Chapter s Operating System 5.1.1 Resource allocation and related functions CPU Sharing The CPU can be shared in a sequential manner only. Hence only one program can execute at any time. Other programs in the system have to wait their turn. It is often important to provide fair service to all programs in the system. Hence preemption is used to free the CPU so that it can be given to another program. Deciding which program should be given the CPU and for how long is a critical function. This function is called CPU Scheduling, or simply scheduling. Partitioning is a bad approach for CPU Sharing, allocation from a pool is the obvious approach to use. CPU共享 CPU只能串行共享因此它一次只能执行一个程序,其他程序必须依次等待。 通常情况下,系统会要求平等对待所有的程序,用抢占来释放CPU以执行 其他程序。因此决定该执行哪个程序并执行多长时间是一个十分重要的功 能,这一功能被称为CPU调度或简称调度。显然,资源分区不适用于CPU 共享,同此,从资源池中分配成为惟一的选择 什算机专业语 5-18Chapter 5 Operating System 计算机专业英语 5-18 CPU sharing The CPU can be shared in a sequential manner only. Hence only one program can execute at any time. Other programs in the system have to wait their turn. It is often important to provide fair service to all programs in the system. Hence preemption is used to free the CPU so that it can be given to another program. Deciding which program should be given the CPU and for how long is a critical function. This function is called CPU Scheduling, or simply scheduling. Partitioning is a bad approach for CPU Sharing, allocation from a pool is the obvious approach to use. CPU共享 CPU只能串行共享,因此它一次只能执行一个程序，其他程序必须依次等待。 通常情况下，系统会要求平等对待所有的程序，用抢占来释放CPU以执行 其他程序。因此决定该执行哪个程序并执行多长时间是一个十分重要的功 能，这一功能被称为CPU调度或简称调度。显然，资源分区不适用于CPU 共享，同此，从资源池中分配成为惟一的选择。 5.1.1 Resource allocation and related functions