Byte addressing 8 bits; in fact, depending on the platform, byte sizes of 1 to 48 bits have been used in the past. Therefore, the term "octet" is used where the context makes byte-length ambiguous. For example, in the 1980s, Honeywell mainframes had 36-bit words, and were byte-addressable in 9-bit bytes, or "nonets", They used 7- or 8-bit character codes, either of which were stored one to each 9-bit byte, making characters individually addressable. To illustrate why byte addressing is useful, consider the IBM 7094, which is word-addressable and has no concept of a byte. It has 36-bit words, and stores its
Zero-byte file be zero bytes (a common convention terminates text files with a one- or two-byte newline, however). Conversely, zero-byte files must use some disk space to be indexed by a filesystem (though none for content, in most cases). In some cases, zero-byte files may be used to convey information like file metadata (for example, its filename may contain an instruction to a user viewing a directory listing such as documents-have-been-moved-to-partition-D, etc.); or to put in a directory to ensure that it is nonempty, since some tools such as backup and revision control software may ignore the empty directories. There are many