Title sad some importance notes BCA Notes Nepal.pdf ✅

1 System Analysis and Design (SAD) UNIT I What is a system? System is an interrelated set of components, with identifiable boundary, working together for some purpose. Examples • Solar system • Digestive systems • Public transport system • Central heating system • Computer system • Information system A set of objects and relationships among the objects viewed as a whole and designed to achieve a purpose A system has nine characteristics: • Components or Subsystems • Interrelated components • A boundary • A purpose • An environment • Interfaces • Input • Output • Constraints Component: An irreducible part or aggregation of parts that make up a system, also called a subsystem. A subsystem is simply a system within a system. Automobile is a system composed of subsystems: • Engine system • Body system • Frame system • Each of these subsystem is composed of sub-sub --systems. • Engine system: carburetor system, generator system, fuel system, and so son Interrelated components • Dependence of one subsystem on one or more subsystems 1
2 Boundary • The line that marks the inside and outside of a system and that sets off the system form its environment • The overall goal or function of a system Environment • Everything external to a system that interacts with the system Interface • Point of contact where a system meets its environment or where subsystems meet each other. • A limit to what a system can accomplish Input • Whatever a system takes from its environment in order to fulfill its purpose Output • Whatever a system returns from its environment in order to fulfill its purpose Fig: A Fast food Restaurants as a system Environments: customers, food, distribution, banks, etc Bad System • Fail to meet requirements • Poor performance • Poor reliability
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