch size having a storage capacity of about 100 MB, Depending on the
formatting style used by a particular computer system. In a zip disk can be
easily inserted into removed from a zip drive or video cassette in a VCR.
Disk Packs:-
In this types a disk pack consist of multiple (two of move) hard disk platters
mounted on a single central shaft these two surface are not user for data
recording in a disk pack. When not in use, disk packs are stored in plastic
cases. This gives virtually inherited storage capacity to disk packs.All the
disks of a disk pack revolve together at the same speed as metioned before the
disk drive of a disk pack has a separate dead/write head for each disk surface,
excluding the upper surface of the topmost disk and the lower surface to the
bottom most disk.
Optical Disk:-
In optical disk storage system consist of a rotating disk which is coated with
a thin matter or some other material that is highly relative laser been
technology is used for recording of data on the disk optical disk are also
known as laser disk or optical laser disks.
Optical disk drive:- An optical disk drive contains all the machenical,
electrical and electronic components for holding an optical disk that can be
used for reading or writing of information.
Type of writing disk:- All optical disks are round plotters. They come in
different size and capacities.
1.)
CD-ROM
2.)
Worm disk
CD-ROM:- CD-ROM stands for (COMPACT
DISK READ ONLY MEMORY). It is read of audio/Video CD and other programs.
The CD-ROM disk is a shiny, silver color metal disk of 5-1/4" diameter. It
has a storage capacity of about 650 MB.
Worm disk:- Worm disk stands for (Write
Once Read only Memory) worm disk allow the users to creates their own
CD-ROM disk by using a CD-Recordable drive which look like standard CD-ROM disk
are purchased black and encoded using a CD/R drive.
Magnetic tape: - Magnetic tape is the most popular
storage medium for large data the magnetic tape medium is a plastic ribbon
which is usually ½ or ¼ inch wide and 50 to 2400 feet long. It is coated with a
magnetically recording material such as Iron oxide or chromium dioxide magnetic
tape just like audio or video tape.
Disk Drive: - A magnetic disk has to be mounted on a disk drive before it
can be used for reading or writing of information.
A disk drive contains all the mechanical
electrical and electronic components for holding one or more disk and for
reading or writing of information or to it otherwise.
By which devices to read and write of any types of information
from CD (Compact disk) and floppy is called disk drive.
Disk formatting: - Disk formatting is one of the base
takes handled by the computer’s operating system. If the formatting is done by
the remove and add of newer operating system.
Note: - That, this is not possible by he user
of disks between computers having in compactable disk drive.
Magnetic disk:- It is secondary storage device. It is
most popular storage medium for direct access secondary storage. It is made of
metal or plastic which is usually coated on both sides with iron oxide.
All magnetic disk are round platter
they comes in some different sizes, different types of packing and it can be
made of rigid metal or flexible plastic.
Floppy disk: - A floppy disk is a round, flat piece
of flexible plastic coated with magnetic oxide. It is encasing in a square
plastic or jacket cover capacity of floppy: - 1.33MB size of floppy 3-1/2 inch,
5-1/4 inch.
NUMBER SYSTEM
Number System:-
–Every Computer understand for only on
binary number but human being understand
decimal number letter and other
special character in coded form .
Number System is basically of two
types.
1) Non positional number system.
2) Positional number system.
1) Non positional Number
system- Non positional number system human beings counted on fingers. In this system but do not calculate the accurate
result this method to use for counting
is stones , pebbles or sticks, were used to indicate values .
Such as – I for 1
II for 2
III for 3
Iv for 4
V for 5
2) Positional Number
System- In this number system there are only a few symbols called digits this
symbol represent different values depending on the position they occupy in the
number. There are four types of number system.
1) Decimal Number System.
2) Binary Number System.
3) Octal Number System.
4) Hexa Decimal Number
System.
Decimal Number System – 9n this system that we used in day
life is called the decimal number system .The decimal number system to be 9ets
(0,1,2,3,4,5,6,7,8,9,) is total Ten digits
Binary Number System – In this system is used to (0,1) is called binary number system . We have only two digits or
symbols.
Such as-(0,1)
Octal Number System - In Octal number system the base is 8.50 in this
system there are only eight symbols or
digit 0,1,2,3,4,5,6,7 and (8 or 9 do not exist in this system.
Hexa Decimal Number System- In Hexa decimal number system is one
with a base of 16. The base of sixteen
suggests choices of sixteen character digits or symbols. The first 10 digits
are the digit of decimal system .0,1,2,3,4,5,6,7,8,9 the remaining six digit
are denoted by A,B,C,D,E and F.
Binary Coded Decimal (BCD) – The BCD is the simplest binary code
that is used the BCD code bits represent number .9n number. Such as -0010
If a
decimal consists of move then one digit, each decimal digit is represent
individually by its 4 bit binary equivalent of the decimal number. For ex – the
binary equivalent of 45 is 101101.
ASCII CODE- ASCII Stand
for American standard code for information Interchange. ASCII code is used
extensively in small computers, peripherals, instruments and communications
devices. This code replaced by many on the special codes that where previously
used. It is an even bit code. Micro computer using 8.bit word length use 7 bit
to represent the basic code. The 8th bit is used for parity or it
may be permanently 1 or 0 with 7 bits. We to 128 characters can be coded. It includes
upper and lower case alphabet number and punctuation mark and special characters.
