clipka wrote:
> Darren New <dne### [at] sanrrcom> wrote:
>> Mueen Nawaz wrote:
>>>     Think modems (the phone ones). In the old days, it was all baud. 1
>>> baud is 1bit/s. It probably has stuck since.
>> Technically, one baud is one symbol per second. A 9600bps modem is a 2400
>> baud modem with 2 symbols per baud.
> 
> What? That's nonsense, the units don't match here. You probably mean 2 bits per
> symbol.

Yes, sorry. Two bits per symbol aka two bits per baud.

> But even after *prehistoric* times, when transmission was almost always binary
> (i.e. 1 bit per symbol), the misconception of "baud = bps" stuck for quite a
> while.

Yes.  Except, of course, in the phone company, where it actually made a 
difference. :-)

> The parity would typically be used with only 7 data bits.

Usually, yes. Usually either 8-N-1 or 7-?-2, IME.

> all other cases, chips are usually specified either at multiples of bits, or
> multiples of a data word (the number of bits accessed in parallel), which would
> typically be 1, 4, 8 (sometimes 9) or 16 bits.

Yep. What about the serial type chips, like SD cards and stuff? How do they 
get rated technically, do you know?

> run properly on a particular microcontroller - until finding out that a "char"
> data type (the smallest data type in C, typically equalling a byte) was
> actually 16 bits wide on that rascal.

Yeah. This is why Ada has different types for "a memory unit" and "an I/O unit".

-- 
   Darren New, San Diego CA, USA (PST)
   Insanity is a small city on the western
   border of the State of Mind.

Post a reply to this message