Systems Development Life Cycle Benefits (some)

• Improve quality of systems

• Reduce maintenance costs

• Increase user service

• Written by user

• information requirements defined

• users description of application

• New or modification of application

• State business need

• Reviewed by steering committee

• Benefits to be obtained

• Objective

• Detailed sufficiently

• Impact on user

• Budget

• Cost/benefits analysis

• Alternatives - ex: vendor software available

• Pay-back

• Compatibility with environment - software & hardware

• Additional MIS resources needed

• Analyze existing system

• Implementation schedule

• Approval/disapproval - user, MIS, steering committee

• Analyze existing system - inputs, processing, outputs

• Detail user requirements

• Specify what system is to accomplish

• Review alternatives

• vendor packages vs. built in-house

• main frame, LAN, microcomputer, etc.

• Approaches

• Top-down – general purpose to refined details

• Analyze co. goals & objectives, policies, procedures

• Determine decisions to be made & information needed by management

• Evaluate management information needs vs. efficient processing

• Structured/Modular

• Define each module/subsystem

• Minimizes interdependence

• Hierarchy-input-process-output (HIPO)

• Stylized charts depict detailed levels of systems

• Documentation technique by IBM

• Systems design & programming standards

• Program specifications

• Workflows & programming (no coding)

• File layouts

• Reports, screen layouts

• System flowcharting standards

• System narrative

• Database – modify or design

• Data conversion procedures

• Controls

• Transaction trails

• Uniform processing of transactions; like transactions processed same way

• Initiation/subsequent execution of transactions

• Automatically performed

• Management approved

• Hardware

• Security

• Data communications

• Test plans

• Quality assurance

• Data element definitions - each field in each file listed & defined, etc.

• Procedure manuals – technical, forms, etc.

• Code programs from specifications determined in systems design phase

• Computer system changes

• Strict control

• Use working copy when redesigning program

• Structured programming

• Divide programs into modules by functions

• Code programs separately

• Facilitates security

• Speeds development

• Facilitates maintenance

• Computer aided systems engineering (CASE)

• Maintain all system documentation on computer

• Automate some of coding process

• Test each program

• Use incomplete/incorrect data

• Test all branches of program

• Test edit capabilities

• Compare with expected results

• User tests & accepts changes and test results

• System test - test series of programs in sequence

• Convert data files - from old to new system

• Control conversion - record counts, hash totals, reconciliation's, etc.

• Review & sign-off

• Run parallel old & new system - if possible

• Convert by module

• Train and educate users

• Change controls

• Modifications/changes

• authorized

• compare code for unauthorized program changes

• per standards

• tested

• approved by user & MIS management

• Follow-up

• Develop and put into operation refined versions of systems

• Design later when necessary information available