Re: VSS Layers introduction

Functionality of appending and/or modifying a node from one branch with
a node from another branch with the same signal path is already
available in VSS. On December 15, 2016 I made the following commit to
GENIVI/vehicle_signal_specification:

https://github.com/GENIVI/vehicle_signal_specification/commit/518dfbeb2a434c9c55ec27e06c84f6e8caf941bd#diff-4a931512ce65bdc9ca6808adf92d8783

The commit message states:

>>>>>

Allow appending and modification of signals

The specification allows appending and modification of signals defined
in one branch by the same signal in another branch. For example the default
signal Drivetrain.Transmission.Speed defined as

- Speed:
  type: Int32
  min: -250
  max: 250
  unit: m/s
  description: Vehicle speed, as sensed by the gearbox.

in spec/Signal/Drivetrain/Transmission.vspec could have some fields adjusted
by a private branch spec/Private/OEM/Drivetrain/Transmission.vspec

- Speed:
  min: -10

to just update the minimum speed.

Previously, that did not work as the entire node was replaced resulting in
a 'crippled' node. That is resolved. All fields, except for type, can be
modified
and new fields can be added.

Signed-off-by: Rudolf J Streif <rstreif@jaguarlandrover.com>

<<<<

I created the functionality to allow the addition of proprietary CANdb
frame specs to signals from a private OEM branch.

Now that does not cover everything from Gunnar's slides (in particular
there is no wildcard support) but it's a starting point.

:rjs

On 1/14/20 12:26 PM, Gunnar Andersson wrote:
> As requested today, here is a link to the introduction/rationale slides
> for "VSS Layers".   
>
> A small caveat, this presentation is a work in progress and describes
> the rationale on a very fundamental level.  The idea is simple of
> course, and very generic, because it is useful/needed in a whole bunch
> of areas, not only for access control even if that that was one of the
> driving areas.
>
> There of course needs to be some work to tie this into the W3C protocol
> specifics by means of examples etc.  We concluded today that it is
> basically in line with what is needed in Ulf's recent implementation
> work as well as previous similar things that Daniel mentioned had been
> tried in his organization in the past, so hopefully this is useful,
> even if it does not today provide all the concrete examples in the W3C
> protocol context.
>
> Happy to have the discussion about comparing this to previous similar
> ideas and to define more of the details.
>
> Thanks,
> - Gunnar
>
> [1] 
> https://at.projects.genivi.org/wiki/pages/viewpageattachments.action?pageId=40402952&sortBy=date&highlight=VSS+composable+layers+-+draft+20200114.pdf&&preview=/40402952/47711024/VSS%20composable%20layers%20-%20draft%2020200114.pdf
>
> or shorter:
> https://bit.ly/2TnrV05
>
-- 
-----
Rudolf J Streif
CEO/CTO ibeeto
+1.855.442.3386 x700