Anything can be considered as a system. A human body, a home, a car, a train, an airplane, a production line, a piece of furniture, a phone, a coffee machine, transportation, education, healthcare, banking, telecommunications, supply chain, etc.
Every system can be broken down into a number of subsystems. A system can also be considered as a subsystem of another system. This also means that a subsystem can be considered as a system and can be broken down itself into subsystems or sub subsystems. Interesting, huh??
So, what does a system mean? There are many definitions of a system but I like to think about it as anything which can do something (or has a function) based on certain input (any system needs input) and produce a certain output. If we think of the human body as a system, it can do many things; live, work, travel, climb a mountain, etc. The human body needs air, food, and water to function so these are the input to the system. The outputs of the human body include mechanical movements, radiant heat, sounds, minute electrical signals generated from the heart, as well as excretions and secretions. The human body system can be broken down into several subsystems and each subsystem can be considered as a system like integumentary system, skeletal system, muscular system, lymphatic system, respiratory system, digestive system, nervous system, endocrine system, cardiovascular system, urinary system, and reproductive systems. The human body can also be considered a subsystem of the earth.
Using the same analogy which I used to think about the human body as a system, try to think the same way about anything else, e.g., your car, house, phone, bed, etc. Anything which does a certain function to satisfy a certain need can be considered as a system. The need(s) to a certain system serves as a requirement(s) which the system must meet to perform its main function or purpose of use. Therefore, the process of creating/making any system starts by gathering the user(s)’s requirements to design a system that meets the user(s)’s needs.
In relation to the theme of “what do engineers really do” which I started in my previous post, engineers design systems based on the user(s)’s requirements, implement the design of the system, test the implemented system, validate that the design and the implemented system meet the user(s)’s requirements, and resolve user(s)’s problems generated from the use of the system.