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Browse Prior Art Database

Managing Alternate Views of Virtual Storage

IP.com Disclosure Number: IPCOM000118747D
Original Publication Date: 1997-Jun-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 4 page(s) / 77K

Publishing Venue

IBM

Related People

Evans, KR: AUTHOR [+2]

Abstract

Disclosed is a mechanism for managing alternate views (also referred to here as sub-views) of the same virtual storage within an addressable space of computer memory. The ability to manage multiple views of storage is provided by a set of tables and associated control structures, as depicted in the Figure which follows. A table (called the sub-view range table) is provided to describe the "viewability" of each segment of virtual storage which is defined through sub-views. Note, in MVS/ESA with a 2 gigabyte address space comprised of 2048 1-megabyte segments, each of which contains 256 4-kilobyte pages, this table would consist of 2048 entries.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Managing Alternate Views of Virtual Storage

      Disclosed is a mechanism for managing alternate views (also
referred to here as sub-views) of the same virtual storage within an
addressable space of computer memory.  The ability to manage multiple
views of storage is provided by a set of tables and associated
control structures, as depicted in the Figure which follows.  A table
(called the  sub-view range table) is provided to describe the
"viewability" of each  segment of virtual storage which is defined
through sub-views.  Note, in  MVS/ESA with a 2 gigabyte address space
comprised of 2048 1-megabyte segments, each of which contains 256
4-kilobyte pages, this table would  consist of 2048 entries.

The structure is depicted in the following diagram:

                            (Image Omitted)

      Each sub-view range table entry describes one segment of
virtual storage and the ability of that storage to be manifested in
the various sub-views.
  o  Some entries describe segments which are globally viewable,
      i.e., viewable in all sub-views.
  o  Some entries may not have been described in any sub-views
      and, therefore, are viewable in no sub-views but are
      available for assignment.
  o  Some entries may describe segments which are assigned at a
      more granular level, i.e., at the page level.  In this
      case, the entry points to a lower level table, called the
      sub-segment range table.
  o  All other entries describe segments which can only be viewed
      in specified sub-views, either a single sub-view or multiple
      sub-views.  When the...