https://en.wikipedia.org/wiki/Byte> The size of the byte has historically been hardware-dependent and no definitive standards existed that mandated the size. Sizes from 1 to 48 bits have been used.[4][5][6][7] The six-bit character code was an often-used implementation in early encoding systems, and computers using six-bit and nine-bit bytes were common in the 1960s. These systems often had memory words of 12, 18, 24, 30, 36, 48, or 60 bits, corresponding to 2, 3, 4, 5, 6, 8, or 10 six-bit bytes. In this era, bit groupings in the instruction stream were often referred to as syllables[a] or slab, 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 binary-encoded values 0 through 255 for one byte, as 2 to the power of 8 is 256.[8] The international standard IEC 80000-13 codified this common meaning. Many types of applications use information representable in eight or fewer bits and processor designers commonly optimize for this usage. The popularity of major commercial computing architectures has aided in the ubiquitous acceptance of the 8-bit byte.[9] Modern architectures typically use 32- or 64-bit words, built of four or eight bytes, respectively.
[4] https://en.wikipedia.org/wiki/Byte#cite_note-Buchholz_1956_1...
[5] https://en.wikipedia.org/wiki/Byte#cite_ref-Buchholz_1956_1_...
[6] https://en.wikipedia.org/wiki/Byte#cite_note-Rao_1989-6
[7] https://en.wikipedia.org/wiki/Byte#cite_note-Tafel_1971-7
[8] https://en.wikipedia.org/wiki/Byte#cite_note-ISO_IEC_2382-1_...
[9] https://en.wikipedia.org/wiki/Byte#cite_note-CHM_1964-10