Defining your printers

Printers are usually output-only devices; however, they can be implemented so that they send input.

You need to decide whether to have single-user or multiple-user structures share the same printer. If your application programs are sensitive to queue names, you might be limited to one or the other approach.

Single-user structure

Using a single-user structure that represents a printer is the simplest method for defining a printer. In this case, messages sent to the printer are printed in the sequence in which they originate. Interleaving of output can occur. Multi-segment messages always have all segments printed in contiguous sequence. Multiple messages might behave differently, depending on their method of origination.

Multiple-user structures

Multiple users are supported for printers. All messages for a single user are printed, and the next user is selected for printing only when the current user has no more output. Although interleaving of messages for the same user occurs as it does for single-user structures, the switching of users can also be equivalent to message interleaving from an application standpoint. Application and operational awareness of the way printers are shared is important.

The challenges of sharing printers are not unique to dynamic terminals, and in fact are the same as for static terminals.

IMS prints a separator page whenever the next message to be printed is from a different user. You can control the contents of this separator page by using an exit routine to change its content; however, this page is always printed, even if blank. Messages from the same user are not separated by a separator page. Using the NOTERM option can prevent the DFS3650 separator message from being used.