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Proceedings of the 2nd National Conference on Information Technology
For Business Transformation (ITBT’ 2011); November 4-5, 2011;
Ajay Kumar Garg Engineering College, Ghaziabad
Digging Deep into Legacy System
Dr. Vinay Goyal Amit Jain
Professor (CSE) Assistant Professor
Jind Institute of Engineering & Technology, IIMT Group of Colleges,
Jind. Haryana (India). Meerut. U.P. (India).
E-mail: vinayeq@yahoo.com E-mail: amit_jainci@yahoo.com
Abstract
This research paper presents an intense insight
into multiple aspects of Legacy System. At the
outset, an introduction to legacy system and its
components has been studied. Then, the several
issues related to renovation and revamping of
legacy system has been discussed, and in the
end segment, a detailed assessment related to
several scenarios involved in legacy system has
been studied.
Keywords: Legacy System, Components,
Issues, Renovating, Revamping, Assessment,
Conclusion
Introduction:
Over a decade & so, many organizations had
splurged a lot of capital on software systems and
in order to get a return on that venture, as the
software on which their business operates must
be functional for long years. The life span of
software systems is very unpredictable, but
many large systems continue in use for more
than a decade. Some organizations still depend
on software systems that are more than two
decade old. Many of these older systems are still
business-critical. That is, the business relies on
the services provided by these software’s and
any malfunction of these services would have a
severe effect on their day to day operation of the
business. These mature systems have been
agreed as legacy systems.
These heritage systems are not, of course, the
systems that were initially delivered as they are
now, rather the exterior and interior factors, such
as the position of the nationwide and worldwide
economies, ever changing markets, changing
laws, administration changes and structural
restructuring, have led these systems to undergo
such amount of restructuring that their
maintenance is now far too expensive for the
organizations. Due to these changes, many new
as well as customized software requirements
came into force, so all these were amended into
the software systems inescapably and they
changed as the business changed. Therefore,
legacy systems incorporate a huge number of
changes which have been completed in excess of
many years. The basic idea is that all systems
undergo a continuous evolution by switching
among four main phases: simplification,
ordinary reactive and preventive maintenance,
extraordinary adaptive maintenance, and
replacement. Many different inhabitants have
been drawn in assembling these changes and it is
remarkable for any one individual to have a
absolute acceptance of the system.
Upgrading of legacy information systems is
often large, multiyear project that relates to
noteworthy challenging task. Information
systems are decisive to companies in several
aspects, and making a single operation of the
restructured edition can be too hazardous.
Moreover, a rejuvenation effort of a large
system requires a momentous investment in
terms of wealth and time; projects of this extent
are sturdily pressured to exhibit early
repayment. Industries frequently replace their
tools and technology with up to date systems.
Nevertheless, scrapping legacy systems and
replacing them with modern software does grips
considerable business threat. Legacy tools lack
ISBN No: 978-81-88132-32-4
Proceedings of the 2nd National Conference on Information Technology
For Business Transformation (ITBT’ 2011); November 4-5, 2011;
Ajay Kumar Garg Engineering College, Ghaziabad
coverage capabilities, which can be time-
consuming in an organizations potential to craft
gainful decisions. With legacy tools, IT
managers can’t confer with stored conversation
or can have a look at videos of support sessions,
or can’t gather customer comments. Legacy
systems were mostly developed for centralized
environment. These systems are usually
inflexible and non-scalable [2].
Components of Legacy System
Legacy software components have been defined
as “jobs, programs, modules, or procedures
within existing application systems which are
more than five years old [3]. A legacy system
encompasses primarily six components which
relate to multifaceted nature of existence. They
are a set of software, hardware, data and
business methodologies.
Any modification being made to any one portion
of the system inescapably engrosses
supplementary alteration to several components.
The several rational elements of a legacy system
[5] and their associations are as:
1. System Software: The legacy systems depend
upon several diversified support software as well
as the utilities supplied by the software
organization and they are being used in system
development. Yet again, there is a possibility
that these may be outdated and may no longer be
maintained by their original service providers.
So in that scenario it is utmost difficult for the
organization to keep them functional over a
period of time.
2. Hardware: In several instances, legacy
systems have been designed for mainframe
hardware which is not in existence or which is
costly to retain and which may not be attuned
with existing technology procuring strategy. So
in that the organizations need to get themselves
poised in relation to changing technology.
3. Application software: The application system
which deals with several business services is
generally poised of a numerous diverse
programs which have been written at different
instances. At times, the term legacy system
refers to these application software systems
rather than the whole system.
4. Processed data: These set of data are being
maintained with the organizations as the
software is being used for many years. In several
cases, an enormous amount of data has been
collected over the lifespan of the system. There
is a possibility that this data may be
incompatible and may be replicated in numerous
locations, as of now.
5. Business ethics and strategy: These are
description of how the business should be
conceded and depends upon business
methodology. At times, the mechanism involved
in legacy application system may be rooted in
these ethics and strategies.
