Let's start with the computer case. This is the metal enclosure that contains many of the other hardware components. It comes in various shapes and sizes, but a typical tower model is between 15-25 inches high. Want to know what's inside? Okay, go get a screwdriver and let's open it up. Seriously, if you are really into computers, the best way to learn is to actually get hands-on. To save us some time, however, have a look at this desktop computer case. A computer enthusiast replaced the metal side panel with a transparent one, so we can have a look inside.
Computer tower with translucent side panel
Although that photo looks pretty cool, it is a bit hard to recognize the individual components, especially
with all the connecting wires running through it. This figure shows a more schematic version of a desktop computer, which makes it easier to point out the essential hardware components.
The various components of a computer case
computer tower schematic
The computer case contains a power supply unit to convert general-purpose electricity to direct current for the other components. The most critical component is the motherboard a plastic board on which several essential components are mounted. This includes the central processing unit, or CPU, the main memory and expansions slots for other hardware components. The internal hard disk drive serves as the mass storage device for data files and software applications. An optical disk drive makes it possible to read from and write CDs and DVDs. Other hardware components typically found inside the computer case (but not shown in the figure) are a sound card, a video card, and a cooling mechanism, such as a fan.