Systems design

Systems design is the process or art of defining the architecture, components, modules, interfaces, and data for a system to satisfy specified requirements. One could see it as the application of systems theory to product development. There is some overlap with the disciplines of systems analysis, systems architecture and systems engineering.^[1][2]

Overview

If the broader topic of product development "blends the perspective of marketing, design, and manufacturing into a single approach to product development^[3], then design is the act of taking the marketing information and creating the design of the product to be manufactured. Systems design is therefore the process of defining and developing a systems to satisfy specified requirements of the user. Until the 1990s systems design had a crucial and respected role in the data processing industry. In the 1990s standardization of hardware and software resulted in the ability to build modular systems. The increasing importance of software running on generic platforms has enhanced the discipline of software engineering.

Object-oriented analysis and design methods are becoming the most widely used methods for computer system design^{[citation needed]}. The UML has become the standard language used in Object-oriented analysis and design^{[citation needed]}. It is widely used for modeling software systems and is increasingly used for high designing non-software systems and organizations^{[citation needed]}.

Logical design

The logical design of a system pertains to an abstract representation of the data flows, inputs and outputs of the system. This is often conducted via modelling, which involves a simplistic (and sometimes graphical) representation of an actual system. In the context of systems design, modelling can undertake the following forms, including:

• Data flow diagrams
• Entity Life Histories
• Entity Relationship Diagrams

Physical design

The physical design relates to the actual input and output processes of the system. This is laid down in terms of how data is inputted into a system, how it is verified/authenticated, how it is processed, and how it is displayed as output.

Physical design, in this context, does not refer to the tangible physical design of an information system. To use an analogy, a personal computer's physical design involves input via a keyboard, processing within the CPU, and output via a monitor, printer, etc. It would not concern the actual layout of the tangible hardware, which for a PC would be a monitor, CPU, motherboard, hard drive, modems, video/graphics cards, USB slots, etc.

Alternative design methodologies

Rapid Action Development (RAD)

Rapid Action Development (RAD) is a methodology in which a systems designer produces prototypes for an end-user. The end-user reviews the prototype, and offers feedback on its suitability. This process is repeated until the end-user is satisfied with the final system.

Joint Action Development (JAD)

JAD is a methodology which evolved from RAD, in which a systems designer consults with a group consisting of the following parties:

• Executive sponsor
• Systems Designer
• Managers of the system

JAD involves a number of stages, in which the group collectively develop an agreed pattern for the design and implementation of the system.

Systems design: Topics

• Requirements analysis - analyzes the needs of the end users or customers

• Benchmarking — is an effort to evaluate how current systems are used

• Systems architecture - creates a blueprint for the design with the necessary specifications for the hardware, software, people and data resources. In many cases, multiple architectures are evaluated before one is selected.

• Design — designers will produce one or more 'models' of what they see a system eventually looking like, with ideas from the analysis section either used or discarded. A document will be produced with a description of the system, but nothing is specific — they might say 'touchscreen' or 'GUI operating system', but not mention any specific brands;

• Computer programming and debugging in the software world, or detailed design in the consumer, enterprise or commercial world - specifies the final system components.

• System testing - evaluates the system's actual functionality in relation to expected or intended functionality, including all integration aspects.

See also

• Electronic design automation
• Electronic system level
• Embedded system
• Graphical system design
• Operating Systems Design and Implementation
• Structured Systems Analysis and Design Method
• Systems Development Life Cycle
• Systems thinking

References

1. ^  This article incorporates public domain material from the General Services Administration document "Federal Standard 1037C".
2. ^ Department of Defense Dictionary of Military and Associated Terms
3. ^ Ulrich & Eppinger (2000). Product Design & Development. Irwin McGraw-Hill. ISBN 0-07-229647-X. 

Further reading

• C. West Churchman The Design of Inquiring Systems: Basic Concepts of Systems and Organization. Basic Books, New York, 1971, SBN 465-01608-1
• Levin, Mark Sh., Composite Systems Decisions, Springer, New York, 2006
• Maier, Mark W., and Rechtin, Eberhardt, The Art of Systems Architecting, Second Edition, CRC Press, Boca Raton, 2000
• Saltzer, J.H, et al., End-to-End arguments in Systems Design in: ACM Transactions in Computer Systems Vol. 2, nr 4 (Nov 1984), pp 277–288.
• Ulrich, Karl T. and Eppinger, Steven D., Product Design and Development, Second Edition, Irwin McGraw-Hill, Boston, 2000

External links

Look up systems design in Wiktionary, the free dictionary.

• [1] Internet definitions.
• Interactive Systems Design by Chris Johnson, 1993.
• Department of Systems Design Engineering, Faculty of Engineering at the University of Waterloo, Ontario, Canada.
• System Design and Management, Systems Design and Management at the Massachusetts Institute of Technology, Cambridge, MA, USA.
• Course on System Design by Mark Sh. Levin