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10.1 Complex systems 267

amount of control software. By contrast, an air traffic control system includes thou-
sands of hardware and software components plus human users who make decisions
based on information from that computer system.
A characteristic of all complex systems is that the properties and behavior of the
system components are inextricably intermingled. The successful functioning of
each system component depends on the functioning of other components. Thus, soft-
ware can only operate if the processor is operational. The processor can only carry
out computations if the software system defining these computations has been suc-
cessfully installed.
Complex systems are usually hierarchical and so include other systems. For
example, a police command and control system may include a geographical infor-
mation system to provide details of the location of incidents. These included systems
are called ‘subsystems’. Subsystems can operate as independent systems in their
own right. For example, the same geographical information system may be used in
systems for transport logistics and emergency command and control.
Systems that include software fall into two categories:

1. Technical computer-based systems These are systems that include hardware and
software components but not procedures and processes. Examples of technical
systems include televisions, mobile phones, and other equipment with embed-
ded software. Most software for PCs, computer games, etc., also falls into this
category. Individuals and organizations use technical systems for a particular
purpose but knowledge of this purpose is not part of the system. For example,
the word processor I am using is not aware that is it being used to write a book.

2. Sociotechnical systems These include one or more technical systems but, cru-
cially, also include people who understand the purpose of the system within the
system itself. Sociotechnical systems have defined operational processes and
people (the operators) are inherent parts of the system. They are governed by
organizational policies and rules and may be affected by external constraints
such as national laws and regulatory policies. For example, this book was cre-
ated through a sociotechnical publishing system that includes various processes
and technical systems.

Sociotechnical systems are enterprise systems that are intended to help deliver a
business goal. This might be to increase sales, reduce material used in manufactur-
ing, collect taxes, maintain a safe airspace, etc. Because they are embedded in an
organizational environment, the procurement, development, and use of these sys-
tems are influenced by the organization’s policies and procedures, and by its work-
ing culture. The users of the system are people who are influenced by the way the
organization is managed and by their interactions with other people inside and out-
side of the organization.
When you are trying to develop sociotechnical systems, you need to understand
the organizational environment in which they are used. If you don’t, the systems may
not meet business needs and users and their managers may reject the system.