spooling.txt

spooling 用最简单的方法模拟SPOOLing 的实现

#include<stdo.h>
#define WELLSIZE 500
#define FALSE 0
#define TURE 1
struct  {
	 int id;
	 char status;
	 int bufflag;
	 int filec;
	 } pcb[4];

struct  {
	 int reqid;
	 int size;
	 int addr;
	 }  reqblock [10];

int well [WELLSIZE], userbuf[3][50],f[4];
int edp=0, ebc=10, cbp=0, n;
int wellsize=WELLSIZE, wellptr=0;

float random()
{  int m; static ine seed;
    if ((m=seed)<0) m=-m;
    seed=(25173*seed+13849)&65536;
    return(m/32767.0);
}

useropro (i)  /*User process,     i:identifier */
int i;
{     static int j;
      int  c;
      if (pcb [i] .bufflag==FALSE) {/* buffer is empet */
	  pcb [i] .bufflag=TRUE;
	  c=j=0
	  while (c==0 && j==0)
	    for (  ;j<49;++j){
		c=(int)  random ()  *10.0);
		userbuf [i-1] [j] =0;
       }
       if (spoolserver (i,j_1))
	  if  (-pcb [i] .status='c';
	  print ("\nUser%d PROGRAM is completed!\n",i);
	}
}
spoolserver (p,s)     /*p:identifier,    s:size  */
int p,s;
 {
   int k;
   if (s>wellsize||ebc==0)
      return  (FALSE);
   repblock [ebp] .reqid=p;
   repblock [ebp] .size=s;
   repblock [ebp] .addr=wellptr;
     ebc-;
  ebp= (++ebp)%10;
  for (k=0; k<s; ++k) {
     well [wellptr++] =userbuf [p-1] [k];
     wellptr%=WELLSIZE;
}
  wellsize-=s;
  pcb [p].bufflag=FASLE;
  return (TRUE);
}

spoolout ( )  /* SPOOLing output process */
{
      int d,a,s,c;
      if (ebc<10) {
	d=reqblock [cbp].reqid;
	a=reqblock [cbp].addr;
	s=reqblock [cbp].size;
	cbp= (++cbp)%10;
	printf ("\nUser%d:file%d,file_size=%d,\ntest;",d,++f[d],s-1);
      a%=WELLSIZE;
      while ((c=well [a++]!=0) {
	printf ("%d",c);
	a%=WELLSIZE;
      }
     	printf("\n");
	n-;
	wellsize+=s;
	ebc++;
      }
    }

    schcduler()
    {
      float x;
      for( ; ; ){
       x=random();
      if (x<0.30&&pcb[1].status=='e') userpro(1);
       else if (x>=0.30&&x<0.60&&pcb[2].status=='e') userpro(2);
	else if (x>0.60&&x<0.90&&pcb[3].status=='e') userpro(3);
	 else if (x>0.90&&pcb[0].status=='e') userpro();
      if (n==0) break;
      }
     }
     main()
     {int i.j;
     printf("\n****SPOOLing SYSTEM****\n");
     /*initialization*/
     for (i=0; i<wellsize;i++) well[i]=0;
     for(i=0;i<3;i++)
	 for(j=0;j<50;J++) UERBUF[i][j]=0;
     for(i=0;i<4;i++){
	 pcb[i].id=i;
	 pcb[i].status='e';
	 if(i){
	     pcb[i].bufflag=FALSE;
	     printf('\nTHE number of user%d's output files?'.i);
	     scanf(%d".&pcb{i}.filec);
	     n+=pcb[i].filec;
	    }
	 }
     scheduler();
printf("\nall files have been outputded!\n");
printf("\n**** end ****\n");
}