CHAPTER 1: THE SYSTEMS DEVELOPMENT  Physical design – the logical specifications of

ENVIRONMENT the system from logical design are

transformed into the technology-specific
Information Systems Analysis and Design
details from which all programming and
 Complex organizational process system construction can be accomplished
 Used by a team of business and systems 4. Implementation - the information system is
professionals coded, tested, installed and supported in the
organization
Application Software 5. Maintenance - an information system is
systematically repaired and improved
 Computer software designed to support
organizational functions or processes

Systems Analyst Standard and Evolutionary Views of SDLC

 Organizational role most responsible for analysis and

design of information systems

A Modern Approach to Systems Analysis & Design

1. 1950s: focus on efficient automation of existing

processes
2. 1960s: advent of procedural third generation
languages (3GL) faster and more reliable computers Systems development life cycle
3. 1970s: system development becomes more like an
engineering discipline
4. 1980s: major breakthrough with 4GL, CASE tools,
object-oriented methods
5. 1990s: focus on system integration, GUI applications,
client/server platforms, Internet
6. The new century: Web application development,
wireless PDAs and smart phones, component-based
applications, per-use cloud-based application services.
Evolutionary model

Developing Information Systems The Heart of the Systems Development Process

 System Development Methodology

 A standard process followed in an organization to
conduct all the steps necessary to analyze,
design, implement, and maintain information
systems

Systems Development Life Cycle (SDLC)

 Traditional methodology used to develop, maintain, Analysis–design–code–test loop

and replace information systems
 Phases in SDLC:
1. Planning - an organization’s total information
system needs are identified, analyzed,
prioritized, and arranged
2. Analysis - system requirements are studied and
structured
3. Design - a description of the recommended
solution is converted into logical and then
physical system specifications
The heart of systems development
 Logical design – all functional features of the
system chosen for development in analysis are
described independently of any computer
platform
 eXtreme Programming

 Short, incremental development cycles

 Automated tests
 Coding and testing operate together
 Advantages:
 Communication between developers
 High level of productivity
 High-quality code
Traditional waterfall SDLC

Object-Oriented Analysis and Design (OOAD)

Problems with Waterfall Approach
Based on objects rather than data or processes
 Feedback ignored, milestones lock in design specs
even when conditions change 1. Object:
 Limited user involvement (only in requirements phase)  a structure encapsulating attributes and
 Too much focus on milestone deadlines of SDLC behaviors of a real-world entity
phases to the detriment of sound development 2. Object class:
practices  a logical grouping of objects sharing the same
attributes and behaviors
3. Inheritance:
Different Approaches to Improving Development  hierarchical arrangement of classes enable
subclasses to inherit properties of superclasses
 CASE (Computer-Aided Software Engineering) Tools
 Diagramming tools enable graphical
representation.
 Analysis tools automatically check for Rational Unified Process (RUP)
consistency in diagrams, forms, and reports.
 An object-oriented systems development
 Documentation generators standardize technical
methodology
and user documentation
 Establishes four phase of development: inception,
elaboration, construction, and transition
 Each phase is organized into a number of
Agile Methodologies separate iterations

 Motivated by recognition of software development as

fluid, unpredictable, and dynamic.
 Three key principles: Our Approach to Systems Development
 Adaptive rather than predictive
 Criticisms of SDLC:
 Emphasize people rather than roles
 Forcing timed phases on intangible processes
 Self-adaptive processes
(analysis and design) is doomed to fail
 Being used if your project involves:
 Too much formal process and documentation
 Unpredictable or dynamic requirements
slows things down
 Responsible and motivated developers
 Cycles are not necessarily waterfalls
 Customers who understand the process and will
get involved

Factor That Distinguish Agile and Traditional Approaches

to Systems Development

Agile Methods Factors Traditional Methods

Well matched to small Size Methods evolved to
products and teams. handle large products
Reliance on tacit and teams. Hard to
knowledge limits tailor down to small
scalability projects
Untested on safety- Criticality Methods evolved to
critical products. handle highly critical
Potential difficulties products. Hard to
with simple design and tailor down to product
lack of documentation that are not critical