open my $fh, "<" , "reallyBigBinaryFile.bin";
binmode $fh;
my $offset = 0;
$/ = "~END"
while (1)
{
   seek($fh,$offset);
   $record = <$fh>; # Windows and drive show 16x 512b LBAs read here
   # length $record is 16 to 64
   $offset = newOffset($record);
}