The System Life Cycle

H’MM

Objectives• Define the terms system, analysis, and design• Describe the principal functions of the systems analyst• List and describe the phases of the systems development

life cycle• Describe the various data gathering and analysis tools• Describe a selection of systems design tools• Explain the concept of prototyping• Explain the role of the maintenance task in the systems

development life cycle

Contents• What is Systems Analysis and Design?• Systems Analyst• Systems Development Life Cycle• Various Methods of System Development• Preliminary Investigation• Analysis• Design• Development• Implementation

Systems Analysis and Design

What is it?• System

• organized set of related components established to accomplish certain task

• Natural• Planned and placed by people

• Computer system• A system that has computers as one of its components

System Analyst

• Professional computer employee who performs analysis and design

• Change agent • Overcome reluctance of users to change

• Typical career path• Programmer• Programmer / Analyst• Systems Analyst

FunctionsCoordination• Schedules and system-related tasks• Personnel

• Manager• Programmers• Users• Vendors of computer equipment• Mail room employees• Contractors

Communication• Oral presentations• Written documentation

Planning and design• Plans and designs new system• Involved from beginning of project through

final implementation of the system

Personal Qualities• Analytical mind• Good communication skills• Self-discipline• Self-direction• Organizational skills• Creativity• Ability to work without tangible results

• Who he may be or what he may be doing ?• Seek out information about business functions

through organizations procedure manuals and forms, etc.

• Find out how the existing system work, what the flow of information through the system look like.

• Know why the organization wants to change its current operations

• Determine how and where a computer information system can benefit all users of the system

• Actually does more than just solve current problems• May handle planned expansion of a business• Assess what future needs of the business may

be and the changes should be considered to meet these needs

• May recommend alternatives for improving the situation

• Perform a cost-benefit analysis over the alternatives to support management take a decision

• Develop a plan to implement the decision

• What may NOT be the prime objectives• Study a business to see which existing processes

should be handled by computer and which should be done by non-computerized methods• It is a secondary objective

• Determine what changes should be made in business• Change should be a result not an intent

• Determine how to best solve an information system problem• Technical ideas be given only if they improve

business system

• Roles they may adopt …• Information Analyst

• Performs System Analysis tasks only• System Designers or Application Developers

• Performs System Analysis and Design tasks• Programmer Analysts

• Performs System Analysis, Design and Programming tasks

• Whatever be the role, interaction with users is must!

• The System development life cycle (SDLC) is a process used by a systems analyst to develop an information system, training, and user (stakeholder) ownership.

• The SDLC aims to produce a high quality system that meets or exceeds customer expectations, reaches completion within time and cost estimates, works effectively and efficiently in the current and planned Information Technology infrastructure, and is inexpensive to maintain and cost-effective to enhance.

System Development Life Cycle (SDLC)

• "Systems Development Computer systems are complex and often (especially with the recent rise of service-oriented architecture) link multiple traditional systems potentially supplied by different software vendors.

• To manage this level of complexity, a number of SDLC models or methodologies have been created, such as "waterfall"; "spiral"; "Agile software development"; "rapid prototyping"; "incremental"; “V”; and "synchronize and stabilize"

History• The systems life cycle (SLC) is a methodology used to describe the

process for building information systems, intended to develop information systems in a very deliberate, structured and methodical way, reiterating each stage of the life cycle.

• The systems development life cycle, according to Elliott & Strachan & Radford (2004), "originated in the 1960s, to develop large scale functional business systems in an age of large scale business conglomerates. Information systems activities revolved around heavy data processing and number crunching routines".

• Several systems development frameworks have been partly based on SDLC, such as the structured systems analysis and design method (SSADM) produced for the UK government Office of Government Commerce in the 1980s. Ever since, according to Elliott (2004), "the traditional life cycle approaches to systems development have been increasingly replaced with alternative approaches and frameworks, which attempted to overcome some of the inherent deficiencies of the traditional SDLC".

The Waterfall Model

The Spiral Model

Agile Software Development

Rapid Prototyping Model

The “V” Model

Synchronize and Stabilize Model

The Incremental Model

The System Life Cycle

Analysis

Design

Development and Testing

Implementation

Documentation

Evaluation