在基于线程的多任务处理，什么是调度程序，所分配的最小代码单位?

Z-stack中协议各层都对应一个任务

Z-stack中每个任务都有一个任务ID

Z-stack中任务ID越高的任务其优先级也越高

Z-stack中每个任务都有一个事件处理函数

Think you can walk, drive, take phone, calls, e-mail and listen to music at the same time Well, New York’s new law says you can’t (46) The law went into force last month, following research and a shocking number of accidents that involved people using electronic gadgets(小巧机械)when crossing the street.

Who’s to blame (47) "We are under the impression that our brain can do more than it often can," says Rene Marois, a neuroscientist(神经科学家)in Tennessee. "But a core limitation is the inability to concentrate on two things at once."

The young people are often considered the great multitaskers. (48) A group of 18- to 21-year-olds and a group of 35-to 39-year-olds were given 90 seconds to translate images into numbers, using a simple code. (49) But when both groups were interrupted by a Phone call or an instant message, the older group matched the younger group in speed and accuracy.

It is difficult to measure the productivity lost by multitaskers. But it is probably a lot. Jonathan Spira, chief analyst at Basex, a business-research firm, estimates the cost of interruptions to the American economy at nearly ＄ 650 billion a year. (50) The surveys conclude that 28 percent of the workers’ time was spent on interruptions and recovery time before they returned to their main tasks.

公平性

均衡使用资源

用户界面友好

极大的流量

用户如果只启动一个应用程序，则该程序就可以自始至终独占CPU资源

由于CPU中有多个执行部件，可同时执行多条指令，所以才能同时执行多个任务的处理

从微观上看，前台任务和后台任务能同时得到CPU响应

Windows操作系统在执行32位应用程序时，采用的是按时间片轮转的调度方法

程序间的同步

程序间的通信

运行状态

运行时间

从微观上看，前台任务和后台任务能同时得到CPU响应

由于CPU中有多个执行部件，可同时执行多条指令，所以才能同时执行多个任务

用户如果只启动一个应用程序，则该程序就可以自始至终独占CPU资源

Windows操作系统在执行32位应用程序时，采用的是按时间片轮流的调度方法

任务派发

任务审批

任务处理

总结归档

Think you can walk, drive, take phone, calls, e-mail and listen to music at the same time Well, New York’s new law says you can’t (46) The law went into force last month, following research and a shocking number of accidents that involved people using electronic gadgets(小巧机械)when crossing the street.

Who’s to blame (47) "We are under the impression that our brain can do more than it often can," says Rene Marois, a neuroscientist(神经科学家)in Tennessee. "But a core limitation is the inability to concentrate on two things at once."

The young people are often considered the great multitaskers. (48) A group of 18- to 21-year-olds and a group of 35-to 39-year-olds were given 90 seconds to translate images into numbers, using a simple code. (49) But when both groups were interrupted by a Phone call or an instant message, the older group matched the younger group in speed and accuracy.

It is difficult to measure the productivity lost by multitaskers. But it is probably a lot. Jonathan Spira, chief analyst at Basex, a business-research firm, estimates the cost of interruptions to the American economy at nearly ＄ 650 billion a year. (50) The surveys conclude that 28 percent of the workers’ time was spent on interruptions and recovery time before they returned to their main tasks.

所有任务都能够占用CPU

任务之间切换比较容易

前台程序运行会受影响

系统对用户命令响应速度会变慢