Structure of Lesson
11.1 Objectives
11.2 Introduction
11.3 Impact Printers
11.3.1 Dot Matrix printers
11.3.2 Daisywheel printer
11.3.3 Chain printer
11.3.4 Band Printer
11.3.5 Drum Printer
11.4 Non impact printer
11.4.1 Inkjet printers
11.4.2 Laser Printers
11.4.3 Thermal printers
11.5 Plotters
11.5.1 Flatbed Plotter
11.5.2 Drum Plotter
11.5.2 Drum Plotter
11.6 Summary
11.7 Glossary
11.8 Suggested Answer to SAQ
11.9 References/Bibliography
11.10 Suggested Readings
11.11 Model Questions
11.1 Learning Objectives
This chapter will give
the detailed knowledge of commonly used device i.e. Printers. Printers can be
classified on the basis of print technology and print methodology. On the basis
of print technology, we can classify the printer as impact and non impact
printers. On the basis of print methodology, the printers are classified as
character printers, line printers and page printers. Also the comparisons
between these printers on the basis of quality of printing other features will be
explained. This chapter will further describe the detailed functioning of
various types of plotters.
Printer
11.2 Introduction
The success of business
depends to a large extent on the right decision at right time. For correct
decisions, accurate processing of large data is required to be done on proper
time. The accurate processing of data can be done by computers to produce
output for analysis. This analysis is further used in business to take
decision. Basically, output generated by
computer is backbone of analysis. So output should be meaningful and convenient
to use. Computers can produce output in two ways, display output on screen for
immediate use and stored and printed output for later us. So the output is
generated in two ways as Hardcopy and softcopy. Hardcopy is the information
printed on the paper. It is a permanent copy of data on paper by output devices
like printers and plotters. Softcopy is the information displayed on the screen
and stored in secondary storage devices. Here we will focus on the devices that
generate hardcopy of computer-generated information. Printers are used to
produce hardcopy as output. Based on
the technology used, they can be classified as Impact or Non-impact printers.
11.3 Impact printers
Impact printers use the
typewriting printing method wherein a hammer strikes the paper against a ribbon
in order to produce output. Impact printer must be used if printing a
multiple copy report so that the duplicate copies receive the imprint. These
types of printers are noisy, slow, and produce low quality output. Various
types of impact printers and their working is given below.
11.3.1 Dot Matrix Printer
These printers are also
called serial printers. They are named s
because these printers print characters by a matrix of dots . Each dot is
produced by striking a pin on a paper
against ribbon. In early days dot matrix printers were the most widely used hard
copy output devices. Now days, these printers are normally used in banks for
printing account statement and pass books. These printers are widely used where
cost effective print quality is required. The images are formed by a print head
that is composed of a series of little print hammers that look like heads of
pins. The print head usually has 9 pins to 24 pins. Increase in Pins count
leads to superior print quality. Widely used 24 pin impact printer not only
produce better print quality of text but ability to print NLQ (Near letter
quality) text in single pass. This type of printer can also print higher
quality of graphics in less time. But this printer is still inferior to the
printer having Letter quality printing. Dot matrix printer can either be 80
columns printer depending on the maximum number of character that can be
printed in a line. Some of dot matrix printers available in India
The major part of
dot-matrix printer is its print head. The characters are formed by the print
head. Print head has number of pins arranges in vertical columns and electromagnetic
field is used to shoot these pins in the form of character. In some printer a
magnet print head is used, in these types of print head spring shoots the pins
of print head. As the printer head moves in horizontal direction, the print head
controller sends electrical signals which forces the appropriate pin to strike
against the inked ribbon, making dots on the paper and forming
the desired characters.
11.3.2 Daisy wheel printers
It is a serial impact
printer, in which printing element is a plastic hub that has a large number of
flexible radial petals. Each petal has one or more differently raised printing
characters, then a servo motor rotates the wheel it is moved horizontally step
by step under computer control and stops when the desired character is in the
print position. A hammer then fires on the positioned character against an
inked ribbon. The hammer is mounted on a sliding carriage. Different type of
font printing can also be done by daisy wheel printer. Each font has its daisy wheel before the
printing starts user changes the daisy wheel to the desired font. If a document
has multiple font type printing data, then it becomes tedious to change the
daisy wheel font during the printing. Many daisy wheel printers offer bold type
printing by double or triple striking on specified character. Like all other impact printers, daisy wheel
printers are noisy, and are slower than dot matrix printers. They produce high
resolution output often called letter quality printing. It is also called smart
printer because it is bidirectional and has built in microprocessor control
features.
DAISY WHEEL PRINTER
Advantages
·
It prints letter quality printing.
·
It is bidirectional and built in microprocessor
·
It can print in any desired font
Disadvantages
·
It is noisy
·
It is serial printer and prints slowly
·
It cannot print graphics
·
To change the font style daisy wheel has to change which is
tedious job.
11.3.3 Chain Printer
It is a line printer. It
prints entire line in single operations. These types of printers are
electro-mechanical devices which print complete line of print. Its speed varies
in 300 to 2000 lines per minute. It is a high speed printer. These printers are
also known as chain printers. The print technology in the chain printer is a metallic
chain containing the embossed characters that rotates horizontally in front of
paper. A metallic chain consists of five channels and each channel consists of
48 characters. As the chain rotates,
print hammer strikes the paper against ink ribbon on the proper character on the chain. The chain
is cycles continuously until a complete print line has been formed. The print
page is then advanced one line and the process is repeated. The speed of the printer can increased by
using a chain that contains the entire uppercase , lowercase alphabets ,
numbers and special symbols in a repeated manner. Due to repetition hammer does
not have to wait long to get positioned at a desired print character.
11.3.4 Band Printer
It is a type of line printer. These printers
are variations of chain printers. On a band printer, a thin steel band is used
on which several sets of fully formed characters are embossed. This band is
continuously moving in front of hammers. In a band printer, the paper is
momentarily stopped, when the desired character passes over a given column, the
hammer activates, pressing the ribbon against the paper to form image. Again, a
selection of different bands depends on the type of printing.
