A process is a set of related components that produce or change something.
When studying an information system, there may be one large process or several
smaller processes. The scope of the process is not important to our definition of
information, or later to our definition of communication. However, the choice
of how to view a process will affect how one may study or understand the process.
For example, the reader may view the entire process that takes the author’s
thoughts and results in the thoughts being understood by the reader as a communication
process, or one may view numerous small steps in the writing, publishing,
and reading processes as linked processes. Whether viewed as one large process
or several smaller processes, the information presented at the end of the entire
large process or at the end of the set of smaller processes is the same.
The amount of information produced by a process may be measured, as with
Shannon’s model, as the logarithm [Har28] of the inverse of the probability of the
state of nature found at the output of the process. This may be used for the values
of both discrete and continuous output variables. An output variable with a value
having associated probability of may be computed as having
bits
of information, for example.
We refer to a process that produces output from a context (defined as the set of
values presented to the input of a process) as an information channel. The channel
is that set of components that implements the functionality inherent in the process.
A channel might be implemented by a computer and its program, or it might be a
mechanical device such as a pantograph that reproduces an input movement at the
output with a pre-specified degree of magnification.