LEGACY MIGRATION AS PLANNED ORGANIZATIONAL
CHANGE
Teta Stamati, Panagiotis Kanellis, Konstantina Stamati, Drakoulis Martakos
Department of Informatics and Telecommunications, University of Athens, Athens, Greece
Keywords: legacy migration, enterprise modeling, organisational change
Abstract: Traditionally, legacy migration has been viewed as the simple replacement of aged or problematic hardware
and software, including the applications, interfaces and databases that compose an information system
infrastructure. Our position is that this view is outdated and is at best myopic taking into account that the
role of technology is not merely supportive but today pervades every aspect of the way enterprises conduct
their business. As such, our position is that migration should be approached as a planned change process
that first and foremost requires an understanding and an approach that covers the range of issues and
organisational entities involved. In this context, this paper presents such a structured approach that defines
the landscape, deals with the semantics of legacy migration and, can be applied by organisations that
recognise the need to manage the process in a controlled and not in a piecemeal and ad hoc fashion.
1 INTRODUCTION
Any modification or enhancement of a legacy
system within an organisation inevitably brings
changes in the way work is organised. Similarly, any
organisational change should be reflected in the
corporate systems. However, due to the rate of
change experienced in contemporary commercial
settings, organisations are witnessing the disabling
effects that the build-up of legacy systems has on the
ability to respond to such change (Brodie &
Stonebraker, 1995). Legacy systems are
characterised as being very brittle with respect to
change (Ganti & Brayman, 1995; Wu et al., 1997)
with small modifications or enhancements leading
frequently to unexpected project failures (Brodie &
Stonebraker, 1995; Bateman & Murphy, 1994). To
complicate matters, legacy systems are usually
mission-critical systems and must be operational at
all times (Brodie & Stonebraker, 1995). Projects
tend to fail for a number of reasons (Brodie &
Stonebraker, 1993, 1995; Bennet, 1995) but a
common thread that arguably runs through the
majority of them is the fact that legacy migration is
viewed solely as a technical challenge. To the best
of our knowledge, existing migration approaches
tend to ‘see’ the legacy system as a standalone and
self-contained application or database, defining steps
and activities to be performed at the technical level.
This ignores social and organisational issues that any
change process involves. Today, due to the rate of
change, legacy migration is not merely the
replacement of existing systems with sets of newer
systems offering the same functionality. Migration
should widen its scope so as to include
organisational change as well as change in computer
systems that enables the enterprise change. This
wider scope requires a mindset and approaches that
can accommodate a wider range of issues,
emphasizing the cognitive and social and not merely
the technical aspect. In this paper we present a
broader, generic approach to legacy migration as
planned organisational change which is based on six
‘knowledge states’ (Kavakli & Loucopoulos, 1999)
and imposes three views or ‘profiles’ on the process,
namely the intentional, operational and
informational. The paper begins by providing an
overview of the approach and then proceeds in a
sequential manner describing and analysing the three
aforementioned profiles. The last section concludes
the paper.
2 A GENERIC APPROACH FOR
LEGACY MIGRATION
What underlies our approach for legacy migration
which we term “Migrate Method” is the following
definition: “Migration is a process, which involves
business change and this involves more than just the
501
Stamati T., Kanellis P., Stamati K. and Martakos D. (2004).
LEGACY MIGRATION AS PLANNED ORGANIZATIONAL CHANGE.
In Proceedings of the Sixth International Conference on Enterprise Information Systems, pages 501-508
DOI: 10.5220/0002630605010508
Copyright
c
SciTePress
movement or reorganization of database systems,
application programs and program interfaces”.
In general, the motivation for any migration
process is the incremental transition from an initial
organisational situation A, which is unsatisfactory in
some aspect, to a desired situation B where the
problem is addressed. Possible causes to such
change include perceived opportunities, threats,
social pressures or political decisions, including for
example the opportunities offered by new
technologies, increased customer demand for better
service quality or the globalisation of markets. The
main objective of our approach is the provision of a
semantic roadmap based on a set of Knowledge
States that define a migration process. We approach
migration not as an undirected process, but as a
purposive activity driven by organisational goals.
