COP 5611 Operating Systems Spring 2010 Dan C. Marinescu Office: HEC 439 B Office hours: M-Wd 1:00-2:00 PM

Lecture 14 Reading Assignment: Chapter 8 from the online textbook Homework 3 due on March 3 Midterm: Wednesday March 17, the first week after Spring Break Last time: Faults, Failures and Fault-Tolerant Design Measures of Reliability and Failure Tolerance Tolerating active Faults Today: Coding Replication Voting Repair Next time Tolerating Software and Hardware Faults 2 2 2 2 2

Quad-component super-diode

Triple-redundant super-module with three voters

Reliability increases for triple-modular redundancy when mission time is short compared with MTTF

When mission time is comparable with MTTF reliability for the triple modular redundancy decreases

Failure points for a five-modular redundancy system