The 19" form factor for rack servers represents a pervasive set of dimensions. There is hardly a component that does not accommodate this server form factor, including switches, and routers, patch panels, USVs, KVMs and, finally, complete computers.
The main advantage of a 19" case is how it can save space by accommodating components that can be stacked on top of it. To do this, a corresponding 19" rack is required. This is classified by the maximum number of height units (U = unit), while 42 is the upper limit. For small offices or in the basement workshop, models with about 12 U-18 U will be plenty, while we would recommend large racks in commercial use.
The most technically ambitious are computers in only one height unit (1U), because all components, including sufficient cooling devices, hard drives and an optical drive need to fit into a total height of only 4.4 cm. Moreover, they offer by far the greatest flexibility, because if necessary, you can put it anywhere; moving to another location is not a problem thanks to the 19" technology.
Using an MSI 1U system, we offer an overview of what a typical setup involves.