第第 1111 組組

MISMIS報告報告

Phases of any information systemPhases of any information system

~ ~ recognition of a business problem or recognition of a business problem or opportunityopportunity

~ refinement of idea into a specific ~ refinement of idea into a specific statement of what the work system should statement of what the work system should accomplishaccomplish

~ analyst or designers decide how to create ~ analyst or designers decide how to create computer programs- the technical staff computer programs- the technical staff either writes or buys themeither writes or buys them

4 4 Phases:Phases:1. Initiation :1. Initiation :

~ ~ the process of defining the need to change the process of defining the need to change an existing work systeman existing work system

~ identifying the people who should be ~ identifying the people who should be involved in deciding what to doinvolved in deciding what to do

~ describing how the work system should ~ describing how the work system should operate differentlyoperate differently

~ and how any information system supports ~ and how any information system supports itit

This phase may occur in response to :

~ recognized problems, high error rates in data,

Planning process :

It is part of a planning process in which the organization is searching for ways to improve and innovate , even if current systems pose no problems

A key outcome :

Is an understanding of a proposed information system's purpose and goals.

2. 2. Development :Development :

~ ~ the process of building or acquiring and the process of building or acquiring and configuring hardware , software, and other configuring hardware , software, and other resources needed to perform both the resources needed to perform both the required IT- related functions and the required IT- related functions and the required functions not related to IT.required functions not related to IT.

~ how it starts :

by deciding exactly how the computerized and manual parts of the work system will operate- then- it goes to acquire the needed resources.

~ what it includes :

creating documentation explaining how both the work system and the information system are suppose to operate .

~ thorough testing :

it concludes with the thorough testing of the entire information system to identify and correct misunderstandings and programming errors .

~ It does not mean " the system works " :

it only means that the computerized parts of the work system operate on a computer .

~ key goal :

is to assure that work system and IS features really solve problems the users want solved .

3 . 3 . Implementation :Implementation :

~ ~ is the process of making a new or is the process of making a new or improved work system operational in the improved work system operational in the organizationorganization

~ how it starts :

when the software runs on the computer and has been tested

~ activities included :

it includes planning , user training ,conversion to the new IS and work system .and follow -up to make sure the entire system is operating effectively.

~ the implementation phase may involve a major change in the way organizations or individuals operate.

4 . 4 . Operation and Maintenance ;Operation and Maintenance ;

~ ~ is the ongoing operation of the work is the ongoing operation of the work system and the information system, plus system and the information system, plus efforts directed at enhancing either system efforts directed at enhancing either system and correcting bugs.and correcting bugs.

~ it requires at minimum ;

it requires that someone be in charge of ensuring that the work system is operating well. That the IS is providing the anticipated benefits

Overview of alternative approaches for building information systems :

Traditional system life cycle:

Uses a prescribed sequence of steps and deliverables to move reliably from user requirements to an IS in operation .

The traditional system life cycle establishes tight controls to guarantee that technical and organizational issues are addressed at each step .

Capability maturity model(CMM) :

Tracks the extent to which an IT organization uses this type of life cycle in its development work.

Prototype :

Information system is a working model of an information system built to learn about its true requirements .

Application Package :

Consist of commercially available software that addresses a specific type of business application .

End- user development :

~ Is the development of IS by work system participants rather than IS professionals.

~ Firms apply end-user development to solve a responsiveness problem involving the inability of IS departments to keep up with individuals' changing information needs.

Traditional System Life Cycle : ~goal :

is to keep the project under control and assure that the IS produced satisfies the requirements.

~ traditional system life cycle divides the project into a series of steps , each of which has distinct deliverables , such as documents or computer programs.

~ many versions of the traditional system life cycle emphasize the building of software and demphasize what happens in the organization before and after software development.

~ initiation :

~ the initiation phase may begin in many different ways.

~ its goal is to analyzed the scope and feasibility of a proposed system and to develop a project plan.

