Front cover - IBM Redbooks

understand everything, because this chapter lays the groundwork for the rest of
the book.
1.2 Important terminology
To achieve a consistent understanding of the terms and concepts used
throughout this redbook, you should be familiar with the following definitions.
1.2.1 Computer system
Because this redbook deals with more than just the new security features and
facilities present in the new release of Notes and Domino (that is, version 6.0) it
is important to understand that computer security applies to computer systems
as whole entities.
A computer system, by definition, includes all the necessary software (meaning,
the operating system and the applications that reside on top of it) and all the
necessary hardware (that is, all physical aspects of the computer).
For a computer system, the definition of hardware is not limited to the computer
and what it requires to process the instructions of the software and handle the
data processed by the software. The hardware also includes the connectivity and
telecommunication devices it needs to communicate, be it over a dedicated line
or wireless network.
Finally, for the sake of brevity, the term “computer” will be used in this redbook to
refer to a computer system and everything it encompasses.
1.2.2 Computer network
Given that a computer system has the means to communicate, it’s important to
look at the medium by which it can communicate.
A computer network can be defined as either:
► A network of data processing nodes that are interconnected for the purpose
of data communication
► A communications network in which the end instruments are computers
A network can be defined with a bit more granularity, in that it is, by definition, an
interconnection of two or more communicating entities. The traditional definition
calls for three communicating entities (such as two computers and a hub or
switch), but given the possibility to use a cross-connected Ethernet cable and
Chapter 1. Fundamentals of IT security 11