Defining Segments, Files, and Areas › Planning › Page Ranges

Page Ranges

Areas are made up of contiguously numbered pages. The low and high page numbers assigned to an area define its page range. The page range of an area:

• Must not overlap that of any other area in the same segment
• Must not overlap that of any other area in a segment included in the same DMCL if the two segments have the same page group

When an area is defined, pages can be reserved for future expansion by using the MAXIMUM SPACE clause. If specified, CA IDMS ensures that no other area included in the same DMCL has a page range that overlaps both the currently allocated and the reserved space. By reserving additional pages, you are assured of being able to extend the area's page range without unloading and reloading the data.