THE PURPOSE OF SYSTEM DEVELOPMENT PUBLIC.

The important.of systems development is compiling a new system to replace system old ones as a whole or improve;repair system which have there. The system old ones require to improve because, existence of problems - problems that appear in system old ones. Problems of arising out such of.
a. Annoyance in growth’s system of organization
The example of annoyance in growth’s system of organization, insincerity.and mistake which intended, its efficiency of operation not and not obey of policy of management.
b.. Growth of organization.
c. For reach the opportunitys ( opportunities).
d Existence of instructions ( directives).
There are the purposes of development of information system is
a.. Solving problems.
b. Reach for opportunitys.
c. Fulfill the instruction that given.
There are the expectations of organization after executing the information system
a. Performance ( performance)
Measured to use and throughput of response time. The improvement of performance in a new system make the system will be effective. Performance can be measurement from throughput and response time where throughput is amount of work of which can done certain in a moment and response time is time mean which delay between two transactions.
b. Information ( information)
The improvement of information quality which presented.
c. Economy ( economic)
Increase the benefit of vs decreasing cost.
d. Control ( operation)
The improvement of control, detecting and improve;the mistake. To detection and repairing some faults and insincerity which possible happened.
e. Efficiency ( efficiency)
The improvement of operating efficiency. Efficiency related with how to use resource without doing extravagance.
f. Services ( service)
Increase the service of system.
There are some principles of system development of information
a.. System for the management.
b. System is a big invesment
Investigation of all alternative (minimizing missing cost opportunity) best investigation have to be valuable : analysis cost-benefit & analysis cost-effectivenes.
c. System need educated people
Not allowed education have to be formal.
d. Step work system cycle life development.
e.. System development [do] not have to numbering.
f. Don't fear to cancel project.
g. System documentation.
Three cycle live development of system are
Model of waterfall

Requirement à Analysis gathers the requirements for the system. This stage includes a detailed study of the business needs of the organization. Options for changing the business process may be considered. Design focuses on high level design like, what programs are needed and how are they going to interact, low-level design individual, interface design and data design. During these phases, the software's overall structure is defined. Analysis and Design are very crucial in the whole development cycle. Any glitch in the design phase could be very expensive to solve in the later stage of the software development. Much care is taken during this phase. The logical system of the product is developed in this phase.
Design à In system design functions and operations are described in detail, including screen layouts, business rules, process diagrams and other documentation. The output of this stage will describe the new system as a collection of modules or subsystems.
Implementation à In this phase the designs are translated into code. Computer programs are written using a conventional programming language or an application generator. Programming tools like Compilers, Interpreters and Debuggers are used to generate the code. Different high level programming languages like C, C++, Pascal and Java are used for coding. With respect to the type of application, the right programming language is chosen.
Testing à In this phase the system is tested. Normally programs are written as a series of individual modules, these subjects to separate and detailed test. The system is then tested as a whole. The separate modules are brought together and tested as a complete system. The system is tested to ensure that interfaces between modules work, the system works on the intended platform and with the expected volume of data (volume testing) and that the system does what the user requires (acceptance/beta testing).
Maintenance à tably the system will need maintenance. Software will definitely undergo change once it is delivered to the customer. There are many reasons for the change. Change could happen because of some unexpected input values into the system. In addition, the changes in the system could directly affect the software operations. The software should be developed to accommodate changes that could happen during the post implementation period.
Model iteratif


The challenge in iterative development is to make sure all the iterations are compatible. As each new iteration is approved, developers may employ a technique known as backwards engineering, which is a systematic review and check procedure to make sure each new iteration is compatible with previous ones. The advantage of using iterative development is that the end-user is involved in the development process. Instead of waiting until the application is a final product, when it may not be possible to make changes easily, problems are identified and solved at each stage of development. Iterative development is sometimes called circular or evolutionary development.
Model spiral