Hence, its effectiveness depends on being able to
make good decisions about what migration goals to
pursue, on selecting the appropriate strategies for
achieving the desired goals, and on guiding the
application of the chosen strategies. In order to be
able to systematically plan and model a legacy
migration process, a series of relevant procedures
are executed. It is possible to make the distinction
between six different types of Knowledge States
involved in a migration process, namely:
i) Knowledge about the current business
processes, the legacy systems that serve these
processes, as well as the requirements for migration
(As-Is).
ii) Knowledge about the stakeholders’ goals and
how they can be satisfied in terms of alternative
migration plans as well as the specific processes that
will achieve the predefined migration goals (Migrate
Goal Model – Migrate Process Model).
iii) Knowledge about a set of proposed migration
transformations that describe a unique way of
pursuing stakeholders’ goals (Migration Scenarios).
iv) Knowledge about the validity of the above
transformations and thus, knowledge about the most
suitable proposed plan (Candidate Migrate
Scenario).
v) Knowledge about the candidate legacy
systems that are to be migrated (Legacy Systems).
vi) Knowledge about the most suitable custom or
off-the-self migration solution based on the profile
of the legacy systems (System Migration).
Two additional states in the framework are
available: the Null State and the Target State. These
describe respectively the state where ‘no knowledge’
about the migration is available and the state where
‘enough knowledge’ has been obtained.
The “Migrate Method” extends across the three
different views or levels of abstraction, which
feature in enterprise modeling. It examines a
migration process from the intentional, operational
and informational perspective. The intentional view
is concerned with the enterprise objectives and the
reasons that prescribe these objectives. It also
considers the actors and the corresponding roles that
they play in the organisation as well as the business
rules. The operational view concerns the business
process level, describing the logical localization of
data in the different departments of the enterprise,
the distribution of functions in these departments
and the actors involved in each function. Finally, the
informational view defines the logical and physical
components of the information systems that support
the business processes. The “Migrate Method”
encompasses all three profiles and integrates the
three complementary views as submodels.
Knowledge States and submodels form the “Migrate
Method” Metamodel (figure 1) that defines the
logical form of the migration process. The
metamodel includes information about the semantics
of legacy migration; it identifies the entities, their
attributes and the explicit relationships between
them. The following paragraphs provide a
description of the three submodels.
With reference to figure 1, a
Migration Goal is a
desired state concerning a legacy system that needs
to be attained. Migration Goals pertain to
stakeholders. A stakeholder is defined as someone
who has an interest in the system design and usage.
Migration Goals are generated by issues. An issue is
a statement of a Strength, Weakness, Opportunity or
Threat that leads to the formation of the goal.
Migration Goals are then realized by Migration
Processes. This is expressed in the metamodel
through the Goal Realisation Relationship. Note that
the Migration Goals cannot be mapped directly onto
Migration Processes.
The transition process from intentions to
processes and thus from the intentional to
operational profile of the migration process,
encompasses the ‘causal transformations’ of general
migration goals into one or more sub-goals that
constitute the means for achieving desired ends.
Each step can result in the identification of new
goals that are linked to the original one through
causal relations, thus forming a hierarchy of goals.
ICEIS 2004 - INFORMATION SYSTEMS ANALYSIS AND SPECIFICATION
502
A directed edge from a goal A to another goal B
implies that the achievement of A depends on the
achievement of B. This goal transformation is
usually referred to as goal satisfycing
1
. For each goal
alternative satisfycing options may be identified,
leading to different ways of resolving this goal.
Additionally, the same subgoal may contribute to the
achievement of two or more goals. Thus, the
resulting structure is a goal graph, called Migration
Goal Model, rather than a hierarchy. Relationships
between goals in the goal graph are of the AND/OR
type and are defined as such in the metamodel. Once
the leave goals are operationalised by migration
processes, the Migration Process Model is
generated.
Any path in the Migration Process Model
including only AND type satisfycing relationships
between goals and their processor goals constitutes a
Migration Scenario documenting how specific
migration goals are (or may be) achieved.
Alternative paths in the Migration Process Model
represent alternative Migration Scenarios. The
validity of a particular Migration Scenario is
1
The term ‘satisfycing’ (Simon, 1979) refers to decision-making
process as a process that seeks satisfactory solutions rather
than optimal ones.
determined through the evaluation of the scenario’s
components and the calculation of measurements.
