6. DATA SOURCES › 6.7 z/Architecture Highlights › 6.7.1 Support for 64-bit Real Storage

6.7.1 Support for 64-bit Real Storage

z/Architecture eliminates the overhead of moving data into
and out of expanded storage by providing full 64-bit real
storage addressing.  Instead of arbitrarily partitioning
memory into real and expanded regions, data centers will be
able to run a single system and have the full amount of
installed memory available as real storage eliminating paging
to expanded storage.

Real storage management changes in z/Architecture mode
include:

- Non-fixed pages (including DREF) can be backed anywhere in
  real storage

- Nucleus, SQA and LSQA (except DREF) will be backed below 2
  GB

- Paging I/O is done directly to/from any real frame

- VIO uses frames above 2GB

- Swap page data sets, duplexing of PLPA and common page data
  sets, and virtual fetch are no longer supported

- Expanded storage support is removed.  The hiperspace APIs
  and internal uses of expanded storage are reimplemented to
  use real storage