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Systematic Method for Minimizing Boolean Functions Over Inequalities With Semantic Dependencies Among Input Parameters

IP.com Disclosure Number: IPCOM000100132D
Original Publication Date: 1990-Mar-01
Included in the Prior Art Database: 2005-Mar-15

Publishing Venue

IBM

Related People

Peysakh, J: AUTHOR

Abstract

A technique is described whereby a systematic method of translating inequalities provides direct and inverse transformations of inequalities to and from a Boolean form. The method further allows the minimization of Boolean functions with semantically dependent input parameters. The concept is important for practical implementation of an Editor for multi-dimension version control of parametric files.

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Systematic Method for Minimizing Boolean Functions Over Inequalities With Semantic Dependencies Among Input Parameters

       A technique is described whereby a systematic method of
translating inequalities provides direct and inverse transformations
of inequalities to and from a Boolean form. The method further allows
the minimization of Boolean functions with semantically dependent
input parameters.  The concept is important for practical
implementation of an Editor for multi-dimension version control of
parametric files.

      Typically, in the development of computer software, the term
"version" applies to a set of programs which are mainly the same, but
have certain variations.  Programs may vary in several different
dimensions, some of them being discrete (like operating system or
compiler) and the others being continuous (like time or version
numbering system). Alterations along the dimensions of a continuous
nature generate sequential versions, in contrast to alterations along
the discrete dimensions which could be viewed as concurrent versions.

      For example, versions "R2 05/02/88 VM" and "R2 05/09/88 VM" are
time-sequential versions of Release 2 (referred to as R2) for Virtual
Machine Operating System (referred to as VM) generated on May 2, 1988
(referred to as 05/02/88) and on May 9, 1988 (referred to as
05/09/88).  On the other hand, versions "R2 05/02/88 VM" and "R2
05/02/88 MVS" represent concurrent versions of Release 2 (R2)
generated on May 2, 1988 (05/02/88) for operating systems VM and MVS,
respectively.

      Maintenance problems can therefore arise when alterations must
be made to the related versions sets, requiring two distinct
modification procedures, such as:
$ A modification to common parts of all versions will require the
determination of all programs from the set and the physical
correction of the problem in every single version that applies.  This
type of modification is very elaborate, error prone and expensive to
implement.
   $ A modification to varying portions of some subset, and
potentially the entire set, of such versions demands an exact
determination of the versions that belong to the subset chosen by
some criteria.  This is then followed by a modification of some code
segment in one of them, then the search for the corresponding piece
of code in the other version, so as to perform a relevant
modification on all versions one at a time.  Due to different sizes
of the code segments, this kind of modification is even more of an
elaborate and expensive modification procedure than the first.

      Known methods of maintaining sequential (and sometimes even
concurrent versions) are implemented as delta-files (as in an XEDIT
environment), conditional compilations (in BAL, PL/I, SCRIPT, etc.)
and alike.  However, difficulties exist when the number of delta
files or conditional instructions, particularly those controlling the
environment, increases. It then becomes difficult t...