import sys from io import BufferedReader from typing import Optional class BadBlockError(Exception): pass class SixtyFourDiskDrive: __DISK_HEADS = 2 __DISK_TRACKS = 1175 __DISK_BLOCKS_PER_TRACK = 2 __DISK_SECTORS_PER_BLOCK = 85 __DISK_BAD_TRACKS_PER_ZONE = 12 __DISK_SYSTEM_SECTOR_SIZE = 232 __DISK_ZONES = [ (0, 232, 158, 0), (0, 216, 158, 158), (0, 208, 149, 316), (0, 192, 149, 465), (0, 176, 149, 614), (0, 160, 149, 763), (0, 144, 149, 912), (0, 128, 114, 1061), (1, 216, 158, 157), (1, 208, 158, 315), (1, 192, 149, 464), (1, 176, 149, 613), (1, 160, 149, 762), (1, 144, 149, 911), (1, 128, 149, 1060), (1, 112, 114, 1174), ] __DISK_VZONE_TO_PZONE = [ [0, 1, 2, 9, 8, 3, 4, 5, 6, 7, 15, 14, 13, 12, 11, 10], [0, 1, 2, 3, 10, 9, 8, 4, 5, 6, 7, 15, 14, 13, 12, 11], [0, 1, 2, 3, 4, 11, 10, 9, 8, 5, 6, 7, 15, 14, 13, 12], [0, 1, 2, 3, 4, 5, 12, 11, 10, 9, 8, 6, 7, 15, 14, 13], [0, 1, 2, 3, 4, 5, 6, 13, 12, 11, 10, 9, 8, 7, 15, 14], [0, 1, 2, 3, 4, 5, 6, 7, 14, 13, 12, 11, 10, 9, 8, 15], [0, 1, 2, 3, 4, 5, 6, 7, 15, 14, 13, 12, 11, 10, 9, 8], ] __DISK_DRIVE_TYPES = [( "development", 192, [11, 10, 3, 2], [0, 1, 8, 9, 16, 17, 18, 19, 20, 21, 22, 23], ), ( "retail", 232, [9, 8, 1, 0], [2, 3, 10, 11, 12, 16, 17, 18, 19, 20, 21, 22, 23], )] __file: Optional[BufferedReader] __drive_type: Optional[str] __block_info_table: list[tuple[int, int]] def __init__(self) -> None: self.__file = None self.__drive_type = None block_info_table_length = self.__DISK_HEADS * self.__DISK_TRACKS * self.__DISK_BLOCKS_PER_TRACK self.__block_info_table = [None] * block_info_table_length def __del__(self) -> None: self.unload() def __check_system_block(self, lba: int, sector_size: int, check_disk_type: bool) -> tuple[bool, bytes]: self.__file.seek(lba * self.__DISK_SYSTEM_SECTOR_SIZE * self.__DISK_SECTORS_PER_BLOCK) system_block_data = self.__file.read(sector_size * self.__DISK_SECTORS_PER_BLOCK) system_data = system_block_data[:sector_size] for sector in range(1, self.__DISK_SECTORS_PER_BLOCK): sector_data = system_block_data[(sector * sector_size):][:sector_size] if (system_data != sector_data): return (False, None) if (check_disk_type): if (system_data[4] != 0x10): return (False, None) if ((system_data[5] & 0xF0) != 0x10): return (False, None) return (True, system_data) def __parse_disk(self) -> None: disk_system_data = None disk_id_data = None disk_bad_lbas = [] drive_index = 0 while (disk_system_data == None) and (drive_index < len(self.__DISK_DRIVE_TYPES)): (drive_type, system_sector_size, system_data_lbas, bad_lbas) = self.__DISK_DRIVE_TYPES[drive_index] disk_bad_lbas.clear() disk_bad_lbas.extend(bad_lbas) for system_lba in system_data_lbas: (valid, system_data) = self.__check_system_block(system_lba, system_sector_size, check_disk_type=True) if (valid): self.__drive_type = drive_type disk_system_data = system_data else: disk_bad_lbas.append(system_lba) drive_index += 1 for id_lba in [15, 14]: (valid, id_data) = self.__check_system_block(id_lba, self.__DISK_SYSTEM_SECTOR_SIZE, check_disk_type=False) if (valid): disk_id_data = id_data else: disk_bad_lbas.append(id_lba) if not (disk_system_data and disk_id_data): raise ValueError("Provided 64DD disk file is not valid") disk_zone_bad_tracks = [] for zone in range(len(self.