Sunday, March 29, 2009

Initial Investigation and Requirement of Analysis

System Investigation Concept

The gap between system purposes and the condition actual system.

The report of detection problem is not real or actual.
1. The purpose is excessive ideal.
2. Lacking of resource and or attitude.
3. Measuring of system is not so accurate.
4. The purpose of system was backward.
5. The difference of ideal system and several system.

Problem solving:

a. An Acurate the inverstigation.
b. Ideal Getting of system consensus.
c. Developed several alternative.
d. Select the best alternative.

Purpose of investigation indicate problem are happen in the system.

The problems in investigation system

When investigation, there are some problem, that is :
a. Time
b. Expense
c. Science
d. Politics
e. Interference


The investigation results are a recommendation that include these following:

- Never take any action –> if there is no problem was found

- System maintenance –> some small problems

- increase ability or user ability

- totally consider to system modification

- put problem into the development system plan

Investigation Tactics

Why we need tactic?

- to find all the problem

- to find out the reason

- to find out the best solution

Investigation tactics is very important for the entire elements system so that the system can accept request solution without disturb their activities.

Some tactics that we can do:

- listening the suggestion from system agent

- don’t give beginning solution

- comparing the stories from system agents about similar cases

- notice the logical inconsistent problem

Investigation Technique

Technique directly (Internal):

- The questionnaire
- Discussion
- Monitoring

Technique Indirectly (External):

- Flow of the procedure
- Reviewing documents
- Sample
- Tabular

Current system Description

- Inputs
- Outputs
- Files
- Data elements
- Transaction and document action volume
- Data Flow Diagram

Requirement of Analysis

Intensive Interaction stage between system analyst by end is user of where team of system development indicate for get faith user.

Four Purpose which wish reached

- Explaining the system completely.
- Describing ideal the information system.
- Giving provide about make the user trusting into system development
- Bringing ideal information system to condition in this time by paying attention to resource constraint


- Discussion
- Questionnaire
- Observation
- Analyse procedure
- Document Observe

Resource constaraint
- Time
- Money
- Membership
- Technological
- Eksternal Factor

The Requirement Document Analyse

1. Instruction analyse
Relationships with end users, the observation process, problems in data collection.

2. The user needs
The need actual, reporting requirements, training needs and the influence of the new system

3. System Constraint
Explain the constraints of time and cost, expertise, membership, technological and factor eksternal
4. Document in the form of data collecting instrument, statistical consensus, the logical flow of data phisical.

Generating System Alternatives

1. create alternative to solve the information system problem
2. Applying best alternative wisely.

Strategy Option

1. Distributed versus centralized processing
Changes in information decision-making from the centralized data processing to the decentralized end user responsibility center

2. Integrated versus dispersed database
System designer must consider the data which are entered in the database and into the file

3. Surround Strategy of System Development
About important environmental strategy in the case of company takeovers because the information system of other companies may vary with the company at this time.

Options Tactics
Before behavior to design operational

Designing Operational Options
Selection in design operational can be group:

1. Online Vs Off Line Data Entry
2. Keyed Vs Machine Readable Data Entry
3. Centralized Vs Decentralized Data Entry

1. Batch Vs Realtime record update
2. Sequential Vs Direct Access to records
3. Single Vs Multiple User update of records

1. Traditional Vs Turn Around Documents
2. Structured Vs Inquiry based reports

Selecting the proper system

System the based of cost and profit with relative. There are 3 way system A, that is more preeminent than other system, if :

1. A have a cost more inferior than B and the profit of both are same.
2. A have a cost more inferior than B and A yielding profit is more much than B.
3. A and B have a some cost, but A's profit is more much.

Some comparation system method
1. Break Even point Analyisis
2. Payback Period
3. Discounted PayBack period
4. Internal Rate of Return

Categorize expense
1. Hardware
2. Software
3. People
4. Suppliers
5. Teleccommunications
6. Physical sites

Detail of expense
Comparing the expense of information system through life of system, projection analyst how much/many change of expense for the future and there is 3 model of is expense of information system that is Linear, Eksponensial and of Step Function.
Expense of information system earn just happened once and earn also happened chronically.

1. Expense of just information system that happened once that is cost ontime and of development cost that happened system development moment.

2. Expense of information system that happened continually among others is cost reccuring and also cost operational where this expense happened information system moment operate every day.

The Information System Factor

Qualitative factors that lead the performance information system that both of them:

a. Reducing mistake storey
b. Reducing the time to fix errors
c. Reduce the response time from the workstation alternative
d. Accelerate the time of providing information
e. Improve security systems
f. Multiply to update the active source record
g. Improving user satisfaction

Company Strategy Factor

a. Customer satisfaction
b. Sales increased
c. Consumer and vendor commitment
d. Product marketing Information

Decision to continue or not

1. If the company decided to develop the system, the information department will do next, namely the System Design Process.

2. If the other way then the System Development Life Cycle (SDLC) will be terminated.

3. Often a problem will be found with the study system and then usually top management will ask for the re-employment the study system.

