1.Overview of Computer System Unit Parts The Computer System Unit The system unit is the box-like case that contains the electronic components of a computer. Many people erroneously refer to this as the CPU. Here you will find devices like the power supply, different drives, the fan, the connectors, and the motherboard. Note that in most cases, the monitor, keyboard, and mouse will not be found inside the system unit layout. Other names for the system unit include the computer chassis, cabinet, box, tower, enclosure, housing, or simply case. The Motherboard The motherboard is sometimes called the system board or main board. It is the main circuit board of a microcomputer. This component contains the connectors for attaching additional boards. All other parts connect in one way or another to the motherboard. This part typically contains the CPU, BIOS, memory, mass storage interfaces, serial and parallel ports, expansion s...