The importance of system information development
- There is the problems occurs with the system old ones.
- There is peculiarity in information and organization growth of systems, like there any unfair of systems management.
- To reach for opportunities.
- There is directives, likes from government.
The purpose or goal of developing an information system
1. For have not problem again
2. For reach opportunities
3. For doing the directives
The improvement which expected of new systems.
- Performance. Performance can we see in compare of throughtput and response time working.
- Information. Information must have to improve on actually (accuracy), on time (time line) and relevant.
- Economy. For example, a company use resource very much so that need cost to run system. With case existence, so here be feel to develop system so that system experience enhanced so that can depress cost .
- Control. Controlling of mistake is not expected. For example on use barcode systems to avoid a robber.
- Efficiency. For example : Using web for marketing so decrease hire employees.
- Services. For example : catalog in library, useful for students find books.
Principle of development systems.
- The development systems is for management. So systems must support requirements of management. After this system is completed to developed, so who will to use information of this system is management.
- The development systems is a investment, with each investment must have to consider: all alternative must be investigated and investment must be valuable or have high cost benefit.
- Systems need person who educated.
- Jobs Schedule or Jobs stages, like system development life cycle for on time and don't have any problems.
- System development don't have to sequence time.
- Don't fear to cancel project.
System Development Life Cycle
- Waterfall cycle.
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.
Requirement : In this phase, the programmers receive a broad statement of a problem that is potentially amenable to a computerized solution. This step is also called the user requirements phase.
Design : The programmers determine how the program will do its task.
Implementation : They write the program. This step is also called coding phase. Verification : Large programs have many parts. These parts must be brought together into a smoothly functioning product, usually not an easy task.
Maintenance : Programs usually have a long life; 5 to 15 years is common. During this time, requirements change and minor or major changes must be made.
- Iterative cycle.
Iterative cycle 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.
1. Initial planning, beginning planning process and or beginning ideas to make a system.
2. Planning, planning here be a thinking that ripe towards system that be made.
3. Requirement, same like in process requirement waterfall model, here systems analysis does need collecting process from customer and or management on towards system and or desirable application.
4. Analysis and design, in this stage us does systems analysis process, fitur everything that need, need from application that be made good to also the application. Beside that, here we also begin to make design plan from system, like interfaces delegation, the data structure, the architecture, and as it.
5. Implementation, implementation process has been continuation from where did we begin to implementation the design that made to into program codes that be read by engine language.
6. Deployment, process deployment here purpose has been distribution process towards system that made, in our meaning distributes before hand system to society before do testing so that we know our system deficit.
7. Testing, process testing here we have done testing towards system and or application that made. This process focus in internal logic from application that made, ascertain that any line coding checking. Beside that here we also have done testing process towards possibility towards errors from system that made.
8. Evaluation, process evaluation here be repair process, maintenance and renewal towards system that made. Repair process here done when application and or system that made to experience error after to customer so that must necessary repair process towards system. Maintenance process and renewal be done caused by development towards an OS so that application must be repaired again to update. In renewal process here will return to do process planning, data collecting (requirement), analysis system and design, implementation, deployment, testing and return again to evaluation. if there development again, so this cycle be repeated again.
- Spiral cycle.
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 project.
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:
a. evaluating the first prototype in terms of its strengths, weaknesses, and risks;
b. defining the requirements of the second prototype;
c. planning and designing the second prototype;
d. constructing and testing the second prototype.
Approaches of developing a system
1. Classical Approach Vs Structured Approach
Classical Approach
Classical approach is approach insides system development that follow stages at system life cycle without supplied with tools and techniques. Troubleshoots that can emerge from approach classic, that is:
- Software development will be difficult. Classical approach less give tools and techniques insides develop system and as finally software development process becoming not directional and difficult to done by programmer.
- Treatment cost or system maintenance will be more expensive. The expensive treatment cost at classical approach caused system documentation that developed less complete and less structured.
- Big error possibility system. System not test during the development stage is principal source from system errors. Classical approach doesn't prepare to manner systems analysis to do testing system, so that system errors possibility will be bigger.
- System success less guaranteed. Emphasis from classical approach work from system developers staffs, not in system user. Because classical approach less involve system user in system development, so system user needs are less matching with the one which desirable and as finally system that applied less success.
- System applications internal issue. Because system user involvement less communication in system development stage, so only will know only in stage will applied. As finally system user will be startled and unaccustomed with new system suddenly introduced.
Structured Approach
Structured approach equipped with tools and techniques that wanted in system development, so that end result from system that developed be got system the structure will be defined well and clear.
2 . Piecemeal Approach Vs System Approach
Piecemeal approach
Piecemeal approach be to system approach development that emphasized at one particular activity or certain application. Activity that chosen, developed regardless of the position at information system or regardless of overall target from organization.
