The ISO 9660 primary volume descriptor begins 32,768 bytes (32 KB) into the disc. If present, an Apple partition map begins 512 bytes into the disc; if there is no partition map, the header for an Apple HFS partition (known as a Master Directory Block, or MDB) begins 1,024 bytes into the disc.
The ISO 9660 primary volume descriptor initiates at a location of 32,768 bytes into the disc. If present, an Apple partition map begins 512 bytes from the start; if absent, the header for an Apple HFS partition (Master Directory Block) starts 1,024 bytes in.