Q & A
a) describe a system.
b) define an information system.
c) state the purpose of an information system.
d) identify the stages of system development.
e) develop a system using a case study.
f) write a report on the case study.
9.2.1 Description of a system.
9.2.2 Definition of an Information system.
9.2.3 Purpose of an Information System.
9.2.4 Stages of system development
- Problem recognition and definition
- Information gathering e.g.
- Requirement specification for the new system
- System design
- System construction
- System implementation
- System review and maintenance
9.2.5 System Documentation
- Reports on fact finding / information gathering
- System flowchart
- Table/file structure / descriptions
- Sample data
- Output reports
- User manual
Langat, J., Musonye, D., & Antony, W. (2008). Foundation Computer Studies Book 3. In J. Langat, D. Musonye, & W. Antony, Foundation Computer Studies Book 3 (Pp. 74-110). Nairobi: Jomo Kenyatta Foundation.
Mburu, S., & Chemwa, G. (2013). Longhorn Secondary Computer Studies. In S. Mburu, & G. Chemwa, Longhorn Secondary Computer Studies (Pp. 91-120). Nairobi: Longhorn Publishers (K) Ltd.
Sommerville, I. (2010). Documentation. Retrieved 03 2017, From Host.Cs.St-Andrews:Https://Ifs.Host.Cs.St-Andrews.Ac.Uk/Books/Se9/Web/Extrachaps/ Documentation.Pdf
System Development definition
System development can be defined in various ways such as:
- The process of creating and maintaining information systems is called systems development or systems analysis and design. According to fairfield.edu
- according to FCA, Systems development is the process of defining, designing, testing, and implementing a new software application or program.
- CMS defines system development as a framework that is used to structure, plan, and control the process of developing an information system.
What is a system?
- A system is a set of organized components which interact in a given environment and within a specified boundary to achieve collective goals and objectives that are emergent.
Description of a System.
- Soft System or
- Hard System
A system is described as soft because of the following characteristics:
- Boundaries keep on changing
- Goals and Objectives usually conflict due to human factors like attitudes and preferences
- Exact measures of performance cannot be clearly captured
A system is said to be hard because of the following characteristics:
- Goals and objectives can clearly be defined
- Outcomes of the systems processes are predictable and can be modeled accurately
Characteristics of Systems
1. Holistic thinking
A system is considered as a whole because many entities will work together to make a complex whole.
A system is made up of different components (subsystems)
3. Boundary and Environment
Each system has a space or boundary within which the components operate. A system has two types of entities namely: internal and external entities.
An internal entity operates from within the system boundary. However, External entities operate from outside the boundary but are part of the system.
The purpose of each system is to perform a particular task or achieve a goal.
A system has the obligation to transform or process data from one state to another
6. System Entropy
The word entropy means decay. Systems decay over time.
7. Inputs and Outputs
A system communicates with environment by receiving inputs and giving outputs
8: Open VS Closed Systems
A system can be described as either open or closed. An open system receives input and gives output while a closed system does not.
A system adapts to changes in the environment in order to give the expected output or to perform to the expected level. This is possible through the feedback which can be used to influence inputs
Purpose of Information Systems
- Information analysis and storage
Through the adoption of information systems, companies can make use of sophisticated and comprehensive databases that can contain all imaginable pieces of data about the company. Information systems store, update and even analyze the information, which the company can then use to pinpoint solutions to current or future problems.
- Assist with making decisions
An organization’s management team uses information systems to formulate strategic plans and make decisions for the organization's longevity and prosperity.
- Assist with business processes
Information systems add controls to employee processes, ensuring that only users with the applicable rights can perform certain tasks.
- To increase efficiency by automation and effectiveness through quickening of processing time and capability to analyse tasks accurately and reliably.
METHODS OF DEVELOPING SYSTEMS
- Systems development life cycle (SDLC)
SDLC – System Development Life Cycle is the process of developing information systems through investigation, analysis, design, implementation and maintenance. SDLC is also known as information systems development or application development.
SDLC is a systems approach to problem solving and is made up of several phases, each comprised of multiple steps.
- Rapid application development (RAD)
RAD is a software development methodology that uses minimal planning in favor of rapid prototyping. A prototype is a working model that is functionally equivalent to a component of the product.
Object-oriented systems development (OOD)
This is the process of planning a system of interacting objects for the purpose of solving a software problem. It is a popular technical approach for analyzing, designing an application, system, or business by applying the object-oriented paradigm and visual modeling throughout the development life cycles to foster better stakeholder communication and product quality.
- Objects carry out actions when asked
- Each object maintains its own data
- Extreme programming (XP)
This is a pragmatic approach to program development that emphasizes business results first and takes an incremental, get-something-started approach to building the product, using continual testing and revision.