A piped array of "octets" (C style character bytes, like void*) of nil or more length is probably the most basic interface possible for relevant hardware.
A structured interface introduces much more complexity. Rather than standardize on any specific 'wire' format a better approach might be to have a bi-directional connection and a standard for negotiating across it.
This might allow different forms of communication (E.G. a shared ringbuffer), negotiation of protocols, signaling when ready / blocked / needing more to proceed, what format(s) to use and if multiple streams should be used (as well as how to multiplex them)... etc. Programs might even be added to the middle to setup the preferences between two applications and then tell the OS that they're done and to just connect the input and output directly.
A structured interface introduces much more complexity. Rather than standardize on any specific 'wire' format a better approach might be to have a bi-directional connection and a standard for negotiating across it.
This might allow different forms of communication (E.G. a shared ringbuffer), negotiation of protocols, signaling when ready / blocked / needing more to proceed, what format(s) to use and if multiple streams should be used (as well as how to multiplex them)... etc. Programs might even be added to the middle to setup the preferences between two applications and then tell the OS that they're done and to just connect the input and output directly.