Re: [LAU] Editing zynadsuxfx/yoshimi patches?

On Wed, May 04, 2011 at 09:53:59AM -0400, Paul Davis wrote:
> On Wed, May 4, 2011 at 9:38 AM, Lieven Moors <lievenmoors@email-addr-hidden> wrote:
>
> > I would like to understand better why this is the case.
> > I guess the fundamental reason would be that UDP is an
> > unsafe protocol, because it doesn't perform checks on the
> > data sent or received. But would't that make it equally unsafe
> > in both directions? Isn't this just two osc servers that are
> > sending messages towards each other?
>
> there are two issues. one is the issue of UDP not being "reliable".
> the other is that OSC messages have no serial number on them. if you
> end up sending the same request twice and get two different responses,
> you have no idea which one actually came first unless you simply don't
> use a reliable transport layer. in that case, the one that arrived
> first is the response to the earlier request. but now you've got an
> unreliable transport layer.
>
> > I would expect to be reasonably sure that the reply makes it
> > from one server to another, just as any other messages would.
> > Wouldn't OSC or liblo be totally broken anyway if I couldn't
> > rely on this sufficiently?
>
> if you're using OSC with UDP transport, you have absolutely no
> guarantee of this. of course, if you are working with a wired LAN,
> this is really deeply unlikely to be an issue. but move into a
> wireless LAN let alone WAN configurations and the possibility that a
> UDP packet will simply fail to arrive gets high enough that you do
> have to take it into consideration.
>
> the simple answer, of course, is to use OSC over TCP which I *think*
> liblo can do (and if it can't, it should be easy to make it). but this
> still doesn't address the ordering issue, because OSC itself has no
> concept of serial delivery (or even time).

Thanks! That cleared things up for me.

For now, I think we're good.

Of course, on a professional level, we already have lots of possible
race conditions, but let's just see how far we get with what we have...

As I see it, we can get the necessary info, in order to control an OSC
app (type-signatures, documentation), and start sending out the right
messages in a convenient way. The next step would be to make a
pseudographical interface that would update itself continually with
#current-value queries. But as you say, OSC might not be sufficient
to do that in a reliable way.

BTW: liblo seems to make it very easy to use TCP...

Thanks again for your advice in this,

lieven

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Received on Wed May 4 20:15:05 2011