4. Model will describe some of the stages of the repeated and sometimes the information will make a decision before the repeat stage system of study.

5. With the alternative, the decision to repeat a previous stage SDLC or not is called Go-No-Go Decision.


Saturday, March 7, 2009

System Development Concept (Part II)

Approaches Of Developing A System

1. Classical approach and structured approach ( looked into used methodologies).

A. Classical Approach
Is classic approach methodologies to develop the system by following the step in system life cycle.

B. Structured Approach
Approach of structure provide the additional system in the form of appliances and techniques to develop the system beside fixed follow idea from system life cycle.

2. Piecemeal approach and system approach (looked into the target to reach).

A. Piecemental Approach
Piecemeal approach is a system development approach that emphasize to an activity or just the application. The selected activity or application is developed without pay the attention from the position in information system or without pay the attention from the organization target comprehensively.

B. System Approach
Approach of system, pay attention the information system as one unity integrated to each activity or his application.

3. Bottom-up approach and Top-down approach (looked into the way of determining requirement of system).

A. Bottom-Up Approach
A bottom-up approach is piecing together systems to give rise to grander systems, thus making the original systems sub-systems of the emergent system. 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. However, "organic strategies" may result in a tangle of elements and subsystems, developed in isolation and subject to local optimization as opposed to meeting a global purpose.

B. Top-Down Approach
A top-down approach is essentially breaking down a system to gain insight into its compositional sub-systems. In a top-down approach an overview of the system is first formulated, specifying but not detailing any first-level subsystems. Each subsystem is then refined in yet greater detail, sometimes in many additional subsystem levels, until the entire specification is reduced to base elements. A top-down model is often specified with the assistance of "black boxes" that make it easier to manipulate. However, black boxes may fail to elucidate elementary mechanisms or be detailed enough to realistically validate the model.

4. Total-system approach andmodular approach (looked into the way of developing it).

A. Total System Approach
Total system approach is the approach which developing a system together according to comprehensive.

B. Modular Approach
Modular approach tries to divide complex system to simple some part, so that system easier will be understood and developed.

5. Great loop approach and evolutionary approach (looked into technology to be used).

A. Great Loop Approach
Great Loop Approach apply change totally at a timely use the sophisticated technology. Have the big risk because speed of change of technology.

B. Evolutionary Approach
Evolutionary approach applies sophisticated technology just for applications that need that moment and will be developed for next periods based on technology development. This approach causes investment not too expensive and can follow fast technology development.

The Meaning Of Methodology, Method And Algorithm

1. Methodology can be defined as:
  • The analysis of the principles of methods, rules, and postulates employed by a discipline.
  • The systematic study of methods that are, can be, or have been applied within a discipline.
  • A particular procedure or set of procedures.
2. Method
Method is How to do or make something

3. Algorithm
Algorithm is a sequence of finite instructions, often used for calculation and data processing.

Classifications Of Development Methodology

1. Functional decomposition methodologies
Functional decomposition methodologies emphasize at resolving of system into smaller subsystems, so that will be more easy to be comprehended, to be designed and applied. Which included in this methodologies is:
  • HIPO (Hierarchy plus Input Process Output)
  • SR (Stepwise Refinement)
  • ISR (Iterative Stepwise Refinement)
  • Information-Hiding
2. Data-oriented methodologies

This methodologies emphasize at characteristic of data to be processed. This methodologies is grouped into 2 class:

A. Data-flow oriented methodologies
There are the include in this group methodologies such as SADT (Structured Analysis and Design Techniques), Composite Design.

B. Data structure oriented methodologies
There are the include in this group methodologies such as JAD (Jackson's system development), W/O (Warnier/Orr).

3. Prescriptive Methodologies

This methodology usually has been provided by software maker factory. In this methodology including:
  • ISDOS (Information System Design and Optimization System)
  • SDM/70
  • SRES and SREM, etc.

Tools For Developing A System

The tools there are in the form of diagram and chart, such as :
• HIPO diagram, Data flow diagram, SADT, structure chart, Jackson's diagrams, etc.

Besides the tools that mention above, there are utilizes that used at all of methodology. The tools as a chart set that grouped by:

• Activity charting: to figuring activity, example: chart's substituting, flowchart, etc.
• Layout charting: to figuring layout
• Personal relationship charting: to figuring person relationship, example: organization chart, working distribution chart

Techniques Used In Developing A System

1. Project Management Technique
Project management technique is the discipline of planning, organizing and managing resources to bring about the successful completion of specific project goals and objectives.

2. Finding Fact Technique
Fact-finding is an important activity in system investigation. In this stage, the functioning of the system is to be understood by the system analyst to design the proposed system. Various methods are used for this and these are known as fact-finding techniques. The analyst needs to fully understand the current system.
The analyst needs data about the requirements and demands of the project undertaken and the techniques employed to gather this data are known as fact-finding techniques.
Various kinds of techniques are used and the most popular among them are interviews, questionnaires, record reviews, case tools and also the personal observations made by the analyst himself. Each of these techniques is further dealt in next pages.

3. Meeting Technique
During conducted system development process, oftentimes meeting performed either by developer team with user and manager.