This measurement reflects the ‘appropriateness’ of a
solution with respect to one or several migration
evaluation goals and can be either quantitative or
qualitative. Based on the evaluation a scenario may
be accepted or rejected.
Migration Processes are expressed in terms of
the Migration Actors and the Migration Roles that
they play. An actor is a physical entity that plays one
or more roles. A role denotes a collection of
responsibilities. Discharging these responsibilities
requires the realisation of a set of role goals. Such
goals are mainly operational goals and they are
expressed in terms of business objects and activities
that realise them.
The Migration Processes are linked to the
Legacy Systems that support the business
operations. A specific Migration Process may
indicate more than one Legacy Systems to be
migrated or else may specify certain components of
the whole system that need replacement or
enhancement whilst it may also point out to
inadequate justification for the migration of some
other legacy components. The association of
Migration Processes to specific Legacy System
Migration Goal
Stakeholder
Issue
Strength
Weakness
Opportunity
Threat
Goal Relationship
Goal Realisation
Relationship
Goal Satisfycing
Relationship
AND_Goal
Relationship
OR_Goal
Relationship
AND/OR_Goal
Relationship
Operational
Goal
Migration
Process
Migration Scenario
Measurement
Quantitative
Measurement
Qualitative
Measurement
Accepted
Scenario
Rejected
Scenario
Evaluation
Goal
Legacy System
H/W
Infrastructure
S/W
Infrastructure
Database
System
Interface
System
Application
System
System Migration
H/W Infrastructure
Migration
Database
Migration
Interface
Migration
Application
Migration
S/W Infrastructure
Migration
Role
Activity
generated_by
n..m
pertain_to
n..m
involved_in
1..n
Argument
justified_by
1..n
1..n
involves
1..n
realises
1..1
has
1..1
has
1..n
identified_by
1..n
composed_of
1..n
performs
lead_to
n..m
affects
1..n
INTENTIONAL SUBMODEL
INTENTIONAL SUBMODEL
OPERATIONAL SUBMODEL
OPERATIONAL SUBMODEL
INFORMATIONAL SUBMODEL
INFORMATIONAL SUBMODEL
Figure 1: The “Migrate-Method” Metamodel
LEGACY MIGRATION AS PLANNED ORGANIZATIONAL CHANGE
503
indicates the informational profile of the migration
process.
The Legacy Systems could be any of the various
physical systems, which are classified below:
i) An application system - software, which is
used to support a particular function or process.
ii) A database system - consists of the actual
database and the DBMS, where the database is a
collection of records stored, according to some data
model.
iii) An interface system - is a piece of software,
which is used to interface a particular application
either with other applications or with system’s users.
iv) A software infrastructure system - is
software, which is dedicated to the operation of a
computer system, typically an operating system.
v) A hardware infrastructure system - is a piece
of physical equipment, whose operation may rely on
software and even firmware. Typical examples are
computer workstations, printers and even a Local
Area Network (LAN).
The connection between Migration Processes
and Legacy Systems is that the latter supports the
former. Based on the above classification, Systems
Migration may involve any of the migration
activities listed below:
i) Application systems migration – the
movement or reorganisation of software applications
to some new improved form or location.
ii) Database systems migration – the movement
or reorganisation of a database to some new
improved form or location.
iii) Interface systems migration – the movement
or reorganisation of interface components to some
new improved form or location.
iv) Software infrastructure migration – the
movement or reorganisation of software
infrastructure to some new improved form or
location.
v) Hardware infrastructure migration – the
movement or reorganisation of hardware
infrastructure to some new improved form or
location.
Some of these migration activities are more
common than others, for example, application and
database systems migration are likely to occur
frequently in an overall legacy migration, but
software and hardware infrastructure systems
migration are probably less likely to occur. It is
worth noting that the various forms of migration
have been listed in descending order of complexity
with application systems migration being the most
difficult and hardware systems migration being the
simplest.
2.1 Intentional Profile
The approach commences at the intentional level, by
understanding the current enterprise situation and
representing the current goals and objectives into the
Current Enterprise Goal Hierarchy. Having obtained
knowledge about the future stakeholders’ goals, the
approach proceeds to model those with respect to the
migration process into the Migration Goal Model.