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.
A preliminary design is created for the new system.
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.
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.
At the customer's option, the entire project can be aborted if the risk is deemed too great. Risk factors might involve development cost overruns, operating-cost miscalculation, or any other factor that could, in the customer's judgment, result in a less-than-satisfactory final product.
The existing prototype is evaluated in the same manner as was the previous prototype, and, if necessary, another prototype is developed from it according to the fourfold procedure outlined above.
The preceding steps are iterated until the customer is satisfied that the refined prototype represents the final product desired.
The final system is constructed, based on the refined prototype.
The final system is thoroughly evaluated and tested. Routine maintenance is carried out on a continuing basis to prevent large-scale failures and to minimize downtime.
There are the approve of development a system
a. Classic approach vs approach of structure.
classic approach
Steps in sdlc.
Do not involve consumer, for emphasizing the system analyst.
Problems: difficult development, expense of costly treatment, possibility of big mistake, efficacy less well guaranted, applying internal issue.
approach of structure
Consumer involve from early to determine the requirement of system.
Using tools-tools like data of flow diagram.
b. Approach of rasher of vs approach of system.
approach of rasher
IEmphasizing at an activity or application.
Heedless of entirety target.
approach of system
See system as one intact unity.
Emphasizing at goal achievement as a whole.
c. Approach of bottom-up vs approach of top-down.
approach of bottom-up
Started from level under that is operational.
Representing classic approach marking.
Recognized with term of data-analysis.
approach of top-down
Started from up level that is planning of strategy.
Representing marking approach of restructure.
Recognized also with decision-analysis.
d. Approach of vs whole system vs approach of moduler.
approach of whole system
Developing system at a time and totally.
Representing classic approach marking.
approach of moduler
Breaking complicated system become the parts of simple.
Developed system become timely, easy to to be comprehended and looked after v.representing marking approach of structure.
e. Approach of great loop approach vs expand.
approach of ( approach great-loop )
Developing system at a time use sophisticated technology.
High risk and finish many expense.
approach expand ( approach evolutionary)
Applying sophisticated technology for certain applications.
Developed to follow requirement.
Cost effective and can keep abreast of technology.
The meaning of methodology, method and algorithm
Methodologies is the methods which is used in science. Method is a way of systematic to do something. And Algorithm is procedure sequence to solve a problem.
There are the clarification of three classification of metodology development of system.
Decomposition functional.
Ephasizing resolving of system become subsistem. The example HPO,, stepwise refinement, refinement stepwise iterative, hiding information.
Data-oriented.
Emphasizing at processed data characteristic:
Oriented data-flow: modules according to data element type.
Oriented data-structure: input structure and of output.
Prescriptive
Usually provided by factory maker of software.
There are the appliance - appliance used to develop a system
In form of graph: hipo, sadt, jackson's diagram, and others.
appliance using schema
a Charting activity: depicting activity, example [of]: chart gant, flowchart, etc.
b Charting layout: depicting the place of system.
c Relationship charting personal: depicting personnel , example : chart organization, chart distribution working.
There are the technique - used technique in developing a system
a Management technique of project for schedule of project , example : cpm and of pert.
b Technique find fact to collect and determine data / fact :
1. Interview
2. Observation
c Technique analyse expense / benefit of cost-benefit and cost-effectiveness analysis.
d Technique to do the meeting.
e Inspection technique.
The difference of system’s analyst and a programer
A. System analyst: studying problems and determine requirement of system to identify resolving.
B. Programmer: writing program code pursuant the design made by analyst.
System analyst undertake to link difference of knowledge that happened between system’s analyst and system of programmer.
There are the knowledge that used an analyst system to influence a system:
a. Data-processing technology, and computer of programming.
b. Knowledge of business in general.
c Quantitative method: regretion, linear programming, etc.
d. Skill of trouble-shooting.
e. Skill of communications between personnel.
f. Skill to construct relation between personnel.