The Differences Of Being A System Analyst And A Programmer

1. System Analyst

A systems analyst is responsible for researching, planning, coordinating and recommending software and system choices to meet an organization's business requirements. The systems analyst plays a vital role in the systems development process. A successful systems analyst must acquire four skills: analytical, technical, managerial, and interpersonal.
Basically a systems analyst performs the following tasks:
  • Interact with the customers to know their requirements
  • Interact with designers to convey the possible interface of the software
  • Interact/guide the coders/developers to keep track of system development
  • Perform system testing with sample/live data with the help of testers
  • Implement the new system
  • Prepare High quality Documentation

2. Programmer

A programmer is someone who writes computer software. The term computer programmer can refer to a specialist in one area of computer programming or to a generalist who writes code for many kinds of software. One who practices or professes a formal approach to programming may also be known as a programmer analyst.


System Development Concept (Part I)

The Importance Of Developing An Information System

1. Problems existence
There is a problems from the old system.

2. Organization Growth
Because the requirement is increasing, the system needed to develop.

3. For reach the opportunities
A chance to improve the organization.

4. Instructions existence (directives)
Instruction existence is instructions from the leader or from outside organization, for example regulation of government.

The Purpose Or Goal Of Developing An Information System

1. Solving the problems
2. Reach the opportunities
3. Complete the directives that given

The Organization’s Expectations After Implementing An Information System

1. Performance
In this case, performance is Measured to use and throughput of response time.

2. Information
Increase the quality of information.

3. Economy
Increase the profit and decrease the cost.

4. Control
The Purpose of control is detect and fix the mistakes or error.

5. Efficiency
The organization must to increase the efficiency of operational.

6. Services
Increase the services of system.

The Principles Of Developing An Information System

1. Developed system for the management.
2. Developed system is a big investment
3. The development of system needs educated people.
4. There is a step or process that must be done in system development.
5. System development process must not massage.
6. Don't be afraid to cancel a project.
7. Documentation is important for guidance in system development

System Development Life Cycle Models

1. Waterfall Models

waterfall models

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.

In waterfall model, the following phases are followed in order:
1. Requirements specification
The most important task in creating a software product is extracting the requirements or requirements analysis. Customers typically have an abstract idea of what they want as an end result, but not what software should do. Incomplete, ambiguous, or even contradictory requirements are recognized by skilled and experienced software engineers at this point. Frequently demonstrating live code may help reduce the risk that the requirements are incorrect.
Once the general requirements are gleaned from the client, an analysis of the scope of the development should be determined and clearly stated. This is often called a scope document. Certain functionality may be out of scope of the project as a function of cost or as a result of unclear requirements at the start of development. If the development is done externally, this document can be considered a legal document so that if there are ever disputes, any ambiguity of what was promised to the client can be clarified.

2. Design
This Phase is process which focusing at four attributes: data structure, system architecture, interface representation, and algorithm. This phase is translate requirement process into software representation.

3. Construction
4. Integration
5. Testing and debugging
6. Installation
7. Maintenance
This Phase is system maintenance process. System possibly will experience of change after submitted to customer.

1. Ideal for supporting less experienced project teams and project managers, or project teams whose composition fluctuates.
2. The orderly sequence of development steps and strict controls for ensuring the adequacy of documentation and design reviews helps ensure the quality, reliability, and maintainability of the developed software.
3. Progress of system development is measurable.
4. Conserves resources.

1. Inflexible, slow, costly and cumbersome due to significant structure and tight controls.
2. Project progresses forward, with only slight movement backward.
3. Little room for use of iteration, which can reduce manageability if used.
4. Depends upon early identification and specification of requirements, yet users may not be able to clearly define what they need early in the project.
5. Requirements inconsistencies, missing system components, and unexpected development needs are often discovered during design and coding.
6. Problems are often not discovered until system testing.
7. System performance cannot be tested until the system is almost fully coded, and under-capacity may be difficult to correct.
8. Difficult to respond to changes. Changes that occur later in the life cycle are more costly and are thus discouraged.
9. Produces excessive documentation and keeping it updated as the project progresses is time-consuming.
10. Written specifications are often difficult for users to read and thoroughly appreciate.
11. Promotes the gap between users and developers with clear division of responsibility.

2. Iterative Models

iterative models

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.

There is process or steps of Iterative Model :

1. Initial planning
2. Planning
3. Requirement
4. Analysis and design
5. Implementation
7. Testing
8. Evaluation

The Advantages :
1. Especially useful for resolving unclear objectives; developing and validating user requirements; experimenting with or comparing various design solutions or investigating both performance and the human computer interface.
2. Potential exists for exploiting knowledge gained in an early iteration as later iterations are developed.
3. Helps to easily identify confusing or difficult functions and missing functionality.
4. May generate spesifications for a production application.
5. Encourages innovation and flexible designs.
6. Provides quick implementation of an incomplete, but functional application

3. Spiral Models

spiral models

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
Advantages :
The spiral model promotes quality assurance through prototyping at each stage in systems development.