Third Quiz in ADSI

System Development

System development can be interpreted as compilation of new system for replacing the all of old system or repairing the existing system.

The important of system development is :

• Existence of problems at the old system, that can be the form of

• An error
• Growth of Organization
• To reach for the opportunity
• Existence of instructions from directives

The purpose of system development

• To resolving the existence of problems
• Reach for the opportunity
• Fulfilling the existence of instructions

The organization’s expectation after implementing an information system

After developing the system, the expectation is upgrading level connected with

• Performance. Upgrading the result of job activity in new system, until its more effective. Performance can be measured from throughput and response time.
• Information. Upgrading of information quality that given.
• Economy. Upgrading in benefit or advantages or decreases cost happen.
• Control. Upgrading in control for detection and repairing the mistakes that happen.
• Efficiency. Upgrading of operation efficiency.
• Services. Upgrading of service that given by system.

The principles of developing an information system

• Developed system is management
• Developed system is big capital investment by considering to
• investigation of all the alternatives
• the best investment has to valuable
• Developed system is require an educated people
• Activity step and duty must be conducted in the process of system development
• the process of system development doesn’t have in sequence
• don’t afraid to canceled the project
• the documentation has to be performed to guidance in system development

There are many of system development life cycle models. three of them is

1. Waterfall model

The waterfall model is a sequential development process, in which development is seen as flowing steadily downwards (like a waterfall) through the phases of Conception, Initiation, Analysis, Design (validation), Construction, Testing and maintenance.

The first formal description of the waterfall model is often cited to be an article published in 1970 by Winston W. Royce (1929–1995). In Royce's original waterfall model, the following phases are followed in order:

To follow the waterfall model, one proceeds from one phase to the next in a purely sequential manner. For example, one first completes requirements specification, which are set in stone. When the requirements are fully completed, one proceeds to design. The software in question is designed and a blueprint is drawn for implementers (coders) to follow — this design should be a plan for implementing the requirements given. When the design is fully completed, an implementation of that design is made by coders. Towards the later stages of this implementation phase, disparate software components produced are combined to introduce new functionality and remove errors.

2. Iterative and incremental development

Iterative and Incremental development is a cyclic software development process developed in response to the weaknesses of the waterfall model. It starts with an initial planning and ends with deployment with the cyclic interaction in between.

Incremental development is a scheduling and staging strategy, in which the various parts of the system are developed at different times or rates, and integrated as they are completed. It does not imply, require nor preclude iterative development or waterfall development - both of those are rework strategies. The alternative to incremental development is to develop the entire system with a "big bang" integration.

Iterative development is a rework scheduling strategy in which time is set aside to revise and improve parts of the system. It does not presuppose incremental development, but works very well with it. A typical difference is that the output from an increment is not necessarily subject to further refinement, and its testing or user feedback is not used as input for revising the plans or specifications of the successive increments. On the contrary, the output from an iteration is examined for modification, and especially for revising the targets of the successive iterations

3. Spiral model

The spiral model is a software development process combining elements of both design and prototyping-in-stages, in an effort to combine advantages of top-down and bottom-up concepts. Also known as the spiral lifecycle model, it is a systems development method (SDM) used in information technology (IT). This model of development combines the features of the prototyping model and the waterfall model. The spiral model is intended for large, expensive and complicated projects.

The steps in the spiral model can be generalized as follows:

1. The new system requirements are defined in as much detail as possible. This usually involves interviewing a number of users representing all the external or internal users and other aspects of the existing system.
2. A preliminary design is created for the new system.
3. A first prototype of the new system is constructed from the preliminary design. This is usually a scaled-down system, and represents an approximation of the characteristics of the final product.
4. A second prototype is evolved by a fourfold procedure:
1. evaluating the first prototype in terms of its strengths, weaknesses, and risks;
2. defining the requirements of the second prototype;
3. planning and designing the second prototype;
4. constructing and testing the second prototype.

Approaches of developing a system

There are several approach for developing a system, that is :

- Looked into the methodology that used is

- Classical approach. This methodology approach, developing system with following the steps in system life cycle, is approach inside system development by following adequate technique.

- Structured approach. This methodology approach, basically trying to provide to the system analysis addition of tools and techniques for developing the system beside remain to follow idea of system life cycle.

