Use of the term connection

The XCF Note Pad Services use terms and concepts similar to those used by the Sysplex Services for Data Sharing (XES). Although the terms and concepts are similar, they are not the same. This similarity could be a source of confusion to those who are familiar with the terms and concepts as used by XES. Most of the confusion will arise over the interpretation and use of the term connection. Both services use this term to express a similar idea. With XES, a connection must be established in order to access a coupling facility structure. With the XCF Note Pad Services, a connection must be established in order to access a note pad. The fact that XCF Note Pad Services establish a XES connection to support the note pad connection tends to further compound the confusion.

The key distinctions between the two notions of connection are listed below:

The XES Connection Service (IXLCONN) creates a connection to a coupling facility structure. If the structure does not exist, it will be created as a side effect of creating the first connection.
With the XCF Note Pad Services (IXCNOTE), the create of a note pad and the create of a connection to a note pad are distinct operations. A note pad must be created before any connections to the note pad can be created. If a note pad does not exist, any attempt to create a connection to the note pad will fail. The create of a note pad does not cause a connection to the note pad to be created.
If a system loses connectivity to a coupling facility that contains a structure, XES invalidates the connection to the structure (in cases where no alternate instance of the structure is accessible). Programs must then invoke the XES Disconnect Service (IXLDISC) to delete the connection. When connectivity to the coupling facility containing the structure is restored, the XES Connect Service (IXLCONN) must be invoked to create a new connection to the structure.
If a system loses connectivity to a coupling facility that contains a note pad, the note pad connection remains intact. The connector will not be able to access the note pad until connectivity to the relevant coupling facility is restored. But when connectivity is restored, the connector can resume its processing with the same connection token. There is no need to delete and then create a new connection when a system loses connectivity to a note pad.

In the context of a note pad, the term connection refers to a note pad connection. When referring to a connection to a coupling facility structure, the terms XES connection or IXLCONN connection are used.