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Release N-> N-1 Version Number Method With Downlevel Code And Fix Direction

IP.com Disclosure Number: IPCOM000101068D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 3 page(s) / 109K

Publishing Venue

IBM

Related People

Ricard, GR: AUTHOR [+2]

Abstract

Version number methods for preventing the transfer of objects from an uplevel system onto a downlevel system are quite common. However, when downleveling is permitted such that an object on an uplevel system is transformed for compatibility with an earlier level system, a method of object version identification must be devised which prevents downleveling if the downleveling transformation has not been performed and prevents transfer of an object between systems which have version-changing fix mismatches regardless of whether or not a downleveling transformation has been performed. (A version-changing fix is one which causes object transformations that are incompatible with the code as it existed prior to the version-changing fix.)

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Release N-> N-1 Version Number Method With Downlevel Code And Fix Direction

       Version number methods for preventing the transfer of
objects from an uplevel system onto a downlevel system are quite
common.  However, when downleveling is permitted such that an object
on an uplevel system is transformed for compatibility with an earlier
level system, a method of object version identification must be
devised which prevents downleveling if the downleveling
transformation has not been performed and prevents transfer of an
object between systems which have version-changing fix mismatches
regardless of whether or not a downleveling transformation has been
performed.  (A version-changing fix is one which causes object
transformations that are incompatible with the code as it existed
prior to the version-changing fix.)

      Version numbering algorithms require that two basic types of
version numbers exist, one associated with an object to be
transferred between systems, and one associated with the current
level of code on a system.  This method requires that these version
numbers be encoded such that each version number contains the
following three fields:

      FIELD NAME     DESCRIPTION
RELEASE     A release number indicating the the current release of
code with which an object is compatible.
FIXVER  A fix version number which indicates the level of fixes with
which an object is compatible. It is assumed that the current fix
level contains all previous version-changing fixes.
NUMRELS            The number of releases for which a version-
changing fix applies, that is, the number of releases until the
version-changing fix and all previous version-changing fixes are
included in a base release (i.e., no additional version-changing
fixes need be applied to bring the base release to the most current
code version.)

      Consider a version-changing fix which occurs late in release 2
and is fixed in the base of release 4.  The following values are
assigned to the code version for each release according to the table
shown in the figure on the next page.

      In general the following rules apply:
-    When a new object is created it is assigned the current code
version number as its object version number.
-    When a new code version number is needed because a new release
is available that contains features incompatible with the old
release, then RELEASE     is incremented but FIXVER     remains
constant.  NUMRELS is zero if all current version-c...