11.3.5 Drum Printer
It is another type of
line printer. In this printer all the characters for printing are placed round a
surface. That round surface is called a drum. This drum is made up of metal. A
fixed font set is embossed on the drum with matching number of columns. These
matching columns are the letters on line that has to printed. The drum is
attached to wheel to spin at high speed. As desired character pass the print
position, the hammers strike the paper from the back, and press the paper
against the ribbon on the drum and cause the desired character to be printed on
the paper. A complete line of output is printed for each revolution of the drum
since all the characters in each set pass their print station during
revolution. Because the drum carrying the characters remains in constant
motion, the strike action of the hammers has to be very fast. These are lower
cost printers. It uses only one hammer instead of using separate hammers for
each column. Another generation of this printer uses two characters drums, one
drum revolution being used to print the entire odd column and another drum
revolution used to print even column. The speed of this printer ranges from 300
to 600 lines per minute.
11.4 Non Impact Printers
These printers are much
quieter than the impact printer. Non-impact printers do not touch the paper
while printing. They use chemical, heat or electrical signals to print the symbols
on paper. These printers do not strike
characters against ribbon on the paper.
11.4.1 Inkjet printers
The concept of inkjet
printing originated in the 19th century, in this type of printing, image is
created on the surface of the paper by spraying droplets of ink. The printer
with this printing technology is inexpensive and is widely used,
professionally. It provides print resolution of around 360 dpi. Some inkjet printers can make full color hard
copies at 600 dpi or more. In the inkjet
printing technique, the print head has several small (as small as pin
hole) nozzles called jets as the paper rolls over on roller, the print head
move on the paper in horizontal direction, the nozzles sprays ink on the paper, forming the
characters or image. These nozzles are attached with cartridges. These
cartridges are filled with ink. For color printing multicolor cartridges are
used. These cartridges can be refilled two or three times. After that, these
are replaced with new ones. The ink in these cartridges is in liquid form. If
these cartridges remain unused for long period of time, the ink may get dried
up and damage the cartridges as well as print head of the printer. This printer
prints with best quality. These printers are used by photographers to print
digital photographs. As the printing is done with liquid ink, it requires
little time to dry. The papers used, in these printers are heavier than the
normal paper, to avoid the bleeding of ink into the paper. These printers are slow and not designed for
high volume of job. These printers are designed for high quality of print jobs.
.
Advantages
·
They can print any language like Hindi, Punjabi and Chinese etc.
·
It provides an excellent middle group between dot matrix and laser
printers.
·
It can prints in several colors.
·
They are inexpensive in nature.
·
Print quality is much higher than other printers.
Disadvantages
·
These printers are slow printers.
·
These printers need heavier paper than other printers to avoid
bleeding of ink.
·
Special care of cartridges and print head is required.
11.4.2 Laser Printers
The term LASERS is
defined as ‘Light Amplification by Simulate Emission of Radiation’. During
1969. Gray Strakweather, from Xerox Corporation had given the idea about the
Laser printer. During 1981, the first laser printer designed for use in office.
. This printer uses a narrow beam light for printing called laser beam. This
laser beam is responsible for transferring high energy source to small area.
This printer is non impact printer and popularly used with personal computers.
It uses the photocopier technology. A separate computer is built up in this
printer to interpret the data that is received from the computer and to control
the laser. When a document is sent to the printer a laser beam draws the
document on a selenium coated drum using electrical charges. After the drum is
charged, it is rolled in toner. Toner consist of dry powder type ink made up of
oppositely charged particles. The toner sticks on the charged portion of the
drum. Because drum and toner (ink) is oppositely charged they attract each
other and ink stick on the drum in a particular shape. Thus, with pressure and
heat toner is transferred off drum to the paper. After the document is
printed the electrical charges is removed from the
drum and excess toner is collected. Laser printers are page printers. The
resolution of laser printers varies from 600 to 1200 dpi. They can print 8 pages per minute (ppm). These
are high speed printers. These printers provide high quality printing with very
less cost. The cartridge of this printer can be refilled again and again and
can be repaired. It uses dry ink to print. Inkjet printer is about ten times
more expensive to operate than a laser printer. It can print on normal paper.
These printers use Print control Languages for printing letters,
database printouts, spreadsheet and simple graphics. This printer has its own
memory called printer buffer. These memory stores the data and images
temporarily before printing and after printing the memory is erased out. Laser
printer can print on transparencies, adhesive labels and lightweight cards. A
laser printer with duplex printing can print on one side of the paper, turn the
paper over, and print on the other side. When a laser printer receives data
from the computer to print, it takes 5 to 30 seconds to prepare the printer to
print a new job. This is in addition to the time it takes to actually print the
document and is called warm-up time. When the printer is turned on, it needs
time to warm up the fuser to operating temperature. If the printer has a
standby mode, the warm-up time becomes even more important. This waiting period
can hinder overall productivity.
Advantages of Laser
Printers
·
It has high speed of printing. Its speed is measured in ppm (page
per minute)
·
Printing Noise level is almost nil.
·
It has capability to print excellent graphics.
·
It prints with high print quality
·
This printer has low cost of printing.
·
Laser printer comes in compact size and varieties of styles.
·
Standard paper is required for printing. Even can print on every
type of paper.
Disadvantages of laser printer
·
Double printing cannot be simultaneously performed.
·
They are costly printers.
·
It is large hardware device which can take up a lot of space.
11.4.3 Thermal printers
The thermal printer is
an alternative to other serial printers.
Thermal printing is digital printing process. These printers use thermal
paper for printing. Thermal paper is special paper that is coated with chemicals
that changes color when exposed to heat. When this paper is passed through the
print head, the coating turns black in the areas where it is heated. Some fax
machines use thermal printing techniques. Output on thermal paper fades quickly when exposed to light,
moreover the hardware is often inexpensive.
Thermal Receipt Printer
11.5 Plotters
In business, there is
immense usage of colorful graphics and engineering designs. This demand has
created a need for corresponding output device. Computer generated designs can
be printed on the paper with printers and plotters. The print technology is
based on two methodologies, Raster printing devices and vector printing
devices. In Raster printing devices, images and text is printed on paper in
small dots. Many printers like dotmatrix printers, inkjet printers etc are the
raster printer devices. In vector printing images and text is printed on paper
with by drawing lines and curves.
