Re: Apple II modem question: How can you go at 19200 when apple II isnt this fast?

[Eric Jacobs <no@no.no>]

itsme wrote:
> 
> I don't think that an apple II can even think at 9600 bps.  (tell me if I
> am wrong)
> 
> Maybe it can, but 19200?  (tell me if it can)
> 
> Does a serial card do buffering so the apple can handle information coming
> in at these speeds, or can it in fact process information or at least
> store it when data is at this speed?

I look at it this way: 19200 bps is at -MOST- 19200/8 or 2400 bytes per second.
Typically it is less than that.

The Apple II is a 1 MHz machine: therefore it can do 1,000,000 cycles per second.

So in order for an Apple II to receive at 19.2 kbps, the program you're
running must be able to receive one byte in a 1,000,000 / 2400 =
416 cycles/byte loop.

In 6502 machine language, it DEFINITELY is possible to store this rate of
data, at least in memory. If it is possible to do something else with it
in that time period, that depends on the software and the task you want to
do.

I didn't do much modemming before I got my GS, but on the GS, my multitasking
BBS software handles two 57.6k serial ports with no problem. (The GS/OS
.CONSOLE driver is what really kills it.)

-ej