Assuring Trustworthiness via Structured Assurance Cases
Figure 1: Physical to Software-enabled and Connected Throttle-to-Accelerator Pedal Transition
ones. For instance, in 1976, the connection
from the accelerator pedal to the carburetor
was a physical rod or cable.
item when any two needed to communicate,
control one another or provide power.
A bus, a communication network, is actually
a couple of connected computer or
microelectronics parts running software. As
shown in Figure 3 below, these pieces of
microelectronics running software are
needed for signaling, with memory and the
CPU for processing of instructions: A
significant advancement that now creates
new opportunities for measuring and
qualifying trust.
Now, as illustrated in Figure 1, it is a sensor
in the pedal that is then connected through
a communication bus to an electric throttle
valve controller that interprets and conveys
the actions from the pedal to the throttle.
There is no longer a physical connection.
That same trend of moving from physical to
software-enabled
connections
was
paralleled by a change in the way vehicles
wired their devices as shown in Figure 2.
Back in the 1976 time-frame, there were
actual physical wires going between each
Figure 2: Point-to-Point Wiring to Bus Connectivity Transition
September 2018
- 46 -