GENERAL OBSERVATION FOR SYSTEMS DEVELOPMENT

The necessary of systems development

1. Problems

Problem in the systems is mistakable of the systems, that make the old system not work optimally. There are some mistakes:

- The miss understanding of system between programmer and user.

- The operations is not correct make the system error.

- Didn’t obey the management rule, so the system will not optimally

- etc

2. The growth of organization is not effectives

The old system is not optimal to fulfill the requirements of organization, so the organization needed new system to complete the job optimally.

3. Get the opportunities

Systems development is needed to get opportunities, for example: the organization want to renew their systems to raising quality and also to upgrade their income.

4. Directives

Systems development is needed, because there are some instruction from the leader, or the rule from the government.

The aim of system development

1. To solve the problems

2. To get the opportunities

3. To fulfill the instructions

For the general the aim has been written on top.

What can we hopes from the new system?

Ø Performance

The new systems can raising the performance of organization. If the performance is low, the new system will be able correcting then upgrade their performance better than the old system.

Ø Information

There are raising about the quality of information, so information that needed always new and fresh because the function of new systems.

Ø Economy

New system will upgrade the benefits or to go down the account.

Ø Control

New systems will control and also fix any problems in organization.

Ø Efficiency

The improvement of operating efficiency. Efficiency related with how to use resource without doing extravagance

Hopes new system can control efficiency jobs:

Outcome

income

Ø Services

New system will raising the services. If old system have bad services, we hope with the new system will give better.

Principle systems development

- Systems for management always developed for raise the information of management system.

- System for big invest.

The system need big invest besides if we use modern technology, so the organization must consider two alternative:

o To go down the opportunities cost has will gone

o To consider by analyst that benefits cost to detect about that invest project can be benefit or no.

- System need specialist in their sector and not always need people who get formal education

- Job levels

The job levels in system development use system development life cycle

- System development not must be processed from first until next procedures, but also can process with random or customs.

SYSTEM DEVELOPMENT LIFE CYCLE

The Systems Development Life Cycle (SDLC) is a abstract model used in project management that describe the stages concerned in the information system development project from an initial probability study through maintenance of the completed application. Various SDLC methodologies have been developed to guide the processes concerned including the waterfall model (the original SDLC method), rapid application development (RAD), joint application development (JAD), the fountain model and the spiral model. Generally, several models are united into some sort of hybrid methodology. Documentation is critical in spite of the type of model chosen or devised for any application, and usually done in parallel with the development process. Some methods work better for definite types of projects, but in the final analysis, the most important factor for the success may be how directly particular plan was followed.

Waterfall method:

In this cycle, the process always start followed the procedures. The process start from bring together about requirements and analyst all of data to the next process. If the requirements have done, we go to next process is called design of the system. We can design the system use all of data from the requirements. And then the design of the system can we implementation with evaluated and also we can do testing to use this system.

Next procedures is how can we verification this system to be good system, and we introduce to many user that will use this system.

If all of procedures on top have done, the system must we protect from the bad sectors using maintenance.

Iterative method

Iterative cycle have the same instruction with the waterfall cycle. The different we found in the maintenance procedures. The system have testing level and evaluation level in this procedures. If we found any mistakes can we bring together be new requirements and go to next level like the picture on top. The levels in iterative cycle which is connected each other.

Spiral method:

This model of development combines the features of the prototyping model and the waterfall model. The spiral model is favored for large, expensive, and complicated project.

Spiral model have many procedures to do:

The new system requirements are definite in as much detail as possible. A prelude design is formed for the new system. At first prototype of the new system is constructed from the preliminary design. The 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. The existing prototype is evaluated in the same manner as was the preceding 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. And also the final system is constructed, based on the refined prototype then evaluated and tested. Routine maintenance is carried out on a continuing basis to prevent large-scale failures and to minimize downtime.

Approaches of developing a system

Classic approach vs. approach of structure

Classic approach methodologies develop system by following steps in system of life cycle. One who develop this system still need techniques and appliances to develop the system. Problemss of arising out in classic approach shall be as follows:

1. Development of software will become difficultly

2. Expense of treatment or conservancy of system will become costlierly

3. Possibility of mistake of big system

4. Efficacy of system less well guaranted

5. Internal issue applying of system.

Approach of structure

Still use tools-tools like data of flow diagram. Approach of structure basically try to provide to additional system analyst of techniques and appliances to develop system beside remain to follow idea of system of life cycle. Conception system development of structure not such a new concept. Assembling technique in factories and scheme of circuit for the appliances of electronic are two example of this concept which used many industrys.

