Hardware Reference
In-Depth Information
8.3.2.4
Software-Implemented Fault Injection
For these experiments, the compile-time version of SWIFI was selected: faults were
injected at the machine code level and the mutilated application (code segment or
data segment) was loaded to the target system afterwards. Two main reasons led us
1.
The intrusiveness is reduced to a minimum, since faults are injected only into the
application software (no additional code, which could probably interfere with the
behavior of the application software, is needed).
2.
Fault injection at the machine code level is capable of injecting faults that cannot
be injected at higher levels by using source code mutations.
The SWIFI experiments started at the Vienna University of Technology, Austria
and continued at the Research and Technology Institute of Daimler Benz AG (then
DaimlerChrysler) in Berlin, Germany.
Both the code and data segments of the application software used as the workload
for the experiments were targeted by the SWIFI technique. Within each segment, the
bit to be faulted was selected randomly to achieve a uniform distribution over the
whole segment. To facilitate the comparison with the HWIFI techniques, we only
consider here the single bit-flip experiments, because they constitute a reasonable
fault scenario for the comparison with these techniques (e.g., heavy-ion radiation
generates, to a large extent, single bit-flips).
8.3.3
Representativeness with Respect to the F Set
In this section, we describe a general framework (
Arlat and Crouzet
2002
)thatis
meant to help address comprehensively the representativeness issue.
From a pragmatic viewpoint, the main objective is to identify the technology
that is both
necessary
and
sufficient
to generate the
F
set to conduct a fault in-
jection test sequence. Several important issues have to be accounted for in this
effort.
8.3.3.1
System Levels and Fault Pathology
where faults can occur and errors can be identified (e.g., physical-device, logic,
RTL, algorithmic, kernel, middleware, application, operation). Concerning faults,
these levels may correspond to levels where real faults are considered and (artificial)
faults can be injected. Concerning errors, the FTMs (especially, the error detection
mechanisms, EDMs) provide convenient built-in monitors.
