6.3. Out-of-Band Data Transfer
In the event section, we looked at how small event data can be communicated to various services or service components using e-Speak’s event model. The amount of data we sent with each event was rather small — several bytes in size. In this section, we discuss service architecture to facilitate bulk data transfer.
We have been using the e-Speak engine to do data transfer without realizing it.
All the remote procedure calls (RPCs) between services and their clients are, in fact, a few code messages being sent through the engine. The engine acted as the conduit in this case to create an end-to-end channel between two software components connected to it.
In the User Data service in Chapter 4, we first exposed this ...