It enables the user to control the speed and sound levels of orchestral music playing on a computer.

VOA: special.2011.05.11

Even those of you who've taken AP computer science or something similar perhaps recall that even just getting a piece of input from the user is ridiculously not obvious.

你们中上了AP计算机科学这门课,或者类似的课程的人可能还记得,即使只是从用户那里得到一个输入,也相当麻烦。

哈佛公开课 - 计算机科学课程节选

But e-books can act more like computer software licensed only to the user who buys them.

VOA: special.2009.07.24