User:AndrewJohnson/Channels as URIs

ACTION ITEMS item #3482213: AI on AJ by Feb 14: Describe protocol distinction problem, his prefix namespace solution, and illustrate with his proposal for what "ezpva" get of 2 channels (one v3 and one v4) should look like.

The fundamental concept of a PV name is common to both Channel Access and PV Access, as are many of the operations that can be performed with one. However the two do not share a common namespace, in that names searched for using Channel Access will not be found if they only exist in PV Access, and vice versa. It is highly desirable to be able to create names that indicate which namespace they are found in, so that users don't have to use a completely different set of tools to work with Channel Access channels than with PV Access.

CSS has already has a solution to this issue, it adopted a standard approach and syntax developed by the internet community: Channel Access PV names start with the prefix ca:// (the original epics:// prefix is being phased out) and according to Gabriele Carcassi PV Access names will use the prefix pva://. CSS provides a configuration parameter that allow a default prefix to be chosen so that names can be given without specifying the prefix.

I recommend that all PV Access tools should search for ...