6. Business methodology: These are
methodologies which are employed in the
business to accomplish certain business goals.
An example, of a business methodology is
related to a production firm wherein orders
related to manufacturing of several products is
accepted and various methodologies involved in
are accumulated, so as carry on the task of
production.
ISBN No: 978-81-88132-32-4
Proceedings of the 2nd National Conference on Information Technology
For Business Transformation (ITBT’ 2011); November 4-5, 2011;
Ajay Kumar Garg Engineering College, Ghaziabad
Thus, as companies strengthen IT processes, this
always give the impression related to little
decisive systems in operation on legacy
platforms that may reveal as complicated to
restore. These systems are vital to maneuver, are
unwavering and dependable, and provide
functionality complex or expensive to imitate in
the new atmosphere. Time and again, these
systems have consistently executed in the
backdrop so long, that the only reason they are
being noticed is they do not adjust in the new
technological advancement or the hardware
upon which they are being currently executed.
Issues in Legacy System
In several instances, the applications executing
on these traditional systems have contemporary
competitors. Migration to new arena is generally
expensive and cumbersome, but to all this
transformation criteria does exist. Nevertheless,
few applications are beyond doubt exceptional.
In addition, to the restrictions forced by
hardware and software, there are equally
significant limits imposed by convention,
documentation, human factors, time frame and
expenditure.
Policies may necessitate that a legacy database
be available for a further decade. Migration of
such application can be too expensive. A
certified software system may confine the
application to a definite edition of software and
operating system. Thus, an interim resolution is
needed to bridge the gap.
Renovating Legacy System
Every vigor to renovate a legacy application
code based should have at its nucleus around
four key areas, which are related to identifying
and managing the core business processes; to
transforming a typically gigantic application into
an agile, flexible upbringing that enables the
organization to influence business logic in novel
applications while maintaining uniformity in
business policy and appropriateness; to splitting
business logic from technology, making it easy
for applications to convene to organizations
changing requirements and endorsing the
reclaim of accessible software resources
concerned, in that way creating a improvisation
in requisites of expenditure, superiority,
overhaul and swiftness.
While replacing a legacy system, one needs a
precarious business policy for a numerous
rationale. There is hardly ever an entire
architecture of the legacy system. The original
plan may have been nowhere to be found. If a
pattern exists, it is doubtful that it integrates
particulars on each and every system transform
that have been completed till date.
Consequently, there is no clear-cut approach of
stating a new-fangled structure which is
functionally identical to the classification that is
in exercise.
Business procedures and the conduct in which
legacy systems maneuver are repeatedly,
inextricably entangled. These courses of action
have been premeditated to acquire benefit of the
software services and to evade its flaws. If the
system is substituted, these developments will
also have to vary with potentially changeable
expenses and outcome.
Vital business policy may be implanted in the
software and may not be acknowledged
elsewhere. A business regulation is a restraint
which relate to some business task and flouting
that restraint can have impulsive effect for the
business.
Suppose a health insurance group may have
established its convention related to evaluation
of the risk through various guiding principle for
settlement of claims. If these conventions are not
preserved, then the organization may agree to
high claims, which will in turn increase the
effect, in terms of costly settlement claim.
Also, innovative software expansion is itself
risky, so that there may be surprising troubles
with a new-fangled system. It may not be carried
on time and for the value projected.
ISBN No: 978-81-88132-32-4
Proceedings of the 2nd National Conference on Information Technology
For Business Transformation (ITBT’ 2011); November 4-5, 2011;
Ajay Kumar Garg Engineering College, Ghaziabad
Maintenance of legacy systems in exercise
evade the risks of substitution but making
changes to existing software usually becomes
more costly as systems acquire more
complexity.
Problem faced in revamping
Legacy software systems which are more than a
few years old are predominantly costly to
transform for quite a lot of rationale. There is a
possibility that different components of the
system have been executed by diverse group.
Consequently, there is no dependable encoding
technique across the entire scheme. Also, the
fraction or the entire of the structure may have
been implemented by an outdated encoding
language. It may be complicated to locate
personnel who have familiarity of these
languages and costly outsourcing of structure
continuance may be obligatory. At times, system
citations are time and again, insufficient and
obsolete. In several cases, the only record is the
system source code. Occasionally, the source
code has been mislaid and merely the executable
edition of the system is on hand.
Also, several years of continuance have typically
ruined the system organization making it even
more complex to comprehend. New plans may
have been added and interfaced with other
component of the system in a temporal manner.
There is a brighter chance that the system may
have been optimized for space consumption or
carrying out pace rather than written for
realization. This causes particular intricacy for
programmers who have cultured new software
engineering practices and who have not been out
in the open to the programming tricks that have
been used in the past.
Also, the information processed by the system
may have been preserved in diverse archives,
which have irreconcilable configuration. There
may be data replication and the information
itself may be outdated, erroneous and
unfinished.