System approach
System approach pays information system as one integration unitary to each activity or the application. This approach also emphasized in overall goal achievement from organization, not only in that information target.
3 . Bottom-Up Approach vs Top-Down Approach
Bottom-Up Approach
This approach begin from level under organization, that is begin from needs formulation to handle transaction and climb level on with formulate information need based on transaction. This approach also be feature classical approaches. Bottom-up approach is used in systems analyst 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.
Top-Down Approach
This approach on the contrary begin from level on organization, that is begin with define target and organization policy. Step furthermore from this approach doing information requirement 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.
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
This approach try to divide complex system to simple some part, so that system easier will be understood and developed. Furthermore consequence system can be developed of the time that planned, easy understand by system user and easy to maintained.
5 . Great-Loop Approach vs Evolutionary Approaches
Great-Loop Approach
This approach apply 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
This 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.
Methodology of development systems
Methodology is unity of the methods used for development information systems. In system development has procedure sequences to solve problem, that is means algoritm. Methodology can use of analysis step and design step.
Classifications of development methodology
Development methodology have 3 classifications, are :
- Functional decomposition methodologies.
This is emphasize at resolving of system into subsystem the smaller ness, easier so that comprehended, designed and applied.
- Data-oriented methodologies
This is emphasize at characteristics from process data will do it. This methodology have 2 classification, there are data-flow methodologies and data structure oriented methodologies
- Prescriptive methodologies
a. ISDOS (Information Systems Design and Optimization System)
This is software developed in University of Michigan. Function of ISDOS is optimization development process information systems. ISDOS have 2 component are PSL and PSA. PSL is main component of ISDOS, is a language for writing user requirement to machine readable form. PSL is designed to output so can analyzed by PSA.
b. PLEXSYS
Function of PLEXSYS is for transformation a high level computer language statement to can executable code for hardware configuration.
c. PRIDE
PRIDE promoted by corporate in USA that name is M. Bryce and Associates. PRIDE is fused software to analyze or design structure system, management data, project management and documenting.
d. SDM/70 (Systems Development Methodology/70)
SDM/70 developed and promoted by company in USA, that is Atlantic, Inc. SDM is software contained of methods, estimation, documentation for helping user to development and maintenance effective systems.
e. SPECTRUM
SPECTRUM is methodology development systems who development and promoted by company in USA, that is SII (Spectrum International Inc.).
f. SRES (Software Requirement Engineering System) and SREM (Software Requirement Engineering Methodology)
SRES development by TRW for SDS (Software Development Systems) from US Air Force.
Tools for developing a system
Tools for developing a system generally in the form of picture or diagram or graph. Tools for developing in the form of graph, there are :
- HIPO diagram, use in HIPO methodologies.
- Data flow, use in structured systems analysis and design.
- Structured chart
- SADT diagrams
- Warnier/Orr diagrams
- Jakson’s diagrams.
Techniques used in developing a system
The technique available to system development usually not special to selected methodologies, but can used in all methodologies. The technique can be used are :
- Management project technique, this technique used for scheduling project.
- Fact finding technique, this technique used for collecting data and finding facts in studies systems.
- cost-effectiveness analysis or cost-benefit analysis technique.
- walkthrough technique.
Analyst system and Programmer
Analyst system is person who studying problems and requirement user to identify them, responsibility to system is as a whole, knowledge of system analyst have to wide and entangle the relation to many people.
Programmer is person who writing coding programs to design built an analyst system make, knowledge programmer enough limited to computer technology, computer systems.
The knowledge a system analyst should posses
System analyst must have to wide knowledge, and needed, like :
- The knowledge about data processing, computer technology, and computer programming. The technical knowledge are about hardware computer, technology data communication, computer languages, operation systems, and other software.
- The knowledge about business is in general. This knowledge covers financial accounting, management accounting, marketing, production.
- The knowledge about quantitative method. Quantitative methods like are linier programming, dynamic programming, regression, network, decision tree.
- The knowledge to resolve problems.
- The knowledge to communication between personnel. System analyst must have capability for communication verbally or in writing. This needed in presentation, meeting and makes accounting.
- The knowledge to relationship between personnel.
Reference:
-HM, Jogiyanto. Analisis & Desain Sistem Informasi. 1990. Yogyakarta: ANDI
-http://www.ffiec.gov/ffiecinfobase/booklets/d_a/08.html
-http://orion.kent.edu/steinberg/sys2.htm
-http://en.wikipedia.org/wiki/Waterfall_model
-http://www.hts.stevenwood.com/ics3m/cos/units/2/activity21/iterative.htm
