System Development

 System 

grated set of components for collecting, storing, processing, and communicating information. Business firms, other organizations, and individuals in contemporary society rely on information systems to manage their operations, compete in the marketplace, supply services, and augment personal lives. For instance, modern corporations rely on computerized information systems to process financial accounts and manage human resources; municipal governments rely on information systems to provide basic services to its citizens; and individuals use information systems to study, shop, bank, and invest.

The Important of Sistem Information

1. Problem 
2. organisationt growth
3. reach for change

The Aim of System Information

existence the problem in the organization cause  disturbed  the course of theirs efforted. So they needed the information system  to  solve theirs problem by quickly. Information system can help the organization get the oppurtunity  to expand  organiz, the example;  some  organization to expand them coorporate  will loosing  many money if their using traditional method, they sholud payed many people to spreading theirs  news products at all country, but  whit information system they can be  thrifty some money  by using internet media because internet is the cheapest media than another ways, making website in the internet  didnt spend a lot of money to build this system. Informations system can manage theirs operations, some executive management didn needed a lot human resource to finded some organiz data (financial and benefit). So by information system can saved and manage human resource and grow up the organization.

The  system expectation

1. Performance

By throughput and response time, actually a good system give a sugestion for operational  management to solving the problem by quckly and output in this sugestion must be accurate and exelence. 

2. Information

Information quality  increased by a good system, cause  system can processed a lot of data and analizes them before reach to management subject, and system can minimize vault about dish up information. 

3. Economy and Efficiency

System should be cheapest than old system, cause new system spend some money for build this technology. Example; human resouce. Organization  didnt needed a lot of employe, by the system they can decrease the employes and thrifty some money to pay them, because system can merge some job into o.

4. Control

System can prohibited the dishonest effort which doing by some peolpe, cause system just worked by what was instaled by them self. 

5. Services

Whit infomation system, the organisation can increase poduct service to customer so they satisfied about our job. Example; some customer live in beyond country doesnt dificult to find our product, by internet they  easy  to get our product.  

System Dvelopment Principle

1. System that developed management.
2. System that developed big capital investment.
3. System that developed to need one who educated.
4. Work stage and duties that must be done in course of system development (System Development Life Cycle).
5. System development process must not massage.
6. Don't be afraid cancel project.
7. Documentation existence for guide in system development.

System Development Life Cycle

• Waterfall model

The first step are requirement, a customer requste to make a good system to our organiz. On here step we must understand what the custtomer needed, we can asked the work of the system. What the function? For hows? And many more question as you needed. And on this step we can make a agreament whit customer about our coorporation. Second step, we has a system development make a system design which competible to this peoblem on we have finished. Third  step, implementation the our system on the customer problem and wanted. Next step are verificaion system, reapaired if  happend some mistake on the system.  And the last step are maintence, this is the important step about development system,  how a best the system if doesn have a good maintance, because system if doesnt have a good maintance will demaged.

• Iterative Model

Iteratif method same as waterfall method but its more details than waterfall, beacuse this method can produce rely on product. An iterative lifecycle model does not attempt to start with a full specification of requirements. Instead, development begins by specifying and implementing just part of the software, which can then be reviewed in order to identify further requirements. This process is then repeated, producing a new version of the software for each cycle of the model. Consider an iterative lifecycle model which consists of repeating the following four phases in sequence: 

• Spiral Model

While the waterfall methodology offers an orderly structure for software development, demands for reduced time-to-market make its series steps inappropriate. The next evolutionary step from the waterfall is where the various steps are staged for multiple deliveries or handoffs.  The ultimate evolution from the water fall is the spiral, taking advantage of the fact that development projects work best when they are both incremental and iterative, where the team is able to start small and benefit from enlightened trial and error along the way. 

System Development Aproach

1. Classical Approach Vs Structured Approach

•  Classical Approach
  

The classical organization is organized in terms of (hopefully) functional departments. Especially in the public sector, we generally encounter with the same function being performed by different (competing) organizational units. In most of the private sector, we are faced with a similar sort of approach, with no regards to a wholistic process approach, only a change in the "shopwindow" with high-tech interfaces, no support of the back office process flows. Recently, just because of this reason, my credit card was almost cancelled, due to a software malfunction newly introduced during regular usage hours. A heard that more than one thousand customers experienced the same sort of problems.

• Stuctured approach
  

User system implicated while building the system, they was also follwoing and  give a sugestion to programer while they do worked. User can give an advis like for what the function of the system and many more sugestion can be submitted. On this case structured approach using an structural tools like data flow diagram, flow chart and etc.

2.Sub-system Approach Vs System Approach

• Sub-system approach
  

This case the system divided into a smallest part, an general case the  system maker  divide a system for easiset them job. Probably this method doesnt finished the all project of system, causes some system cant be walkaway by a part.  

• System  approach
  

the techniques to finished a project, seen an problem by comprehensive. That mean the problem solving cant be devide by a part of system cause this method emphasized the equal of a project.