The plotter is a type of
printer and used for vector graphics printing. These devices were widely used
in printing of engineering designs. Now these devices are replaced by modern
printers. Like printers plotters gives
the hard copy of pictures and designs. Plotters are used to print designs of
ships and machines, plans for buildings and so on. A plotter is printer that
accepts the commands from computer to make line drawings on paper with
automated pen. Plotter can draw point to point line directly as per command. It
generates the two dimensional graphics representation. They are used to produce
large drawings or images such as map of buildings or blue prints of mechanical design
etc.
There are two types of plotters.
·
Flatbed Plotters
·
Drum Plotters
11.5.1 Flatbed Plotters
A flatbed plotter is
also known as Table Plotter. It uses a bed or tray to hold the paper in a fixed
position. This plotters uses robotic arm
attached with pen that can move the pen both in horizontal as well as vertical
directions on the paper mounted over the flatbed or tray. The mechanical movement
of arms is controlled by computer. The instructions given by the computer is
responsible to move arm in x-y directions on the page. Robotic arm can
be mounted with colored pens. The instructions that a plotter receives from a
computer consists of a beginning and ending coordinates for a line. With that information,
the plotter picks up the appropriate pen, position it at the beginning
coordinates, drops the pen down on the surface of the paper and draw to the
ending coordinates . Plotter draw curves by a sequence of very short lines.
Limitation
It limits picture size to the dimension of the tray.
It limits picture size to the dimension of the tray.
It is slow device as
compared to printers.
11.5.2 Drum plotter
In this type of
plotters, a cylindrical drum is used to mount the paper instead of flatbed
tray. The drum is rotated in clockwise direction. There is a single robotic arm
mounted on pen that can move across the drum horizontally. The drum itself
moves the paper forward or backward to enable the pen to draw in any vertical
direction. Any type of diagonal line is drawn by combining a horizontal
movement of the pen on the drum having vertical movement. Drum plotters are
used to produce continuous output, such as plotting earthquake activity or in
ECG machines. It eliminates the
drawback of flatbed plotters of limited print area. It can print on any size of
paper length.
The Plotter
. 11.6 Summary
We have two types of
printing output devices, Raster printing devices and vector printing devices.
Raster printing devices are printers and vector printing devices are Plotters.
We have different types of printer and plotters are available in the market. We
can differentiate them on the basis of technology used in printing. But these
printers have their own advantages and disadvantages.
|
Output Devices
|
Advantages
|
Drawbacks
|
|
Impact Printers
|
||
|
Dot
Matrix Printer
|
Printing cost is very less, durable and reliable
|
Slow speed
printers, Print quality is very Low,
Generates lot of noise during printing, Needs a Special paper to print.
|
|
Daisywheel
Printer
|
Print quality
is better than dot matrix printers, Can print in multiple fonts,
|
Very slow, generate
lot of noise, Cannot print graphics
|
|
Chain
printer
|
Same print
quality as daisy printer, It can also print in multiple font
|
Slow printers,
Not durable, generate noise while printing, Cannot print graphics
|
|
Band
printer
|
Same print
quality as daisy printer, It can also print in multiple font, Faster than
chain Printer
|
Slow printer,
Not durable, generates noise while printing, Cannot print graphics
|
|
Drum
printers
|
Same print
quality as daisy printer, It can also print in multiple font
|
Slow printer,
Not durable, generate noise while printing, Cannot print graphics
|
|
Non
Impact Printers
|
||
|
Ink
Jet Printer
|
Quiet printer,
Print quality is very good, widely professionals. Less expensive
|
Printing speed
is slow as compared to other non impact printers, Printing cost is very high,
Not much durable, Uses wet ink to print.
|
|
Laser
Printer
|
Fast printers,
Print quality is also high, Printing speed is fast, uses dry ink to print,
Cost of printing is very low as compared to inkjet printers
|
Expensive printers,
Takes warm up time to start the job.
|
|
Thermal
Printer
|
Quiet printer
|
Special paper
needed, Special purpose printers, Less durable
|
|
Plotters
|
||
|
Flatbed
Plotter
|
Widely used in
vector graphics printing, and to print designs on paper, Reliable and
durable, Printing cost is depend on the paper, Uses normal writing pen for
printing,
|
Expensive
machines, Printing speed is slow than printers, Limit of Paper size
is dependent upon the paper
mounted tray of the printer, Occupies large space
|
|
Drum
Plotter
|
Large paper
handling capabilities, occupies less space, Reliable and durable, Printing
cost is dependent on the paper, Used
normal wiring pen for printing,
|
Very expensive
|
11.7 Glossary
·
CPS (Characters per second)
·
LQ (Letter Quality)
·
NLQ (Near letter quality (very good print)
·
PPM (Page Per Minute)
·
DPI (Dots
Per Inch)
·
LAN (local area network)
·
CPU (central processing unit)
·
LPM (Line Per Minute)
·
Toner (Dry ink powder used in
laser printer)
·
Cartridges (Apparatus in which ink is packed for
printing)
11.8 Suggested Answer to
SAQ
Question: What is
difference between impact and non impact printer
1. Metaphors:
Impact printer -These
printers use pins or metallic embossed fonts as a print head and strike print
head against ribbon on the paper and generate noise while printing.
Non-impact printer
- Produces text and graphics on paper without actually striking the
paper and generate no noise.
2. Types
Impact printer - Dot-matrix printer, Daisy wheel, Chain
Printer, Band Printers
Non-impact printer
- Inkjet printer, laser
printer and thermal printer.
3. Speed
Impact printer - Printing speed is slow and measured in
CPS, LPM
Non-impact printer -Fast
speed of printing as compared to impact
printers and measures in PPM.
4. Print Quality
Impact printer
- Produce near letter quality (NLQ) print only, which is just
suitable for printing mailing labels,
envelopes, or invoices
Non-impact printer
- Letter-quality printouts
5. Utilization:
Impact printer - These
printer is not used widely, These are used to print financial transaction in
banks and offices.
