CHAPTER -1
SAD
SYSTEM ANALYSIS AND DESIGN
Introduction :- Hi everyone in this Chapter learn in details, what is sad and why is important and where is use. Lets go start now.
What is SAD?
System Analysis and Design (SAD) is an exciting active field in which analysts continually learn new techniques and approaches to develop system more effectively and efficiently.
Before explain SAD, we can learn what is system full details,
:- Systems is a group of elements or components which work together to accomplish a common task.
In another word :- Systems is based on Input – Process – Output manual work can be replaced by computerized systems for accuracy and speed of processing. So before the developers should also understand all basic concepts about the systems.
WHAT IS SAD?
In simple words, systems analysis and design is a study in which we learn how to analyze an existing system and create a better component.
WHY WE NEED IT?
- For systems Developments
- a) Creating a new one.
- b) Updating the existing one (Differences-Differences updating the systems)
TYPES OF SAD:
There are two types of SAD.
1. Systems Analysis:- It is it a process of studying and observing a system to know how it works and to identify its goal and aim. System analysis is conducted for the purpose of studying a system or its parts in order to identify its objectives. It specifies “what the system should do “.
S Systems Design:- It is a process of planning a new system or replacing an existing system. It is done by defining its components or modules to satisfy the specific requirements. It focuses on “ how to accomplish the objectives of the system''.
PROPERTIES / CHARACTERISTIES OF A SYSTEM :
Many characteristics following :-
(a.) Organization :- It implies structure and order. Elements should be well arranged in order to achieve predetermined objective.
(b.) Integration :- It implies how to components of a system are tied together .The parts of the system must work together within the system even though each part perform a unique function .
(c.) Interaction :- It implies manner in which the components operate with each other .
(d.) Interdependence :- It implies how components of a system depend on one to another. The components must be will linked and they must coordinates with each other for proper functioning . Interdependence is important because the output of one subsystem may be required by other subsystem as .
(e.) Central objective :- The objective of the system must be central .It means ,the user must know the main objective of the system in the early phase for successfully design and conversion .
ELEMENTS OF A SYSTEM
(a.) Inputs and outputs :- The information that enters in a system is treated as input .Output is the outcome of input after processing . The main aim of a system is to produce an output which is useful for its users .
(b.) Processor:- It transforms the input into useful output . It is an operational element. It may modify the input either totally or partially depending on the output specification.
(c.) Control:- This elements guides the system . It is a decision making element that controls the pattern of activities governing input, processing and output.
(d.) Feedback:- The output is checked with the desired output set and then necessary steps are taken for achieving the output as per the standards. Positive feedback encourages the performance of the system. Negative feedback is information in nature.
(e.) Boundaries and Interfaces :- The boundaries are the limits under which the components of a system interact with each other . Each system has boundaries that determine its sphere of influence and control .The interconnection and the interaction between the Sub- system is known as the interface .
(f.) Environment :- The things outside the boundary of the system are known as environment .It is source of external and change according to the work .
(a.) Physical System :- Physical systems are tangible entities. It may be static or dynamic in nature. The physical parts of the computer center are desks, and chairs that facilitate operation of the computer are static. A computer is a dynamic system in which programs, data and applications can change according to the users needs.
(b.) Abstract system :- These are non-physical entities or conceptual that may be formulas , representation or model of a real system .
(c.) Open :- An open system must interact with its environment . Its receivers inputs and delivers outputs to the outsides of the system . It must adapt to the changing demands of the users.
(d.) Closed :- A closed system is isolated from environment influences . a completely closed system is rare .
(e.) Adaptive :- Adaptive system responds to the change in the environment in a way to improve their performance and to survive .
Ex :- Human beings animals.
(F.) Non-Adaptive :-Non -Adaptive system is the system which does not respond to the environment.
Ex :- Machines, Software.
(g.) Temporary System :- It is made for specified time and after that they are demolished
Ex :- A Dj (Marriage Box )
System is set up for a program and it is dissemble after the program .
(h.) Permanent :- Permanent system persists for a long time .
Ex :- A business policies or rule of business.
(i.) Natural :- Natural system are created by the nature
Ex :- Solar System.
(j.) Manufactured :- Manufactured System is the created by the man – made system.
Ex :- Rockets, Dams, Trains, Computer, Airplane….etc.
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