Creating Invoke Medium Map (IMM) structured fields
To ensure that pages are reprinted (or viewed) by using the correct medium map, retrieval programs must be able to detect which medium map is active. To ensure that the correct medium map is used, use the Active Medium Map triplet and the Medium Map Page Number triplet (from the appropriate Index Element (IEL) structured field in the index object file), which designate the name of the last explicitly called IMM structured field and the number of pages that are produced since the IMM was called. The retrieval system can use this information to dynamically create IMM structured fields at the appropriate locations when it retrieves a group of pages from the archived document file.
If an ACIF input file consists of more than one document (determined by the BDT and EDT structured fields) and INDEXOBJ=BDTLY is not specified, ACIF removes all BDT and EDT structured fields when it processes the file. This action can cause a document to begin with an incorrect medium map. To prevent an incorrect medium map from being used, specify INSERTIMM=YES. ACIF inserts the appropriate IMM before the first page that was indicated by the BDT structured field that ACIF removed.