Non-impact printer
-Widely used professional printers today
6. Ink source
Impact printer- Uses
ribbon as ink source
Non-impact printer-
These printer uses wet ink or toner as
ink source.
7. Cost:
Impact printer - Less
expensive
Non-impact printer
- More expensive
8. Robustness:
Impact printer - These
printers are reliable and durable.
Non-impact printer- Less durable due to sensitive technology.
Question: What is Draft Mode?
Lowest printable
resolution, it is also the quickest but not the best output, it is usually used
for spell checking before the actual print
Question: Explain the working of
chain printers?
It is a line printer. It
prints entire line in single operations. These types of printers are
electro-mechanical devices which print complete line of print. Its speed varies
in 300 to 2000 lines per minute. It is a high speed printer. These printers are
also known as train printers. The print technology in the chain printer is a
metallic chain containing the emboss characters, that rotates horizontally in
front of paper. A metallic chain consists of five channels and each channel
consists of 48 characters. As the chain
rotates, print hammer strike the paper against ink ribbon on the proper character on the chain. The chain
cycles continuously until a complete print line has been formed. The print page
is then advanced one line and the process is repeated. The speed of the printer can increased by
using a chain that contains the entire uppercase , lowercase alphabets ,
numbers and special symbols in repeated manner. Due to repetition hammer does
not have to wait long to position a desired print character.
Question: Explain the advantages and disadvantages
of inkjet printer?
Advantages
- They
can print in any language like Hindi, Punjabi, and Chinese etc.
- It
provides an excellent middle group between dot matrix and laser printers.
- It
can prints in several colors.
- They
are inexpensive in nature.
- Print
quality is much higher than other printers.
Disadvantages
- These
printers are slow printers.
- These
printers need heavier paper than other printer to avoid bleeding of ink.
- Special
care of cartridges and print head is required.
Question: What is different types and purpose of
the Plotters?
The plotter is computer
printer for vector graphics printing. These devices were widely used in
printing of engineering designs. Now these devices are replaced by modern
printers. Like printers plotters gives
the hard copy of pictures and designs. Plotters are used to print designs of
ships and machines, plans for buildings and so on. A plotter is printer that
accepts the command from computer to make line drawing on paper with automated
pen. Plotter can draw point to point line directly as per command. It generates
the two dimensional graphics representation. They are used to produce large
drawings or images such as map if buildings or blue prints of mechanical
objects.
There are two types of plotters.
·
Flatbed Plotters
·
Drum Plotters
Question: Explain the working of Drum
Plotters?
Drum plotter: In this
type of plotters, a cylindrical drum is used to mount the paper instead of
flatbed tray. The drum is rotated in clockwise direction. There is a single
robotic arm mounted on pen that can move across the drum horizontally. The drum
itself moves the paper forward or backward to enable the pen to draw in any
vertical direction. Any type of diagonal line is drawn by combining a
horizontal movement of the pen on the drum having vertical movement. Drum
plotters are used to produce continuous output, such as plotting earthquake
activity or in ECG machines. It
eliminates the drawback of flatbed plotters of limited print area. It can print
on any size of paper length.
11.9 References/Bibliography
- Introduction to Computers, Peter Nortron, Tata Mc-graw
Hill Publishing company Limited.
- Computer Fundamentals, P.K Sinha, BPB Publications
- Introduction to Computers By Gary Shelly, Steven
Freund, Misty Vermaat, Published ByShelly Cashman Series
- Introduction to computer by Raj Mohan Joshi, Published
by Isha Books,
·
Fine Art Printing for
Photographers: Exhibition Quality Prints with Inkjet Printers
By
Uwe Steinmueller, Juergen Gulbins
·
Handbook of Print Media: Technologies and
Production Methods
Edited by Helmut Kipphan
·
Advances in Non-impact Printing
Technologies for Computer and Office Applications, Proceedings
11.10 Suggested readings
·
Fine Art Printing for
Photographers: Exhibition Quality Prints with Inkjet Printers
By
Uwe Steinmueller, Juergen Gulbins
·
Handbook of Print Media: Technologies and
Production Methods
Edited by Helmut Kipphan
·
Advances in Non-impact Printing
Technologies for Computer and Office Applications, Proceedings
11.11 Model Questions
·
What is Printers?
·
Explain the different types of printers.
·
Explain the working of laser printer?
·
Explain the working of Dot Matrix Printer?
·
What is Difference between Printers and Plotter?
·
Explain the criteria to measure the print quality of Printer?
·
Explain the criteria to measure the print speed of printers?
·
Give the classification of non-impact printing technologies?
·
What
is difference between flatbed plotter and drum plotter?
Structure of the Lesson
12.1 Learning Objectives
12.2 Introduction
12.3 Various Types of Software
12.3.1 Software as observed the user
12.3.2 Platform software
12.3.3 Application Software
12.3.4 Features
12.3.5 Issue of Patents
12.3.6 Software bug
12.3.7 Software Issues
12.3.8 Software Appraisal and choice
12.3.9 Licensing and authorization issues of the software
12.3.10 Legal Entitlements over the software
12.3.11 Software Upgrades
12.3.12 Enterprise Software
12.3.12 Reorganization of Organizational Software
12.3.14 Middle ware
12.3.14.1 Shareware
12.3.14.2
Freeware
12.3.14.3
Opensource
12.4 Summary
12.5 Glossary
12.6 Suggested Answer to SAQ
12.7 References/Bibliography
12.8 Suggested Readings
12.9 Model Questions
12.1 Objectives
This chapter will
introduce about the concept of software and its various types. After reading
this chapter reader will have the knowledge about the software and various commercial
issues regarding software like licensing, patents. This chapter will also
provide the knowledge about various technical issues like testing, debugging
etc.
12.2 Introduction
We are all aware of the term software. Software is actually that
part of computer, which is not tangible, i.e. which we cannot touch but without
it no part of computer can work. It was only when software was invented that
the size of computer decreased and the computer became a multitasker. So,
software is as important as hardware. Let us define software. It is known as a
set of programs, which comprise of all the programs, which are executable on
the computer, libraries, applications and even the scripts. They are actually a
set of clear-cut instructions upon which the computer works.
