Diversity and Multi-Version Systems - Nuclear Power Plant Instrumentation and Control Systems for Safety and Security - page 189

MAIN CONCEPTS AND MODELS OF
MULTI-VERSION COMPUTING

product VR is realized jointly with structure, time
and other types of non-version redundancy.
Diversity or multiversity (MV) is a principle
providing use of several non-trivial versions; this
principle means performance of the same function
(realization of products or processes) by two and
more options and processing of data received in
such ways for checking, choice or formations of
final or intermediate results and decision-making
on their further use.
Multi-version system (MVS) is a system, in
which a few versions-products are used; one-
version systems may be redundant but consist
of a few trivial versions. Multi-diversion system
(МDVS) is MVS, in which two or more VR types
are applied. Multi-version technology (MVT) is
set of the interconnected rules and design actions,
in which in accordance with МV strategy a few
versions-processes leading to development of two
or more intermediate or end-products are used;
thus, for development of MVS МVТ should be
used, for development of one-version systems
multi-version and one-version technology can
be used both.

Taxonomy Scheme of Multi-
Version Computing

A set of concepts concerning the diversity may
be united by a general term “multi-version
computing” on the analogy with a “dependable
computing” (Avižienis et al., 2004). Multi-version
computing is a type of dependable computing or-
ganization based on use of the diversity approach.
The taxonomy scheme of multi-version comput-
ing, developed taking into consideration concepts
in this area, described in international standards,
includes the following elements (Kharchenko et
al., 2009) (Figure 3).
Version is an option of the different realization
of an identical task (by use software, hardware or
FPGA-based products and life cycle processes);
an identical versions of structure redundancy-
based system are trivial. Version redundancy (VR)
is a type of product and process redundancy al-
lowing to create different (non-trivial) versions;

Figure 3. Taxonomy scheme of multi-version computing