Input and output editing options (SLU P)

The type of editing subparameter in the COMPTn parameter of the system definition TERMINAL macro and the Extended Terminal Option (ETO) logon descriptor can be indicated at a component-by-component level for input to and output from components defined as SLU P.

The four types of editing provided are:
BASIC
Requests that no deblocking be performed on input to IMS. MFS cannot be used on input or output.
BASIC-SCS1
Requests that deblocking occur when an SNA character string (SCS)-defined new line (NL-X'15') or form feed (FF-X'0C') character is sent to IMS. MFS is not used on input or output.
MFS-SCS1
Requests that deblocking occur when an SCS-defined new line (NL-X'15') or form feed (FF-X'0C') control character is sent to IMS. MFS-SCS1 formats can be used for both input and output.
DPM-An
Allows messages to be formatted using MFS distributed presentation management (DPM). No deblocking on input to IMS is performed. ‘n' is a number from 1 to 15.

For DPM, the device type symbolic name is specified to MFS as DPM-Xn, where X is A or B. Message formatting is specified on the TERMINAL macro for logical units defined as SLU P by using device type symbolic names of the form DPM-An. DPM-Bn device type symbolic names refer to logical units defined for Intersystem Communication (ISC).

If BASIC or SCS1 is specified, each message received or sent by IMS as one or more related transmissions forms a VTAM® chain:
  • For BASIC, each input transmission to IMS, less any supplied input FM header, is treated as an IMS segment to be presented to MFS or directly to the IMS message processing program.
  • For SCS1, an IMS input segment is created at each SCS-defined new line or form feed control character. IMS segments can be created from a portion of, from all of, or from more than one spanning transmission.

For either BASIC or SCS1, each output segment is sent by IMS in a single transmission, unless it and any IMS-appended FM header are larger than the logical unit's buffer size as indicated to IMS by the OUTBUF parameter on the system definition TERMINAL macro or on the ETO logon descriptor. In this case, IMS sends the segment in as many transmissions as required. Each transmission, except possibly the last transmission of a segment, is the maximum-defined output buffer size.

When DPM or MFS-SCS1 is specified, input and output messages can be formatted by MFS DPM or MFS-SCS1, respectively, on a message-by-message basis. Messages that are not to be formatted are edited as previously described for BASIC or SCS1.