  Single Event Upsets (SEU) as well as permanent faults can significantly
affect the correct on-line operation of digital systems, such as memories and
microprocessors; a memory can be made resilient to permanent and transient
faults by using modular redundancy and coding. In this paper, different memory
systems are compared: these systems utilize simplex and duplex arrangements
with a combination of Reed Solomon coding and scrubbing. The memory systems and
their operations are analyzed by novel Markov chains to characterize
performance for dynamic reconfiguration as well as error detection and
correction under the occurrence of permanent and transient faults. For a
specific Reed Solomon code, the duplex arrangement allows to efficiently cope
with the occurrence of permanent faults, while the use of scrubbing allows to
cope with transient faults.