- Looked into the reached target

- Piecemeal Approach, is approach system development emphasize to an event or application.

- Systems Approach, observe information system as an integrated unity for each event or application.

- looked into the way of determining requirement of system :

- Bottom Up Approach, started from low level organization, that is operational level where the transaction done.

- Top-down approach, started from high level organization, that is strategic planning level.

- looked into how to developing:

- Total-system approach, is approach developing system totally at once time.

- Modular approach. this approach try to breaking complicated system into some simple part or module, so the system is easier to understand and developed.

- looked into the technology that used is :

- Great Loop Approach, applying all change at once time with using sophisticated technology.

- Evolution Approach, applying sophisticated only for applications just needing at that moment and will developing for next periods following the requirements according to growth of existing technology.

the meaning of methodology, method and algorithm is :

• Methodology is methods unit, procedures , job concepts , rules, and postulates that used for a knowledge, art, or other discipline.
• method is a manner or systematic technique to do something.
• Algorithm is the sequence procedure that given by a methodology for resolving the problem.

Methodologies of system development classified become three group :

1. Functional Decomposition Methodologies. This methodology is emphasize in system solver into smaller subsystems, until it is easier to understand, planning and implementation.

2. Data Oriented Methodologies. This methodology is emphasize in characteristic of data that would have proceed. This methodology separate become two class, that is :

• Data-flow oriented methodologies. Generally, This methodology based on system solver into modules that based on the type of data element and behavior of its module logic inside the system.
• Data-structured oriented methodologies. This methodologies has emphasize structure from input and output in system. Then, this structure will used as basic structure from its system. Function relational between module or system elements explained from the structure system.

3. Prescriptive Methodologies

Included this methodologies is :

• ISDOS, is developed software by university of Michigan. The ability of ISDOS is automatic the process of development system.

• PLEXSYS. The ability of PLEXSYS is to do transformation a language of high level computer language into an executable code for a configuration the hardware that expected.

• PRIDE offered by a company in united state, that is M. Bryce & Ass. Pride is a great compilation software for analysis or design structured system, management data, project management and documentation.

• SDM /70 or Systems Development Methodology /70 developed and propagated by a company in united state. This methodology is a software that has content with collection of method, estimation, documentation, and administration instruction for helping user to developing and take care of system

• SPECTRUM
• SRES and SREM

tools for developing a system can be :

1. Graph, that is : HIPO, DFD, SADT, W/O, JSD

2. Chart, that is : activity charting (systems flowchart, program flowchart, paperwork flowchart or called as for flowchart, database relationship flowchart, process flowchat, gantt chart), layaout chating, and personal relationship charting.

there are many techniques used in developing a system :

• project management techniques, that is : CPM (critical path method) and PERT(Program Evaluation and review technique) . This technique used for project scheduling.
• fact finding techniques, technique that can used for collecting the data and finding facts in learning event the exist system. this techniques include : interview, observation, questionnaires, sampling.
• cost-effectiveness analysis (or cost-benefit analysis)
• meeting perform technique
• walkthrough

the differences of being a system analyst and a programmer and also mention what are the knowledge a system analyst should posses

System analyst is the person who analyzing system (learn how the problems arise and determining requirements user of system) for identification possible resolving. Otherwise, a programmer is person create the program code for an application pursuant to building design which have been made by system analyst.

The knowledge a system analyst should posses is :

• Knowledge about data processing technique, computer technique, and computer programming.
• General Knowledge of business
• Knowledge about the quantitative method
• Ability in trouble-shooting
• Ability in communication between personal
• Ability in constructing relation between personal.

reference :

• Prof. Dr. Jogiyanto HM, MBA, Akt. 2005. ANALISIS & DESAIN SISTEM INFORMASI : Pendekatan Terstruktur, Teori dan Praktik Aplikasi Bisnis. Yogyakarta : Penerbit Andi.
• www.klasiber.net/file.php/1/PSI_I.pdf
• http://en.wikipedia.org/wiki/Waterfall_model
• http://en.wikipedia.org/wiki/Iterative_and_incremental_development
• http://en.wikipedia.org/wiki/Spiral_model