Coding for the 3270 ‘unavailable printer' condition

About this task

The ‘unavailable printer' condition arises when a print request is made using the 3270 print request facility, and there are no printers on the control unit, or when the printers are in one of the following conditions:
  • Out of service
  • Not in TRANSCEIVE or RECEIVE status for automatic transaction initiation
  • With a task currently attached
  • Busy on a previous operation
  • Requiring intervention.

The procedure is applicable to 3270 logical units or to the 3270 compatibility mode logical unit when using the PRINTER and ALTPRINTER operands of the CEDA DEFINE TERMINAL command.

The terminal control program recognizes this condition, and issues a READ BUFFER request to collect the data into a terminal I/O area. The TIOA is of the same format as it is when an application program has issued a terminal control read buffer request.

The terminal control program z/OS® Communications Server section (DFHZCP) then queues the TCTTE to the node abnormal condition program with error code X'42' (TCZCUNPRT). The node abnormal condition program (DFHZNAC) writes to the CSNE transient data queue:
  • DFHZC2497 UNAVAILABLE PRINTER (device types 3270P and LUTYPE3)
  • DFHZC3493 INVALID DEVICE TYPE FOR A PRINT REQUEST (all other printer device types).

Before linking to the node error program, DFHZNAC inserts the primary and secondary printer netnames and terminal IDs into the communication area, indicating also whether either printer is eligible for a print request. DFHZNAC links to the node error program with no default actions set.

On return from the node error program, DFHZNAC checks the additional system parameter TWAUPRRC in the communication area (see Figure 2) and, based on its contents, performs one of the following actions:
  • If your NEP sets TWAUPRRC to X'FF' (-1), DFHZNAC assumes that the node error program has disposed of the data to be printed and therefore takes no further action.
  • If your NEP sets TWAUPRRC to zero, DFHZNAC assumes that no printer is available and takes no further action.
  • If your NEP sets TWAUPRRC to neither zero nor -1, DFHZNAC assumes that one of either field TWAPNETN or field TWAPNTID is set. (If both are set, TWAPNTID(termid) takes precedence.) An interval control PUT is performed to the provided terminal. The transaction to be initiated is CSPP (print program), and the time interval is zero.
    • If an error occurs on the interval control PUT, DFHZNAC writes the ‘DFHZC2496 IC FAILURE' message to the destination CSNE. DFHZNAC then links to the node error program again with the TWAUPRRC field set to -2. This is done to give the node error program a last chance to dispose of the data. On the second return from the node error program to DFHZNAC, the latter reexamines TWAUPRRC. If TWAUPRRC is -1, then the node error program has disposed of the data.
    • If no error occurs on the interval control PUT, DFHZNAC checks for the following printer conditions:
      • ‘Out of service'
      • ‘Intervention required'
      • Any condition other than RECEIVE or TRANSCEIVE status.

      If one of these conditions is true, DFHZNAC issues the ‘DFH2495 PRINTER OUTSERV/IR/INELIGIBLE-REQ QUEUED' message to the destination CSNE.

Finally, DFHZNAC terminates any print requests on the originating terminal and performs normal action flag processing on that terminal.