aerodame

   public static int interrupt( int irq, int cmd, int param, Object args ) {
	   TCB myTcb;
	   switch( irq ) {
	      case INTERRUPT_SOFTWARE: // System calls
            ...
            ...
	      case INTERRUPT_DISK: // Disk interrupts
	         // wake up the thread waiting for a service completion
	         ioQueue.dequeueAndWakeup( 2 );

aerodame

   case WAIT:
      // get the current thread id (use Scheduler.getMyTcb( ) )
      // let the current thread sleep in waitQueue under the condition
      // = this thread id (= tcb.getTid( ) )
	return OK; // return a child thread id who woke me up
   case EXIT:
      // get the current thread's parent id (= tcb.getPid( ) )
      // search waitQueue for and wakes up the thread under the condition
      // = the current thread's parent id
	return OK;

aerodame

public class Kernel
{
    private static SyncQueue waitQueue;
    ...

    public static int interrupt( int irq, int cmd, int param, Object args ) {
        TCB myTcb;
        switch( irq ) {
        case INTERRUPT_SOFTWARE: // System calls
            switch( cmd ) {

aerodame

public class Kernel
{
    private static SyncQueue ioQueue;
    ...

    public static int interrupt( int irq, int cmd, int param, Object args ) {
        TCB myTcb;
        switch( irq ) {
        case INTERRUPT_SOFTWARE: // System calls
            switch( cmd ) {

aerodame

public class Inode {
   private final static int iNodeSize = 32;       // fix to 32 bytes
   private final static int directSize = 11;      // # direct pointers

   public int length;                             // file size in bytes
   public short count;                            // # file-table entries pointing to this
   public short flag;                             // 0 = unused, 1 = used, ...
   public short direct[] = new short[directSize]; // direct pointers
   public short indirect;                         // a indirect pointer

aerodame

class Superblock {
   public int totalBlocks; // the number of disk blocks
   public int totalInodes; // the number of inodes
   public int freeList;    // the block number of the free list's head
   
   public SuperBlock( int diskSize ) {
	...
   }
   ...	
}

aerodame

public class Directory {
   private static int maxChars = 30; // max characters of each file name

   // Directory entries
   private int fsize[];        // each element stores a different file size.
   private char fnames[][];    // each element stores a different file name.

   public Directory( int maxInumber ) { // directory constructor
      fsizes = new int[maxInumber];     // maxInumber = max files
      for ( int i = 0; i < maxInumber; i++ ) 

aerodame

public class FileTableEntry {          // Each table entry should have
   public int seekPtr;                 //    a file seek pointer
   public final Inode inode;           //    a reference to its inode
   public final short iNumber;         //    this inode number
   public int count;                   //    # threads sharing this entry
   public final String mode;           //    "r", "w", "w+", or "a"
   public FileTableEntry ( Inode i, short inumber, String m ) {
      seekPtr = 0;             // the seek pointer is set to the file top
      inode = i;
      iNumber = inumber;

aerodame

public class FileTable {

   private Vector table;         // the actual entity of this file table
   private Directory dir;        // the root directory 

   public FileTable( Directory directory ) { // constructor
      table = new Vector( );     // instantiate a file (structure) table
      dir = directory;           // receive a reference to the Director
   }                             // from the file system

aerodame

public class TCB {
   private Thread thread = null;
   private int tid = 0;
   private int pid = 0;
   private boolean terminate = false;

   // User file descriptor table: 
   // each entry pointing to a file (structure) table entry
   public FileTableEntry[] ftEnt = null;