Is a byte always 8 bits?

Question

I\'m working through The Elements of Computing Systems when I read the following excerpt:

The Hack computer includes a black-and-white screen organize

Answer 1

Except perhaps for a brief period after its coinage, a byte has always been eight bits.

The phrase 'one kilobyte' got popularized as 'one kilo by eight', in the sense that you would have a kilo-word (1024 addressable pieces) of memory that was eight bits 'wide', in that each addressable piece was eight bits.

The word was not always eight bits, but when it was not, it was never referred to as 'by eight', it was 'by four' or 'by sixteen', or in the egregious example of some Burroughs bookkeeping machines 'by one-hundred-twenty-eight'. At the other extreme, Honeywell machines originally were organized so that every individual bit in storage had a unique address, so they would have so-many 'kilo by one' memory packages.

In the case of the machine you are talking about it would have "8 kilo by 16" memory, thus an 8K memory map, specifically 8Kx16, where there are only 8192 addresses, and each is 16 bits wide.

It was cheapest, given ASCII and EBCDIC, to have eight-bit address boundaries, for efficient text processing, even when your machine's registers were wider. Machines with narrower registers simply went extinct.

So, yes a byte IS always eight bits, and almost always has been.