The input in the ‘black box’ in figure 2
corresponds to the Current Enterprise Goal
Hierarchy and the outcome to the resulting
Migration Goal Model. Both hierarchies are goal
graphs and their branches are related by one of the
three relationships: AND (
), OR ( ) and the
hybrid ANDOR ( ).
C
urrent
E
nterprise
G
oal
H
ierarchy
Designing
for
migration
C
urrent
E
nterprise
G
oal
H
ierarchy
M
igrate
G
oal
M
odel
M
igrate
G
oal
M
odel
Contextual Forces
Contextual Forces
Satisfy
customer
Ensure product
quality
Minimise
product costs
Provide electronic
services
Provide after sale
support
Develop electronic
marketplace
Develop on line
help to the
Deal with
authorization
Develop new
services
INTRODUCE
Improve efficiency of
enterprise processes
IMPROVE
Introduce new
automated processes
INTRODUCE
Introduce new
Information Systems
IMPROVE
Improve existing
Information Systems
IMPROVE
Improve Organisational
Structures
CEASE
Cease non-profit and
useless enterprise
p
rocesses
IMPROVE
Improve the Process
Workflow Mgt System
IMPROVE
Improve the MIS
INTRODUCE
Introduce new
Knowledge Mgt System
Figure 2: Input and Output of the Migration Goal Modeling
ICEIS 2004 - INFORMATION SYSTEMS ANALYSIS AND SPECIFICATION
504
Both are traversed as well in a breadth-first
manner: all the nodes on one level of the hierarchy
are considered before any of the nodes on the next
level. In both graphs, any goal at each refinement
level describes what needs to be done. At the same
time this goal can also be considered as an end (why)
for another goal, as well as means (how) for still
another goal at a higher level.
The generated Migration Goal Model describes
all the possible routes that an enterprise can follow
to reach its new business goals. This graph includes
details about the stakeholders’ requirements in
addition to alternative ways of acting towards
realising the desired future. Each goal in the
Migration Goal Model is characterised by a verb,
which describes the nature of the change: maintain,
introduce, cease, enable, improve, etc. Figure 2
illustrates a rather simple Migration Goal Model but
in a real-world situation the resulting model is likely
to be very large because the model is normally
developed during brainstorming sessions.
Migration goals express the stakeholders’ needs
and desires, as well as external constraints with
respect to the migration process. The identification
of migration goals is a complex task that
encompasses a number of sub-tasks such as
definition of stakeholders’ goals in a participative
manner, determination of the impact of these goals
on the existing enterprise state, agreement on a
structured set of business requirements, etc. In the
same way, each of these sub-goals may lead to some
other concerns. For example, participative definition
of migration goals includes issues such as: definition
of the individuals that should be involved in the
process, definition of the manner that participants
are going to communicate with each other, definition
of the way that the stakeholders reach agreement on
the process, etc.
2.2 Operational Profile
Once the leaves of the Migration Goal Model are
mirrored by the required Migration Processes, the
approach progresses to the operational view with the
Migration Process Model. This includes a hierarchy
of goals together with the attached processes at the
operational level. Migration processes constitute the
means to fulfill the goals. Each role involved in a
process intends to achieve one or more defined
goals. The goals related to a process present a
hierarchical structure whereby individual role goals
constitute refinement of higher-level goals that
ultimately make up the goals fulfilled by the
processes.
The input in the ‘black box’ in figure 3
corresponds to the Migration Goal Model and the
outcome to the resulting Migration Process Model.
The association of the processes with the goal leaves
in the Migration Process Model exposes the
operational profile of this modeling. These processes
exhibit the activities carried out to complete a
process as well as the actors involved in each
process and the roles that these actors play. This
does not necessary mean that every role in a process
aims to achieve the same goal. Satisfaction of the
specific goals of individual roles supports the
achievements of the operational goals that is realised
by the processes.
