All modern computing platforms, however, use 16-, 32-, or 64-bit words, further divided into eight-bit bytes. On such systems three octal digits per byte would be required, with the most significant octal digit representing two binary digits (plus one bit of the next significant byte, if any). Octal representation of a 16-bit word requires 6 digits, but the most significant octal digit represents (quite inelegantly) only one bit (0 or 1). This representation offers no way to easily read the most significant byte, because it's smeared over four octal digits. Therefore, hexadecimal is more commonly used in programming languages today, since two hexadecimal digits exactly specify one byte. Some platforms with a power-of-two word size still have instruction subwords that are more easily understood if displayed in octal; this includes the PDP-11 and Motorola 68000 family. The modern-day ubiquitous x86 architecture belongs to this category as well, but octal is rarely used on this platform, although certain properties of the binary encoding of opcodes become more readily apparent when displayed in octal, e.g. the ModRM byte, which is divided into fields of 2, 3, and 3 bits, so octal can be useful in describing these encodings. Before the availability of assemblers, some programmers would handcode programs in octal; for instance, Dick Whipple and John Arnold wrote Tiny BASIC Extended directly in machine code, using octal.
All modern computing platforms however use 16- 32- or 64-bit words further divided into eight-bit bytes On such systems three octal digits per byte would be required with the most significant octal digit representing two binary digits (plus one bit of the next significant byte if any) Octal representation of a 16-bit word requires 6 digits but the most significant octal digit represents (quite inelegantly) only one bit (0 or 1) This representation offers no way to easily read the most significant byte because it's smeared over four octal digits Therefore hexadecimal is more commonly used in programming languages today since two hexadecimal digits exactly specify one byte Some platforms with a power-of-two word size still have instruction subwords that are more easily understood if displayed in octal; this includes the PDP-11 and Motorola 68000 family The modern-day ubiquitous x86 architecture belongs to this category as well but octal is rarely used on this platform although certain properties of the binary encoding of opcodes become more readily apparent when displayed in octal eg the ModRM byte which is divided into fields of 2 3 and 3 bits so octal can be useful in describing these encodings Before the availability of assemblers some programmers would handcode programs in octal; for instance Dick Whipple and John Arnold wrote Tiny BASIC Extended directly in machine code using octal