Browse Prior Art Database

Tailored Placement of Storage Descriptors

IP.com Disclosure Number: IPCOM000118295D
Original Publication Date: 1996-Dec-01
Included in the Prior Art Database: 2005-Apr-01
Document File: 2 page(s) / 43K

Publishing Venue

IBM

Related People

Greenstein, PG: AUTHOR [+3]

Abstract

Disclosed is a method for tailoring the placement of storage descriptors in the virtual memory of a computer such that the real memory used to hold those descriptors can be reclaimed and reused for other purposes when the storage they describe is taken offline (removed from use) or does not exist.

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This is the abbreviated version, containing approximately 77% of the total text.

Tailored Placement of Storage Descriptors

      Disclosed is a method for tailoring the placement of storage
descriptors in the virtual memory of a computer such that the real
memory used to hold those descriptors can be reclaimed and reused for
other purposes when the storage they describe is taken offline
(removed from use) or does not exist.

      Storage descriptors are kept in a contiguous array in virtual
storage, arbitrarily backed in real storage, and accessed via index.
This organization provides the best possible performance for storage
descriptor access.  Nevertheless, it also introduces a problem.  When
storage is taken offline, it is rarely possible to reclaim the real
storage used to describe offline storage units.

      The described technique allows the descriptors for a
reconfigurable unit of real storage (storage element) to be contained
within that unit.  Thus, when the unit is reconfigured offline, or if
it does not exist, the corresponding set of descriptors does not
reside in online real storage.

      For each storage element, select a subincrement (or a set of
subincrements) within it to contain descriptors for storage in that
element.  Assuming that storage element 0 contains real storage
addresses a through b, and subincrement xx within storage element 0
contains real  addresses p through q, map the virtual storage for the
descriptor table  part defining the range a--b into real storage
range p--q.

      The descriptor...