Systems models types of models - Systems environment and boundaries




Systems that are intended for use in real-world environments should be designed to function correctly in the widest possible range of circumstances and in the face of many possible difficulties and threats.
Types Of Model :

  1. Physical model : Physical models are the most explicit way in which to describe a system; they capture the hardware composition of a system in terms of the computers (and other devices, such as mobile phones) and their interconnecting networks.
  2. Architectural models : Architectural models describe a system in terms of the computational and communication tasks performed by its computational elements; the computational elements being individual computers or aggregates of them supported by appropriate network interconnections.
  3. Fundamental model : Fundamental models take an abstract perspective in order to examine individual aspects of a distributed system. In this chapter we introduce fundamental models that examine three important aspects of distributed systems: interaction models, which consider the structure and sequencing of the communication between the elements of the system; failure models, which consider the ways in which a system may fail to operate correctly and; security models, which consider how the system is protected against attempts to interfere with its correct operation or to steal its data. 

Boundary and Environment 

What happens “outside” the system will affect it. In general, what happens outside the system, in the system’s environment, is of vital importance. Firstly, the system can affect the environment, and secondly the environment can affect the system. One of the reasons for the failure of many technically brilliant engineering products is due to the lack of attention, by the designers, to the environment. This is not only the environment in terms of the operating conditions but the wider one that includes life cycle aspects, politics, fashion or just human beings.
A key aspect of Systems Thinking therefore is to identify and establish what is inside the system and what is outside in the environment. This requires us to define the system boundary, an interface which separates the system from its environment as shown and detailed below:

  • the boundary separates the system of interest from its environment.
  • the environment contains those elements and further systems that interact in some way
  • with the system of interest. Typically the environment of a system provides its inputs and
  • consumes its outputs.
  • any element or system that does not interact with the system of interest lies outside the
  • environment in the universe.

Deciding what is and what is not part of a system is not easy. Consider the situation given here - what is the system? The purpose of the system is to turn thoughts into marks on paper. The context is the office. Clearly, the pen is part of the system. However, to turn thoughts into marks on paper demands the human and the paper to be part of the system. But, what about the desk? Without the desk, the paper will not be supported at the correct height. Therefore, it is possible to argue the inclusion of the desk as part of the system. If we accept the desk, is it necessary to include the office floor? In which case what about the building, the street, the town - and so on. The choice of what is and what is not the chosen system of interest depends upon the observer and their reason for examining that system. For example if the reason for examining the “turn thoughts into marks on paper” system is to select a pen, then the pen would constitute the system of interest and the human and the paper would be in the environment of that system. If, however, my intent is to design a new pen the system would include the user and the paper and the desk etc., would be in the environment.

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Frequently Asked Questions

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Ans: Functional Information System is based on the various business functions such as Production,  Marketing, Finance and Personnel etc. These departments or functions are known as functional areas of business. Each functional area requires applications to perform all information processing related to the function view more..
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Ans: A system is an interrelated set of business procedures (or components) used within one business unit, working together for some purpose view more..
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Ans: What is manual system or what is automatic system : The main difference between manual and computerized systems is speed. Accounting software processes data and creates reports much faster than manual systems. Calculations are done automatically in software programs, minimizing errors and increasing efficiency. Once data is input, you can create reports literally by pressing a button in a computerized system. view more..
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Ans: Systems that are intended for use in real-world environments should be designed to function correctly in the widest possible range of circumstances and in the face of many possible difficulties and threats. Types Of Model : 1. physical model 2. Architectural models 3. Fundamental models view more..
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Ans: A real-time system is any information processing system which has to respond to externally generated input stimuli within a finite and specified period A distributed system is one in which the components of an information system are distributed to multiple locations in a computer network. view more..
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Ans: Basic principle of successful system : 1. System should be of use for the user. 2.Ready in time. 3. Visible benefits 3. Maintained effectively 4. Well documented view more..
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Ans: The primary role of a systems analyst is to study the problems and needs ofan organization in order to determine how people, methods, and information technology can best be combined to bring about improvements in the organization. A systems analyst helps system users and other business managers define their requirements for new or enhanced information services. view more..
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Ans: Systems Analyst Duties: Defines application problem by conferring with clients; evaluating procedures and processes. Develops solution by preparing and evaluating alternative workflow solutions. Controls solution by establishing specifications; coordinating production with programmers. Validates results by testing programs. view more..
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Ans: Change Agent: The analyst may be viewed as an agent of change. A candidate system is designed to introduce change and reorientation in how the user organization handles information or makes decisions. Then, it is important that the user accepts change. view more..
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Ans: Systems development methodology: A standard process followed in an organization to conduct all the steps necessary to analyze,design, implement, and maintaininformation systems. | Systems development life cycle (SDLC): The series of steps used to mark the phases of development for an information system. view more..
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Ans: Systems Planning and Selection : The first phase of the SDLC, in which an organization’s total information system needs are analyzed and arranged, and in which a potential information systems project is identified.Systems Analysis : Phase of the SDLC in which the current system is studied and alternative replacement systems are proposed. view more..
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Ans: System documentation: Detailed information about a system’s design specifications, its internal workings, and its functionality. Internal documentation: System documentation that is part of the program source code or is generated at compile time. view more..
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Ans: Management should not be lenient on part of documentation, management should never say like  “ as time running short , so just create the system and make the documentation later”. Phase should not be considered complete until documentation is done. Coding should not be considered done unless its has required comment lines. view more..
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Ans: There are various techniques to gather data and facts of system. some of them re as follows : Record view and Background reading Interviews  Questionnaires Group communication Presentation Site visiting Observation view more..
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Ans: Feasibility studies are almost always conducted where large sums are at stake. Also called feasibility analysis. A feasibility study is conducted in order to determine the success and minimize the risks related to the project. When it becomes certain that the specific project could be carried out profitably view more..
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Ans: It is a final report of the feasibility study about the findings and conclusion of the study. it should be possible to review report and take decision on the project based on it view more..
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Ans: System selection means selecting the various hardware, software, and services that are needed for implanting the system. Before the system selection can be done, it is necessary to know the capabilities of required proposed system view more..
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Ans: Costs fall into two categories. There are cost associated with developing the systems and there are costs associated with a operating a system. view more..




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