Evolution Phase
What is Software Evolution?
• During the development of a software they're various phases
one such is the Evolution phase otherwise known as Software
Evolution. It is basically the process of developing the software
then updating it overtime for various reasons, e.g. to add new
features or to remove out-of-date functionalities and so on.
Software Development Stages
• Evolution- The stage in a software system’s life cycle where it is in
operational use and is evolving as new requirements are proposed and
implemented in the system.
• Servicing- At this stage the software remains useful but the only changes
made are those required to keep it operational like bug fixes and changes
to reflect changes in the software’s environment.
• Phase-out- And here the software may still be used but no further changes
are made to it.
Why is the Software Evolution
Important?
• Software Evolution is important because over time the Company/Business
who owns the software may have a change in their needs or way of working.
So Software Evolution is inevitable because a software have to be kept up-
to-date to match current times and phones and computers also have updates
to the software have to be up-to-date to prevent performance issues.
• Other reasons includes: i) Errors and bugs may occur over time, ii) Security
risks may arise due to the outdated software and Also to have the refreshing
feeling of having a New functionality and features.
The Spiral Model of Development and
Evolution
• The spiral model is a systems development
lifecycle (SDLC) method used for risk
management that combines the iterative
development process model with elements of
the Waterfall model. The spiral model is used
by software engineers and is favored for large,
expensive and complicated projects.
The Software Evolution Process
2. System Implementation
or Change Implementation 4. Change Request
1. Release Planning 3. Impact Analysis
This is a simple version of the Software Evolution Process
Release Planning
• During the releasing planning of software evolution
process if all the proposal has been changed means new
functionality, adaptation and fault repair are occur in
the system. In this situation to make a discussion which
changes the implementation for the next version of the
system to release.
System Implementation or Change
Implementation
• System Implementation or change Implementation is the
iteration of software process development where the structure
of a new version of the software is design, implementation,
and testing. In the critical software evolution process, there is
change implementation of the first stage should modify the
system implementation, design, and specification that can be
effective to change the system process.
Impact Analysis
• After the process of the system implementation then the next
step is the impact analysis process. In which the impact analysis
process complete details of the necessary information are
analyzed and emerge change should not appear in the change
analysis process.
Change Request
• In the change request process, the necessary information is required and the
impact analysis process analyzed the necessary information and pass to the
next step release planning process. The release planning process passes the
information to the next step of the change implementation process so any
problem in the implementation process retrieves the information to the
previous step of release planning. If no problem in the change implementation
processes the pass the information to the system release process. All the
information are complete the system analysis process retrieves the first step of
change request process so the evolution process is done. The change request
process sometimes is related to the system release process.
Lehman's laws of software evolution
• In software engineering, the laws of software evolution refer to a series of
laws that Lehman and Belady formulated starting in 1974 with respect to
software evolution, The laws describe a balance between forces driving
new developments on one hand, and forces that slow down progress on
the other hand. Over the past decades the laws have been revised and
extended several times.
Law of Continuing Change
• This law states that any software system that represents
some real-world reality undergoes continuous change
or become progressively less useful in that
environment.
Law of increasing complexity
• As an evolving program changes, its structure becomes
more complex unless effective efforts are made to
avoid this phenomenon.
Law of conservation of organization stability
• Over the lifetime of a program, the rate of development of that
program is approximately constant and independent of the
resource devoted to system development.
Law of conservation of familiarity
• This law states that during the active lifetime of the
program, changes made in the successive release are
almost constant.
The End
