操作系统程序调度算法——先来先服务（FCFS），时间片（RR），短作业（SJF），高响应比（HRRN）java实现实验

操作系统实验——程序调度操作系统实验要求写程序调度，百度查了一下，借鉴了一位老哥的先来先服务，自己写了后面的
先来先服务只要写一个循环，把process集合中的每个process取出，把process结束时间置为当前时间加上服务时间，
然后当前时间加上服务时间即可。

private void calc() { int timeNow = 0; Process opProcess; for (int i = 0; i < processNumber; i++) { opProcess = processList.get(i); int waitTime = timeNow - opProcess.getArrivalTime(); int completionTime = timeNow + opProcess.getServicesTime(); int turnAroundTime = completionTime - opProcess.getArrivalTime(); double turnAroundTimeWithWeight = (double) turnAroundTime / opProcess.getServicesTime(); opProcess.setStartTime(timeNow); opProcess.setWaitTime(waitTime); opProcess.setCompletionTime(completionTime); opProcess.setTurnAroundTime(turnAroundTime); opProcess.setTurnAroundTimeWithWeight( turnAroundTimeWithWeight); timeNow += opProcess.getServicesTime(); } }

这是那老哥博客
[link]https://www.cnblogs.com/daheww/p/10154455.html
时间片轮转法运用一个队列，存储所有等待队列，每次循环先把后来的加入到队尾，再把运行完的加入到队尾，只要进程数大于零且队列不为空，取出队首元素。当前进程剩余运行时间等于总需要服务时间-时间片。然后判断剩余运行时间是否小于等于0.小于等于则结束时间等于当前时间加上进循环之前的剩余服务时间。进程数-1。

private void calc() { int timeNow = 0; Queue queue=new LinkedList(); int processRemain = processNumber; boolean noProcessRunInThisTurn=true; Process opProcess; Process linshi=null; int extime=0; while (processRemain != 0) {if(arrtime.contains(timeNow)){ queue.add(processList.get(arrtime.indexOf(timeNow))); } if(timeNow==extime&&linshi!=null){ noProcessRunInThisTurn=true; if(timeNow!=0&&linshi.getRemainServiceTime()>0) queue.add(linshi); } if(noProcessRunInThisTurn&&!queue.isEmpty()) { opProcess = (Process) queue.poll(); linshi=opProcess; if ((opProcess.getRemainServiceTime() > 0) && (timeNow >= opProcess.getArrivalTime())) { // First time if (opProcess.getServicesTime() == opProcess .getRemainServiceTime()) { int waitTime = timeNow - opProcess.getArrivalTime(); opProcess.setStartTime(timeNow); opProcess.setWaitTime(waitTime); } noProcessRunInThisTurn = false; // Calculating remain service time int rs=opProcess.getRemainServiceTime(); int remainServiceTime = rs - timeSlice; opProcess.setRemainServiceTime(remainServiceTime); // Last time if (remainServiceTime == 0) { int completionTime = timeNow + timeSlice; // The process ends when the current slice is completed. int turnAroundTime = completionTime - opProcess.getArrivalTime(); double turnAroundTimeWithWeight = 1.0 * turnAroundTime / opProcess.getServicesTime(); opProcess.setCompletionTime(completionTime); opProcess.setTurnAroundTime(turnAroundTime); opProcess.setTurnAroundTimeWithWeight(turnAroundTimeWithWeight); processRemain--; timeNow +=1; extime +=timeSlice; } if (remainServiceTime < 0) { int completionTime; // The process ends when the current slice is completed. completionTime = timeNow +rs; int turnAroundTime = completionTime - opProcess.getArrivalTime(); double turnAroundTimeWithWeight = 1.0 * turnAroundTime / opProcess.getServicesTime(); opProcess.setCompletionTime(completionTime); opProcess.setTurnAroundTime(turnAroundTime); opProcess .setTurnAroundTimeWithWeight(turnAroundTimeWithWeight); processRemain--; timeNow += 1; extime+=rs; } if (remainServiceTime > 0) { timeNow += 1; extime+=timeSlice; }//System.out.println("#STEP# Process" + (i + 1) //+ " remain service time:" //+ opProcess.getRemainServiceTime() //+ " , timeBefore:" + (timeNow - 1) + ", timeNow:" //+ timeNow //+ ((remainServiceTime <= 0) ? " Finish" : "")); } } else { timeNow++; //extime++; }// Means no process could run, because they have arrived.} }

短作业短作业很简单就不详细说了直接放代码

private void calc() { int timeNow = 0; Process opProcess; sertimecomparator com=new sertimecomparator(); PriorityQueue pr=new PriorityQueue(10,com); boolean extime=true; boolean run=true; int endtime=0; while(run){ if(arrtime.contains(timeNow)){ if(!pr.contains(processList.get(arrtime.indexOf(timeNow)))){ pr.add(processList.get(arrtime.indexOf(timeNow))); }} if(pr.isEmpty()){ run=false; break; } if(timeNow==endtime)extime=true; if(extime){ extime=false; opProcess=pr.poll(); int waitTime = timeNow - opProcess.getArrivalTime(); int completionTime = timeNow + opProcess.getServicesTime(); int turnAroundTime = completionTime - opProcess.getArrivalTime(); double turnAroundTimeWithWeight = (double) turnAroundTime / opProcess.getServicesTime(); opProcess.setStartTime(timeNow); opProcess.setWaitTime(waitTime); opProcess.setCompletionTime(completionTime); opProcess.setTurnAroundTime(turnAroundTime); opProcess.setTurnAroundTimeWithWeight( turnAroundTimeWithWeight); timeNow += 1; endtime += opProcess.getServicesTime(); } else{ timeNow++; }}} static class sertimecomparator implements Comparator {@Override public int compare(Process o1, Process o2) { if(o1.getServicesTime()o2.getServicesTime()){ return 1; } else return 0; } }

高响应比高响应比就是设了一个优先级，优先级等于等待时间+要求服务时间/要求服务时间。
这个算法需要用到优先队列，优先队列就是优先级最高的在队首，每插入元素一个自动更新队列。
后面就跟前面差不多，判断当前时间有没有到达进程，有则加入优先队列，没有则时间加一
然后取出队首元素，结束时间等于当前时间加服务时间，

private void calc() { int timeNow = 0; Process opProcess; sertimecomparator com=new sertimecomparator(); PriorityQueue pr=new PriorityQueue(10,com); boolean extime=true; boolean run=true; int endtime=0; while(run){ if(arrtime.contains(timeNow)){ if(!pr.contains(processList.get(arrtime.indexOf(timeNow)))){ pr.add(processList.get(arrtime.indexOf(timeNow))); } } for(int x=0; x {@Override public int compare(Process o1, Process o2) { if((o1.getServicesTime()+o1.getWaitTime())/o1.getServicesTime() <(o2.getServicesTime()+o2.getWaitTime())/o2.getServicesTime()){ return 1; } if((o1.getServicesTime()+o1.getWaitTime())/o1.getServicesTime() >(o2.getServicesTime()+o2.getWaitTime())/o2.getServicesTime()){ return -1; } else return 0; } }

【操作系统程序调度算法——先来先服务（FCFS），时间片（RR），短作业（SJF），高响应比（HRRN）java实现】写的不好，欢迎大家交流。