Some Important Concepts System

To more easily understand further the meaning system and information system is necessary to remember some important concepts in the development of the system, namely:

1. Decomposition
To analyze and understand thoroughly a large system, it usually takes a long time. To facilitate this work used the concept of decomposition. Decomposition is a division of systems into components of smaller (subsystems). Decomposition has several advantages, including:

• Analysts to more easily manage and analyze each subsystem in more detail.
• On the development of the system, the system can be decomposed into several modules. Development of several modules can be done in parallel with no dependency requirement between modules are built.

2. Modularity
The concept of modularity associated with decomposition. At the time of decomposition, it is expected that a large system is divided into sub-systems to be relatively the same size. With these modules the workload of the system developed can be distributed evenly on all available resources. System development so much simpler because it only focused on one module first, and do the integration between modules.

3. Coupling
And modules that we get, sometimes found some modules that have dependencies with other modules. In such cases, the modules are interdependent must be paired (in-couple). In this way can be known modules that can work independently and modules that should be completed first before the other modules work.

4. Cohesion
Of the coupling between modules, we can get the module groups with similar characteristics. Here comes the concept of cohesion in which the module should be analyzed together with the mutual cohesion of the group module.

System That Bad

To avoid developing a bad system, keep in mind some of the traits and the bad system:
a. Not meet user needs
b. Poor performance
c. Rehabilitation of low
d. Low usability
e. Examples of difficulty:

• Not scheduled.
• No budget plan.
• Can walk = 100% over budget or schedule.

Definitions Subsystem

A complex system is usually composed of several subsystems. Subsystem can be described as a system within a larger system. For example:
Automobile is a system comprising several subsystems and the following:

1. Machine system
2. Body system
3. Wheel system

Each subsystem can be made ​​and some subsistems the following:
Machine systems: systems carburetor, generator systems, fuel systems, etc.

Characteristics Of System

In order to understand or develop a system, it is necessary to distinguish the elements and systems that shape it. Here are the characteristics of a system that can distinguish a system with other systems:

1. Boundary. Depiction and an element or elements which are included in the system and which are outside the system.
2. Environment. Everything outside the system, providing environmental assumptions, constraints, and input to a system.
3. Input. Resources (data, materials, equipment, energy) and the environment that is consumed and manipulated by a system.
4. The output. Resource or product (information, reports, documents, computer screen display, finished goods) are provided for the system environment by the activities in a system. Component activities or processes in a system that transforms input into the form of semi-finished (output). This component can be a subsystem and a system.
5. Interface. The place where the component or system and its environment to meet or interact.
6. Storage. Area occupied and used for temporary and permanent storage and information, energy, raw materials, and so forth. A storage buffer between the media divulging these components work with various levels that exist and allow the different components and a variety of the same data.

Understanding System

To initiate a discussion of the analysis and design of information systems, an understanding of the system must first be emphasized. Definition of the system evolve according to the context in which sense the system is used. The following definitions will be given some general system

1. And a collection of parts that work together to achieve the same goal.

Example:

• Solar system
• Digestive System
• Public Transportation Systems
• Automotive systems
• Computer Systems
• Information Systems

2. A collection of objects that relate to and interact with each other as well as relationships between objects can be viewed as a whole is designed to achieve one goal.

Thus, simply as a set or sets and the elements or variables that are mutually organized interacting, and interdependent with each other. Murdick and Ross (1993) defines a system as a set of elements that are combined with each other for a common goal. Meanwhile, the system definition in Webster's  Unbriged dictionary are elements that are interconnected and form a single unit or organization.

According to Scott (1996), and the system comprises elements such as input, processing and output. Principal feature of the system according to Gapspert there are four, namely that the system operates in an environment, consist of elements, characterized by interconnected, and have the functions of or saw the main purpose.

System or system approach must be at least had four components, namely input, processing, output, and feedback or control. While Mc. Leod (1995) defines a system as a group of elements that are integrated with the same intent to achieve a goal. Resource flows and output elements and to ensure the process goes well then connected to the control mechanism.

Many experts put forward the concept of systems with different descriptions, but in principle similar to the basic concepts of the system generally. Schronderberg (1971) in Suradinata (1996) briefly describes the system are:

1. These components are interconnected to each other.
2. A whole without separating the constituent components.
3. Together to achieve goals.
4. Has inputs and outputs needed by other systems.
5. There are processes that transform inputs into outputs.
6. Indicates the existence of entropy.
7. Have rules.
8. Has a smaller subsystem.
9. Have a differentiation between subsystems.
10. Have the same goal even though the beginning is different.