On Mon, Jul 31, 2000 11:49 PM, T&B <mailto:list.mac68k@tandb.com.au> wrote:
>I added AT&D0 and got these results:
>
>serial   control        init      kB/s
> 38400   <none>         at&f      2.40
> 38400   cdtrcts        at&f&d0   2.56
> 57600   <none>         at&f&d0   3.34
> 57600   cdtrcts        at&f&d0   3.19, 3.33, 3.89, 3.27   (repeated
tests)
> 57600   cdtrcts        at&f&d0  11.10, 4.02, 4.88
>115200   cdtrcts        at&f&d0   3.14
>
>> and you will see a performance like in MacOS.
>
>I'm getting close, I think. The 11kB/s sustained transfer above indicates
that
>my set up is capable, though I've yet to see the same consistency as my
Mac OS
>router.
>

11.10 is a error probably due to lost clock interupts under heavy load.
57600bps serial link with 8n1 requires 10 Bit/Byte over the serial
link to transmit one byte, so the MAX KB/sec is:
KB/s= (57600 bit/sec) x ( byte/10 bit) x ( KiloByte/1024 Byte)

 3.75  KB/sec = (38400/10*1024)
 5.625 KB/sec = (57600/10240)
11.25  KB/sec = (115200/10240)

When testing the modem's performance you need to use 
compressed files for testing. 
And you need to know the Rx connection speed for that
connection.

Let's say you have a perfect connection (not a good asumption)
and the Rx rate is 53000bps. what is the maximum KB/sec? 
~5.175 KB/sec. (symbol rate)

But what if the file being transfered is very compressable?
Then the transfer can be limited by the speed of the serial
port (assuming that the symbol rate is grate enough.)

To test the maximum performance of the serial port you need to
find a file (to ftp) that is very compressable.




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