[Coco] os9/drivewire driver: success!

[Aaron Wolfe]

On Tue, Nov 10, 2009 at 2:54 PM, William Astle <lost at l-w.ca> wrote:
> Aaron Wolfe wrote:
>> One question about combining SERREAD and SERCHECK:
>>
>> My original idea was that SERCHECK would return the number of bytes in
>> the server's buffer, and then SERREAD would ask for a flush of X
>> bytes, typically the number returned by SERCHECK.  The server would
>> then write out the # of bytes requested.  This was (in my head) a way
>> to improve performance for things like rzsz over the virtual serial
>> port.
>>
>> By combining them, I will be cutting the potential throughput in half
>> since there are two bytes for each data byte, and also taking a
>> penalty of having to ask for each byte individually (which is
>> admittedly how my current driver works, but it was supposed to be
>> better :)
>>
>> Are there outside factors that mitigate the losses in combining the
>> calls?  If there is some other reason it will be slow anyway, then I
>> agree it would make it simpler to combine them.
>> -Aaron
>
> Why not make the request include a maximum number of bytes to return.
> Then have the response include the number of bytes returned and those bytes.
>
> This would require tinkering the drivewire scheme so it could handle
> variable length return packets in some manner but it should provide the
> maximum theoretical efficiency.
>

This would be nice, but as it stands the dw calls require you to know
how many bytes are coming/going when you call them.. not sure if I'm
ready to touch anything in dw itself :)  maybe at some point though..
i agree this would be ideal.

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