open(BLOB, $blob_file) ||die "Cannot open the blob file\n";
binmode BLOB;

my $bytes = 0;
my $offset = 0;
my $buf;

while( $bytes != 0 )
{
  $bytes = read(BLOB, $buf, 500000, $offset);
  die "Error reading $blob_file $!" unless defined $bytes
}

close BLOB;

# $buf now contains all the bytes from $blob_file