“This take minutes,” said Jobs. “We’re scanning and matching your library, so we don’t need to upload it.” Only songs that cannot be matched on iTunes will be uploaded. In contrast, cloud music services from Google and Amazon require a person to manually upload their past music files, he pointed out, a process he claimed would take most people “weeks.”

Jobs boasted that iCloud was a significant victory in a long battle for Apple. “A lot of us have been campaigning for years to get rid of the file system,” he said, saying that iCloud makes it possible for apps to simply show users all of their documents, songs, or photos, without any need to consider the location of files on disk.

However, iCloud requires users to manage their devices in new ways. For example, only the last 1,000 photos uploaded to iCloud will be synced with iPhones, iPads and iPod touches, and a user must take action to protect any image from being deleted as a result. The iCloud service will also only make photos available for syncing for only 30 days.

At WWDC, Jobs also introduced the latest version of OS X, which makes using a laptop feel more like using a phone or tablet. Many functions—such as scrolling, flipping through photos, or moving backward and forward through a browser’s history—can now be done with multitouch gestures instead of the more traditional point, click, and drag.

The combination of iCloud with Apple’s coming mobile operating system will allow make its mobile devices more like standalone computers. Users will be able to activate and operate iPads and iPhones without ever needing to connect them to a computer running iTunes.

“We’re living in a post PC world,” said Scott Forstall, Apple’s SVP for iOS software, who shared the stage with Jobs. “If you want to cut the cord, you can.”

Forstall said that many of Apple’s customers were now people without computers who wanted their iPad or iPhone to be their only device.