Summary: Nonblocking and Orphan­Free Message Logging Protocols \Lambda
Lorenzo Alvisi y Bruce Hoppe Keith Marzullo z
Cornell University Department of Computer Science
Ithaca NY 14853
Abstract
Currently existing message logging protocols demon­
strate a classic pessimistic vs. optimistic tradeoff. We
show that the optimistic--pessimistic tradeoff is not inher­
ent to the problem of message logging. We construct a
message--logging protocol that has the positive features of
both optimistic and pessimistic protocols: our protocol pre­
vents orphans and allows simple failure recovery; however,
it requires no blocking in failure--free runs. Furthermore,
this protocol does not introduce any additional message
overhead as compared to one implemented for a system in
which messages may be lost but processes do not crash.
1 Introduction
Message logging protocols are a common method of
building a system that can tolerate process crash fail­
ures. These protocols require that each process periodi­

Source: Alvisi, Lorenzo - Department of Computer Sciences, University of Texas at Austin

Collections: Computer Technologies and Information Sciences