Part A: Systems analysis and design
Information systems concepts and technology
Key takeaways
- An information system combines people, processes, data and technology to collect, process, store and distribute information that supports an organisation's operations and decisions.
- Its five components are hardware, software, data, people and procedures.
- Systems theory treats any system as interrelated components working toward a common purpose; systems thinking looks at how a change to one part ripples through the whole.
- Programming languages are procedural, object-oriented, functional or scripting, and Java, the language this paper teaches, is the object-oriented example.
- A good information system is reliable, usable, secure, maintainable, scalable and cost-effective.
Before analysing or designing any system, this opening chapter fixes what a system and an information system actually are, the theory behind thinking in systems, and a first look at the programming languages Part B develops in depth.
Information systems overview and concepts
An information system combines people, processes, data and technology to collect, process, store and distribute information supporting an organisation's operations and decisions, the same definition CISSE's own database-systems paper opens with, revisited here from a systems-analysis angle.
Systems theory
Systems theory treats any system, technical or organisational, as a set of interrelated components working toward a common purpose, exchanging inputs and outputs with its environment and with each other, a way of reasoning about complexity that applies equally to a single program, a whole information system, or the organisation the system serves.
Systems thinking and applications
Systems thinking is the discipline of viewing a problem as part of a larger interconnected whole rather than in isolation, understanding how a change to one component ripples through the rest of the system, directly relevant to systems analysis (see the chapter on systems analysis), where a requirement rarely affects only one isolated part of an organisation.
Components of an information system
Types of information systems
Organised by the level of management they serve, Transaction Processing Systems (operational), Management Information Systems (middle management), Decision Support Systems and Executive Information Systems (senior management), the same pyramid CISSE's own database-systems paper develops in full.
Overview of programming languages
A programming language is a formal, structured notation for writing instructions a computer can execute, the tool systems analysis and design ultimately produces working software through, developed in depth in Part B.
Types of programming languages
| Type | Example | Note |
|---|---|---|
| Procedural | C, Pascal | Organised around a sequence of instructions and procedures |
| Object-oriented | Java (the language Part B teaches), C++ | Organised around objects combining data and behaviour |
| Functional | Haskell, parts of modern JavaScript | Organised around evaluating functions, avoiding changing state |
| Scripting | Python, JavaScript | Typically interpreted, suited to rapid, lightweight development |
Characteristics of a good information system
- Reliable: performs correctly and consistently
- Usable: intuitive and efficient for its actual users
- Secure: protects data and access appropriately
- Maintainable: can be corrected and adapted over time (see the chapter on maintenance)
- Scalable: can grow with increasing demand
- Cost-effective: delivers value proportionate to its cost
Personnel involved in Systems Analysis and Design
Exam tip
The language types above recur through the rest of this paper, and Java (developed in Part B) is the object-oriented example to anchor every definition to when a question asks you to classify or compare paradigms.
Self-check
(a) List the five components of an information system. (5 marks)
(b) Distinguish a procedural programming language from an object-oriented one, naming one example of each. (3 marks)
(c) State three characteristics of a good information system. (3 marks)
(d) Distinguish the role of a systems analyst from that of a systems designer. (2 marks)
Show worked answer
(a) Hardware, software, data, people, and procedures.
(b) A procedural language is organised around a sequence of instructions and procedures, e.g. C. An object-oriented language is organised around objects combining data and behaviour, e.g. Java.
(c) Any three of: reliable; usable; secure; maintainable; scalable; cost-effective.
(d) A systems analyst gathers requirements and translates business needs into a technical specification. A systems designer designs the system's architecture, interfaces and data structures based on that specification.