(For more findings, please refer to minutes and attached documents)
Interfaces between a HAL and the using code in the Android platform are specified with an IDL named HIDL.
HIDL is a variant of Android Interface Definition Language (AIDL). For its specific purpose it seems as appropriate and useful as most other IDLs. In order to realize its benefits however, IDLs really should not be created specific for a platform. Further discussion can be seen in Comparing IDLs.
To summarize, switching IDL is often not by itself a worthwhile activity. The driver for the work on the Vehicle data HAL is rather to understand if another set of frameworks and tools are appropriate to provide a more flexible access to vehicle data. Vehicle data access is today specified with a fairly small/limited interface inside Android.
- Android applications access to the vehicle data. This is the data of the particular car in which an Android-based ECU is located.
- The bigger, as investigated by GENIVI Connected Services project among other things.
Comparing IDLs
GENIVI generally promotes the usage of Franca IDL as a platform- and context neutral choice, a single language to be applied everwhere. However, when creating new to be used only within a specific environment, such as defining new Android services, it might often not a benefit to only replace one IDL with another (typically by creating automatic code-generators and translators).
Doing so only makes sense as part of a larger work, in which a new or developed framework provides additional capability, and/or where scaling advantages are realized by using the same technology and language everywhere.
This section could include a brief IDL comparison to understand the possibility off mapping one IDL/technology to another. (related: A more comprehensive work has been done previously as part of Generic Communication Protocols Evaluation Project)