Information Technology Reference
In-Depth Information
•
technology develops so fast that as soon as a solution for a computer-domain pair
has been found, it is outdated by new technological innovations;
•
the problem is simply too difficult to solve, at least for us.
In spite of the above we shall propose a modest analysis of the situation, and
hopefully come up with some recommendations for further work. Important require-
ments to a renewed approach to software engineering and information systems
engineering are:
•
the theoretical framework must make it possible to build
integrated models
of
systems which consist of both digital and non-digital components;
•
information models must represent the
meaning
of data, that is, data should be
explicitly related to the phenomena they represent;
•
system models must be
comprehensible
on every level of systems detail;
•
system models must permit
specification in terms of solutions
on every level of
detail, in order to provide for executable specifications;
•
system models must support the need for
validation
of design proposals during
their development;
•
system models must support
different specification detail
, both formal and
informal specifications;
•
system models must encourage
systematic evolution of specification detail
from
low level of detail to high level of detail;
•
system models should support proven
engineering practice
.
These many facets of information systems engineering will be discussed in the
sequel. Requirements to the information systems engineering approach will be sug-
gested. It seems that conceptual modeling is central to finding good solutions for
many of the unsolved problems.
2 Information Systems, Data Systems, Domain Systems
and How They Relate
Information systems consist of collections of data, and of information processes
that collect, store, transform and distribute data in forms that make sense to the
receivers of the data. That is,
data
is seen to be
information
when the data is pre-
sented in a form that is understood by the receiver. In advanced societies almost all
data are collected, stored, processed and distributed in digital form by computers.
Almost every system in every domain has a sizable information system component.
Communicating digital devices are everywhere. Software is everywhere. Digitized
information (data) is everywhere.
We shall distinguish between the
information system
and the
domain system
(“the
other system”) which is served by the information system. We shall also distinguish
between the
information system
and its
data system
(the computerized parts of the
information system). We shall use the term
total system
for the “whole” formed by
the information system and the domain system.
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