COM+ Queued Components Automatic asynchronous messaging is an
important technique for scalable, component-based applications.
Microsoft provided its first asynchronous messaging mechanism in
the form of Microsoft Message Queue Server (MSMQ). This
technology is the basis for Queued Components, a COM+ feature
that makes asynchronous messaging as simple as calling regular
COM Components. Asynchronous messaging is an established
technology that is one of the fundamental building blocks of
many Windows DNA applications. In short, asynchronous messaging
is a technique in which tasks are initiated by a component or
application, but are executed in a delayed fashion while the
caller proceeds immediately with other tasks. This is useful in
a variety of scenarios. Imagine an online store, for instance.
Shoppers order items, go to the checkout screen, and click a
button to complete the order. At that point, a backend
application performs a number of tasks. Credit card information
is verified, inventory is adjusted, the