SOFTWARE
SOFTWARE:- Software
is the only media through which we can interact with computers. Of course, its
is the invisible media quit similar to the invisible notes in the mind of a
musical composer or a person driving vehicle as quoted in the above example.
That is why sometime hardware is defined as the computer components those are
physically visible while those set of instruction which drives the computer
components in the invisible form are termed as software. Nothing useful can be
done with the computer hardware, even if hardware is linked logically together
to form an effective working unit, unlike and unless it is driven by a set of
instruction understandable to computer called as software.
System Software
It is a collection of
complex programs which help to operate, control and enhance the processing
capabilities of computer usually supplied by manufacturers.
There are two of system software
(a)
Operating
Systems
(b)
Programming
Language
Operating system :- Operating manages the computer’s overall resources
and schedules its operations.
ANSI’S ( American
National standard Institution’s) definition of Operating system is software which controls the
execution of computer programs and which may provide scheduling, debugging,
input/output control, accounting, compilation, storage assignment, data
management and related services.
The
main tasks of the operating system involve:
a. Helps to communicate between operator
and computer
b. Monitors and controls computer
peripherals
c. Offers software monitoring and
multiprogramming services.
It acts as an interface
between user program and components of computer comprising of
(a) Control Programs
(b) Processing Programs
Control Programs
Control programs are useful to control the entire
hardware internally and user has no control to alter it.
It
is further made up of following three modules:
(a)
Operating System supervisor
Operating System
Supervisor, also known as OS Master Program controls the over all management of
computer system. It co-ordinates all parts of OS and resides in the primary
storage section of the processor whereas the other programs resides in an
on-line system so that supervisor can call up and store them temporary in the
processor when needed. In most of the Personal Computers Os Supervisor and
other OS Programs are stored in a floppy disk/hard so that it is automatically
loaded into primary storage. It works with BIOS (Basic Input/Output System).
BIOS is a part of operating System that links the specific hardware devices to
the software.
(b) Job Control Program
Job Control Program is
needed in multitasking or batch processing environment. In order to handle more
than one job the instruction are coded in Job Control Language (JCL). Job
control program reads and executes these codes. It further schedules multiple
tasks to balance input/output and processing requirements. It also handles
system interruption are signals which tell the processor to stop current task
and handle other one. It becomes duty of OS to keep track of interrupted
program so that its execution is restored later.
Monitoring System
Monitoring System
monitors status of computer system during processing operation and supplies
information about its function and operation e.g if an error is detected
Operating System sends message to Operator or operating System may put warning
message and passes control to the next job.
MS-DOS/PC-DOS
Disk Operating system
designed and developed for 16 & 32 bit machines and Intel’s microprocessors
by various software suppliers around mid 1980s. Also in 1980 Seattle
UNIX
(b)
Initially developed at Bell Laboratories in 1969 for mini, mainframe,
super computer systems. UNIX is a multitasking and multi-user operating system.
The two standard version of UNIX are Open Look, and Motif. System V.$ is open look offered by Unix international
and Sun Microsystems. OSFI is Motif offered by open software foundation led by
IBM, Digital and Hewlett-Packard. MS-DOS and UNIX currently the most popular
operating systems.
PROGRAMMING LANGUAGES :- Programming Language are set of
language used to express programs and consist of all the symbols, character and
usage permit communication between human and computer. These are having their
own vocabulary and grammar or syntax like other languages e.g Hindi, English,
Tamil etc. The term ‘syntax’ is a computer jargon which refers to the set of
rulers that determines the set of possible instruction instructions in the
particular language understandable to the computers. Programming language learning
is quite similar to learn any of the human understandable language.
These may be divided into following classes.
1. Low Level Language :- A low level language is called machine level language.It has a simple
instruction set of command through which all the tasks are done. The instruction
given to the computer is not binary codes but one of English words. Hence –
writing program is assembly language was much easier and simple then machine
code of the converts. A low level language was closely related to the hardware
configuration as the assembly instruction set refers to the memory registers of
the computer.
1. Assembly Level Language: - As programming is a difficult in a binary language. A new
language introduced as all assembly language. This language some command for
doing a certain task as Add, Subs, Pop, Push, etc. Which is being translated by
an assembler to make it machine under stable it this language programming
become easy but the problem with this language that it is complete machine
depend language as windows 98, Windows XP, Unix, Linex etc.
2. High Level Language: - These are programming language in which instruction are
given in English –like text rather than in binary digits (0s and 1s), that the
computer understands, are known as high level language – A language the user
some command on any computer system world wide such language user some key
boards to develop to a program.
Which program goes to the
computer to translate it not the machine understandable and it is being
executed by the computer system.
Eg :- Basic logo, COBOL,
C, C++ etc.
TRANSLATOR
With
help of this option or program in lower level and higher level convert the language
into machine. There are three types of translator for the language:-
- Assembler: -
This translator is used to convert the program written in low level
language assembly into machine language.
- Compiler:-
Compiler are used to convert the high level language into machine level
language. This errors and error us statement and convert the program into
machine code. A separate command is used to execute the program.
- Interpreter:- Interpreter are also used to convert high level language into machine level language. An interpreter checks for error statement by statement the statement and this process is continued but steps when statement is encountered end of the program is reached.
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