Download: to copy information from a remote computer onto your own machine. Uploading is the same procedure in reverse. Electronic mail (e-mail): paperless messages delivered through a network of linked computers. Internet: the ultimate network of linked computers. More precisely, it stitches together various computer networks at universities, government laboratories, and increasingly corporations around the world. Through it, users can exchange all kinds of computer data: text, sound, pictures, and in some cases video. PC Cards (PCMCIA Cards): credit-card size devices that fit into special slots found in portable computers. Some models add memory, others work as second hand drives, still others operate as modems and links to computer networks.