进程调度算法的模拟

1．用语言来实现对n个进程采用不同调度算法的进程调度。

2．每个用来标识进程的进程控制块PCB用结构来描述，包括以下字段：

（1）进程标识ID，其中0为闲逛进程，用户进程的标识数为1，2，3…。

（2）进程优先级Priority，闲逛进程（idle）的优先级为0，用户进程的优先级大于0，且随机产生，优先数越大，优先级越高。

（3）进程占用的CPU时间CPUtime，进程每运行一次，累计值等于4。

（4）进程总共需要运行时间Alltime，利用随机函数产生。

（5）进程状态，0：就绪态；1：运行态；2：阻塞态。

（6）队列指针next，用来将多个进程控制块PCB链接为队列。

3．优先数改变的原则

（1）进程在就绪队列中每呆一个时间片，优先数增加1。

（2）进程每运行一个时间片，优先数减3。

4．在调度前，系统中拥有的进程数PCB_number由键盘输入，经初始化后，所有的进程控制块PCB链接成就绪队列。



先到先服务 优先级 轮转法 最短作业优先

-Process scheduling simulation

1. Use language to achieve the n processes using different scheduling process scheduling.

2. The process used to identify each process control block PCB used to describe the structure, including the following fields:

(1) process identification ID, where 0 is the process of wandering, the identity of the user process number 1, 2, ....

(2) process priority Priority, wandering process (idle) priority is 0, the user process priority greater than 0, and randomly generated, the greater the priority number, the higher the priority.

(3) process CPU time CPUtime, each process runs once, the cumulative value equal to 4.

(4) process requires a total running time Alltime, using random function generator.

(5), process status, 0: Ready state　1: Run the state　2: blocking state.

(6) queue pointer next, is used to link multiple process control block PCB for the queue.

3. Change the principle of priority number

(1) process to stay in a ready queue in each time s