On Apr 13, 2005, at 11:57 PM, Chris Wilkson wrote:
> On Wed, 13 Apr 2005, Ruffin Bailey wrote:
>
>> Why would the number of bits in a byte have to have anything to do
>> with
>> powers of 2? The max number, whether 7 bit, 13 bit, or 8 bit would
>> still be a binary number. ??
>
> Because decoders and encoders using bits as control lines will always
> address 2^n locations. Either you implement them, or you don't. But
> if you need 5 states, you need 3 bits to represent that. Then you have
> created 3 bogus states. You need to define them or else "Bad Things"
> can happen. You can define them by hardwiring, but you might as well
> make them useful if you can.
>
> In the case of decimals digits, you need 4 bits to encode each
> character
> with. If your system is already 6 bits, just to encode the text
> characters,
> you're wasting 2 bits when doing BCD. You might as well make your word
> 8 bits wide so you can encode 2 digits without waste.
... thus earning the mit.edu behind his email nick. ;^)
Ruffin Bailey
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