操作系统实习报告 -1

操作系统实习报告日期：实习题目：基于Windows环境的读者写者问题完成人姓名：杨雪亚班级：物联网工程学号：2014141461034实习内容简要描述创建一个控制台进程。此进程包含n个线程。用这n个线程来表示n个读者或写者。每个线程按相应测试数据文件(后面有介绍)的要求进行读写操作。用信号量机制分别实现读者优先和写者优先的读者-写者问题。运行结果显示要求：要求在每个线程创建、发出读写操作申请、开始读写操作和结束读写操作时分别显示一行提示信息，以确定所有处理都遵守相应的读写操作限制。主要代码结构（附注释）publicclassreaderfirst{classwriterextendsThread{//写者进程publicwriter(intno,doublest,doublert);publicvoidrun();}classreaderextendsThread{//读者进程publicreader(intno,doublest,doublert);publicvoidrun();}publicvoidrun();//数据写入和读取publicstaticvoidmain(Stringargs[]){//主程序 (newreaderfirst()).run(); }}结果分析（或错误原因分析）运行结果如左注释：如果上述表格空间不够，可以另附表格进行说明附代码:importjava.util.concurrent.Semaphore;publicclassreaderfirst{ Semaphoremutex=newSemaphore(1);//提供互斥reader_count信号量 Semaphorewrt=newSemaphore(1);//提供读者写者同步信号量 intrwn=0;//读者等待数 intreader_count=0;//读者数，初始值为0 classwriterextendsThread{//写者进程 intnum; doublesleeptime; doubleruntime; publicwriter(intno,doublest,doublert){ num=no; sleeptime=st; runtime=rt; } publicvoidrun(){ try{ sleep((int)(sleeptime*1000)); System.out.println("第"+num+"号写者想写,现在共有读者"+reader_count +"个"); if(rwn==0){ wrt.acquire(); System.out.println("第"+num+"号写者正在写，请等待..."); sleep((int)(runtime*1000)); System.out.println("第"+num+"号写者写完了"); wrt.release(); } }catch(InterruptedExceptione){ //TODOAuto-generatedcatchblock e.printStackTrace(); }System.out.println(num+”“+sleeptime+”“+runtime); } } classreaderextendsThread{//读者进程 intnum; doublesleeptime; doubleruntime; publicreader(intno,doublest,doublert){ num=no; sleeptime=st; runtime=rt; } publicvoidrun(){ try{ sleep((int)(sleeptime*1000)); System.out.println("第"+num+"号读者想读"); rwn++; mutex.acquire(); rwn--; if(reader_count==0){ wrt.acquire(); } reader_count++; System.out.println("第"+num+"号读者正在读"); System.out.println("现在共有"+reader_count+"个读者"); mutex.release(); sleep((int)(runtime*1000)); mutex.acquire(); reader_count--; System.out.println("第"+num+"号读者读完了,此时共有"+reader_count +"个读者"); if(reader_count==0){ wrt.release(); } mutex.release(); }catch(InterruptedExceptione){ //TODOAuto-generatedcatchblock e.printStackTrace(); }System.out.println(num+”“+sleeptime+”“+runtime); } } publicvoidrun(){ readerr1=newreader(1,3,5); writerw2=newwriter(2,4,5); readerr3=newreader(3,5,2); readerr4=newreader(4,6,5); writerw5=newwriter(5,5.2,3);