It is not an object which has mass or which exists in a
three-dimensional space but it is stored in the memory of computers. Hardware
cannot work without the software and vice versa. If we talk at the most
fundamental level, the first set of instructions o computers were written in
machine language i.e. 0 and 1, but this was very specific to the concerned
machine only and same set of instructions would work only for one computer its
specific for. The machine language consists of a binary code (0 and 1) that dictates
the computer about what to do. But today
software is user friendly and comes in pre-packaged forms, which can be used
for a number of computers at the same go. Software may be bringing about huge
changes in the computer like changing locations of the file, changing names and
many others but we are not able to observe the way it is bringing about those
changes. However, there are numerous other ways in which we can observe the
changes made in the computer by the software instructions e.g. display on
computer monitor changes.
12.3 Various Types of Software
System Software: It is the main software,
which helps in running the computer system and the entire as well as the
hardware. The various examples include servers, window systems, drivers,
diagnostic tools etc. It also include libraries of in-built functions, system
services, drivers for printers and other hardware, system preferences, and
other configuration files.
Application software: This kind of software allows
the users to achieve more than one computer related specific tasks. If you want to understand it, think of terms
like window applications and other software present in current smartphones,
tablets etc. (APPS). Other application software includes business software,
medical software, designing software, gaming software etc. Web applications give
output on web pages e.g. PHP, ASP.NET ETC.
Programming Software: These types of software
aid the programmers in writing programs in an easy manner. These include
interpreters, compilers, linkers, debuggers etc. Software programmers to
create, maintain or debug the computer systems use this type of software. Further,
there are embedded software, which are put as firmware in the tiny electronic
chips to be used by single users in automobiles. Firmware can actually be
defined as sequence of instructions that is substituted for hardware.
Language of Software: Software is usually
written in various programming languages. Actually, a programming language is
the one, which is used by programmers to develop various applications, scripts
and other group of commands. Examples include COBOL, FORTRAN, BASIC, SQL,
FOXPRO etc. The table given below will
give a birds eye view of the various types of applications and the languages
used to develop these software.
Table:
Different types of languages used for specific types of applications and
programs
Types of application/Software
|
Characteristics
|
Languages used
|
|
Artificial
Intelligence Development
|
Creating character
interactions in computer games, chatbots etc.
|
C,C++, Prolog, AIML
|
|
Database Development
|
Creating and maintaining
characters
|
DBASE, FoxPro
|
|
Game Development
|
Development of computer
games and other software
|
Java
|
|
Computer drivers or
other hardware interface development
|
To embed systems and
generate device drivers
|
Assembly, C
|
|
Internet and Web Page
Development
|
Creating own web pages,
developing internet applications, Internet related tasks
|
HDML, HTML, Java,
JavaScript, Perl
|
|
Script Development
|
To create and develop
scripts to increase performance
|
Auto hotkey, Perl
|
12.3.1 Software as observed the user
More commonly, we find that the software visualized by the viewers
is different from as developed by the software developer. The latest
general-purpose computers are having 3 fundamental layers of software e.g.
platform, application and user software as perceived by the user.
12.3.2 Platform software
A platform in the
fundamental unit of the computer hardware, Which integrates software and on
which the software applications are run. It includes the software, which help
the user to form a link between computer and its allied parts. Such software
includes drivers, GUI and also the operating system. This kind of platform
software is packaged along with the computer but it is possible to change the
platform software of the personal computers.
12.3.3 Application Software
This kind of software usually doesn’t come bundled up with the
computer but they have to be bought individually. These are the ones, which are
used to play video games, office suites and also include other software like
word processing software, video games, office suites, word processing software,
presentation software, multimedia software etc. Even systems software can be
thought of as application programs. In some cases, application software are
pre-packaged with the computer but still, they are run as separate programs.
Even systems software can be thought of as application programs.
User written software: This software are
created by the users to suit their specific needs. They can also be bundled
within default application software and actually if they are deftly packed,
they are indistinguishable from the original bundle of software. E-mail
filters, spreadsheet templates etc. are all user written software.
Importance of quality of
software: It is rather quite significant to have good quality software
because many important jobs are dependent on the software especially in MS
office, windows, Linux etc., we cannot afford to have bugged software. Faulty
software can damage the system and also crash it. Moreover, it may generate
undesirable and unforeseen responses. Quality in software can be defined in
terms of code characteristics. It is actually the conformation of all characteristics
required from a good professional software e.g. functional and performance
needs (speed, storage area needed, security, network friendliness etc. and
document development features. Nevertheless, its quite difficult to measure the
quality of as software e.g. we can objectively measure speed, power consumption
but security issues are very difficult to assess.
The software are basically prepared to deliver a particular
facility. These facilities include the types of output generated by the
software e.g.
·
Numerical result
·
Screen shots
·
Web pages etc. and the features of the software
to deliver a particular kind of service are deliberated in terms of
Functionality, execution, movability and compactness.
Speed: If the application is asked to perform a function, it takes a little bit
of time before delivering the service asked for. The time taken in performing
the function is sum total of three different things i.e.
- System time
- CPU time
- Network latency
- Total Wall time or real elapsed
time
So, in order to measure develop a software on lines of a good
speed software, the developer must take into account all the above mentioned
times.
Space
utilization of the software: The RAM or disk space utilized by the application
is of prime importance. Software, which stimulates CPU cache miss, can also
influence the speed of the software. With the starting of computer, many software
also get started, some of them are not actually required at that time. Even
this slows down the computer and it needs to be managed properly to keep vital
resources of the computer free for usage. Here, data design of the software is
very important as a poor design results in slowing down of the system.
Network usage: Network usage can be
defined as the network traffic at particular time as compared to the total
amount of traffic that can be supported by the network. Bandwidth usage
involves all incoming (data downloaded from net) and outgoing (data sent out
from the computer in form of emails. etc.)
Software should be so designed that it efficiently uses the bandwidth.
Durability of the software: Good quality software
doesn’t need to be repaired very often. It is very troublesome at the users end
to fix the software again and again. The code used to write the software should
not be fragile otherwise the patchwork has to be done again and again.
