这些进程对用户体验没有直接的影响，系统可能在任意时间终止它们，以回收内存供前台进程、可见进程及服务进程使用。
These processes have no direct impact on the user experience, and the system can kill them at any time to reclaim memory for a foreground, visible, or service process.
可见，访问内存中的数据要快一百万(或者说106)倍。
Accessing data in memory is thus literally a million (or 106) times faster.
可见，尾部调用使用了更多一些指令，但是它们可以节省相当多内存。
As you can see, tail-calls take a few more instructions, but they can save quite a bit of memory. There are a few restrictions for using them.
应用推荐