Saturday, March 7, 2009

System Development Concept (Part II)

Approaches Of Developing A System

1. Classical approach and structured approach ( looked into used methodologies).

A. Classical Approach
Is classic approach methodologies to develop the system by following the step in system life cycle.

B. Structured Approach
Approach of structure provide the additional system in the form of appliances and techniques to develop the system beside fixed follow idea from system life cycle.

2. Piecemeal approach and system approach (looked into the target to reach).

A. Piecemental Approach
Piecemeal approach is a system development approach that emphasize to an activity or just the application. The selected activity or application is developed without pay the attention from the position in information system or without pay the attention from the organization target comprehensively.

B. System Approach
Approach of system, pay attention the information system as one unity integrated to each activity or his application.

3. Bottom-up approach and Top-down approach (looked into the way of determining requirement of system).

A. Bottom-Up Approach
A bottom-up approach is piecing together systems to give rise to grander systems, thus making the original systems sub-systems of the emergent system. In a bottom-up approach the individual base elements of the system are first specified in great detail. These elements are then linked together to form larger subsystems, which then in turn are linked, sometimes in many levels, until a complete top-level system is formed. This strategy often resembles a "seed" model, whereby the beginnings are small but eventually grow in complexity and completeness. However, "organic strategies" may result in a tangle of elements and subsystems, developed in isolation and subject to local optimization as opposed to meeting a global purpose.

B. Top-Down Approach
A top-down approach is essentially breaking down a system to gain insight into its compositional sub-systems. In a top-down approach an overview of the system is first formulated, specifying but not detailing any first-level subsystems. Each subsystem is then refined in yet greater detail, sometimes in many additional subsystem levels, until the entire specification is reduced to base elements. A top-down model is often specified with the assistance of "black boxes" that make it easier to manipulate. However, black boxes may fail to elucidate elementary mechanisms or be detailed enough to realistically validate the model.

4. Total-system approach andmodular approach (looked into the way of developing it).

A. Total System Approach
Total system approach is the approach which developing a system together according to comprehensive.

B. Modular Approach
Modular approach tries to divide complex system to simple some part, so that system easier will be understood and developed.

5. Great loop approach and evolutionary approach (looked into technology to be used).

A. Great Loop Approach
Great Loop Approach apply change totally at a timely use the sophisticated technology. Have the big risk because speed of change of technology.

B. Evolutionary Approach
Evolutionary approach applies sophisticated technology just for applications that need that moment and will be developed for next periods based on technology development. This approach causes investment not too expensive and can follow fast technology development.

The Meaning Of Methodology, Method And Algorithm

1. Methodology can be defined as:

  • The analysis of the principles of methods, rules, and postulates employed by a discipline.
  • The systematic study of methods that are, can be, or have been applied within a discipline.
  • A particular procedure or set of procedures.
2. Method
Method is How to do or make something

3. Algorithm
Algorithm is a sequence of finite instructions, often used for calculation and data processing.

Classifications Of Development Methodology

1. Functional decomposition methodologies
Functional decomposition methodologies emphasize at resolving of system into smaller subsystems, so that will be more easy to be comprehended, to be designed and applied. Which included in this methodologies is:
  • HIPO (Hierarchy plus Input Process Output)
  • SR (Stepwise Refinement)
  • ISR (Iterative Stepwise Refinement)
  • Information-Hiding
2. Data-oriented methodologies

This methodologies emphasize at characteristic of data to be processed. This methodologies is grouped into 2 class:

A. Data-flow oriented methodologies
There are the include in this group methodologies such as SADT (Structured Analysis and Design Techniques), Composite Design.

B. Data structure oriented methodologies
There are the include in this group methodologies such as JAD (Jackson's system development), W/O (Warnier/Orr).

3. Prescriptive Methodologies

This methodology usually has been provided by software maker factory. In this methodology including:
  • ISDOS (Information System Design and Optimization System)
  • SDM/70
  • SRES and SREM, etc.

Tools For Developing A System

The tools there are in the form of diagram and chart, such as :
• HIPO diagram, Data flow diagram, SADT, structure chart, Jackson's diagrams, etc.

Besides the tools that mention above, there are utilizes that used at all of methodology. The tools as a chart set that grouped by:

• Activity charting: to figuring activity, example: chart's substituting, flowchart, etc.
• Layout charting: to figuring layout
• Personal relationship charting: to figuring person relationship, example: organization chart, working distribution chart

Techniques Used In Developing A System

1. Project Management Technique
Project management technique is the discipline of planning, organizing and managing resources to bring about the successful completion of specific project goals and objectives.

2. Finding Fact Technique
Fact-finding is an important activity in system investigation. In this stage, the functioning of the system is to be understood by the system analyst to design the proposed system. Various methods are used for this and these are known as fact-finding techniques. The analyst needs to fully understand the current system.
The analyst needs data about the requirements and demands of the project undertaken and the techniques employed to gather this data are known as fact-finding techniques.
Various kinds of techniques are used and the most popular among them are interviews, questionnaires, record reviews, case tools and also the personal observations made by the analyst himself. Each of these techniques is further dealt in next pages.

3. Meeting Technique
During conducted system development process, oftentimes meeting performed either by developer team with user and manager.

The Differences Of Being A System Analyst And A Programmer

1. System Analyst

A systems analyst is responsible for researching, planning, coordinating and recommending software and system choices to meet an organization's business requirements. The systems analyst plays a vital role in the systems development process. A successful systems analyst must acquire four skills: analytical, technical, managerial, and interpersonal.
Basically a systems analyst performs the following tasks:
  • Interact with the customers to know their requirements
  • Interact with designers to convey the possible interface of the software
  • Interact/guide the coders/developers to keep track of system development
  • Perform system testing with sample/live data with the help of testers
  • Implement the new system
  • Prepare High quality Documentation

2. Programmer

A programmer is someone who writes computer software. The term computer programmer can refer to a specialist in one area of computer programming or to a generalist who writes code for many kinds of software. One who practices or professes a formal approach to programming may also be known as a programmer analyst.

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