Strength of the software: Good quality software possesses
good tolerance towards system failure, unresponsive third party resources. In
case, the quality of the software is not good it becomes very prone to freezing
or crashing. So, software should be tolerant enough to severe and testing
conditions.
Simplicity for user: Actually, ease to use software is not very
objective. It is a relative and matter, which is difficult to calculate. The
various parameters upon which the quality of a software can be determined is
how clearly it conveys the errors, how it recovers after failure etc.
Reproducibility: It is additionally recognized as determinism
or repeatability. It is a parameter that takes into account the repeatability
of results i.e. whether the software gives the same result time after time. There
are numerous reasons responsible for non-reproducible results, the chief of
which is a bad data model design.
Issue of compatibility: This issue addresses the compatibility between
new and older versions of the software. Further, good software should be so designed
that shifting of data from old to new should not take a lot of time/expensive
and it should be cost effective.
Safekeeping: Good software should be
secure and should possess restricted access if so desired. The data, which is processed by the software,
should not be compromised. Actually, this aspect is of utmost importance and
anybody who wants to keep their data confidential must have secure software.
Consumption of power: As most of the current day smart phones are having such application
software which are used quite often by the user, it is but obvious that the
software must not use too much of battery (power) so that battery remains
charged for a longer time.
Code coverage: Good quality software
has higher code coverage. Code coverage is actually a parameter, which
illustrates the degree to which the source code of the program has been tested.
Software which has higher code coverage means that it has been sufficiently
tested and has a lesser probability of containing software bugs.
Testability: Good software is
designed to possess high level of testability. High testability needs an inter-dependence
between architecture as well as testing methods used. An inadequate software
with poor testability needs to be redesigned which is an extremely costly
affair. So, at the initial step only it is justifiable to invest in software
architecture and development methodologies to prevent repairs and redesigns.
Portability: Good quality of
software possesses portability i.e. they possess the ability to run on
different types of computers as well as operating systems. including small
capacity computers, mobile phones, various web browsers etc.
Safety of thread: Good software should not get into a logjam.
Improper thread safety of software leads to live locks, resource famishing and
deadlocks. A code should be so written that it may be partly executed by
thread, executed by the same thread and also by another thread.
Compactness: Good quality software
needs to have smaller binary size and also should possess rapid compilation. If
software is smaller in size, it will have fewer bugs because no. of bugs remains
persistent with respect to size of the code.
Maintenance: Good quality software is
easy to debug, faster to fix, easier to understand. Maintenance of software is
improved with good testability and malleable design. Software maintenance is a
very important aspect and it is also subjective in quantification.
Documentation: Many users are of a
view that side by side separate documentation written in English language is
pretty essential. On the other hand there are people who testify that at least
one fourth of the code should be in form of commands. A third party believes
that code in itself is the most fit manifestation of documentation.
Software should be
legible: Legible means readable. Readability of the code is very important. The
good software should be having a unified style of code. Being legible means
that a software should be easily read by the developer even if its written by
another developer.
Software should be saleable: All the good software should have the ability to easily extend a
certain feature, enlarge or add novel features, additional chores etc. In
fact, good software is developed keeping
the potential prospects needs in mind.
The quality of the software is actually the reaction of the user
to it, a user friendly software which gives good results and positive feedback
from user is subjectively a good quality software. Nevertheless, it must kept
in mind that the quality of software is actually the result of good ground work and focused on quality
parameters like stability, compactness, portability, network usage, code
coverage, testability, flexibility, security, thread security, maintainability,
legibility, scalability, documentation.
12.3.5 Issue of Patents
We know that patent is a right or a license conferred by
government for a given period of time to an invention or original development
like a software, it excludes others from marketing, selling or in any other way
using a given patent for commercial purposes.
Software can actually be patented in some countries. All the
countries of the world don’t give a right to patent the software. Actually,
granting of patents is contentious in case of patents because algorithms used
to develop software may not be original and other developers may use them also.
However, software is intellectual properties of the developers and should be
patentable .
12.3.6 Software bug
Grace Hopper used the term software bug for the first time in 1945
when an actual bug or moth short-circuited a computer system. From that time
onwards, the term computer bug started being used. A software bug is in fact, a
defect, weakness, letdown, and inaccuracy in a program/system. Due to this bug
that may be intrinsic in the software, wrong or awry results are obtained.
Unexpected results and wrong calculations are obtained due to these faults and
errors. The bugs or errors can be of different types like user interface error,
error in handling data, boundary related errors, errors in calculations,
control flow errors etc. Software with a huge number of bugs is called“buggy”
software. Following reasons most commonly cause software bugs:
·
Mistakes by the developer
·
Errors at the end of humans
·
Faulty Source code
·
Incorrect code produced by the compiler
Mistake Metamorphism: Metamorphism means a change in shape. In
software terminology, software means the evolution of “bugs”. Starting from a
mistake at the level of human beings, it is evolved as a failure at the level
of execution. The various stages of mistake metamorphism are as follows:
Mistake---Anomaly-----Fault---Failure----Error-----Exception------Crash-----Bug------Defect------Incident------Side
effect
How to avoid and block the bugs
A lot of labor and energy of software is focused
on tracing various techniques, which will help in prevention of bugs while
writing software. These techniques include:
·
Style of the
programming: The appearance of bugs happens due to error committed by the
programmer especially when he makes a logic error. Many advances in the style
of programming are being made to reduce the likeliness of the bugs and also
simpler to locate the bugs. Typos-i.e. errors like missing object, missing or
extra brackets, repeating of objects. These so-presumed small errors at the
earlier stages may result in failure of execution or appearance of bugs and to
find the errors becomes very time-consuming as well as laborious because it
means going through the program again line by line.
·
Programming techniques: Errors and software bugs often produce
anomalies in the inner data of a program. The programmer should write programs
so as to keep checking the inner uniformity of the data while running. As soon
as an anomaly is encountered, the program comes to a stop, thus the anomaly is
detected and fixed easily and at the same instant, so that the bug can be
located and fixed. However, in certain cases it may not come to a halt but
continue running and send information to the user about the anomaly so that it
may be corrected.