This involve 2 steps :

feasibility study :is a user oriented overview of the proposed IS' purpose and feasibility . A system's feasibility is considered from economic, technical, and organizational view points.

project plan : breaks the project into sub projects with start and

completion times. It also identifies staffing ,resource requirements , and dependencies between project steps.

~ ~ development :development :

~ ~ it creates computer programs plus it creates computer programs plus installed hardware that accomplish the data installed hardware that accomplish the data processing described in the functional processing described in the functional specification.specification.

1. 1. first step – detailed requirements analysis first step – detailed requirements analysis ;which produces a user – oriented ;which produces a user – oriented description of exactly what the IS will do.description of exactly what the IS will do.

~ it produced a document called the ~ it produced a document called the external specification.—the external external specification.—the external specification shows thee data input screens specification shows thee data input screens and major and major

reports and explains the calculations that reports and explains the calculations that will be automated.will be automated.

2. 2. next step is internal system design : in next step is internal system design : in which the technical staff decides how the which the technical staff decides how the data processing will be configured on the data processing will be configured on the computer.computer.

~ it produce internal specification : a ~ it produce internal specification : a technical blueprint for the IStechnical blueprint for the IS

3. 3. An essential step is hardware acquisition and An essential step is hardware acquisition and installation.installation.

~ programming is the creation of the computer ~ programming is the creation of the computer code that performs the calculation , collects the code that performs the calculation , collects the data , and generates the reports.data , and generates the reports.

~ the testing done during the programming step is ~ the testing done during the programming step is called unit testingcalled unit testing

~ documentation is another activity that can ~ documentation is another activity that can proceed in parallel with programming and proceed in parallel with programming and hardware acquisition.hardware acquisition.

~ ~ system testing : after the individual system testing : after the individual programs have been tested , the entire IS programs have been tested , the entire IS must be tested to ensure that programs must be tested to ensure that programs operate together to accomplish the desired operate together to accomplish the desired functions.functions.

~ testing plan : is a precise statement of ~ testing plan : is a precise statement of how the IS will be tested.how the IS will be tested.

~ ~ implementation :implementation :

~ ~ is the process of putting a system into is the process of putting a system into operation in an organizationoperation in an organization

~ it begins : with implementation planning ~ it begins : with implementation planning – the process of creating plans for – the process of creating plans for training ,conversion , and acceptance testingtraining ,conversion , and acceptance testing

~ training : is the process of ensuring that ~ training : is the process of ensuring that system participants know what system participants know what they need they need to know about the work system and the IS.to know about the work system and the IS.

~ ~ conversion—following the training comes the conversion—following the training comes the carefully planned process of conversion from the carefully planned process of conversion from the old business processes to new ones using the new old business processes to new ones using the new IS.IS.

~ to minimized risk and wasted effort ,most ~ to minimized risk and wasted effort ,most conversion s accur in stages , which can be done conversion s accur in stages , which can be done in several waysin several ways

~ a phased approach- uses the new IS and work ~ a phased approach- uses the new IS and work system for a limited subset of the processing system for a limited subset of the processing while continuing to use old methods for the rest of while continuing to use old methods for the rest of the the processing .processing .

~ the simultaneous use of old system and ~ the simultaneous use of old system and the new system is called running in parallel.the new system is called running in parallel.

~ acceptance testing: is testing of the IS by ~ acceptance testing: is testing of the IS by the users as it goes into operationthe users as it goes into operation

~ post-implementation audit is the last step ~ post-implementation audit is the last step in the implementation phase. Its purpose is in the implementation phase. Its purpose is to determine whether the project has met its to determine whether the project has met its objectivesobjectives

~ ~ Operation and Maintenance :Operation and Maintenance :

~ ~ it starts after users have accepted the new system.it starts after users have accepted the new system. ~ ongoing operation and support is the process of ~ ongoing operation and support is the process of

ensuring that the technical system components ensuring that the technical system components continue to operate correctly and that the users use continue to operate correctly and that the users use it effectivelyit effectively

~ operations manual specifies when these jobs ~ operations manual specifies when these jobs should be done .should be done .

~ maintenance is the process of modifying the IS ~ maintenance is the process of modifying the IS over timeover time