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Introduction to System Analysis Design

  • What is System?
    System is known as collection of components of a plan.
    System can be any software, any application or any computer related program.
  • What is Analysis?
    Analysis is known as research or detail examination on any particular topic by the information or data about that topic given to us.

  • What is Designing?
    Designing is the process of creating construction of system.
    It is reference for coding.

  • Properties of System:
    Organization:
    It implies structure and order. It is arrangement of components that help to achieve objective.
    Like as, a computer system is designed around an input device, a central processing unit, an output device and one or more storage units. When linked together they work as a whole system.

    Interaction:
    It refers the manner in which each components functions with other components of system.
    For example, purchasing must interact with production, in computer system CPU must interact with the input device to solve the problem.

    Interdependence:
    It means the components or parts which depends on one another.
    For example, in any system the programming, its operations and output depends upon the input.

    Integration:
    It is how the different parts of the system works together even though each part performs a different task.

    Central Objective:
    It is main purpose or goal of an software ,application or system. So, user must know the central objective of any system for successful designing.
    For example, there is an application for game whose central objective is develop general knowledge of user by fun and entertainment. If programmer or analyst knows this central objective  then he can have successful designing and work of application.

  • Elements of a System:


    1. Outputs and Inputs
    Major objective of system is output which has value to its user.
    Input is feed by system to produce the output.
    It is important to determine the output to specify input of required nature and amount.
    For example, if we want to design an application which is to produce certificate of particular design we should know or we should have an idea that which type of design user wants and what  information should be written in certificate. After having this type of idea of output we can provide requried information and design in form of input.

    2. Processor
    It does the actual transformation of input to output in system.
    It modify input totally or partially according to specification of output.
    Input also modify to enable processor to handle transformation.

    3. Control
    The control element guides the system.
    The control on the system can be from user side and also can be from admin side.
    For example, in any application if we want to enter a password so it must contain the specified elements. This control for creating a password is done by admin for users security. And in applications like whatsapp, facebook or instagram after the login process we can make our account settings by our self  and can control our account. it is user side control.

    4. Feedback
    Feedback comes after the system is implemented.
    It can be positive or negative. Negative feedback provides informs to do changes in system.Positive feedback informs to make system more efficient to work.
    By feedback controller analyst can know users requirement.

    5. Environment
    It shows how the system should be functioned by the use of system in environment.
    For example, developer will develop the organize all the functions and operations which will 
    be convenient to environment.

    6. Boundaries and Interface
    A system should have its boundaries that identify its components, processes and interrelationship when it interfaces with another system.

  • Types of Systems 

    1. Physical or Abstract System
    • Physical system
    Physical system can be counted and seen. They can be static or dynamic.
    For example, physical parts of system can be considered as static system and programs, data, application which can be change according to user's demands can be considered as dynamic system.

    • Abstract system
    These systems are imaginary entities and non-physical. They exists in thoughts they don't have any physical existence.
    For example, models makes easier to understand the system or relationship between its components. So, its basic objective is to point the key interrelationships or basic element of complex system.

    2. Open or Close System
    • Open system
    It regularly exchanges feedback with external environment.
    For example, information is regularly shared with external environment.

    • Close system
    A closed system does not interact with its environment. It is isolated from environmental influences. A completely closed system is rare in reality.

        • Characteristics of Open system
        1. Input from outside
     
      Open system accepts input from external sources and produces output. They are self adjusting and self regulating. When it functions properly it reaches a steady state.

        2. Entropy
        Entropy means loss. All dynamic systems tend to run down over time and it results in entropy. To resist it system seeks new inputs or modify the processes to return to steady state. If merchandise increase the cost of product without any modification in quantity or quality it will make business unprofitable-a state of disorganization.

        3. Process, Output and Cycles
       
    This system produces useful output and the system or process operates in cycles and the system produces output by following a continuous flow path called process.

        4. Differentiation
       
    Open system have tendency to increasing specialization of function and a greater differentiation of their components. This characteristics offer a compelling reason for increasing value of the concept of system in the system analyst's thinking.

        5. Equifinality 
       
    It means that how the same results or output can be achieved by using different processes.
    For example, in C programming if we want to reverse a string we can do it by its shortcut function or by writing the full program. We will get same results by these both programs.

    3. Adaptive and Non-Adaptive System
    • Adaptive system
    It responds to the change in the environment in a way to improve their performance and to survive.
    For example, human beings, animals.

    • Non-Adaptive system
    It does not respond to the environment.
    For example, machines.

    4. Permanent and Temporary System
    • Permanent system
    They are for long time.
    For example, business policies

    • Temporary system
    They are made for specified time and after that they are demolished.
    For example, if there is any online quiz which is organized for particular time then the quiz will be terminated after that particular time.

    5. Natural and Manufactured System
    • Natural system
    They are designed by the nature.
    For example, Solar system

    • Manufactured system
    These systems are manufactured by men.
    For example, Rockets, dams, trains.

    6. Deterministic of Probabilistic System
    • Deterministic system
    These systems' operations are imaginary or operates in a predictable manner and the interaction between system components is known with certainty.
    For example, two molecules of hydrogen and one molecule of oxygen makes water.
     

    • Probabilistic system
    It shows uncertain behavior. The exact output is not known.
    For example, weather forecasting, mail delivery.

    7. Social, Human-Machine, Machine System
    • Social system
    These systems are made up of people.
    For example, social clubs, societies.

    • Human-Machine system
    Human and machines both are involved to perform a particular task.
    For example, computer programming.

    • Machine system
    All the tasks are performed only by machines.
    For example, robots

    8. Man-Made Information System
    Information reduces uncertainly about state or event. Information system is basis for interaction between user and analyst. It can defined as a set of devices, procedures and operating system designed around user based criteria to provide information and communicate it to the user for planning, control and performance. Man-made information system is an interconnected set of information resources to manage data for particular organization under Direct Management Center (DMC). It includes hardware, software, communication, data, and application for producing information according to the need of an organization.

  • Types of Man-Made Information System

    1. Formal Information Systems
    Information is based on organization represented by organization chart or by instructions, memos etc. Charts is a map of positions and their authority relationships indicated by boxes and connected by straight lines.
     
    2. Informal Information System
    It is employee based system which solves the day to day work related problems.

    3. Computer Based System
    This system is depends on the computer for handling business applications. System analysis relies heavily on computer for problem solving. So, analyst must be familiar with computer technology and have experience in handling people in an organizational context. 
    For example, railway reservation system, banking system.

  • Categories of Information

    1. Strategic Information
    It relates to long range planning policies for next few years and required by top most management. This type of information is achieved with the aid of Decision Support System (DSS).
    For example, trends in income (revenues), financial investment, and human resources, and population growth.

    2. Managerial Information
    This type of Information is required by middle management for short and intermediate range planning which is in terms of months. It is achieved with the aid of Management Information Systems (MIS).
    For example, sales analysis, cash flow projection.

    3. Operational Information
    It is required by low management for daily and short term planning to enforce day to day rules, regulations and operational activities. It is achieved with the aid of Data Processing Systems (DPS).
    For example, keeping employee attendance records and current stocks available.
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