Systems Devt
Transcript of Systems Devt
-
7/29/2019 Systems Devt
1/34
1
References:
Laudon, K. C. and Laudon, J. P., Management
Information Systems: Managing the Digital Firm,
12th edition, Prentice-Hall, 2011.
-
7/29/2019 Systems Devt
2/34
Our Main Focus
Why do systems development?
Understand the importance of linking the information
system to business needs.
Understand the need to create a system request. Understand how to assess technical, economic, and
organizational feasibility.
Understand Systems development Life Cycle and
phases.
-
7/29/2019 Systems Devt
3/34
Why the need for systems
development?
System Development has three primary business
objectives:
- Ensure the delivery of high quality systems; - Provide strong management controls;
- Maximize productivity.
-
7/29/2019 Systems Devt
4/34
Systems Development
Definition:
A conceptual model used in project
management that describes the stages involved
in an information system development project,
from an initial feasibility study through
maintenance of the completed application.
-
7/29/2019 Systems Devt
5/34
Systems as Planned
Organizational Change
Building a new system is a kind of
organizational change
Includes changes in H/W, S/W, jobs,skill, management and organization
When we design new system
Need to redesign the organization
5
-
7/29/2019 Systems Devt
6/34
Systems Analyst specialization
Most important skills:
Technical, business, analytical, interpersonal,
management, ethical, communication,
problem-solving, decision-making Roles:
Business analyst
Systems analyst Infrastructure analyst
Change management analyst
Project manager etc
-
7/29/2019 Systems Devt
7/34
7
The activities that go into producing an
information system solution to an
organizational problem or opportunity are
called systems development
-
7/29/2019 Systems Devt
8/34
Preliminary Investigation object
can be achieved in following steps:
Request Clarification
Feasibility study
Estimating Costs and Benefits
Request Approvals
-
7/29/2019 Systems Devt
9/34
Feasibility Analysis involves 8 steps:
Form a project team & appoint a project leader.
Prepare system flowcharts.
Enumerate potential candidate system.
Describe & identify characteristics of candidatesystems.
Determine & evaluate performance & cost
effectiveness of each candidate system.
Weigh system performance & cost.
Select the best candidate system.
Prepare & report final project directive to
management.
-
7/29/2019 Systems Devt
10/34
Feasibility Study Report
The report contains the following
sections:-
Cover letter Table of
Overview
Detailed findings
Economic justification
Recommendations & conclusions
Appendixes
-
7/29/2019 Systems Devt
11/34
Types of feasibility study:
There are six types of feasibility:
Technical feasibility
Economic feasibility
Operational feasibility
Legal and Political Feasibility
Schedule Feasibility
-
7/29/2019 Systems Devt
12/34
System Analysis or Requirement
Analysis:
Thisphaseof System Development is
being completed in following step:
Collection of data and facts
Analysis of Present System
Analysis of Proposed system
-
7/29/2019 Systems Devt
13/34
13
Collection of Data & Facts:
1. Documents review:
2. Questionnaires:
3. Interviews:
4. Observation.
-
7/29/2019 Systems Devt
14/34
Analysis of Present
System
Review of Historical Aspects of organization
Analyze Present inputs to the system
Review of all data file maintained irrespective of
online or offline
Review methods, procedures & data
communications
Analyze Present outputs of system
Review internal controls
Model the existing physical system and logical
system
Undertake overall analysis of present system
-
7/29/2019 Systems Devt
15/34
Analysis of Proposed
System
Output / Reports
Maintenance of Database
Data Inputting Process
Methods and Procedures to show the
relationship between Input and Output
Work volume including peak periodwork volume
-
7/29/2019 Systems Devt
16/34
System Design
The overall plan or model for that system
Consists of all the specifications that give
the system its form and structure What makes one design superior to others
is the ease and efficiency with which itfulfills user requirements within a specific
set of technical, organizational, financial,and time constraints
-
7/29/2019 Systems Devt
17/34
Programming (Software Coding)
System specifications that were prepared
during the design stage are translated into
software program code
-
7/29/2019 Systems Devt
18/34
System Testing
Exhaustive and thorough testingmust be conducted to ascertainwhether the system produces the
right resultse.g., Unit testing, system testing,
UAT
Systems development teamworks with users to devise asystematic test plan
18
-
7/29/2019 Systems Devt
19/34
Conversion
Process of changing from the oldsystem to the new system
e.g., parallel strategy, directcutover, pilot study and phasedapproach
Detailed documentation showinghow the system works from both atechnical and end-user standpointis finalized during conversion stage
19
-
7/29/2019 Systems Devt
20/34
Operation & Maintenance
After the new system is installed andconversion is complete, the system is saidto be in operation
During this stage, the system will bereviewed by both users and technicalspecialists to determine how well it hasmet its original objectives and to decide
whether any revisions or modifications arein order
Could conduct post-implementation audit
20
-
7/29/2019 Systems Devt
21/34
21
Systems Development Process
Changes in hardware,software, documentation, orprocedures to a production
system to correct errors,meet new requirements, orimprove processingefficiency are termedmaintenance
-
7/29/2019 Systems Devt
22/34
22
Alternative Systems Development
Approaches
System development life cycle (waterfall)method has defined, linear stages of systemsdevelopment and support
Prototyping model is used for developingprototype systems for soliciting userrequirements or building system
-
7/29/2019 Systems Devt
23/34
The Waterfall Model
The waterfall model specifies a set of
sequential phases for software
development Each step cannot begin until the
previous step has been completed
anddocumented.
