The RTS (remote temperature sensor)

The RTS (remote temperature sensor) system exists to measure the temperatures of a set of
furnaces, and to report those temperatures to an operator at some other location. In the original
example, the operator was located at a “host” computer. The RTS sends periodic temperature
updates to the host computer, and the host computer sends control requests to the RTS, to
change the frequency at which periodic updates are sent. These requests and updates are done
on a furnace by furnace basis. That is, each furnace can be reporting its temperature at a different
frequency. The RTS is presumably part of a larger process control system. The control part
of the system is not discussed in this example, however.
We are interested in analyzing the RTS for the qualities of performance, security, and availability.
To illustrate these analyses, we have made the model problem richer and more complex
than its original manifestation. In addition to the original set of functional requirements, we
have embedded the RTS into a system architecture based on the client-server idiom. The
remote temperature sensor functionality is encapsulated in a server that serves some number of
clients. To remain consistent with the original problem, our analysis will assume that there are
16 clients: one per furnace.
The RTS server hardware includes an analog-to-digital converter (ADC), that can read and
convert a temperature for one furnace at a time. Requests for temperature readings are queued
and fed, one at a time, to the ADC. The ADC measures the temperature of each furnace at the
frequency specified by its most recently received control request.