And this is because as you start writing--saving files to your hard drive, what happens is you might save this file here, then this one, then this one, then this one, but very reasonably you might go back eventually and delete this one.

这是因为当你开始对硬盘驱动器进行读写时,你可以保存一个文件到磁盘的某处，然后再一个，再一个，又一个，最后你可能回到这,并删除这一个文件。

哈佛公开课 - 计算机科学课程节选

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