What is a PC?

Here is one way to think about it: A PC is a general-purpose information processing device. It can take information from a person (through the keyboard and mouse), from a device (like a floppy disk or CD) or from the network (through a modem or a network card) and process it. Once processed, the information is shown to the user (on the monitor), stored on a device (like a hard disk) or sent somewhere else on the network (back through the modem or network card).

We have lots of special-purpose processors in our lives. An MP3 player is a specialized computer for processing MP3 files. A GPS is a specialized computer for handling GPS signals. A Nintendo DS is a specialized computer for handling games, but it can't do anything else. A PC can do it all because it is general-purpose.

Personal computers are normally operated by one user at a time to perform such general purpose tasks as word processing, Internet browsing, Internet faxing, e-mail and other digital messaging, multimedia playback, computer game play, computer programming, etc. The user of a modern personal computer may have significant knowledge of the operating environment and application programs, but is not necessarily interested in programming nor even able to write programs for the computer. Therefore, most software written primarily for personal computers tends to be designed with simplicity of use, or "user-friendliness" in mind. However, the software industry continuously provide a wide range of new products for use in personal computers, targeted at both the expert and the non-expert user.

A minimal setup of a typical contemporary desktop computer would be

• Computer case with power supply (usually sold together)
• Motherboard
• Processor with a heat sink and fan (usually sold together)
• At least one memory card
• Mass storage
• Keyboard and mouse for input
• Monitor for output

The motherboard connects everything together. The memory card(s), graphics card and processor, are mounted directly onto the motherboard (the processor in a socket and the memory and graphics cards in expansion slots). The mass storage is connected to it with cables and can be installed in the computer case or in a separate case. Same for keyboard and mouse, except that they are external and connect to the I/O panel on the back of the computer. The monitor is also connected to the I/O panel, either through an onboard port on the motherboard, or a port on the graphics card.
The mass storage can be

• Hard disk
• Floppy drive or Zip drive (both with removable media)
• Optical drive (CD or DVD, removable, usually read-only)

The operating system (e.g.: Microsoft Windows, Mac OS, Linux or many others) can be located on either of these, but typically it's on one of the hard disks. A LiveCD is also possible, but it is very slow and is usually used for installation of the OS, demonstrations, or problem solving.