Read all about codenames here

"Code names are also commonplace in the computer world where products are informally given names during development. These names are usually only meant for use inside the company, and are dropped once the product is given an official designation under which it is to be marketed to the public. In recent years there has been a growing tendency of computer companies to make their codenames more public and more prominent; for example, Apple Computer whose most recent Mac OS X versions were publicly marketed by their codenames "Panther", "Tiger" and the upcoming Leopard; and Microsoft whose future Microsoft Windows release, which is still under development, was initially identified publicly by its codename "Longhorn", with Windows XP being Whistler, and Media Center Edition 2004 and 2005 being Harmony and Symphony, respectively."