[hpsdr] Odyssey dsPIC33 RAM usage

[Murray Lang]

Frank Brickle wrote:
> ... One last observation about this, and then I will retire from 
> haranguing you and the group. ...
>
Me too. Sorry about the waffle everyone.

Yes, connections are messages and those messages get passed via queues 
(which might have a maximum size of 1). Messages can contain data and/or 
commands. So as well as passing buffers, the queue could contain 
commands originating from the executive such as "cleanup", "reset", 
"die" etc. Where a third party kernel might fall short is with a "T" 
connector, which copies the message to two outputs: one connecting to, 
for example, an IFFT and the other to a panoramic display. All of the 
message objects could be preallocated in a pool, to which they are 
returned when they are finished with.

I was first introduced to this exact scheme at University in late 1990 
with the IBM AVK Kernel, which was the driver for their Microchannel 
video and audio capture card. It was actually written by Asymmetrix, who 
then had a very successful product called "ToolBook". This was my first 
glimpse of professional, production C code and I was struck by how 
beautiful it was. The similarity to the Windows 3.0 message based 
multitasking kernel was obvious at the time.

QRT already.

Murray VK6HL


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