When you're working on a file, it's saving constantly to RAM but also hopefully to disc, the hard disk so you don't actually lose it if the power goes off.

当你打开一个文件，它不断地保存在内存中,但对于光盘，硬盘,当你断开电源的时候，数据不会丢失。

哈佛公开课 - 计算机科学课程节选

The mp3 ended the era of the compact disc, first through illegal file-sharing services like Napster, later through legal downloading destinations like the iTunes Store.

FORBES: Apple's iTunes Store Turns 10 In Triumph, But Faces Uncertainty

So if you pop in a DVD "infected" with Protect DVD-Video, it can't be read by Windows Media Player, Media Center Edition, or any DirectShow-based software, thanks to a Universal Disc Format that tricks your machine into believing that the IFO file is zero bytes long.

ENGADGET: Protect DVD-Video prevents discs from playing on your PC

And if you're going to save money by taking services online, that will mean ending some "offline" services - so prepare for the backlash when taxpayers are told they can no longer file their returns via the post, or get a road tax disc at the Post Office.

BBC: Open government - in tune with the Zeitgeist?