Glossary

A node is the physical runtime platform for a Jtrix application. A node may span one or more machines, or (probably more for demonstration purposes and testing) several nodes may run on one machine. Several Jtrix applications can run simultaneously on one node.

A netlet is a self contained program which runs on a Jtrix node. A netlet is written in terms of the Jtrix base API, which is implemented by the node. A netlet runs in a virtual environment, allowing platform mechanisms such as files and sockets to be used, even though these mechanisms may manipulate simulated or remote resources.

A service is a resource available to a netlet.

A netlet is entitled to use any service for which it holds an appropriate warrant. A warrant is evidence that a contract exists between the netlet and the service. Warrants may be transferred between netlets, after which the recipient netlet may use the service. Different warrants may apply to the same service, conferring different rights to that service.

A netlet is said to bind a warrant when it connects to a service. When a netlet binds a warrant to connect to a service, an appropriate new netlet is created on the node to supply the service. The netlet created may be specified statically as part of the warrant or dynamically by a binding server. The two netlets are then connected.

The connection between the two netlets is the service session. A service netlet may, under certain circumstances, supply the same service to more than one netlet. In this case we get a second service session.

Through a service session, a netlet may access one or more facets which are interfaces implemented by the netlet providing the service. These facets provide the service functionality. Depending on the warrant used to bind the service, different facets may be available.

All these terms are discussed in more detail in the following sections.