Types of Software Systems : Diagnostic Software Systems, Sensor and Signal Processing Systems, Simulation Systems

The type of software system refers to the processing that will be performed by that system.
Diagnostic Software Systems:
These systems helps in diagnosing the computer hardware components. When a new device is plugged into your computer, a diagnostic software system does some work. The "New Hardware Found" dialog can be seen as a result of this system.

Sensor and Signal Processing Systems:
The message processing system helps in sending and receiving messages. These systems are more complex because they make use of mathematics for signal processing. In a signal processing system, the computer receives input in the form of signals and then transforms the signals to a user understandable output.

Simulation Systems:
Simulation is the process of designing a model of a real system and conducting experiments with this model for the purpose of understanding the behavior of the system or evaluating various strategies for the operation of the system. A simulation is a software package that re-creates or simulates, albeit in a simplified manner, a complex phenomenon, environment, experience providing the user an opportunity for some new level of understanding.
Simulation systems are easier, cheaper and safer to use as compared to real systems and often the only way to build the real systems. For example, learning to fly a fighter plane using a simulator is much safer and less expensive than learning on a real fighter plane. System simulation mimics the operation of a real system such as the operation in a bank or the running of an assembly line in a factory.
Simulation in the early stage of design cycle is important because the cost of mistakes increases dramatically later in the product life cycle. Also, simulation software can analyze the operation of a real system without the improvement of an expert i.e. it can also be analyzed with a non-expert like a manager.