·
Methods of developing
the program: A number of patterns have been put through to manage the
programming activity well and free from errors and number of bug production is
minimized. These are in fact covered under the regulation of software
engineering e.g. precise program requirements are used to state precise conduct
of the programs. It is however quite unfortunate that formal program
requirement is unfeasible and unrealistic. In the current times, more common
methods involve preprogrammed unit as well as acceptance testing. These
approaches are designed to catch hold of the bugs and minimize their fixing
effort and cost.
·
Programming language
support: A number of modern day programming languages include such
intrinsic characteristics, which assist the programmers in prevention of
bugs.
·
Scrutiny of the code: There are certain tools
that assist the developers in scrutinizing the code by reviewing the program
text past the compiler's competences to locate future difficulties. Though in broad
sense, the difficulty of tracing all programming faults is not resolvable; these
tools manipulate the information that human programmers are inclined to commit
the identical types of slipups while writing software.
·
Equipment: The correct
implementation of software while it is running is examined to detect errors
such as tailbacks, logjams etc. Further, monitoring is needed to provide or to
give assertion towards proper working. Monitoring is done by embedded monitors
in the code or as tools.
·
Common categories of
computer bugs: Computer bugs are our enemies and we must understand our enemies
in order to conquer them. Debugging is performed to get rid of errors. Software
programmers are always looking for new types bugs and ways to remove them. Bugs
can be of different types like arithmetic bugs, logic bugs, syntax bugs,
resource bugs, logic bugs, syntax bugs, resource bugs, multithreading
programming bugs, interfacing bugs, performance bugs, team-working bugs etc. On
the other hand, programming errors are of three types compilation errors
(prevent the program from running), run-time errors (occur while a program is
running) and logic errors.
12.3.7 Software Issues
Due to increase in the popularity and usage of software, new
issues have come to the front. These issues are mainly concerned with appraisal,
choice, licensing and authorization, up- gradation, open sourcing etc.
12.3.8 Software Appraisal and choice
The appraisal, evaluation and choosing is the right software is of
prime importance and is dependent on a number of key considerations. To select
the right software, first of all, one must fully comprehend the nature of
requirement of the software. We must also fully assess the benchmarks and
yardsticks that the software must fulfill. The entire team, which has to
contribute to the development/using the software, must hold a meeting and
critically assess whether the decided software fulfills the needs of the
organization. The team should study the projected substitutes and reach the
final decision for the software, which best suits, all the needs.
Factors controlling the
choice/selection of particular software
·
Whether the need is of a single user software or
multi user software in a particular place or multi user in physically
diversified areas
·
Whether the software proposes to give certain
tools that can be used for supervising by the administration
·
Whether it offers security or not.
Price Tag of the
software: The price of the software includes all the prices i.e. the
initial cost, cost of installation, cost of up gradation, cost of maintenance
and also the cost involved in buying different versions and single/multi user
license.
Competence of the
software: The issue of competence of software is very crucial. It has to be
taken into account that the software that being bought today, whether it is
also fit and competence to meet the potential needs of tomorrow.
Software compatibility: The compatibility
issues of the software are also of prime importance because the software needs
to be compatible with the prevailing hardware and software combinations.
12.3.9 Licensing and authorization
issues of the software
All the software, which is developed by various companies, should
be licensed because a lot of effort, labor, expertise and skill go into the
development of software. The software must not be copied, pirated and sold
without the permission of the developing company. So, licensing is a major
issue of concern for the current needs.
12.3.10 Legal Entitlements over the
software
All the laws that work to provide the intellectual protection
rights to other intellectual properties have to be extendable to the software
also. Actually, there needs to be a legal entitlement over the software because
it has been prepared but inputs of human mind and intellect, innovation and
creativity. In fact, the Software Publishers association imposes the copyright
rules and commandments in the companies, corporations etc via the conventional
recommendations. According to these conventions,
·
If the information system managers do not
possess the evidence of buying the software, they have no right to continue
possessing the software, else they must buy new license, failing which, they stand
liable to punishment.
·
Fee must be paid for renewal/up gradation of the
license. By definition, a license is actually an entitlement approved by the
government to carry out an activity, which is otherwise illegal.
·
Software Publishers association keeps a check on
the companies to invigilate the appropriate utilization of the license. If a
company is found guilty of improper utilization of the license, it is
accountable and liable to substantial fine.
·
System managers will thoroughly check the
records and maintain the records for the correct licenses of their software.
Many people unmindfully copy the original software but little do
they realize that doing so is criminal and punishable by law. Furthermore, the
cost of piracy runs in millions in terms of money, time and security. Many
people who use pirated software in the hope of saving a small amount of initial
investment fall prey to the malware and security threats associated with the
pirated or copied software. A research has shown that more than sixty percent
of companies who have used forged software have faced huge security threats.
Moreover, the same research showed that about half of the consumers faced the
problem of slow PC and had to remove the software. In addition the users of
counterfeited software were very much concerned about data loss.
If small companies indulge in such a piracy, they are more gullible
to loss because large companies are rich enough to face huge losses but smaller
companies are on he risk of getting completely ruined due to incurrence of
losses.
Ethically speaking also, the cause of innovation and intellect is
also defeated and it is ethically incorrect to do so. However,
as the number of computers and computer companies are on the rise, the business
of fake software is also in the rise. This in turn has caused a number of
tracking software companies to grow.
12.3.11 Software Upgrades
Software upgrades are a major concern in these times. The
companies, which have developed the software want it to be upgradable i.e. it
should have the ability to be revised to suit the upcoming needs. Many
companies charge money for up-gradation. However, they may just make minor
changes and present a new version often. These new versions may actually have
nothing new to offer. In yet other cases, they may also be buggy and pose a
risk of loss of data etc. Nevertheless, certain upgrades introduce revised
features to suit the impending needs.
12.3.12 Enterprise Software
In the competitive world of modern times, it is realized that
various organizations must regularly keep reorganizing their software structure
to meet the growing needs of the companies. Due to this, many times the
companies need to change their hardware in order to meet the compatibility
issues. It must be borne in mind that a large organization may have thousands
of software working in harmony and it is quite expensive and cumbersome to acquire
the upgrades each time.