Once an initial Migration Process Model has
been developed, it is necessary to refine the model in
order to eliminate changes, which may prove
Figure 3: Input and Output of Migration Process Modeling
Definition
of
processes
M
igrate
G
oal
M
odel
M
igrate
G
oal
M
odel
INTRODUCE
Improve efficiency of
enterprise processes
IMPROVE
Introduce new
automated processes
INTRODUCE
Introduce new
Information Systems
IMPROVE
Improve existing
Information Systems
IMPROVE
Improve Organisational
Structures
CEASE
Cease non-profit and
useless enterprise
p
rocesses
IMPROVE
Improve the Process
Workflow Mgt System
IMPROVE
Improve the MIS
Organisational Forces
Organisational Forces
M
igrate Process
M
odel
M
igrate
P
rocess
M
odel
Z1. Z2, Z3
A
1, A2, A3, A4
P1, P2, P3, P4
INTRODUCE
Improve efficiency of
enterprise processes
IMPROVE
Introduce new
automated processes
INTRODUCE
Introduce new
Information Systems
IMPROVE
Improve existing
Information Systems
IMPROVE
Improve Organisational
Structures
CEASE
Cease non-profit and
useless enterprise
p
rocesses
IMPROVE
Improve the Process
Workflow Mgt System
IMPROVE
Improve the MIS
IN
T
RODUCE
Introduce new
Knowledge Mgt System
LEGACY MIGRATION AS PLANNED ORGANIZATIONAL CHANGE
505
difficult or even impossible to achieve. This
refinement is carried out by ‘pruning’ the initial
Migration Process Model. Pruning involves cutting
off either branches or leaves to eliminate certain
change, which may be difficult to achieve.
Pruning is carried out using evaluation criteria
against which the desired goals are evaluated. The
pruning exercise is likely to be carried out by a
domain expert, or even a group of domain experts.
This is so because of two reasons: firstly domain
knowledge is necessary for the selection of suitable
evaluation criteria and secondly the actual
performance of the pruning calls for knowledge of
what can and cannot be achieved in terms of
migration goals.
The “Migrate Method” proceeds to define a
structured way of identifying and evaluating the
alternative transitions for migration within the whole
Migration Process Model. Thus, the approach
encompasses the Migrate Scenarios Generation
technique. Migration Scenarios are defined as
possible alternative transition for change. They
enable the stakeholders to convey their ideas very
easily by developing a shared understanding of the
future system’s functionality and leading to the
validation of this system.
Alternative Migration Scenarios are modeled as
alternative ways of traversing the Migration Process
Model. They occur as a consequence of the OR
relationships that exist in a generic Migration
Process Model. Each Migration Scenario is a sub-
hierarchy of migration goals, which are related
through AND relationships only and specifies a
unique way of pursuing stakeholders’ goals. Using
the definition of a Migration Scenario, the process of
Scenario Generation can be carried out
systematically. It involves traversing the change
process model and identifying the sub-trees, which
consist of only AND links and marking each of these
sub-trees as single change scenarios. This process is
repeated exhaustively using a depth-first search until
all possible scenarios have been identified.
The process Scenario Generation starts with a
Migration Process Model and ends with a set of
excerpts from the same Migration Process Model,
which correspond to different scenarios. Figure 4
illustrates the identification of scenarios.
Evaluation of alternative scenarios is concerned
with evaluating competing migration options.
Alternative Migration Scenarios are modeled as
alternative ways of traversing the Migration Process
Model. The evaluation of scenarios requires the
active participation of the stakeholders. Stakeholders
are the ones who determine whether a solution is
valid or not. The evaluation task is facilitated by the
identification of criteria for judging the alternative
scenarios for migration and commences with the set
of scenarios that have been retrieved from the
Migration Process Model with the Scenario
Generation process. It ends with the Candidate
Migration Scenario that represents the most
desirable route to change (figure 5).
