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.
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 computer case contains a power supply unit (#6) to convert general-purpose electricity to direct current for the other components. The most critical component is the motherboard (#2), a plastic board on which several essential components are mounted. This includes the central processing unit, or CPU, (#3), the main memory (#4), and expansions slots (#5) for other hardware components. The internal hard disk drive (#8) serves as the mass storage device for data files and software applications. An optical disk drive (#7) makes it possible to read from and write to 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.