3ESS tape format printer

print_block.py

#!/usr/bin/env python

import struct
import sys

if __name__ == '__main__':
    filename = sys.argv[1]
    f = open(filename, "rb")

    read_len = 50

    # Read in big-endian bytes
    while True:
        data = f.read(2*read_len)
        if(len(data) == 0):
            break
        successful_len = len(data)//2

        preamble = struct.unpack(f'>{successful_len}H', data)

        for word in preamble:
            # Reverse the entire word
            binary_word = "{:016b}".format(word) # [::-1]
            binary = (" ".join((binary_word[0:4],
                            binary_word[4:8],
                            binary_word[8:12],
                            binary_word[12:])))
            octal = "{:07o}".format(word)
            print(binary, " | ", octal)