V=R area

This area is used for the execution of job steps specified as fixed because they are assigned to V=R regions in virtual storage (see Real regions). Such jobs run as nonpageable and nonswappable.

The V=R area is allocated starting directly above the system region in central storage. The virtual addresses for V=R regions are mapped one-to-one with the central addresses in this area. When a job requests a V=R region, the lowest available address in the V=R area in central storage, followed by a contiguous area equal in size to the V=R region in virtual storage, is located and allocated to the region.

If there is not enough V=R space available in the V=R area, the allocation and execution of new V=R regions are prohibited until enough contiguous storage is made available.

The V=R area can become fragmented because of system allocation for SQA and LSQA or because of long-term fixing. When this happens, it becomes more difficult — and may be impossible — for the system to find contiguous storage space for allocating V=R regions. Such fragmentation may last for the duration of an IPL. It is possible that fragmentation will have a cumulative effect as long-term fixed pages are occasionally assigned frames from the V=R area.