open (DISFILE,"<".$datfile) or die "Can't do it";
&lock_files(DISFILE);
---PERFORM CALCULATIONS OR WHATEVER--
&Unlock(DISFILE);
close DISFILE;
sub lock_files{
my $timeout = 0;
my $SomeFile = shift;
  until(flock($SomeFile,2)){
    sleep .20;
     if(++$timeout > 50){
          print "Server Time out Message";
     }#end if

 }#end until

}#end sub lock files
sub Unlock{
  my $SomeFile = shift;
  flock($SomeFile,8);
}#end unlock