Information Systems Development

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2 Δεκ 2013 (πριν από 3 χρόνια και 8 μήνες)

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Information Systems Development
Methods

Panagiotis Kanellis
,
Επιστημονικός Συνεργάτης Τμήματος Πληροφορικής ΕΚΠΑ

Business Consulting
,
377 Syngrou Ave.
,
175 64 Athens
,
Greece

Email: kanellis@di.uoa.gr

Δρακούλης Μαρτάκος
,
Επίκουρος Καθηγητής Τμήματος Πληροφορικής ΕΚΠΑ

Κτίρια Πληροφορικής, Πανεπιστιμιόπολη,
1
57 84

Αθήνα

Email:
martako
σ
@di.uoa.gr

Learn about...


The Traditional Systems Life Cycle


Prototyping


Developing with Application Software
Packages


End
-
User Development


Outsourcing Information Systems

The Traditional Systems Life
Cycle


Oldest method for building information systems


Still used today for complex medium/large
system projects


Traditional methodology for developing an IS that
partitions the systems development process into six
formal stages that must be completed sequentially with
a very formal division of labor between end users and
information systems specialists


Stages of the Systems Life
Cycle


Project Definition


Systems Study


Design


Programming


Installation


Post
-
Implementation

Limitations of the Life
Cycle Approach


Very resource intensive


Is inflexible and inhibits change


Ill suited to decision
-
oriented applications

Prototyping


Process of building an experimental system
quickly and inexpensively for demonstration and
evaluation so that end users can better
determine information requirements



It is an iterative process

Steps in Prototyping


Identify the user’s basic requirements


Develop a working prototype


Use the prototype


Revise and enhance the prototype


When no more iterations are required, the approved
prototype then becomes an operational prototype that
furnishes the final specifications for the application

Developing Systems with
Application Software Packages

Set of prewritten, precoded application software
programs that are commercially available for
sale or lease



Where functions are common to many companies


Where information systems resources for in
-
house
development are in short supply


When desktop microcomputer applications are being
developed for end
-
users


Advantages of Applications
Software Packages


Most of the design work has been
accomplished in advance


Fewer internal information systems
resources are necessary to support a
package
-
based system


Reduce some of the organizational
bottlenecks in the systems development
process (users have to accept it as is)

Disadvantages of Applications
Software Packages


Have not yet achieved the level of sophistication
and technical quality needed to produce
multipurpose packages


May not meet all of an organization’s
requirements


Extreme customization may result in the
package becoming unrecognizable


Vendor may stop providing support

Selecting Software
Packages


Request for Proposal (RFP)

-

Detailed list of
questions submitted to vendors of packaged
software or other computer services to
determine if the vendor’s product can meet the
organization’s specific requirements

Application Package
Development Cycle

Application Package Development Cycle
SystemsAnalysis
Identify Problem
Identify User Requirements
Identify Solution Alternatives
Identify Package Vendors
Evaluate Package vs. In-House Development
Evaluate Packages
Select Package
Systems Design
Tailor User Requirements to Package Features
Train Technical Staff on Package
Prepare Physical Design
Customize Package Design
Redesign Organizational Procedures
Programming, Testing, and Conversion
Install Package
Implement Package Modifications
Design Program Interfaces
Produce Documentation
Convert to Package System
Test the System
Train Users on Package
Production and Maintenance
Correct Problems
Install Updates or Enhancements to Package
End
-
User Development

The development of IS by end users with little or
no formal assistance from technical specialists



made possible by the 4th
-
generation software tools


users can access data, create reports, create web pages
without professional help


the role of IS specialist becomes supportive


systems can be created very rapidly



Advantages/Disadvantages of 4th
Generation Tools


Productivity gains of 300 to 500%



Capabilities remain limited


Require large amounts of computing resources


Slow response times for high volume processing


4th generation tools are most likely to create systems
rapidly and effectively when system builders lay the
appropriate groundwork

Benefits and Problems of
End
-
user Development


Improved requirements determination


User involvement and satisfaction


Control of the systems development process by users


Reduced application backlog


Insufficient review and analysis when user and analyst
functions are no longer separate


Lack of proper quality assurance standards and controls


Uncontrolled data


Proliferation of “private” information systems

Policies and Procedures to
Manage End
-
User Computing


Cost justification of end
-
user information systems projects


Hardware and software standards for user
-
developed
applications


Company
-
wide standards for microcomputers, word processing
software, DBMS, graphics software, and query reporting tools


Quality assurance reviews, specifying whether only individual
and users or whether specialists from the information systems or
internal audit departments should review end
-
user developed
applications


Controls for end
-
user developed applications covering testing,
documentation, accuracy, and completeness of input and
update, backup, recovery, and supervision

Outsourcing Information
Systems

The practice of contracting computer center operations,
telecommunication networks, or applications
development to external vendors



Economy


Loss of control


Service Quality

Vulnerability of Strategic Information


Predictability


Flexibility


Making fixed costs variable


Freeing up human resources for other projects


Freeing up financial capital


When to Use Outsourcing


When there is only a limited opportunity for the firm to
distinguish itself competitively through a particular
information systems application or a series of
applications



When outsourcing does not strip the company of the
technical know
-
how required for future information
systems innovation



When the firm’s existing information systems capabilities
are limited, ineffective, or technically inferior