In future, the decreasing feature size and the reduced power
supply will make it much more difficult to built reliable microprocessors.
Economic pressure will most likely result in the reliability of microproces-
sors being tuned for the commodity market. In the dependability domain
we expect the continued spreading of mixed-mode computing systems,
i.e., systems that execute both critical and non-critical functionality. To
permit the efficient execution of non-critical applications and the correct
execution of critical applications, we introduce the concept of Software
Encoded Processing (SEP). SEP enforces a crash failure semantics of the
underlying CPU. It does not require the source code of encoded programs
and provides probabilistic guarantees. To achieve this, arithmetic codes
and signatures are used to detect corrupted data and faulty executions
of programs.