$pid_c=fork();   #create child as working slave
  if ($pid_c==0){system("growisofs -Z $device=$isofile >$tmpfile 2>&1");exit;}; #child process does the job
  if ($pid_c!=0)           #parent job only does output
  {
    for(;;)
    {
      select(undef,undef,undef,0.1);          #sleep for 0.1 sec
      # Fortschritt abprüfen...
      if (kill(0,$pid_c)==0){last;} #child finished; go on
    }
  }