Requests for printed output

A CICS print request asks CICS to copy what is on the requesting screen to the first available printer on the same control unit. The overhead involved depends on whether a printer is available, and whether the requesting terminal is remote or local to CICS.

If no printer is available, and the request is from a remote or a local device:
  • CICS reads the buffer to the display terminal. This involves transmitting every position on the screen, including nulls.

    For requests from a local device, the READ BUFFER command takes place at channel speeds, so that the large input message size does not increase response time too much, and does not monopolize the line.

  • An error task is generated so that the terminal error program can dispose of the message. If a printer is available and the request is from a local device, this step is not needed.
  • The 3270 print task (CSPP) is attached to write the entire buffer to the printer when it is available.

If a printer is available, and the request is from a remote device, CICS sends a very short data stream to the control unit asking for a copy of the requesting device buffer to be sent to the output device buffer.