CO5021 Systems Development Week 1 Introduction to System Development: Reducing the Risk of IT Development Failure

Some Formal Course Objectives To provide you with new ways of looking at information in the world in order to solve business problems; To introduce you to concepts and methods of System Analysis and design (SAD); To describe the systems development life cycle (SDLC); To teach you effective methods for gathering essential information during system analysis; To teach you effective methods for designing systems to solve problems effectively.

But Why Bother? ‘Software engineers’ (and other types of IT specialists) aren’t always popular with ‘real’ engineers e.g. civil, mechanical and electrical engineers They sometimes maintain that we aren’t as ‘professional’ as they are IT qualification schemes and professional bodies not as rigorous (yet) IT projects have a bad reputation for coming in behind schedule, over budget and off quality Other groups of engineers have had plenty of time and opportunity to learn from earlier mistakes, e.g. Tay Bridge Disaster (1879) Tacoma Narrows Bridge failure (1940) As a young profession, IT has some catching up to do…. Lives can depend on IT too… Formal analysis, design and testing methods are essential professional skills in IT

Characteristics of Systems Systems are made up of interrelated subsystems (e.g. a nuclear reactor is composed of boilers, reactor components etc.). Functional decomposition – dividing a system into components based on subsystems (which are in turn further divided into subsystems). System boundary – the separation between a system and its environment (which inputs and outputs cross). Automation boundary – separation between the automated part of system and the manual part.

“Systems” Thinking To identify something as a system, and describe it properly, we must first be able to identify:- characteristics and functions inputs and outputs to systems where the boundaries are (or should be) subsystems relationships among subsystems.

What is System Development? Systems Development: Activities that go into producing an information system to solve an organisational problem (or make the most of an opportunity) Systems analysis Systems design Programming Testing Conversion Production and maintenance.

System Development Analysis – understand information needs understanding and specifying in detail what an information system should do Design – define the system architecture (based on needs) specifying in detail how the parts of an information system should be implemented Implementation – the actual construction of the system

System Analysis Establishing information requirements Who needs what information, where, when, and how? Define objectives of new/modified system Detail the functions new system must perform Faulty requirements analysis is a leading cause of systems failure, and causes high systems development costs.

System Design Describe system specifications that will deliver functions identified during systems analysis Cover all managerial, organisational, and technological components of system solution.

Systems Design: Role of End-Users User information requirements drive system building; Users must have sufficient control over design process to ensure that system reflects their business priorities and information needs; Insufficient user involvement in design effort is major cause of system failure;