Introduction to Systems


We build systems like the Wright brothers built airplanes-- build the whole thing, push it off a cliff, let it crash, and start over again.
R.M.Graham

If builders built buildings the same way that programmers wrote programs, the first woodpecker would destroy civilisation.
Gerald Weinberg

CONTENTS



INTRODUCTION


We shall study the characteristics of a system, its attributes and some basic concepts and strategies for studying them. Our philosophy is that an accounting information system is merely a kind of system, and therefore, a study of the basic principles of systems in general is important for a thorough understanding of accounting information systems in particular. Our approach to the study of accounting information systems, as will become clear, is an engineering one, where one proceeds through a methodical path of specification, design, construction, testing & evaluation, operation and maintenance.


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What is a system?

A system is a set of inter-dependent components (some of which may be systems in their own right) which collectively accomplish certain objectives.


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Different views of a system:

A Contextual view:

Any system operates by interacting with its environment. The contextual view describes graphically the interaction of the system with the various entities in its environment. The interactions consist of dataflows from and to such entities.The contextual view clarifies the boundary of the system and its interfaces with the environment in which it operates.



A Control view:

Any system must manipulate certain variables in order to achieve its objectives. It determines the manipulation needed by processing its outputs/states in relation to certain control parameters.




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Attributes of Complex Systems: (Booch, 1994)


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Some basic concepts & strategies in the study of systems.

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References


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Updated on August 17, 1998 by gangolly@cnsunix.albany.edu