3. Bottom-Up Approach vs Top-Down Approach

• Top down approach
  

The technique for writing a program using top-down methods is to write a main procedure that names all the major functions it will need. Later, the programming team looks at the requirements of each of those functions and the process is repeated. These compartmentalized sub-routines eventually will perform actions so simple they can be easily and concisely coded. When all the various sub-routines have been coded the program is done.

Advantages of top-down

1. Separating the low level work from the higher level objects leads to a modular design.
2. Modular design means development can be self contained.
3. Having "skeleton" code illustrates clearly how low level modules integrate.
4. Fewer operations errors (to reduce errors, because each module has to be processed separately, so programmers get large amount of time for processing).
5. Much less time consuming (each programmer is only involved in a part of the big project).
6. Very optimized way of processing (each programmer has to apply their own knowledge and experience to their parts (modules), so the project will become an optimized one).
7. Easy to maintain (if an error occurs in the output, it is easy to identify the errors generated from which module of the entire program).

 

Disadvantages of top-down programming

1.  Functionality either needs to be inserted into low level objects by making them return "canned answers"—manually constructed objects, similar to what you would specify if you were mocking them in a test, or otherwise functionality will be lacking until development of low level objects is complete.
   

• Bottom up approach
  

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.

4. Total-System Approach vs Modular Approach

• Total-system approach
  

Total-system approach to be approach develop system together according to comprehensive. This approach less synchronized for complex system, because will be difficult be developed. This approach be feature classic approaches. 

• Modular approach

in a system approach to ge the enginnered concept working in a globally important croping system to addres real constrains. The system can be easiest to understood and maintenence, cause they cropping the complex case to simple parts.  

5. Great-Loop Approach vs Evolutionary Approaches 

• great-loop approach
  

great-loop approach  have a big risky for  oganiz cause great loop approach straightaway to build a system. And great loop approach spend alot of money, this method needed alot of resource for build, studied, and maintance the system.

• Evolutionary approach
  

Evolutionary approaches to software development are not only supported by leading software development processes they are in fact the norm for agile processes.  You also learned that there are some significant problems with the near-serial, BDUF approaches favored by many traditional data professionals.  Most importantly you discovered that it is possible to take an evolutionary approach to data-oriented development activities, techniques that are described in greater detail in following chapters.  The bottom line is that if you want to work with an agile team you need to be prepared to work in an evolutionary manner.  It is a choice to work in this way, just as it’s a choice to not do so.  Agile software developers embrace change and therefore decide to work in an evolutionary manner. 

Methodologi

Software engineering is the practice of using selected process techniques to improve the quality of a software development effort.  This is based on the assumption, subject to endless debate and supported by patient experience, that a methodical approach to software development results in fewer defects and, therefore, ultimately provides shorter delivery times and better value.  The documented collection of policies, processes and procedures used by a development team or organization to practice software engineering is called its software development methodology (SDM) or system development life cycle (SDLC).

Method definition

orderly procedure or process to make an product, in this case exactly information system. a mode or system of classifying natural objects according to certain common characteristics; as, the method of Theophrastus; the method of Ray; the Linnaean method. 

Algoritma

An algorithm is a specific set of instructions for carrying out a procedure or solving a problem, usually with the requirement that the procedure terminate at some point. Specific algorithms sometimes also go by the name method, procedure, or technique.

System Development tools

•         grafik: HIPO, SADT, Jackson’s diagram, and etc

•         diagram:

1.   Activity charting, example: Gant chart, flowchart, and etc
   
2. Layout charting, example organization layout.
3. personal relationship charting, example; organization chart, working distribution chart

System development techniques

•         Project management techniques

Manage an project schedule, this a leading role to finished the project by timely. And make a our customer satisfied about our system.

•         Fact techinques

Collected and fixed some data then we proccesing for own project. Collected and fixed data can be execute by two ways; the first  quistioner; give a question to resouce person about solve a project. Number two is observation; we can observe the case of our project.

•         Cost-benefit and cost-effectiveness analysis techniques

Cost-benefit and cost-effectiveness analysis is important on build a system, without this the organisatiton will be bangkrupt and failed, so many people will be a uneployement.

•         Meeing techniques

This is an based solving problem techniques, whitout it problem solving will be slowly. In this case we must devided some job finising by a group.

•         Inspection techniques

Are the standard techniq for inspection our suborninates while worked, they must doing they job and discipline. In  other that our project quickly finished.

classifications of development methodology

Functional decomposition

solve the problem to subsystem , example; HIPO, Stepwise refinement, iterative stepwise refinement, information hiding

Data-oriented

solve the problem appropriete problem, example; data flow oriented, structured data, and etc

Prescriptive

given from sofware factory.

 The Diference and Techniques between Analyz and Programmer

The diiferent between  analyz system and programer; analyz system as a communicator between customer and programer, so that the problem can be solve by exactly. And the system will be functional appropriated accompaniying customer requsedted. Analyz system give a programer a drawn about a system then programmer will be implemetation that diagram to be application system. 

• Analyz system
  

Analyzer system techniques; economy business, must have good communication, have a great relationship.

• Programer
  

Programer techniques; linear programing, proccesing data and programing languae, problem solving skilled.