[Rock-dev] Periodic task mandatory for needs_reliable_connection?

[Sylvain Joyeux]

I don't really understand the question, sorry ...

needs_reliable_connection is currently only a hint used by syskit (nothing
else uses it). Syskit does *not* require the driver's task to be periodic,
but it *does* require you to specify the "minimum period" (i.e. the minimum
time between two consecutive samples) as produced by the device. Even if
the task is non-periodic, the device usually is. The hokuyo driver, for
instance, is not periodic (it processes data as it comes), and one simply
declares the *device* period in syskit.


On Tue, Apr 15, 2014 at 11:59 AM, Christian Rauch
<Christian.Rauch at dfki.de>wrote:

> Hi,
>
> is there another way to guarantee a reliable connection without periodic
> samples (e.g. indexed samples)?
>
> Our camera (IDS) provides frames as they become available which are then
> processed by the object detection component on a
> 'needs_reliable_connection' port. The only workaround I see so far is to
> call the camera task periodically which results in unneeded calls of the
> updateHook.
>
> What is the common practice on this? Should sensors deliver data
> periodically even if there is no new data or should processing components
> not rely on every single data sample package but only on the last one? Even
> if the task is periodic, a sample might be lost.
>
> Regards,
> Christian
>
>
> --
>  Christian Rauch
>  Space Robotics
>
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