Elements/Components of a System:
In most cases, systems analysts operate in a dynamic environment where change is a way of life. The environment may be a business firm, a business application, or a computer system.
To reconstruct a system, the following' key elements must be considered;
a. Inputs & Outputs
a. Inputs & Outputs:
A major objective of a system is to produce an output that has value to its user. Whatever the nature of the -output (goods, services, or information), it must be in line with the expectations of the intended user. Inputs are the elements (material, human resources, or data) that enter the system for processing. Output is the outcome of processing. A system feeds on input to produce output in the same way that a business brings in human, financial, and material resources to produce goods and services. Determining the output is the first step in specifying the nature, amount, and regularity of the input needed to operate a system. For example, in systems analysis, the first concern is to determine the user's requirements of a proposed computer system i.e. specification of the output that the computer is expected to provide.
The processing is the element of a system that involves the actual transformation of input into output. It is operational component of a system. Processing may modify the input totally or partially, depending on the specifications of the output. This means that as the output specifications change, so does the processing.
The control element guides the system. It is the decision making subsystem that controls the pattern of activities governing input processing and output. In an organizational context, management as a decision making body controls the inflow and outflow of activities that affect the welfare of the business. In computer system, the operating system and accompanying software influence the behavior of the system.
In system analysis, knowing the attitude of the individual who controls the area for which a computer is being considered can make a difference between the success and failure of the installation.
Management support is required for securing control and supporting the objective of the proposed change.
Open Loop Systems:
In these systems control is carried out by monitoring output and by receiving environmental input. Some control is therefore exercised from outside the system, by intervention administered externally.
Closed Loop Systems:
In these systems output is fed back to input and there is no input from the environment. The output thus initiates the control activity to alter the system's input or its activities.
Control in a dynamic system is achieved by feedback. Feedback measures output against a standard in some form of cybernetic (automatic, electronic, streamlined) procedures that includes communication and controls. Output information is fed back into the input and/or to management (controller) for consideration, calculation, or reflection. After the output is compared against performance standards, change can result in the input or processing and, consequently, the output.
Another form of feedback comes after the system is implemented. The user informs the analyst about the performance of the new installation. This feedback often results in enhancements to meet the user's requirements.
Types of Feedback:
Very generally, this result in successively greater deviations from the results actually sought. In fact, positive feedback results in some control activity which causes performance or output to continue deviating (or even increases the deviation) from what is required to happen. Positive feedback is necessary for organizational growth.
Negative feedback shows that the system is deviating from the intended path and that some change is therefore required to correct this situation. The control action to be taken generally reverses the trend.
The environment is the system within which an organization operates. It is the source of external elements that disturb the system. In fact, it often determines how a system must function. The environment is the collection of elements; these elements surround the system and often interact with it.
A system should be defined by its boundaries, the limits that identify its components, processes, and interrelationships when it interfaces with another system. Systems are normally delimited by boundaries, which separates them from its environment. Anything within the boundary is part of system; any thing outside is part of the environment. What is included in the system and what is included in the environment depend on the particular problem being studied.