# Why is it easier to implement bytes as 8 bits rather than 9 bits? [duplicate]

From book to book I always find the same sentence. For example:

8 bits is an even power of 2, which makes it somewhat easier to design computer hardware with 8-bit bytes than with 9-bit bytes.

The Computer Book (Sterling Milestones) by Simson L Garfinkel & Rachel H. Grunspan

I cannot find any circuit or detailed explanation why that statement is true.

The perfect answer will be a circuit that shows why it is easier to implement.

I know about all other reasons i.e., BCDIC, ASCII, IBM System / 360 and etc. But it's just words, I need a proof with circuit. If one say that it is easier to implement, it means nothing without proof.

It's like to say 1 + 2 + 3 + ... = -1/12.

This statement is true, but it is complete nonsense without proof. Same thing with byte. Show circuit and I will believe.

• Fewer bits means less hardware. Jan 4, 2021 at 13:11
• @Finbarr I'm not sure any of the answers to that question actually state why it makes the design easier. A couple touch on it, but the explanations are still quite vague and not really convincing IMHO (they talk about addressing, which is usually not relevant within a byte). Jan 4, 2021 at 13:56
• Note that many early mainframe computers did not use the 8-bits = 1 byte paradigm. The Univac 1100 series computers from the early '70's had a 36-bit word as the basic integer data structure, with subdivisions down to a sixth-word (6 bits). ASCII characters were handled as fourth-words (9 bits), with the lower 8-bits being used. So there is nothing sacrosanct about 8 bits to a byte at the hardware level. Jan 4, 2021 at 14:32
• I know about all other reasons i.e., BCDIC, ASCII, IBM System / 360 and etc. But it's just words, I need a proof with circuit. If one say that it is easier to implement, it means nothing without proof. It's like to say 1 + 2 + 3 + ... = -1/12. This statement is true, but it is complete nonsense without proof. Same thing with byte. Show circuit and I will believe. Jan 4, 2021 at 15:43
• I think you are misreading the statement. It is "easier" that has nothing to do with performance or implementation, etc. it is also means that this is the authors opinion and not a statement of fact, as such you really need to ask the author (reminding yourself constantly this is not a statement in fact, just their opinion). 9 bits is no harder or easier than 8 bits and vice versa. Jan 5, 2021 at 5:29