The system unit is a case that contains electronic
components of the computer used to process
data. System units are available in a variety
of shapes and sizes. The case of the system unit,
sometimes called the chassis, is made of metal or
plastic and protects the internal electronic
components from damage. All computers and
mobile devices have a system unit (Figure 4-1).
On desktop personal computers, the electronic
components and most storage devices are part
of the system unit. Other devices, such as the
keyboard, mouse, microphone, monitor, printer,
USB flash drive