Browse Prior Art Database

Methodology for Accessing a Large Amount of Data

IP.com Disclosure Number: IPCOM000116718D
Original Publication Date: 1995-Oct-01
Included in the Prior Art Database: 2005-Mar-31
Document File: 2 page(s) / 29K

Publishing Venue

IBM

Related People

Thompson, DK: AUTHOR

Abstract

Disclosed is a methodology for accessing data by a Relative Byte Address (RBA) greater than 4GB using the Virtual Storage Access

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 100% of the total text.

Methodology for Accessing a Large Amount of Data

      Disclosed is a methodology for accessing data by a Relative
Byte Address (RBA) greater than 4GB using the Virtual Storage Access

Method (VSAM*).  This relative byte value may not be contained in one
full word of storage.

      When the location of a record within a data set is specified as
an RBA, the access to the record is limited by the size of the
argument which is used to contain the relative byte address.  The
data may be described by an argument which exceeds a full word of
storage when a mechanism is used to specify the length of the
argument.  The relative byte address specified in the argument is
divided by the logical record length to determine the logical record
which contains the requested relative byte.

      The logical record containing a specified byte is accessed
using an algorithm to convert the logical record number to a location
on the device.  Byte addressability is not required to locate a
record containing data.  If a limit of 4G is placed on the number of
logical records which are allowed, the size of the data may be
increased to 2TB (tera-bytes) for a 512 byte logical record or 128TB
for a 32K byte logical record.
  *  Trademark of IBM Corp.