The binary format is obsolete because it encodes information about the files in a way that is not portable between different machine architectures. The HPUX formats are provided for compatibility with HPUX's cpio which stores device files differently. The tar format is provided for compatability with the tar program. By default, cpio creates binary format archives, for compatibility with older cpio programs. When extracting from archives, cpio automatically recognizes which kind of archive it is reading and can read archives created on machines with a different byte-order.
GNU find is one way to produce a list of null-terminated filenames.
Append to an existing archive. Only works in copy-out mode. In copy-in mode, swap both halfwords of words and bytes of halfwords in the data. Equivalent to -sS . Initially the block size is 512 bytes.