12.3.12 Reorganization of Organizational
Software
It is very unsafe, costly and bungling to upgrade software in
larger organizations and must not be indulged into until it is absolutely
necessary to do so. Actually, these days the companies prefer to buy
pre-packaged applications that form a good support system between various
functional segments (HR, finance, marketing etc.) of the system. Such events
have popularized the concept of enterprise software, which is purposed-designed
software that actually is prepared to meet the furtherance of demands.
12.3.14 Middle Ware
This type of software is designed to link various application
modules running id different languages. Middleware is sometimes
called plumbing because it connects two sides of an application and passes
data between them.
12.3.14.1 Shareware: Shareware are
those software you can use on a trial basis before paying for it or buying
a license to use it. Once you pay for a shareware program, the program is fully
functional for the given time limit and after that it will ask for license.
12.3.14.2 Freeware: Freeware are the
software you can download, pass around, and distribute without any initial
payment. However, the great part about freeware is that you never have to pay
for it. Freeware does not cost anything; it is still copyrighted, so other
people can't market the software as their own.
12.3.14.2 Open source: Open
source, as the name explains means the source code is open that is you can read
the source code of the software. You can also modify and distribute it to
anyone you want, as per license agreements.
12.4 Summary
In this chapter, we have learnt all about software, which is
actually that part of computer, which is not tangible, i.e. which we cannot
touch but without it no part of computer can work. It was only when software
was invented that the size of computer decreased and the computer became a
multi-tasker. It is known as a set of programs, which comprise of all the
programs, which are executable on the computer, libraries, applications and
even the scripts. They are actually a set of clear-cut instructions upon which
the computer works. We have seen that two main types of software are system
software and application software. System Software: It is the main software, which
helps in running the computer system and the entire as well as the hardware.
The various examples include servers, window systems, drivers, diagnostic tools
etc. Application software: This kind of software allows the users to achieve
more than one computer related specific tasks. Apart from these, yet another
type of software i.e. PROGRAMMING SOFTWARE is also common that aids the
programmers in writing programs in an easy manner. It is rather quite
significant to have a good quality software because many important jobs are
dependent on the software especially in MS office, windows, Linux etc., we
cannot afford to have bugged software. Quality in software can be defined in
terms of code characteristics. It is actually the conformation of all characteristics
required from a good professional software e.g. functional and performance
needs (speed, storage area needed, security, network friendliness etc. and
document development features.). Due to increase in the popularity and usage of
software, new issues have come to the front. These issues are mainly concerned
with appraisal, choice, licensing and authorization, up- gradation, open
sourcing etc. Software upgrades are a major concern in these times. The
companies, which have developed the software want it to be upgradable i.e. it
should have the ability to be revised to suit the upcoming needs.
12.5 Glossary
Portability: The ability to run on different types of
computers as well as operating systems.
Software bug: A defect, weakness,
letdown, and inaccuracy in a program/system.
Code coverage: A parameter, which illustrates the degree to
which the source code of the program has been tested.
User written software: software are created by
the users to suit their specific needs.
System Software: It is the main
software, which helps in running the computer system and the entire as well as
the hardware.
Application software: software that allows
the users to achieve more than one computer related specific tasks.
12.6 Suggested
Answer to SAQ
Question: What are the
factors controlling choice and selection of a particular software?
·
Whether the need is of a single user software or
multi user software in a particular place or multi user in physically
diversified areas.
·
Whether the software proposes to give certain
tools that can be used for supervising by the administration.
·
Whether it offers security or not.
Question: What are
software bugs?
A software bug is in fact, a defect, weakness, letdown, and
inaccuracy in a program/system. Due to this bug that may be intrinsic in the
software, wrong or awry results are obtained. Unexpected results and wrong
calculations are obtained due to these faults and errors. The bugs or errors
can be of different types like user interface error, error in handling data,
boundary related errors, errors in calculations, control flow errors etc.
Software with a huge number of bugs is called“buggy” software. Following
reasons most commonly cause software bugs:
·
Mistakes by the
developer
·
Errors at the
end of humans
·
Faulty Source
code
·
Incorrect code
produced by the compiler
Question: What is
Application software?
This kind of software usually doesn’t come bundled up with the
computer but they have to be bought individually. These are the ones, which are
used to play video games, office suites and also include other software like
word processing software, video games, office suites, word processing software,
presentation software, multimedia software etc. Even systems software can be
thought of as application programs. In some cases, application software are
pre-packaged with the computer but still, they are run as separate programs.
Even systems software can be thought of as application programs.
Question: What are
legal entitlements of the software?
According to laws, if the information system managers do not
possess the evidence of buying the software, they have no right to continue
possessing the software, else they must buy new license, failing which, they stand
liable to punishment. Further, they must pay the fee for renewal/upgradation of
the license. By definition, a license is actually an entitlement approved by
the government to carry out an activity, which is otherwise illegal. Software Publishers
association keeps a check on the companies to invigilate the appropriate
utilization of the license. If a company is found guilty of improper
utilization of the license, it is accountable and liable to substantial fine.
These days the information system managers are thoroughly checking records and
maintaining records for the correct licenses of their software.
Question: Define
software?
It is known as a set of programs, which comprise of all the
programs, which are executable on the computer, libraries, applications and
even the scripts. They are actually a set of clear-cut instructions upon which
the computer works.
12.7 References/Bibliography
·
Introduction to Software Process Improvement By
Gerard O'Regan
·
Introduction to Software Packages Edited by
Sheila Frankel
·
A Concise Introduction to Software By Pankaj Jalote
12.8 Suggested
readings
·
New Perspectives on Computer Concepts 2014: Comprehensive
By June Jamrich
Parsons, Dan Oja
·
New Perspectives on Computer Concepts 2014: Comprehensive
By June Jamrich Parsons,
Dan Oja
12.9 Model Questions
·
Differentiate between User written software and
application software
·
Why is software licensing important?
·
What is software up gradation?
·
What is middleware?
·
What is enterprise software?