Scenarios
Generation
M
igrate Proc ess
M
odel
M
igr ate
P
rocess
M
odel
A
1, A2, A3, A4
Z1. Z2, Z3
P1, P2, P3, P4
IN TRO DU CE
Improve efficiency of
enterp rise proce sses
IM PRO VE
Introduce new
autom ated processes
INTRODU CE
Introduce new
Information Systems
IM PRO V E
Improve existing
Information System s
IM PRO VE
Improve O rganisational
Structures
CEAS E
Cease non-profit and
useless enterprise
p
rocesses
IM PRO VE
Im prove th e Process
Workflow Mgt System
IM PR O V E
Im prove the M IS
INTRO DUCE
Introduce new
Know ledge M gt System
P1, P2, P3, P4
INTR O DU CE
Improve efficiency of
enterprise processes
IM PR OV E
Introduce new
automated processes
IM PROVE
Im prove existing
Information Systems
IM PROVE
Improve Organisational
Structures
CEAS E
Cease non-profit and
useless enterprise
p
rocesse s
IM PR OV E
Improve the Process
Workflow Mgt System
IM PR OV E
Improve the M IS
Z1 . Z 2 , Z 3
S
cenarios for
M
igr ation
S
cenarios for
M
igration
A
1, A2, A3, A4
IN TR O D U CE
Improve efficiency of
enterprise processes
IM PR O V E
Introduce new
automated processes
INTRO D UCE
Introduce n ew
Inform ation Sy stem s
IMPRO VE
Improve O rganisational
Structures
CEAS E
Cease non -profit and
useless enterprise
p
rocesses
IN TR O D U CE
Introduce n ew
Knowledge M gt System
Fi
g
ure 4: In
p
ut and Out
p
ut of the Mi
g
ration Scenarios Generation Process
ICEIS 2004 - INFORMATION SYSTEMS ANALYSIS AND SPECIFICATION
506
2.3 Informational Profile
The Candidate Migration Scenario is modeled as a
submodel of the initial Migration Process Model
describing explicitly the most significant migration
goals fulfilled by corresponding processes. The
association of the Migration Processes with the
Migration Goal leaves in the Candidate Migration
Scenario indicates the beginning of the information
system modeling. These processes exhibit the
activities carried out to complete a process as well as
the specific Legacy Systems that support these
activities.
Figure 6 illustrates the process of System
Migration. The System Migration commences with
the analysis of the processes described in the
Candidate Migration Scenario and ends with the
matching of the processes with the corresponding
Legacy Systems that should be migrated. The
factors, which are used to measure the degree of
complexity of various forms of migration, are the
following:
(a) Complexity – complex systems are often
difficult to understand and are difficult to
decompose in terms of function and data into
smaller, more manageable sub-components; (b)
Cohesion – measures the strength by which systems
are stuck or bonded together; (c) Coupling – relates
to how systems link to one another with systems that
contain many interfaces and complex links
exhibiting a high degree of coupling; (d) Modularity
– in general modular systems are easier to migrate
than those, which are not modular; (e) Inertia – a
measure of the extent to which a system resists, or
refuses change or movement. It should not be too
difficult to understand how these factors impact on
legacy migration. They are commonly used as
metrics in assessing the degree of flexibility of
systems in the more general sense. For example,
factors (a)-(d) are metrics, which are often used to
quantify software systems in terms of
maintainability and portability.
The identification of the Legacy Systems that
should be migrated is carried out by domain experts
since it requires specific knowledge and skills. At
this stage migration engineers should try to identify
the best solution whether, for example, this should
take the form of a custom or off-the-self migration
application as different migration solutions suit
different legacy systems. The selection of the most
appropriate solution depends on a number of factors
such as the cost, time limits etc. For instance, the
process ‘Upgrade all systems to a new interface
using 4GL tools’ may require a ‘screen-scraping’
migration solution if the organisation sees that a
quick and low-cost solution is most appropriate.
Scenarios
Evaluation
S
cenarios for
M
igration
S
cenarios for
M
igration
A
1, A2, A3, A4
IN TR O D UCE
Improve efficiency of
enterprise processes
IMPRO VE
Introduce n ew
autom ated processes
INTR O D UCE
Introduce new
Information Systems
IM PROVE
Improve Organisational
Structures
CEASE
Cease non -profit and
useless enterprise
p
roce ss es
INTR O DUCE
Introduce n ew
Knowledge Mgt System
C
andidate
S
cenario
C
andidate
S
cenario
P1, P2, P3, P4
INT ROD U CE
Im prove efficiency of
enterprise processes
IM PROVE
Introduce new
automated processes
IM PROV E
Im prove existing
Information Systems
IM PROV E
Improve Organisational
Structures
CEASE
Cease non-profit and
useless enterprise
p
rocesse s
IM PROV E
Imp rove the Process
Workflow Mgt System
IM PROVE
Improve the MIS
Z1. Z2, Z3
P1, P2, P3, P4
INT ROD U CE
Improve efficiency of
enterprise processes
IM PROV E
Introduce new
automated processes
IM PROVE
Improve existing
Information Systems
IM PROVE
Imp rove Organisational
Structures
CEAS E
Cease non-profit and
useless enterprise
p
rocesse s
IM PROV E
Imp rove the Process
Workflow Mgt System
IM PROV E
Imp rove the M IS
Z1. Z2, Z3
Figure 5: Input and Output of the Migration Scenarios Evaluation P
r
ocess
LEGACY MIGRATION AS PLANNED ORGANIZATIONAL CHANGE
507
3 CONCLUSIONS
Existing migration approaches view migration as the
replacement of a current operational system to a new
platform, retaining and if possible, enhancing the
legacy system’s functionality and causing as little
disruption to the operational and business
environment as possible. However, and to the best of
our knowledge, none offers an integrated and
structured approach for planning and monitoring a
migration project considering it as a general change
process.
