SEND MAP control options

There are many control options for the BMS SEND commands. Some apply only to particular devices or special features of BMS, and we defer describing these until we get to the associated device support or feature. The following device control options, however, apply generally.

  • ERASE, ERASEAUP, and FRSET all modify the contents of the device buffer, if the terminal has one, before writing your output into it. ERASE sets the entire buffer to nulls (X'00'). If the terminal has the alternate screen size feature, ERASE also sets the buffer size. Therefore, the first SEND MAP in a task normally specifies the ERASE option, both to clear the buffer and to select the buffer size. See 3270 write commands in The output datastream for more information about alternate screen size.

    ERASEAUP (erase all unprotected fields) sets the contents of all fields in the buffer that are unprotected (that is, fields which the operator can change) to nulls. This is useful for data entry, as we explain in DATAONLY option in Merging the symbolic and physical maps.

    FRSET (field reset) turns off the modified data tag of all fields in the buffer; 3270 field attributes explains more about this option.

  • FREEKB (free keyboard) unlocks the keyboard when the output is sent to the terminal. You typically want to do this on a display terminal.
  • ALARM sounds the audible alarm, if the terminal has one.
  • FORMFEED, PRINT, L40, L64, L80, and HONEOM are specific to printing and are explained in CICS 3270 printer options. NLEOM also is used mainly in printing, and is explained in the same section. NLEOM requires standard BMS.
Some of these options can also be specified in the map itself, in particular, the options that are expressed in the 3270 write control character and coded in the CTRL option of the DFHMDI or DFHMSD macros: PRINT, FREEKB, ALARM, FRSET, L40, L64, L80, HONEOM.
Note: CTRL options are always treated as a group, so if you include any of them on your SEND MAP command, BMS ignores the values for all of them in your map definition and uses only those in the command. As noted earlier, you can also send device control options separate from your map data, using a SEND CONTROL command. You can use any option on SEND CONTROL that you can use on SEND MAP, except those that relate expressly to data, such as NLEOM.

Other BMS SEND options: WAIT and LAST

When a task writes to a terminal with a BMS or terminal control SEND command CICS® normally schedules the transmission and then makes the task ready for execution again. Actual transmission occurs later, depending on terminal type, access method and other activity in the system. If you want to ensure that transmission is complete before your program regains control, use the WAIT option.

WAIT can increase response time slightly, because it prevents overlap between processing and output transmission for a task. (Overlap occurs only until a subsequent SEND, RECEIVE, or end of task, however, because CICS finishes one terminal operation completely before starting another.)

You can improve response time slightly for some terminals by using the LAST option. LAST indicates that the output you are sending is the last output for the task. This knowledge allows CICS to combine transmission of the data with the z/OS® Communications Server end-of-bracket flow that occurs at end of task.