字节为什么会是8 bit

今天看javanio的书时看到的

 

                              

Bytes Are Always Eight Bits, Right?
These days, bytes are almost universally recognized as being eight bits. But this
wasn't always the case. In ages past, bytes ranged anywhere from 3 to 12 or more
bits each, with the most common being 6 to 9 bits. The eight-bit byte was arrived at
through a combination of practicality and market forces. It's practical because eight
bits are enough to represent a usable character set (English characters anyway), eight
is a power of two (which makes hardware design simpler), eight neatly holds two
hexadecimal digits, and multiples of eight provide enough combined bits to store
useful numeric values. The market force was IBM. The IBM 360 mainframe, first
introduced in the 1960s, used eight-bit bytes. That pretty much settled the matter.