It's far from clear from your description exactly what you are trying to do.

Could you clarify what you mean by "tag name"? Also what you mean by "assigning byte to a tag name"?

The only interpretation that comes to mind is that you want to read the file and assign sequences of bytes to named variables...which you might do many ways, but maybe perlfunc:unpack would be a starting point. Something like this.

open BYTES, '<', 'bytesfile' or die $!;
my $bytes = do{ local $/; <BYTES> }; # Slurp all 1600 bytes into a sca
+lar.
close BYTES;

my( $first, $last, $other...) = 
unpack 'A9 A7 A5 ...', $bytes;
[download]

Using unpack 'raw' like this for 70 fields would be extremely unwieldy, but there are ways it could be made less so, but explaining all possibilities only to have you reply, "No! That's not what I meant at all!", would be pointless:)