Specifying candidate printers
With BSC 3270, using VTAM®, requests for copying the screen content to a printer are directed to the first available printer on the same control unit as the screen.
Definition: First available printer refers to the sequence of TERMINAL macros for the devices. A predetermined sequence controls the order in which the printer components are selected for message output. The following figure shows two display workstation printer groups.
The first printer defined after a display is a candidate printer for that display. Any subsequently defined printer is also a candidate if no display is defined between it and the first candidate. In the preceding figure, if a request is made for a printed copy of Display 1 or Display 2, IMS sends a 3270 copy command to Printer 3, if it is available. If Printer 3 is not available, IMS considers Printer 4. Printer 6 is not a candidate for Display 1 or Display 2, but it is a candidate for Display 5.
The copy function is not permitted to cross 3270 control-unit boundaries. For IBM® 3274 and 3276 with SNA protocols, IMS sends the print request to the display, and the printer is selected by the controller. The printer need not be defined to IMS.