Information Technology Reference
In-Depth Information
is about enhancing existing systems, providing new front-ends to established back-ends,
capitalizing on existing relational technology for data storage, and building interfaces to
existing packages. It allows organizations to wrap the existing services into new offerings or
products, so as to reuse their investments in existing packages, databases, and legacy
systems within the context of component technology.
The Critical Problems Underlying e-Business Development
The overall picture confronting enterprises today could be characterized as this (Cook,
1996, 2000): at the core is the installed base of existing IT systems, which includes the legacy
data and business logic. Around the edge are increasingly proactive customers, to which the
enterprise must offer an increasing quality of service through existing and new channels. In
between, the enterprise is reengineering its business processes, with a focus on knowing its
customers better, and offering continuous improvement of its products and services. From
an IT perspective, the legacy systems become surrounded by a matrix of go-between
componentry providing services to support the changing business, with increased flexibility
and reduced development times as compared with legacy systems. This is often a challenge
requiring skilled and thorough design, taking into account such attributes as reliability,
efficiency, usability, maintainability, testability, portability, and the most essential reusabil-
ity. Nonetheless, a common reaction to the pressure of immediate business needs is to
virtually abandon planning and control in the name of producing fast results (Gartner Group,
1995). Yet, incremental releases that are developed in isolation solely to meet tight deadlines
will eventually result in fragmented systems that lack consistency and fail to provide
integrated support. Worse still, this presents a problem that grows out of control exponen-
tially with the number of increments delivered.
The Architectural Way to e-Business Solution Building
We believe that a key requirement of an incremental approach to e-business solution
building is to base increments on a sound architecture (Boehm & Basili, 2000) that enables
components to be plugged in as service providers to the increments. Besides, this should
be an architecture for model building (Zachman, 1987), which supports such goals as
management of scale and complexity, interoperability, and adaptability. In large organizations
with complex business processes, there is a need to manage scale and complexity in software
development in such a way that the resulting software structure mirrors business needs as
closely as possible (Gartner Group, 1996). This requires the architecture to establish the
definitions, rules, and relationships that will form the infrastructure of models from business
process to code. More, this architecture should support the idea of software evolution among
a mix of legacy systems and databases, off-the-shelf packages, and newer applications.
ARCHITECTURAL MODELING BASICS FOR
QSE
To help our PBL students embark on their journey of system development, we selected some
recurring architectural modeling concepts for them to learn and practice through trial, error, and
mentoring. These concepts are based on fundamental principles (Hartley, Hruschka, & Pirbhai,
2000) that we believe are applicable to IS modeling, regardless of the underlying techniques used.