Thus, the organizations which have a huge
legacy system are consequently forced to
countenance with an elementary impasse. If they
persist with the legacy systems and making
changes as necessary, their costs will inexorably
boost. If they choose to reinstate their legacy
systems with new systems, this will be
expensive and the new systems may not endow
with as efficient business hold as the legacy
systems had. Henceforth, many businesses are
coming across various software engineering
procedures which may widen the life span of
legacy systems and which can lessen the
expenses of maintaining these systems.
Assessment of Legacy System
Businesses which solely depend on several
legacy systems and which have inadequate
finances for up keeping and promoting these
systems have to select how to acquire the finest
return on their deal. This means that they should
make a practical estimation of their legacy
systems and then make a decision on what is the
most apt policy for developing these systems.
The several methodologies are related to
scrapping the system completely. This
alternative should be preferred when the system
is not making an efficient input to business
processes. This occurs when business processes
have changed since the system was set up and
they are no longer entirely reliant on the system.
This state of affairs is most common when
mainframe terminals have been reinstated by
personal computer and off-the-shelf software on
these technologies has been tailored to endow
with the computer support that the business
process desires.
Also, going on with the system is an alternative
that should be preferred when the system is still
required but where it is moderately steady and
users do not ask for a numerous changes in the
system.
If there is a possibility of transforming the
system in several modes to recover its
ISBN No: 978-81-88132-32-4
Proceedings of the 2nd National Conference on Information Technology
For Business Transformation (ITBT’ 2011); November 4-5, 2011;
Ajay Kumar Garg Engineering College, Ghaziabad
functionality, then it should be chosen when the
system eminence has been ruined by standard
change and whether the regular change to the
system is still desired or not. If at all there is an
alternative of rejuvenating the complete system
then, the same should be implemented at a
realistic expenditure. But at times, this can be a
option wherein lot of resources in terms of
manpower, finance and other assets need to be
recollected and put forward in a direction to
completely reconstruct the system again, in
accordance with the latest technological
advancement. This is how a legacy system can
be rejuvenated in order to reap rich benefits to
the organization from time to time.
Conclusion
A legacy system is a mature system that still
provides indispensable business services with
regular maintenance & updating being involved
in the same from time to time. Legacy systems
are not just application software systems. They
are socio-technical, computer-based systems, so
include business methodologies, application
software, support software and hardware. Many
researchers and practitioners express opinion
that software reuse has a potential to bring
productivity breakthroughs and can
fundamentally change the way we develop
programs.[4] Most legacy systems include a
several programs and shared data which is
linked to these programs. This data may be held
in files or in an outdated database management
system. Most legacy systems have been intended
from a functional viewpoint and are composed
of sets of interacting functions which
communicate through parameters and global
shared data areas. The business value of a legacy
system and the quality of the application
software and its environment should be assessed
to help decide whether to replace, transform or
maintain the system. The business value of a
system is an assessment of the effectiveness of
the system in supporting business goals. The
quality of the system depends on the quality of
the business methodologies, the quality of the
application software itself and the quality of the
hardware and software which is used to support
the system. Thus, Legacy System is vital to the
growth of organizations.
References:
[1] Aniello Cimitile, Anna Rita Fasolino, Filippo
Lanubile “Legacy Systems Assessment to
Support Decision Making”, IEEE Proceeedings.
[2] Chia-Chu Chiang, “Reengineering a Legacy
Tool for Software Evolution” Proceedings of the
14th Annual IEEE International Conference and
Workshops on the Engineering of Computer-
Based Systems (ECBS'07).
[3] Semih Cetin, N. Ilker Altintas, Halit
Oguztuzun, Ali H. Dogru, Ozgur Tufekci and
Selma Suloglu “Legacy Migration to Service-
Oriented Computing with Mashups”
Proceedings of the International Conference on
Software Engineering Advances(ICSEA 2007).
[4] Stan Jarzabek “Software reengineering for
reusability” Proceedings of the IEEE
Conference 1993.
[5] Ian Somerville, “Legacy Systems”, 2000.
About the Authors:
Dr. Vinay Goyal
Internationally recognized expert in Software
Engineering and Academician and has more
than 15 years experience, published numerous
papers in this field. His current research interests
include Soft computing Techniques, Data
Compression, Software Re-Engineering and
Mathematical Modeling. He is presently,
designated as Professor in Department of
Computer Science & Engineering, at Jind
Institute of Engineering & Technology, Jind
(Haryana), India. He has two books in his credit.
ISBN No: 978-81-88132-32-4
Proceedings of the 2nd National Conference on Information Technology
For Business Transformation (ITBT’ 2011); November 4-5, 2011;
Ajay Kumar Garg Engineering College, Ghaziabad
Amit Jain is a Doctoral Researcher at
Department of Computer Application of
Teerthanker Mahaveer
University, Moradabad.
He is currently working
on Legacy Systems, Re-
Engineering, Software
Evolution and Software
Migration. His research
interest includes Service-oriented architecture.
He holds MCA degree from Pune University
and is currently designated as Assistant
Professor, in at IIMT Management College,
Meerut, Uttar Pradesh, India
ISBN No: 978-81-88132-32-4