There is no file browser / directory in iPad
"... we'd like to point out that we haven't mentioned files, folders, or windows. That's because there's no such thing in the universe of the iPad."
"iPad's Biggest Advantage - No File System."
"Apple's commitment to simplicity may have gone too far. In particular, the iPad offers no conventional system of files and folders for storing work."
"Apple is dramatically rethinking how applications organize their documents on iPad, leaving behind the jumbled file system and making file access between the iPad and desktop computers seamless. ... Apple's new iPad jettisons the conventional shared file system and introduces a new, streamlined convention for working with document files that ordinary users should find much more understandable."
Apple is doing something rather daring with their new iPhone OS. They are essentially omitting features that people once took for granted in a typical computer. And one of the biggest things they've omitted is the visual file system. Instead, in the iPhone OS, the concept of the file is essentially gone. It's been replaced by "apps and their stuff."
"It's the first mainstream computer that doesn't have a file directory, doesn't require backups, and doesn't call for a multi-step process just to add programs."
"NO TRADITIONAL FILE STRUCTURE.
At its heart, there is no HD, root folder or any access into the device other than icons on the home screens. ... The iPad doesn't let you connect with the files on other devices or organize them the way you are used to on your desktop. Each app keeps its data together in its own system. ... No drag and drop and the basic folder concept is gone."