It is document-driven.
-
7/29/2019 Systems Devt
24/34
3- 24
-
7/29/2019 Systems Devt
25/34
The Limits of Waterfall Model
Inflexibility Cannot easily swim upstream
Over-Reliance on Documentation
Relies too much on documentation Detachment from Technology
One size methodology cannot fit all technologies.
Detachment from Marketplace Slow-paced methodology (Time consuming).
Detachment from the Profession Programming is not the same as assembly of cars or
baking breads, nor programmers work the same wayas manufacturing workers or bakers.
-
7/29/2019 Systems Devt
26/34
Prototyping
Building experimental system rapidly and
inexpensively for end users to evaluate
Prototype: Working but preliminary version of
information system Approved prototype serves as template for final system
Steps in prototyping
1. Identify user requirements
2. Develop initial prototype
3. Use prototype
4. Revise and enhance prototype
26
-
7/29/2019 Systems Devt
27/34
27
Prototyping Contd
-
7/29/2019 Systems Devt
28/34
Advantages of prototyping
Useful if some uncertainty in requirements or
design solutions
Often used for end-user interface design
More likely to fulfill end-user requirements
Disadvantages
May gloss over essential steps May not accommodate large quantities of data or
large number of users
May not undergo full testing or documentation28
Prototyping Contd
-
7/29/2019 Systems Devt
29/34
29
End-User Development
Some types of information systems can be developedby end users with little or no formal assistance fromtechnical specialists
Software tools (e.g., Microsoft Access and CrystalReport) enable end users to create reports or develop
software applications Adv:
Allowing users to specify the own business needsimproves requirements gathering
Contributing to higher level of user involvement and
satisfaction Disadv:
Higher organizational risks
Poor IS management and control
-
7/29/2019 Systems Devt
30/34
means using an external vendor to build or
operate a firm's information systems.
The system may be custom built or may use asoftware package.
In either case, the work is done by the vendorrather than by the organization's internal
information systems staff.
30
Outsourcing
-
7/29/2019 Systems Devt
31/34
Outsourcing (cont.)
Advantages
Allows organization flexibility in IT needs
Disadvantages
Hidden costs, e.g.
Identifying and selecting vendor
Transitioning to vendor
Opening up proprietary business processes to
third party
31
-
7/29/2019 Systems Devt
32/34
Rapid application development (RAD)
Process of creating workable systems in a very short periodof time
Utilizes techniques such as:
Visual programming and other tools for building graphicaluser interfaces
Iterative prototyping of key system elements
Automation of program code generation
Close teamwork among end users and information
systems specialists
32
-
7/29/2019 Systems Devt
33/34
Used to accelerate generation of information
requirements and to develop initial systems design
Brings end users and information systems
specialists together in interactive session to discusssystems design
Can significantly speed up design phase and involve
users at intense level
33
Joint application design (JAD)
-
7/29/2019 Systems Devt
34/34
Focuses on rapid delivery of working software by
breaking large project into several small sub-
projects
Subprojects Treated as separate, complete projects
Completed in short periods of time using iteration and
continuous feedback
Emphasizes face-to-face communication over
written documents, allowing collaboration and
faster decision making
34
Agile development