Information Systems Overview

Chapter 4 System Development

• All notes must be written in exercise books; no printed notes are accepted.
• A system is a set of linked items carrying out a task to achieve one or more objectives. Systems may be soft or hard.

Soft Systems and Hard Systems

• Soft systems are human-based activities with fluid/changing boundaries, conflicting goals, and difficult-to-define performance metrics.
• Hard systems have clearly defined goals and objectives with predictable outcomes. These processes can be accurately modeled.

System Classification

• Deterministic systems have precisely knowable outputs based on their inputs. (e.g. computers).
• Probabilistic systems have outputs that can be predicted, but not precisely known, based on inputs. (e.g. business/economic systems).
• Cybernetic systems are self-regulating and adapt to the environment through feedback, adjusting inputs based on outputs. (e.g. humans, plants).

Characteristic of Systems

• Holistic Thinking – systems are considered as a whole, with components surpassing individual parts.
• Sub-Systems – a system is composed of different components (subsystems).
• Boundaries – external elements that influence (and are influenced by) a system's state.
• Processor – a system element that transforms input into output.
• Objectives/Purpose – the objectives of a system; real or stated goals for an organization.

Environment and Boundaries

• Environment – the environment in which a system operates within an organization; the contributing reasons for its existence.
• Boundaries – external elements; their changes affect the system respectively; the limit of a system.

Interdependence and Feedback

• Interdependence – components or subsystems must be coordinated and linked to maximize system effectiveness.
• Feedback – a system check to confirm predetermined goals, detecting deviations.

Control and Inputs and Outputs

• Control – the process enabling systems adaptation to environmental changes, aiming for expected levels.
• Inputs and Outputs – a system's communication with its environment through inputs and outputs.

System Entropy

• Entropy means decay. Systems naturally decay over time, becoming useless due to changing technological advances or shifts in user requirements, management initiatives.

Open and Closed Systems

• Open systems interact with their environment; they receive input from and provide output to.
• Closed systems do not interact with their environment.

Information System

• An information system is a collection of people, procedures, technologies and resources that gather, transform, and disseminate information within an organization.

Purpose of Information System

• Assist in decision making
• Provide responsive service to meet user needs.
• Facilitate information sharing.
• Facilitate interaction and dissemination of data throughout the organization.

Why Develop New Information Systems?

• New changes in the organization.
• Problems in the current system.
• New opportunities.

Theories of System Development

• Traditional Approach
• Rapid Application Development (RAD)
• Structured Approach

Traditional Approach

• This approach relies heavily on the skills and experience of individual staff members to carry out development tasks.
• The existing system is replaced with a computerized one, but overall structural changes are minimal

Rapid Application Development (RAD)

• This modern approach is adapted from current heavily IT dependent businesses.
• The model prioritizes fast development for competitive advantage

Structured Approach

• The structured approach employs a defined series of stages during system development. This approach is sequential and systematic

Stage of System Development

• Problem Recognition and Definition
• Information Gathering
• Requirements Specification
• System Design
• System Construction
• System Implementation and Testing
• System Operation
• System Review and Maintenance

Problem Recognition and Definition

• Recognising if the need is justified

Information Gathering

• Collecting data through methods like record inspection, interviews, and questionnaires.

Requirements Specification

• Defining detailed needs including output, input, files/data stores, and hardware and software requirements.

Output Specification

• Detailed description of output activities; report generation for decision making. Importance of quality, formality and understanding.

Input Specification

• Detailing input contents, volume, modes, devices, and layout/sequences for maintaining master files.

File/Data Stores

• Identifying and analyzing the need for data files necessary for efficient system operations

Hardware and Software Requirements

• Determining technical requirements like costs, reliability, and user-friendliness.

System Design

• Detailing the physical system design based on the logical design specified during system analysis.

System Construction

• Coding, installing, and testing modules, inputs, outputs and files for functional system development.

Testing the System

• Testing the designed output and inputs against pre-defined requirements specifications

System Implementation

• Installing, testing the system, converting data from old to new systems, and training users. Activities involved include file creation/conversion, staff training, and change management.

File Creation and Conversion

• Setting up master files for the new system; either completely new or conversion from old system files

Training Staff

• Convincing staff about the new system's effectiveness, addressing anxieties and enabling staff to manage the new tasks

Methods of Training

• Demonstration, Film show, Manual reference, Group discussion, Visits

Changeover

• Process of transitioning from the old system to the new. Types include direct, parallel, and phase changeover.

Direct Changeover

• Immediately switching to the new system, abandoning the old. Advantages include speed and cost-effectiveness. Disadvantages include significant risk

Parallel Changeover

• Both the new and old system operate concurrently. Advantages include training and minimal risk. Disadvantages include cost and complexity.

Phase Changeover

• The system is implemented in stages or phases. This method may be more cost effective. But is dependent on the first phase going well

System Review and Maintenance

• Periodic adjustment, correction, and enhancement of the implemented system to address errors or accommodate evolving requirements.

System Documentation

• Documentation related to the system's design including facts, methods, weaknesses, requirements, flowcharts, tables, test data and users' manual.

Review Questions 1

• Defining information systems
• Differentiating between soft and hard systems
• Listing 5 characteristics of a system
• Defining system control
• Explaining why feedback is needed in a system
• Defining system boundary
• Explaining 3 information systems purposes
• Defining online analytical processing
• Drawing a system diagram

Review Questions 2

• Explaining 3 system development theories
• Stating the disadvantage of RAD
• Defining system development lifecycle
• Explaining the stage when system transfer ownership to end users
• Highlighting 3 circumstances that necessitate creating new information systems
• Defining feasibility study
• Listing 4 methods used in gathering information for system development
• Stating 2 advantages of interviews over questionnaires
• Stating 2 disadvantages of using interview method for information gathering
• Giving an automated information gathering technique example

Review Questions 3

• Explaining the 4 areas involved in requirement specification

• Explaining 3 factors to consider for output design

• Explaining 4 factors to consider in designing a good file

• Explaining the importance of backup and recovery during file design.

Revision Questions 1

• Outlining 7 steps in structured system development.

• Explaining 3 system implementation tasks

• Explaining 3 disadvantages of questionnaires

• Explaining proxemics in interviews.

• Explaining the advantages of straight changeover over parallel changeover

• Defining file conversion

• Differentiating between system and program flowcharts

• Drawing and explaining 4 system flowchart symbols

Revision Questions 2

• Defining "attribute"

• Explaining the importance of automated fact-finding methods in detail

• Explaining why observational methods can be disadvantageous during fact-finding

• Stating a disadvantage of the Traditional System Approach

• Outlining factors to consider when selecting hardware and software

• Outlining the contents of a user manual

This quiz covers fundamental concepts in information systems, including system boundaries, feedback mechanisms, and characteristics of open systems. Explore topics like economic feasibility, data collection methods, and the role of control in systems. Perfect for students studying information technology or systems analysis.