2

Designing new systems or modifying existing ones should always be aimed at helping an organization achieve its goals

The primary emphasis of systems implementation is to make sure that the right information is delivered to the right person in the right format at the right time

Maintenance and review add to the useful life of a system but can consume large amounts of resources..

3

Stages in Systems Analysis & Design

Last Week Systems Investigation Analysis

This Week Systems Design Implementation Maintenance Review

4

Systems Design

Answers the question “How will the information system do what it must do to solve a problem?”

Has two dimensions: logical and physical

Logical design: description of the functional requirements of a system. What the system will do to solve the problem (earlier). No hardware or software considerations here.

Physical design: specification of the characteristics of the system components necessary to put the logical design into action.

RFQ and/or RFP. These are based on the logical design.

5

Logical Design

Output requirements

Input requirements

Process requirements

File and database requirements

7

Physical Design

Hardware specifications

Software specifications

Database specifications

8

Physical Design (continued)

Telecommunications specifications

Personnel specifications

Procedure and control specifications

10

Figure 13.4: The Levels of the Sign-On Procedure

ID = Username & PW Verification = For

systems and applications that are sensitive or secure another code is needed.

Authorization. Restricts the users access.

11

Interface Design and Controls (continued)

Interactive processing

Menu-driven systems

Help commands

Table lookup facilities

Restart procedures

12

Table 13.1: The Elements of Good Interactive Dialogue

13

Design of System Security and Controls Preventing, detecting, and correcting errors

Early in the design stage Also develop a good backup system.

Disaster planning and recovery

Disaster planning: the process of anticipating and providing for disasters:

Maintaining integrity of informationKeep information systems running

14

Design of System Security and Controls (continued) Disaster recovery: the implementation of the

disaster plan

Disaster planning and recovery (continued)

Software and database backup

Telecommunications backup

Personnel backup

15

Design of System Security and Controls (continued) A number of firms offer disaster recovery services.

Hot site Cold site

Backups—2 copies, one onsite one offsite Can outsource

Backups– Backup software is expensive and complicated. Who will be responsible. Training. Can backup the servers and individual hard drives.

Policy to use only the network to save. Types of backups

Selective—Backup programs? Incremental backup Full Can you “Restore Archive bit

17

Evaluating and Selecting a Systems Design

Preliminary evaluation

To dismiss the unwanted proposals

Begins after all proposals have been submitted

Final evaluation

A detailed investigation of the proposals offered by the vendors remaining after the preliminary evaluation

18

Figure 13.7: The Stages in Preliminary and Final Evaluations

19

Evaluation Techniques

Mentioned in an earlier chapter ROI, earnings growth, market share, customer

satisfaction, TCO

Group consensus Cost/benefit analysis Benchmark tests Point evaluation

20

Figure 13.8: An Illustration of the Point Evaluation System

22

The Design Report

Primary result of systems design

Reflects the decisions made and prepares the way for systems implementation

Serves as documentation for new SA&D.

23

Figure 13.11: Typical Steps in Systems Implementation

24

Acquiring Hardware from an IS Vendor An IS vendor is a company that offers hardware,

software, telecommunications systems, databases, IS personnel, and/or other computer-related resources

Buying computer hardware

Leasing computer hardware

Renting computer hardware

“Pay-as-you-go,” “on-demand,” or “utility” computing

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Acquiring Software: Make or Buy?

Externally developed software: lower cost, lower risk, ease of installation

In-house developed software

Meeting user and organizational requirements

More features and increased flexibility in terms of customization and changes

26

Acquiring Software: Make or Buy? (continued) In-house developed software (continued)

Greater potential for providing a competitive advantage

Chief programmer teams

The programming life cycle

Tools and techniques for software development

30

Acquiring Database and Telecommunications Systems

Relational databases

Object-oriented database systems

Databases are a blend of hardware and software

Telecommunications systems require a blend of hardware and software

31

User Preparation

Readying managers, decision makers, employees, other users, and stakeholders for new systems

Training users

32

IS Personnel: Hiring and Training

IS manager

Systems analysts

Computer programmers

Data-entry operators

Or Outsource

33

Site Preparation

Preparation of the location of a new system

Making room for a computer in an office

Special wiring and air conditioning

Special floor

Additional power circuits

35

Installation

The process of physically placing the computer equipment on the site and making it operational

Normally the manufacturer is responsible for installing computer equipment

Someone from the organization (usually the IS manager) should oversee the process

36

Testing

Unit testing: testing of individual programs

System testing: testing the entire system of programs

Volume testing: testing the application with a large amount of data

Integration testing: testing all related systems together

Acceptance testing: conducting any tests required by the user

37

Start-Up

The process of making the final tested information system fully operational

Direct conversion (also called plunge or direct cutover)

Phase-in approach. Components of the new system are phased in the old are phased out.

Pilot start-up. One branch at a time.

Parallel start-up

39

Systems Operation and Maintenance Systems operation: use of a new or

modified system

Systems maintenance: checking, changing, and enhancing the system to make it more useful in achieving user and organizational goals. Very expensive.

Can be up to 5 times greater than the total cost of development.

40

Types of Maintenance

Slipstream upgrade

Patch

Release

Version

41

Figure 13.19: Maintenance Costs as a Function of Age

42

Figure 13.20: The Value of Investment in Design