Understanding queues

As we learned in Chapter 1, Introduction and Installing Tuxedo, parts of Tuxedo's APIs were standardized in XATMI specifications with the hope that developing applications according to XATMI specifications would lead to vendor-neutral solutions and it would be easy to port applications from one XATMI implementation to another. This idea looks good on paper, but no specification can cover all aspects of behavior and be abstract at the same time. No surprises there.

The server provides resources that the client can access. A server can also act as a client and ask for the resources provided by another server as shown in the following diagram. The XATMI specification does not say how the request and response should be delivered between the client and server:

Figure 3.1 – Client-server model

Tuxedo uses queues for that. Servers have a request queue where they receive requests from clients. Servers and clients have a response...