磁盘调度算法集锦

#include<iostream.h>#include<math.h>int average; //平均寻道数int total; //总寻道数int reqnum; //总磁盘请求进程数目int dist=0;struct position{int section ; //扇区号int disknum; //盘面号int track; //磁道号int direction; //运动方向(向外为1，向里为0)int linear_addr; }diskh;struct proces{ int track; int num; proces *next;};proces *ph;int lasttrack=0;void init(){ diskh.section=1; diskh.linear_addr = 204800; diskh.track=diskh.linear_addr/(2*1024); // 得到磁道号 total=0; average=0; reqnum=0; proces *p=new proces; p->num=0; p->track=0; p->next=NULL; ph=p;}////////////////////////////////////////////////void fifo(){ proces *p=ph; while(p->next!=NULL) { cout<<"第"<<(p->next)->num<<"进程得到服务"<<endl; total=total+int(fabs(((p->next)->track)-diskh.track)); diskh.track=(p->next)->track; reqnum++; p->next=(p->next)->next; //删除得到服务的进程节点 } average=total/reqnum;}void sstf(){ proces *p=ph; while(p->next!=NULL) { proces *pp=ph; proces *ppp; dist=10000; while(pp->next!=NULL) { if (fabs((pp->next->track)-diskh.track)<dist) { dist=int(fabs((pp->next->track)-diskh.track)); ppp=pp; //最终值记录选择服务的前一个进程节点 } pp=pp->next; } reqnum++; cout<<"第"<<(ppp->next)->num<<"进程得到服务"<<endl; total=total+fabs(((ppp->next)->track)-diskh.track); diskh.track=(ppp->next)->track; ppp->next=(ppp->next)->next; //删除得到服务的进程节点 } average=total/reqnum;}////////////////////////////////////////////////////////////////////////void scan() //在界面上指定磁头运动方向{ proces *p=ph; while(p->next!=NULL) { dist=10000; if (diskh.direction==1) { proces *pp=p; proces *ppp; while(pp->next!=NULL) { if((pp->next->track)>diskh.track&&int(fabs((pp->next->track)-diskh.track))<dist) { ppp=pp; //最终值记录选择服务的前一个进程节点 dist=int(fabs(((pp->next)->track)-diskh.track)); } pp=pp->next; } if (ppp->next==NULL) //没找到满足要求的请求进程 { diskh.direction=0; } else { cout<<"第"<<(ppp->next)->num<<"进程得到服务"<<endl; reqnum++; total=total+fabs(((ppp->next)->track)-diskh.track); diskh.track=(ppp->next)->track ; ppp->next=(ppp->next)->next; //删除得到服务的节点 } } if(diskh.direction==0) { proces *pp=p; proces *ppp; while(pp->next!=NULL) { if(((pp->next)->track)<diskh.track&&fabs((pp->next->track)-diskh.track)<dist) { ppp=pp; //最终值记录选择服务的下一个进程节点 dist=int(fabs(((pp->next)->track)-diskh.track)); } pp=pp->next; } if (ppp==NULL) //没找到满足要求的请求进程 { diskh.direction=0; } else { cout<<"第"<<(ppp->next)->num<<"进程得到服务"<<endl; reqnum++; total=total+fabs(((ppp->next)->track)-diskh.track); diskh.track=(ppp->next)->track; ppp->next=(ppp->next)->next; //删除得到服务的节点 } } } average=total/reqnum;}/////////////////////////////////////////////////////////////////void cscan(){ proces *p=ph; while(p->next!=NULL) { dist=10000; proces *max=new proces; max->track=0; proces *min=new proces; min->track=10000; proces *pp=p->next; while(pp!=NULL) { if((pp->track)>(max->track)) { max=pp; } if((pp->track)<(min->track)) { min=pp; } pp=pp->next; } if (diskh.direction==1) { proces *pp=p; proces *ppp; while(pp->next!=NULL) { if((pp->next->track)>=diskh.track&&int(fabs((pp->next->track)-diskh.track))<dist) { ppp=pp; //最终值记录选择服务的前一个进程节点 dist=int(fabs(((pp->next)->track)-diskh.track)); } pp=pp->next; } cout<<"第"<<(ppp->next)->num<<"进程得到服务"<<endl; reqnum++; total=total+fabs(((ppp->next)->track)-diskh.track); diskh.track=(ppp->next)->track ; if(diskh.track==max->track) //当磁头运动到最大磁道时定位它到最小磁道 { diskh.track=min->track; } ppp->next=(ppp->next)->next; //删除得到服务的节点 } if(diskh.direction==0) { proces *pp=p; proces *ppp; while(pp->next!=NULL) { if(((pp->next)->track)<=diskh.track&&fabs((pp->next->track)-diskh.track)<dist) { ppp=pp; //最终值记录选择服务的下一个进程节点 dist=int(fabs(((pp->next)->track)-diskh.track)); } pp=pp->next; } cout<<"第"<<(ppp->next)->num<<"进程得到服务"<<endl; reqnum++; total=total+fabs(((ppp->next)->track)-diskh.track); diskh.track=(ppp->next)->track; if(diskh.track==min->track) { diskh.track=max->track; } ppp->next=(ppp->next)->next; //删除得到服务的节点 } } average=total/reqnum;}void main(){ init(); proces *p=ph; for(int i=1;i<5;i++){ proces *pp=new proces; pp->next=NULL; pp->num=i; pp->track=i*40; p->next=pp; p=pp; }// fifo(); //测试已通过//sstf(); //测试已通过// scan(); //测试已通过// cscan(); //测试已通过 cout<<total<<endl; cout<<average<<endl;}