8 Chapter 2 From Client-Server to Mobile Agents
some beneﬁts from using mobile agents in the future; otherwise it is claimed
that agent mobility is a pretty useless feature. This view can be best described
by the statement that mobile agents are a solution in search of a problem.
Second, we try to deﬁne mobile agents from the viewpoint of software
engineering and distributed systems. We will see that mobile agents in our
understanding do not have much to do with artiﬁcial intelligence but are
to be considered another design paradigm for a special type of distributed
systems. From this viewpoint, emphasis lies on research of the consequences
of the mobility of code, and it is these consequences that we focus on in
Naturally, both research communities can beneﬁt from each other. Some
work has already been done to add intelligent agents with mobility as
a common feature, and recently people have begun to work to make mobile
agents more intelligent, for example, to help them plan their itineraries.
Hopefully, both branches of research will join each other eventually.
2.1.1 The Artiﬁcial Intelligence Point of View
Let’s start with the notion of software agents. The word agent derives from
the Latin word for actor, meaning a person who acts on behalf of another.
In different languages the notion agent is used with different meanings. In
English-speaking countries, for example, the word agent is often used in
a more general context, whereas in German-speaking countries an agent
mostly works for the secret service. Usually, a real estate agent is employed
to aid in renting or buying a house, and a travel agent is visited to aid in
planning a vacation. In physical science, an agent can be an active sub-
stance that causes a reaction. Other sciences also use the term agent.For
example, in legal sciences an agent provocateur is a person hired to incite
suspected persons to commit some illegal action that will make them liable
In computer science, the term agent has been used since the mid-1970s.
It was introduced to the area of artiﬁcial intelligence. Most authors refer to a
paper written by Hewitt  as origin of the term agent. According to Foner
, the ﬁrst reference can be traced back to Vannevar Bush and Douglas
Engelbart in the late 1950s and early 1960s.
1. Stated by John Ousterhout during an interview that is published online [IEEE IC-Online, 1997].