aerodame

public class Deadlock {
    
    public Deadlock( ) {
	Mutex mutex[] = new Mutex[4];

	for ( int i = 0; i < 4; i++ )
	    mutex[i] = new Mutex( );

	A threadA = new A( mutex );
	B threadB = new B( mutex );

aerodame

public class Deadlock {
    public Deadlock( ) {
	Mutex mutex[] = new Mutex[4];

	for ( int i = 0; i < 4; i++ )
	    mutex[i] = new Mutex( );

	A threadA = new A( mutex );
	B threadB = new B( mutex );
	C threadC = new C( mutex );

aerodame

   // Provide a quick debugger of the TCBs in queue
   // Format of output is = Q[i]-> { [p,t] [p,t] [p,t] ... } 
   private void dumpQueue(int time) {
      int N;
      if (DEBUG) {
         System.out.print("T("+time+"): ");
         // scan through each multilevel queue
         for (int i=0; i < 3; i++) {
            // how many TCBs are in queue
            N = queue[i].size();

aerodame

public class ThreadDriver {
   public static void main( String[] args ) {
      String args[2];

      args[0] = "ping"; args[1] = "10000";
      new PingPong( args ).start( );

      args[0] = "PING"; args[1] = "90000";
      new PingPong( args ).start( );
   }

aerodame

public class PingPong extends Thread {
   private String word;
   private int loop;
   public PingPong( String[] args ) {
      word = args[0];
      loop = Integer.parseInt( args[1] );
   }
   public void run( ) {
      for ( int j = 0; j < 100; j++ ) {
         SysLib.cout( word + " " );

aerodame

public class PingPong extends Thread {
   private String word;
   private int loop;
   public PingPong( String[] args ) {
      word = args[0];
      loop = Integer.parseInt( args[1] );
   }
   public void run( ) {
      for ( int j = 0; j < 100; j++ ) {
         SysLib.cout( word + " " );

aerodame

   // ----------------------- Start Debugger Method ---------------------------
   // Provide a simple debugger of the TCBs in queue
   // Format of output is = Q[]-> { [p,t] [p,t] [p,t] ... }
   // Where p = Process ID
   //       t = Thread ID
   // -------------------------------------------------------------------------
   private void dumpQueue(int time) {
      if (DEBUG) {
         System.out.print("\nT("+time+"): ");
         // how many TCBs are in queue

aerodame

   Disk disk = new Disk( 1000 );

   // a disk read operation:
   while ( disk.read( blockId, buffer ) == false )
      ; // busy wait
   while ( disk.testAndResetReady( ) == false )
      ; // another busy wait
   // now you can access data in buffer

aerodame

import java.util.*;
import java.lang.reflect.*;
import java.io.*;

public class Kernel {
    // Interrupt requests
    public final static int INTERRUPT_SOFTWARE = 1;  // System calls
    public final static int INTERRUPT_DISK     = 2;  // Disk interrupts
    public final static int INTERRUPT_IO       = 3;  // Other I/O interrupts

aerodame

   Disk disk = new Disk( 1000 );
   SyncQueue ioQueue = new SyncQueue( );
   ...
   ...
   // a disk read operation:
   while ( disk.read( blockId, buffer ) == false ) {
      ioQueue.enqueueAndSleep( 1 ); // relinquish CPU to another ready thread
      // now check to ensure disk is not busy
      while ( disk.testAndResetReady( ) == false )
         ioQueue.enqueueAndSleep( 2 ); // relinquish CPU to another ready thread