Piecemeal approach vs. system approach

Piecemeal approach is system approach development that emphasized at one particular activity or certain application. This approach don’t heed overall target. System approach pays information system as integration unitary to each activity or the application. This approach also emphasized in overall goal achievement from organization, not only in that information target.

Approach of bottom-up vs. approach of up-down

Bottom-Up Approach had begun from level under organization, that is begun from needs formulation to handle transaction and climb level on with formulate information need based on transaction. This approach also is feature classic approaches. Bottom-up approach is used in systems analysis stage is called also with data analysis, because that be pressure data that be cultivated before hand, information that be produced to follow to follow the data. this approach strarting from under level organization, that is operational level where transaction has done.

Top-Down Approach on the contrary begun from level on organization, that is begun with define target and organization policy. Step furthermore from this approach information need analysis. After information is determined, so process goes to transaction processing, that is determination output, input, data base, operating procedure and control. This approach be feature from structured approach. Top-down approach when used in systems analysis stage called also with term decision analysis, because that be pressure information that wanted for decision making by management beforehand, then data necessary cultivated to defined to follow information that wanted.

Comprehensive system vs. modular approach

approach by totally represent approach developing system in concern by totally. this is approach less synchronized for the system of big money, because will become difficult to be developed. this approach also represent marking of classic approach

Total-system approach to be approach develops system together according to comprehensive. This approach less synchronized for complex system.

Modular Approach tries to divide complex system to simple some part, so that system easier will be understood and developed. Furthermore consequence system can be developed of time that planned, easy understood by system user and easy to maintain. This approach be feature structured approaches.

great-loop approach vs. evolutionary approach

Great-loop approach applies change comprehensive according to together use sophisticated technology. This change contains many risks, because computer technology so great-loop. This approach also too expensive, because need investment at the same moment for all technology that used and difficult to developed because too complex. Evolutionary approach apply sophisticated technology just for applications that need that moment and then be developed for periods next based on technology development. This approach causes investment not too expensive and can follow fast technology development.

system development methodologies

The meaning of methodology, method and algorithm ????

Methodology is unity of methods, procedures, jobs concepts, the rule of postulates and used by an science, artistic or the other discipline. Method those are utilized in scholarship.

Method is someway systematic to work something

Algorithm is medley procedural to solves a problems

The classifications of development methodology

There are three classifications of developing a system, such as:

Functional decomposition

Functional decomposition is emphasizing system resolving becomes subsystem. Examples of this classification are HIPO, Stepwise refinement, iterative stepwise refinement and information hiding.

Data-oriented

Data-oriented is emphasizing on processed data characteristic.

• Flow oriented data: types appropriate modules data elements
• Structure oriented data: input structure and output
• Prescriptive methodology

which the included in this methodologies:

- ISDOS (information system design and optimization system)

- PLEXSYS

The function is to transform statement fro computer language into executable code to configure hardware that we need.

- PRIDE

Software to analyst and design some structure system for development system.

- SDM/70(system development methodology/70)

- SPECTRUM

- SRES AND SREM

- Other prescriptive methodologies

Usually been provided by software maker factory

Tools for developing a system

• Get graph form: HIPO, SADT, Jackson’s diagrams, etc.
• Tool that utilizes to design:

Activity charting: figuring activity, example: chart’s substituting, flowchart, etc.

Layout charting: figuring layout

Personal relationship charting: figuring person relationship, example: organization chart, working distribution chart

Techniques used in developing a system

• Project management techniques à to scheduling project, example: CPM and PERT
• Tech finds fact à to gather and determines data / fact

*> Interview

*> Observation

• analysis’s tech cost / benefit à cost benefit and cost effectiveness analysis
• Going tech shuts close
• Inspection tech

The differences of being a system analyst and a programmer and the knowledge a system analyst should posses

System analyst studying problems and determine system user requirements to identify resolving.

Programmer writing program code bases engineering that made by analyst

Ø System analyst on call bridges distinctive happening science among system user and Data processing technology, computer and mathematics

Ø Science carries on business in common

Ø Quantitative method: regression, programming linear, etc. it

Ø Trouble-shooting membership

Ø Communication membership among person

Ø Membership builds relationship among person programmer