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 bits are still there, much like bits are still left when you erase a file on your hard disk but they're forgotten about.

二进制数还在那里，就像你在硬盘上删除一个文件,二进制还在那里,但是它们被遗忘了。

哈佛公开课 - 计算机科学课程节选