__DISK_ZONES)): zone_bad_tracks = [] start = 0 if zone == 0 else system_data[0x07 + zone] stop = system_data[0x07 + zone + 1] for offset in range(start, stop): zone_bad_tracks.append(system_data[0x20 + offset]) for ignored_track in range(self.__DISK_BAD_TRACKS_PER_ZONE - len(zone_bad_tracks)): zone_bad_tracks.append(self.__DISK_ZONES[zone][2] - ignored_track - 1) disk_zone_bad_tracks.append(zone_bad_tracks) disk_type = disk_system_data[5] & 0x0F current_lba = 0 starting_block = 0 disk_file_offset = 0 for zone in self.__DISK_VZONE_TO_PZONE[disk_type]: (head, sector_size, tracks, track) = self.__DISK_ZONES[zone] for zone_track in range(tracks): current_zone_track = ( (tracks - 1) - zone_track) if head else zone_track if (current_zone_track in disk_zone_bad_tracks[zone]): track += (-1) if head else 1 continue for block in range(self.__DISK_BLOCKS_PER_TRACK): index = (track << 2) | (head << 1) | (starting_block ^ block) if (current_lba not in disk_bad_lbas): self.__block_info_table[index] = (disk_file_offset, sector_size * self.__DISK_SECTORS_PER_BLOCK) else: self.__block_info_table[index] = None disk_file_offset += sector_size * self.__DISK_SECTORS_PER_BLOCK current_lba += 1 track += (-1) if head else 1 starting_block ^= 1 def __check_track_head_block(self, track: int, head: int, block: int) -> None: if (track < 0 or track >= self.__DISK_TRACKS): raise ValueError("Track outside of possible range") if (head < 0 or head >= self.__DISK_HEADS): raise ValueError("Head outside of possible range") if (block < 0 or block >= self.__DISK_BLOCKS_PER_TRACK): raise ValueError("Block outside of possible range") def __get_table_index(self, track: int, head: int, block: int) -> int: return (track << 2) | (head << 1) | (block) def __get_block_info(self, track: int, head: int, block: int) -> Optional[tuple[int, int]]: if (self.__file.closed): return None self.__check_track_head_block(track, head, block) index = self.__get_table_index(track, head, block) return self.__block_info_table[index] def load(self, path: str) -> None: self.unload() self.__file = open(path, 'rb+') self.__parse_disk() def unload(self) -> None: if (self.__file != None and not self.__file.closed): self.__file.close() self.__drive_type = None def get_drive_type(self) -> str: return self.__drive_type def read_block(self, track: int, head: int, block: int) -> bytes: info = self.__get_block_info(track, head, block) if (info == None): raise BadBlockError (offset, block_size) = info self.__file.seek(offset) return self.__file.read(block_size) def write_block(self, track: int, head: int, block: int, data: bytes) -> None: info = self.__get_block_info(track, head, block) if (info == None): raise BadBlockError (offset, block_size) = info if (len(data) != block_size): raise ValueError(f"Provided data block size is different than expected ({len(data)} != {block_size})") self.__file.seek(offset) self.__file.write(data) if __name__ == "__main__": id_lba_locations = [ (7, 0, 1), (7, 0, 0) ] if (len(sys.argv) >= 2): dd = SixtyFourDiskDrive() dd.load(sys.argv[1]) print(dd.get_drive_type()) for (track, head, block) in id_lba_locations: try: print(dd.read_block(track, head, block)[:4]) except BadBlockError: print(f"Bad ID block [track: {track}, head: {head}, block: {block}]") dd.unload() else: print(f"[{sys.argv[0]}]: Expected disk image path as first argument")