Browse Prior Art Database

Method to Locate Keyed Data Associated with a Logical Unit

IP.com Disclosure Number: IPCOM000116681D
Original Publication Date: 1995-Oct-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 33K

Publishing Venue

IBM

Related People

Thompson, DK: AUTHOR

Abstract

Disclosed is a design for Virtual Storage Access Method (VSAM*) indexes which allow for access to data with a Relative Byte Address greater than what may be represented by one full word (4 bytes) of storage. These indexes may contain more data than may be addressed by a relative byte address (RBA) contained in one full word of storage.

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Method to Locate Keyed Data Associated with a Logical Unit

      Disclosed is a design for Virtual Storage Access Method (VSAM*)
indexes which allow for access to data with a Relative Byte Address
greater than what may be represented by one full word (4 bytes) of
storage.  These indexes may contain more data than may be addressed
by a relative byte address (RBA) contained in one full word of
storage.

      The index contains many records to describe the location of
data contained in the associated data component.  This advance deals
with changing the contents of the index to contain a number for the
logical unit containing the data.  This number is the number of the
first logical record in the logical unit.  Each entry in the index
record describes the location of the associated data record for the
index entry.

      The index contains records which describe the location of other
index records to locate the index record which is used to locate the
data.  An index entry used to obtain the location of an index record
contains the logical record number of the associated index record.

      The index records which are used to locate the data are said to
be at one level.  The index records which locate the index data are
at the next level, and so on.  The index records at one level contain
the number of the next index record at the same level with the last
index record at a level containing zero.
  *  Trademark of IBM Corp.