Focus in this paper is architecture

Focus in this paper is architecture of the computer system, i.e.
how that system is designed in terms of interactions between large
building blocks. This is a technology perspective. System architecture
is not that visible to the radiological user, in contrast to the
user interface. Moreover, whereas evolutions in the user interface
clearly are of immediate concern to any radiologist [1], the same
can hardly be claimed for system architecture. However, architecture
of the overall system has an important impact on functionality
and cost, especially for large, complex systems. Radiologists, and in
particular decision makers, should have at least a basic understanding
of PACS architecture, and in particular of the consequences of
architectural choices.
There is no inherently good or bad architecture for a computer
system. Design choices are determined by requirements as well as
technological possibilities. Both have changed since the introduction
of large-scale PACS.
Technological progress has been steady over the last decades.
In many areas of computer industry, capacity or power doubles
roughly every 18 months. This observation is informally referred to
as Moore’s law. This is literally an exponential increase in power,
or about a factor of 100 after a decade. General belief is that this