CSPG - page retrieval

Some transactions, especially those performed on screens, produce a response that is too large to be displayed or printed at one time. The whole response is held on direct access storage, and only the first portion (called a page) is displayed. You can manipulate these pages, through basic mapping support (BMS), using the CSPG page retrieval transaction.

You can use paging to view all pages of the response, in any order. All the pages produced by a transaction make up a logical message.

A page retrieval session begins when you enter the first page retrieval command, or when the first page is presented by automatic transaction initiation (ATI). During the session, CICS passes commands directly to BMS terminal paging, without following the normal transaction identification procedure.

When using BMS for IBM 3780 Communication Terminal transactions, switch off the SPACE COMPRESS EXPAND (standard feature), TRNSPCY (special feature), and the INHIBIT IRS (special feature) switches.

Pages to be manipulated with paging commands must have been created by BMS, which must be active in the system to service the commands. Paging commands enable you to:
  • Retrieve a page.
  • Display information about logical messages queued for your terminal.
  • Chain a logical message, that is, retain the previous logical message on direct access storage while you enter a new transaction.
  • Purge a logical message, that is, erase it from direct access storage; a paging session must be ended by purging the message.
  • Copy a page to another terminal.

You select the above functions by entering a unique identification code for each function. This code is 1–7 characters long, and is defined by the PGRET, PGCHAIN, PGPURGE, and PGCOPY system initialization parameters.

Do not use codes that are the same as the leading characters of any transaction defined to CICS by a TRANSACTION resource definition.