[Coco] CocoNIC

[RETRO Innovations]

On 9/17/2016 3:46 AM, Brett Gordon wrote:
> Jim, I took Barry to mean just that: drivewire over tcp. So the stack would
> be like this:
>
> Hdbdos
> drivewire
> tcp
> ip
> ethernet
> coconic
> (Ancillary needed protocols: arp, and maybe dhcp)
Understood, but drivewire is a "stream" protocol, while tcp/ip is mainly 
a "packet" protocol.  And, HDBDOS is probably a packet protocol.  The 
double conv makes life more difficult.

HDBDOS:  save sector 5
DRIVEWIRE: <save sector>
                       <5>
                        <0> number of bytes in lo/hi format.
                       <1>
                        <byte 0>
                     <byte 1>
                      ...
                      <byte 255>  (I am making some assumptions on DW, 
but it has to be something like that...

So, to make this work, the code under DW and the becker port has to go:

GOt <save sector>, store cmd
got <5>, store
got <0> store in low byte of length
got <1> store in high byte
Now, loop until we get <len> bytes
Uh oh, what if the code stops sending me bytes before the end?  Do I 
wait, or kill the command?
Ah, done with byte storage
Now, go parse save sector 5 with 256 bytes

In essence, I think the code under DW will have to parse DW commands to 
know what to do, even if it just passes the data off to a DW server, 
because it has to know when it is OK to send a packet (so it has to 
parse the commands to get the length).  It seems easier to just hook the 
HDBDOS commands directly as a peer of DW.

JIm


> So what Barry's suggesting is mostly a software thing.  Here's the fun
> part:  Hdbdos is out of ROM space and RAM space... banking is a solution to
> ROM.  the lack of RAM may be a harder nut to crack.
Well, if your RAM needs are modest, I just picked up some 32kB SRAM for 
a price that will only add $1.50 to the design.  But, it's not 128kB :-)

I did not realize HDBDOS is out of space.
>
> Given your c64 experience, and our quite smaller pool of programmers, I
> wouldn't do more on the hardware end until our programmers *prove* they can
> hold up their part of the bargain! :)
Hehe.  Well, I don't want to sound demanding, just noting that I really 
am at a disadvantage as a 6809 programmer.

Jim