my $myRange = $rangeEnd - $rangeStart;
seek($fh,$rangeStart,0);
my $currentIncrement=0;
my $numberOfIncrements = $myRange / $readSz;
do {
$n1 = read($fh, $buf1, $readSz);
# DO STUFF WITH $buf1 #
$currentIncrement++;
} until !defined($n1) || $n1 == 0 || $currentIncrement==$numberOfIncrements;