Byte using six-bit and nine-bit bytes were common into the 1960s. These machines most commonly had memory words of 12, 24, 36, 48 or 60 bits, corresponding to two, four, six, eight or 10 six-bit bytes. In this era, bytes in the instruction stream were often referred to as "syllables", before the term byte became common. The modern "de-facto" standard of eight bits, as documented in ISO/IEC 2382-1:1993, is a convenient power of two permitting the values 0 through 255 for one byte (2 in power of 8 = 256, where zero signifies number as well). The international standard IEC 80000-13
Byte addressing systems, such as the PDP-10, use word addressing but facilitate access to individual bytes using special instructions which can access memory using a "byte pointer", which contains both a word address and the index of a specific byte within the word. Byte addressing Byte addressing refers to hardware architectures which support accessing individual bytes of data rather than only larger units called words, which would be "word-addressable". Such computers are sometimes called "byte machines" (in contrast to "word machines"). The basic unit of digital storage is called a bit, storing a single 0 or 1. Many common architectures can address