日期:2014-05-16  浏览次数:20753 次

关于安全性算法有个地方我不懂,谁能解释一下,谢谢!!
系统所执行的安全性算法可描述如下:
(1)设置两个向量
工作向量Work。它表示系统可提供给进程继续运行所需要的各类资源数目,它含有m个元素,执行安全算法开始时,work :=Allocation。
Finish。它表示系统是否有足够的资源分配给进程,使之运行完成,开始时先做Finish[i]:=false;当有足够资源分配给进程时,令Finish[i]:=true。
(2)从进程集合中找到一个能满足下述条件的进程:
①Finish[i]=false
②Needi ≤Work
如找到,执行步骤(3);否则,执行步骤(4)。
(3)当进程只获得资源后,可顺利执行,直至完成,并释放出分配给它的资源,故执行
Work :=Work+Allocationi;
Finish[i]:=true;
  Go to step 2;
(4)如果所有进程的Finish[i]=true,则表示系统处于安全状态;否则,系统处于不安全状态


我想知道Allocation 和Allocationi 具体有什么区别?为什么(1)中是Allocation 而(3)中的是Allocationi了?


 谢谢 !!!

 

------解决方案--------------------
和Needi意思差不多,都是指i的资源数,Needi是i需要的,Allocationi是i已经分配的。
------解决方案--------------------
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