Six Phases of systems Analysis & Design by aroIg6MI

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									                Six Phases of systems Analysis & Design
Six phases of system development life cycle:
A “system” is defined as a collection of related components that interact to perform a task
in order to accomplish a goal. The point of system analysis & design is to ascertain how a
system works and then take steps to make it better.
A “system Analyst” is an information specialist who performs system analysis, design,
and implementation.
Six phases of System Analysis & Design: -
This is a six-phase problem solving procedure for examining an information system and
improving it. “ The SDLC, system development life cycle is defined as the step-by-step
process that many organizations follow during system analysis and design.
                           Preliminary investigation
                           System analysis
                           System design
                           System development
                           System implementation
                           System maintenance
First phase: conduct a preliminary investigation: -
The objective of phase 1, preliminary investigation, is to conduct a preliminary analysis
Purpose alternative solutions, describe costs and benefits and submit preliminary plan -
recommendations.
In this first phase again we have four steps those are: -
                           Conduct preliminary analysis
                           Propose alternative solutions.
                           Describe costs and benefits of each solutions
                           Submit preliminary plan with recommendations.
1.conduct preliminary analysis:
                 This includes stating the objective defining the nature and scope of the
problems.
Determine the preliminary:
         To define the objectives of the organization, you can do the following.
Read internal document about the organization:
         These can include original corporate characters, prospectors, annual reports, and
procedures manuals
Read external documents about the organization:
         These can include new articles, accounts in the business press, reports by
securities analyst, audits by independent accounting firms, and similar documents.
Interview important executives:
         With in the company with in the particular area you are concerned with, you can
also interview key users. Source of this may be done face


1. Determine the nature & scope of the problems:



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This may derive from the very fact that you have been asked to do a systems analysis and
design project.

2. Propose Alternative solutions: -
In this other possible solutions can come from interviewing people inside the
organization clients on customers affected by it, suppliers, and consultants. With this data
you have 3 choices.
                           Leave the system as is
                           Improve the system
                           Develop a new system
3. Describe Costs & Benefits: -
Which ever of the three alternatives is chosen, it will have costs and benefits. Costs may
depend on benefits, which may after savings. Input errors or redundant output may be
reduced. Systems and subsystem may be better integrated. Customers or suppliers may
interact better with the system. Security may be improved costs may be cut.
4. Submit a preliminary plan: -
    In this step you need to wrap up all your findings in a written report. The readers of
    this report will be the executives, who are a position to decide in which direction to
    proceed-wake changes, and how much to allow the project.
    If magnet approves the feasibility study, then the system analysis phrase can begin.
Second phase: Do Analysis of the system: -
System analysis is to gather data, analysis the data, and write a report. System analysis
describes what a system should do to satisfy the needs of the users.
Gather Data: -
In gathering data, there are a handful of tools that systems analysis use, most of them not
terribly technical. They include
Written documents: -
Written documents means reports, forms, manuals, memos, business plans, policy
statements, and soon. An organization want shows levels of management and formal lines
of authority.
Interviews: -
Interviews with managers, workers, clients, suppliers, and competitions will also give
you insights.
Structured interviews:-
Structured interviews means include only question you have planned and written out in
advance. By sticking e- this script and not asking other questions . Unstructured
interviews means you can vary from the line of questions and purpose other subjects if it
several production.
Questionnaires: -
Questionnaires are useful for getting information form large groups of people when you
cannot get around interviewing every one.
Observation: -
Observation through observation you can experience the conflicts and responsibilities of
the people you are working with




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Sampling: -
If your data gathering please involves a large number of events/people, if may simplify
things just to study a sample.
Analyze the data:-
Modeling tools enable a system analyst to present graphic, on pictorial, representations of
a system. Example of these is
Dataflow diagrams:-
A DFD graphically shows the flow of data through a system. A data dictionary defines all
the elements of data that make up the date flow.
System flowcharts:-
A system chart diagrams the major inputs, outputs, and process of a system.
Connectivity diagrams:-
Connectivity diagrams are used to map network connections of people, data, and
activities at various locations.

Grid charts:-Shows the relationship between data on input documents and data on
output documents.
Decision tables:- Shows the decision rules that apply when certain conditions occur and
what actions to take.
3.Write a reports:-
Once you have completed the analysis, you need to document this please. This report to
management should have three parts.
                          It should explain how the existing system works.
                          Second it should explain the problems with the existing
                             system.
                          Finally, it should describe the requirements for the new
                             systems & make recommitment on what to do next.
The third phase: Design the system
The objective of phase3, system design is to do a preliminary design and then a detail
design, and write a report.
Do a preliminary design: -
A preliminary design, often called a logical design, describes the general functional
capabilities of a proposed information system. It reviews the system requirements and
then considers major components of the system.
Same tools that may be used in the design are case tools and project management
software.
CASE TOOLS: - Case (for computer aided software engineering ) tools are programs
that automate various activities of the SDLC in several phases.
        Prototyping refers to using workstations, case tools and other s/w applications to
build working models of systems components so that they can be quickly tested and
evaluated thus, a prototype is a limited working system developed to test out design
concept.

PROJECT MANAGEMENT S/W:
        This s/w consists of programs used to plan, schedule, and control the people,
costs, and resources required to complete a project on time. This will often uses 2 charts


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->a crautt chart uses lines and bars to indicate the duration of a serious of tasks.
A pert (program evaluation review technique) chart slows not timing but also r’ slips
among the tasks of a project.
DO A DETAIL DESIGN:
        A detail design, also called a physical design, describes how a proposed
information system will deliver the general capabilities described in the preliminary
design. The detail design usually consider the following parts of the system in this order
     Out put requirement
     Input requirement
     Storage requirement
     Processing requirement
     System control and backup
WRITE A REPORT:
        All the work of the preliminary and detail design will end up in a large, detailed
report

FOURTH PHASE:
        DEVELOP THE SYSTEM:
               In phase 4, systems development, the systems analysis / others In the
organization, acquire the s/w, acquire the h/w, and then test the system.
AQUIRE THE SOFTWARE:
        In the make-on-by decision, you decide whether you have to create a program-
have if custom-written-or buy it, meaning simply purchasing an existing s/w package
-> Acquire h/w
->Test the system
        ->Unit testing also called modular testing
        ->System testing: parts are linked together & test it
FIFTH PHASE:
        IMPLEMENT THE SYSTEM:
        System implementation, consists of converts the hardware, software, and files to
the new system and training the users
CONVERT TO THE NEW SYSTEM:
        Conversion, the process of converting from an old information system to anew
one, individuals converting h/w, s/w, and files there are four strategies for handling
conversions
->Direct approach
->Parallel approach
->Phased approach
->Pilot approach

COMPILE FINAL DOCUMENTATION:
Developing good document at is an ongoing process during all phases of SDLC.
TRAIN THE USERS:
       Training is done with veracity of tools. Some times is done by the organizations
own staffers; at other times it is contracted out.




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THE SIXTH PHASE: MAINTAIN THE SYSTEM
        Systems maintenance, adjust and improves the system by having systems audits,
user feed back, and periodic evaluation and by making changes based on new conditions
two tools that are some times considered part of maintenance part phase are
->AUDITING:
        Means an independent review of an organization information system to see if all
records and systems are as they should be often a system analyst will an audit trial
EVALUTION:
Auditing, which is usually done by an accounting, is one evaluation
                These are sir phases of SDLC.




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