Migration involves general organisational
change as well as change in the information systems
themselves. Our position is that migration processes
for contemporary organizations need a well-
structured and wide in scope approach that takes into
consideration the semantics of planned
organizational change. The approach presented in
this paper defines a number of interlinked
procedures that model the transformation of a
current organisational state to a desired future state.
We do not claim that our approach represents some
form of magical tool for planning and carrying out
successful migration projects. We would rather like
to see it as a roadmap that includes the semantics of
a landscape far wider and complex than previous
migration approaches have considered. As such we
believe that its value derives from the fact that it can
primarily be used for revisiting our current, but
arguably outdated, mindsets for legacy migration.
From an applied point of view it can also help for
the generation of information models and the
informed selection of a tool-set of appropriate
techniques that can be used to carry out the
modeling and other tasks that need to be performed
for moving from one ‘knowledge state’ to another.
For legacy migration, organizations need both, and
we believe that the approach presented herein can be
employed for making the first steps towards these
directions.
REFERENCES
Bateman, A. and Murphy, J, 1994. Migrating of Legacy
Systems, School of Computer Applications, Dublin
City University, Working Paper CA-2894.
Brodie, M. and Stonebraker, M., 1993. DARWIN: On the
Incremental Migration of Legacy Information
Systems. GTE Labs Inc., Internal Report No TR-022-
1092-165
.
Brodie, M. and Stonebraker, M., 1995. Migrating Legacy
Systems: Gateways, Interfaces & The Incremental
Approach, Morgan Kaufmann Publishers, Inc.
Ganti, N. and Brayman, W., 1995. The Transition of
Legacy Systems Architecture to a Distributed
Architecture, John Wiley & Sons, Inc.
Kavakli, K. and Loucopoulos, P., 1999. Legacy
Information and Business Process Change,
Communications of the Association for Information
Systems, Vol. 2, No. 6.
Simon, H., 1979. Rational Decision Making in Business
Organizations, American Economic Review, Vol. 69,
No. 4, pp. 493-513.
Wu, B., Lawless, D., Bisbal, J., Grimson, J., Wade, V.,
O’Sullivan, D., Richardson, R., 1997. Legacy System
Migration: A Legacy Data Migration Engine,
Proceedings of the 17
th
International Database
Conference, pp. 129-138.
System
Migration
C
andidate
S
cenario
C
andidate
S
cenario
P1, P2, P3, P4
INTRODUCE
Improve efficiency of
enterprise processes
IMPROVE
Introduce new
automated processes
IMPROVE
Improve existing
Information Systems
IMPROVE
Improve Organisational
Structures
CEASE
Cease non-profit and
useless enterprise
p
rocesses
IMPROVE
Improve the Process
Workflow Mgt System
IMPROVE
Improve the M IS
Z1. Z2, Z3
P1:
Improve the S/W of the System.
P2:
Upgrade the H/W of the System.
P3:
Examine and re-evaluate the
predefined Workflows (data).
P4:
Re-examine the access to the
System.
Z1:
Upgrade the H/W of the System
Z2:
Upgrade the S/W of the System
Z3:
Reconsider the update the data of
the System
P1: Software Infrastructure System
Migration
P2: Hardware Infrastructure
Migration
P3: Database System Migration.
P4: Application System s Migration.
Z1: Hardware Infrastructure
Migration
Z2: Software Infrastructure System
Migration
Z3: Database System Migration
Figure 6: Input and Output of the System Migration Process
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