Saturate.c

# Saturate.c

#define _FILE_OFFSET_BITS 64  /* enable large file support  */
#include <stdio.h>
#include <stdlib.h>
#include <sys/types.h>
#include <unistd.h>
#include <string.h>

float nCM=0; /* count of 100's of megs we've written */


void finish(const char *where) {
        printf("%s: wrote %.1f gig file\n",where,0.1*nCM);
        exit(0);
}

void hitError(const char *where) { perror(where); finish(where); }

void writer(int id)
{
        char c=0; /* The byte we're writing */
        int cm=100*1024*1024;
        FILE *f[50];

        int     r;
        int     block[262114];
        int     i;
        char    fName[40];
        int     numFiles=4;

        printf("This is the %i writer, going to create %i files.\nOpened : ", id, numFiles);

        for(i=0; i<numFiles; i++)
        {

        sprintf(fName, "test.%i\0", i);

        f[i]=fopen(fName,"wb");

        if (f[i]==NULL) hitError("Error in fopen of ");
        printf("%s ", fName);
        }
        printf("\n");


        while (nCM<10000) {

                for(i=0; i < numFiles; i++)
                        r=fwrite(&block, 1048576, 1, f[i]);
                nCM++;
        }
}


int main(int argc, char *argv[])
{
        int i=0;
        int maxProc=12;
        pid_t pid[50];

        for(i = 0; i < maxProc; ++i) {
            pid[i] = fork();
            if (pid[i] == -1) {
                  exit(-1); /* error */
                } else if (pid[i] == 0) {

                /* child */

                writer(i);
                waitpid(pid[i], 0, 0);
                break;
                 } else {
  //                    printf("doing parent things\n");
                }
        }

// Wait for PIDs to finish

printf("All done spawning, lets wait for them to finish.\n");
      for(i=0; i<maxProc; i++)
      {
      printf("#%i ,", pid[i]);
      waitpid(pid[i],0,0);
      }

        waitpid(pid[i],0,0);
    printf("Last PID done.");

     writer();
     finish("Done");
}