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DETERMINISTIC and PROBABILISTIC SYSTEM

A deterministic system is one in which the occurrence of all events is known with certainty. In

such a system, given a description of the system state at a particular point of time and its

operation, the next state can be perfectly predicted.

Example: A correct computer program which performs exactly according to set of instructions.

Probabilistic System is one in which the occurrence of events can’t be perfectly predicted

though the behavior of such a system can be described in terms of probability. A certain

degree of error is always attached to the prediction of the behavior of the system.

Example: set of instructions given to a person who may not follow the instructions exactly as

given.

OPEN and CLOSED SYSTEM

An open system is that interacts with its environment and thus exchanges information from a

material or energy with the environment. Open system are adaptive in nature as they tend to

react with the environment in such a way so as to favor there continued existence such

systems are self-organizing in the sense that they change their organization in response to

changing conditions.

A closed system is one which does not interact with its environment. Such systems in business

world are rare but relatively closed systems are common. Thus, the systems that are relativelyisolated from the environment but not completely closed are termed as closed system.

Example: A computer program is relatively closed system because it accepts and processes

previously defined inputs and provides output too in a previously defined way.

USER MACHINE SYSTEM

In User Machine System both i.e. human as well as machine performs some activities in the

accomplishment of as goal. The machine elements may be computer hardware and software isrelatively closed and deterministic whereas the human elements of the system are open and

probabilistic.

SDLC – SYSTEM DEVELOPMENT LIFE CYCLE

The systems development life cycle (SDLC) is a conceptual model used in project management

that describes the stages involved in an information system development project, from an

initial feasibility study through maintenance of the completed application.Systems

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4.  Design

The logical system design arrived at as a result of system analysis and is converted into

physical system design. In the design phase the SDLC process continues to move from

what questions of the analysis phase to the how. The logical design produced during the

analysis is turned into a physical design - a detailed description of what is needed to

solve original problem. Input, output, databases, forms, codification schemes and

processing specifications are drawn up in detail. In the design stage, the programming

language and the hardware and software platform in which the new system will run are

also decided. Data structure, control process, equipment source, workload and

limitation of the system, Interface, documentation, training, procedures of using the

system, taking backups and staffing requirement are decided at this stage.

  General Design (framework) :- How will the problem will be solved

  Detailed Design

o 

Inputo  Output

o  Files

o  Procedure

  What is the flow of system

  Coding: The system design needs to be implemented to make it a workable

system. This demands the coding of design into computer language, i.e.,

programming language. This is also called the programming phase in which the

programmer converts the program specifications into computer instructions,

which we refer to as programs. It is an important stage where the defined

procedures are transformed into control specifications by the help of a computer

language.

  Testing (working properly or not): After codifying the whole programs of the

system, a test plan should be developed and run on a given set of test data. The

output of the test run should match the expected results.

o  User Testing

o 

User Acceptance Testing

o  Combined Module Testing

5.  Implementation

After having the user acceptance of the new system developed, the implementation

phase begins. Implementation is the stage of a project during which theory is turned

into practice. The major steps involved in this phase are: