Overview of Software Engineering and Overview of The Software
Software Engineering:-
Let
us first understand what software engineering stands for. The term is made of
two words, software and engineering.
Software is more than just a
program code. A progra
Engineering on the other hand,
is all about developing products, using well-defined, scientific principles and
methods.
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Software engineering is an engineering branch associated with development of software product using well-defined scientific principles, methods and procedures. The outcome of software engineering is an efficient and reliable software product.
Software
engineering is defined as a process of analyzing user requirements and then designing,
building, and testing software application which will satisfy those requirements.
Definitions:
Let’s look at the various definitions of software engineering:
IEEE
defines software engineering as:
(1) The application of a systematic, disciplined,
quantifiable approach to the development, operation and maintenance of
software; that is, the application of engineering to software.
(2) The study of approaches as in the above statement.
Fritz
Bauer, a German computer scientist, defines software engineering as:
Software engineering is the establishment and use of sound
engineering principles in order to obtain economically software that is
reliable and work efficiently on real machines.
(3) Boehm defines software engineering, which involves, ‘the
practical application of scientific knowledge to the creative design and
building of computer programs. It also includes associated documentation needed
for developing, operating, and maintaining them.’
Why Software Engineering is Popular?
Here are important reasons behind the popularity of software engineering:
- Large software – In our real life, it is quite more comfortable to build a wall
than a house or building. In the same manner, as the size of the software
becomes large, software engineering helps you to build software.
- Scalability- If the software development process were based on scientific
and engineering concepts, it is easier to re-create new software to scale an
existing one.
- Adaptability- Whenever the software process was based on scientific and
engineering, it is easy to re-create new software with the help of software
engineering.
- Cost- Hardware industry has shown its skills and huge manufacturing has lower the cost of the computer and electronic hardware.
- Quality Management- Offers better method of
software development to provide quality
software products.
Software Evolution:-
The process of developing a software product using software engineering principles and methods is referred to as software evolution. This includes the initial development of software and its maintenance and updates, till desired software product is developed, which satisfies the expected requirements.
Evolution
starts from the requirement gathering process. After which developers create a
prototype of the intended software and show it to the users to get their
feedback at the early stage of software product development. The users suggest
changes, on which several consecutive updates and maintenance keep on changing
too. This process changes to the original software, till the desired software
is accomplished.
Even
after the user has desired software in hand, the advancing technology and the
changing requirements force the software product to change accordingly.
Re-creating software from scratch and to go one-on-one with requirement is not
feasible. The only feasible and economical solution is to update the existing
software so that it matches the latest requirements.
Software Evolution Laws
Lehman has given laws for software evolution. He divided the software into three different categories:
S-type (static-type) - This is a software, which works strictly according to defined specifications and solutions. The solution and the method to achieve it, both are immediately understood before coding. The s-type software is least subjected to changes hence this is the simplest of all. For example, calculator program for mathematical computation.
P-type (practical-type) - This is a software with a collection of procedures. This is defined by exactly what procedures can do. In this software, the specifications can be described but the solution is not obvious instantly. For example, gaming software.
E-type (embedded-type) - This software works closely as the requirement of real-world environment. This software has a high degree of evolution as there are various changes in laws, taxes etc. in the real world situations. For example, Online trading software.
E-Type software evolution
Lehman has given eight laws for E-Type software evolution -
- Continuing change - An E-type software system must continue to adapt to the real world changes, else it becomes progressively less useful.
- Increasing complexity - As an E-type software system evolves, its complexity tends to increase unless work is done to maintain or reduce it.
- Conservation of familiarity - The familiarity with the software or the knowledge about how it was developed, why was it developed in that particular manner etc. must be retained at any cost, to implement the changes in the system.
- Continuing growth- In order for an E-type system intended to resolve some business problem, its size of implementing the changes grows according to the lifestyle changes of the business.
- Reducing quality - An E-type software system declines in quality unless rigorously maintained and adapted to a changing operational environment.
- Feedback systems- The E-type software systems constitute multi-loop, multi-level feedback systems and must be treated as such to be successfully modified or improved.
- Self-regulation - E-type system evolution processes are self-regulating with the distribution of product and process measures close to normal.
- Organizational stability - The average effective global activity rate in an evolving E-type system is invariant over the lifetime of the product.
Software Paradigms
Software
paradigms refer to the methods and steps, which are taken while designing the
software. There are many methods proposed and are in work today, but we need to
see where in the software engineering these paradigms stand. These can be
combined into various categories, though each of them is contained in one
another:
Programming
paradigm is a subset of Software design paradigm which is further a subset of
Software development paradigm.
Software Development Paradigm
This
Paradigm is known as software engineering paradigms where all the engineering
concepts pertaining to the development of software are applied. It includes
various researches and requirement gathering which helps the software product
to build. It consists of –
- Requirement
gathering
- Software
design
- Programming
Software Design Paradigm
This
paradigm is a part of Software Development and includes –
- Design
- Maintenance
- Programming
Programming Paradigm
This
paradigm is related closely to programming aspect of software development. This
includes –
- Coding
- Testing
- Integration
Need of Software Engineering:
The
need of software engineering arises because of higher rate of change in user
requirements and environment on which the software is working.
- Large software - It is easier to build a wall than to a house or building, likewise, as the size of software become large engineering has to step to give it a scientific process.
- Scalability- If the software process were not based on scientific and engineering concepts, it would be easier to re-create new software than to scale an existing one.
- Cost- As hardware industry has shown its skills and huge manufacturing has lower down he price of computer and electronic hardware. But the cost of software remains high if proper process is not adapted.
- Dynamic Nature- The always growing and adapting nature of software hugely depends upon the environment in which user works. If the nature of software is always changing, new enhancements need to be done in the existing one. This is where software engineering plays a good role.
- Quality Management- Better process of software development provides better and quality software product.
Challenges of Software Engineering:
Here
are some critical challenges faced by software engineers:
- In safety-critical areas such as space, aviation, nuclear power plants, etc. the cost of software failure can be massive because lives are at risk.
- Increased market demands for fast turnaround time.
- Dealing with the increased complexity of software need for new applications.
- The diversity of software systems should be communicating with each other.
Attributes for Software Products:
The characteristics of any software product include
features which are displayed by the product when it is installed and put in
use.
They are not the services which are provided by the
product. Instead, they have related to the products dynamic behavior and the
use made of the product.
Examples of these attributes are:
Efficiency, reliability, robustness, maintainability, etc.
However, the relative importance of these characteristics varies from one software
system to another.
Optimizing the above attribute is very challenging.
For example, offering a better UI can reduce system efficiency.Summary:
Software engineering is a process of analyzing user requirements
and then designing,
building,
and testing software application which will satisfy that requirements
Important
reasons for using software engineering are: 1) Large software, 2) Scalability
3)
Adaptability
4) Cost and 5) Dynamic Nature.
In
late 1960s many software becomes over budget. Therefore it offers unreliable
software
which is expensive to maintain.
The
late 1970s saw the widespread uses of software engineering principles.
Software
engineering concept 1) Computer Science 2) Management Science 3) System
engineering
and 4) Economics
Increased
market demands for fast turnaround time is the biggest challenges of
software
engineering field.
1)
Maintainability, 2) Dependability, 3) Efficiency and, 4) Usability are the most
important
attributes of software products.
Three
most important characteristics of good software are 1) Operational 2)
Transitional
3 ) Maintenance.