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..

Stages in Systems Analysis & Design Last Week Systems Investigation Analysis This Week Systems Design Implementation Maintenance Review

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.

Logical Design Output requirements Input requirements Process requirements File and database requirements

Logical Design (continued) Telecommunications requirements Procedure requirements Controls and security requirements Personnel and job requirements

Physical Design Hardware specifications Software specifications Database specifications

Physical Design (continued) Telecommunications specifications Personnel specifications Procedure and control specifications

Object-Oriented Design Design key objects and classes of objects in the new or updated system Consideration of the problem domain, the operating environment, and the user interface Consideration of the sequence of events that must happen for the system to function correctly A sequence of events is often called a scenario A scenario can be diagrammed in a sequence diagram

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.

Interface Design and Controls (continued) Interactive processing Menu-driven systems Help commands Table lookup facilities Restart procedures

Table 13.1: The Elements of Good Interactive Dialogue

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 information Keep information systems running

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

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

Generating Systems Design Alternatives Request for proposal (RFP): a document that specifies in detail required resources such as hardware and software Financial options Purchase, Lease, or Rent. Another slide

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

Figure 13.7: The Stages in Preliminary and Final Evaluations

Evaluation Techniques Mentioned in an earlier chapter ROI, earnings growth, market share, customer satisfaction, TCO Group consensus Cost/benefit analysis Benchmark tests Point evaluation

Figure 13.8: An Illustration of the Point Evaluation System

Figure 13.9: Freezing Design Specifications

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.

Figure 13.11: Typical Steps in Systems Implementation

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

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

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

Figure 13.13: Steps in the Programming Life Cycle

Tools and Techniques for Software Development Structured programming Improving the logical program flow by breaking the program into groups of statements, called structures CASE tools: used during software development to automate some of the techniques Object-oriented implementation A collection of existing modules of code, or objects, can be used across a number of applications

Tools and Techniques for Software Development (continued) Cross-platform development: allows programmers to develop programs that can run on computer systems having different hardware and operating systems, or platforms Integrated development environment: combines the tools needed for programming with a programming language into one integrated package Structured walkthrough: a planned and preannounced review of the progress of a program module, a structure chart, or a human procedure

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

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

IS Personnel: Hiring and Training IS manager Systems analysts Computer programmers Data-entry operators Or Outsource

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

Data Preparation Also called data conversion Ensuring all files and databases are ready to be used with new computer software and systems

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

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

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

User Acceptance User acceptance document: formal agreement signed by the user that states that a phase of the installation or the complete system is approved

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.

Types of Maintenance Slipstream upgrade Patch Release Version

Figure 13.19: Maintenance Costs as a Function of Age

Figure 13.20: The Value of Investment in Design

Systems Review—Final Step Process of analyzing systems to make sure that they are operating as intended Often compares the performance and benefits of the system as it was designed with the actual performance and benefits of the system in operation Event-driven review: review triggered by a problem or opportunity such as an error, a corporate merger, or a new market for products Time-driven review: review performed after a specified amount of time

Factors to Consider During Systems Review Mission Organizational goals Hardware and software Database Telecommunications

Factors to Consider During Systems Review (continued) Information systems personnel Control Training Costs Complexity

Factors to Consider During Systems Review (continued) Reliability Efficiency Response time Documentation

Summary Systems design answers the question “How will the information system do what it must do to solve a problem?” Systems design has two dimensions: logical and physical Logical design is description of the functional requirements of a system Physical design is specification of the characteristics of the system components necessary to put the logical design into action

Summary (continued) Steps of systems implementation: hardware acquisition, software acquisition, user preparation, personnel: hiring and training, site preparation, data preparation, installation, testing, start-up, and user acceptance Systems operation is the use of a new or modified system Systems maintenance involves checking, changing, and enhancing the system to make it more useful in achieving user and organizational goals

Summary (continued) Systems review is the process of analyzing systems to make sure that they are operating as intended Event-driven review is triggered by a problem or opportunity such as an error, a corporate merger, or a new market for products Time-driven review is performed after a specified amount of time