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
64-bit computing in 64 bits depends on the integer representation used. With the two most common representations, the range is 0 through 18,446,744,073,709,551,615 (2 − 1) for representation as an (unsigned) binary number, and −9,223,372,036,854,775,808 (−2) through 9,223,372,036,854,775,807 (2 − 1) for representation as two's complement. Hence, a processor with 64-bit memory addresses can directly access 2 bytes (=16 exabytes) of byte-addressable memory. With no further qualification, a "64-bit computer architecture" generally has integer and addressing processor registers that are 64 bits wide, allowing direct support for 64-bit data types and addresses. However, a CPU might have external data buses or address