slide1 n.
Download
Skip this Video
Loading SlideShow in 5 Seconds..
Upper Bound on Reliability PowerPoint Presentation
Download Presentation
Upper Bound on Reliability

Loading in 2 Seconds...

play fullscreen
1 / 4

Upper Bound on Reliability - PowerPoint PPT Presentation


  • 150 Views
  • Uploaded on

FAULT TOLERANT SYSTEMS http://www.ecs.umass.edu/ece/koren/FaultTolerantSystems Part 2 – Canonical Structures Chapter 2 – Hardware Fault Tolerance. Upper Bound on Reliability. If structure is too complicated - derive upper and lower bounds on R system

loader
I am the owner, or an agent authorized to act on behalf of the owner, of the copyrighted work described.
capcha
Download Presentation

PowerPoint Slideshow about 'Upper Bound on Reliability' - breena


An Image/Link below is provided (as is) to download presentation

Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author.While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server.


- - - - - - - - - - - - - - - - - - - - - - - - - - E N D - - - - - - - - - - - - - - - - - - - - - - - - - -
Presentation Transcript
slide1

FAULT TOLERANT SYSTEMShttp://www.ecs.umass.edu/ece/koren/FaultTolerantSystems Part 2 – Canonical StructuresChapter 2 – Hardware Fault Tolerance

upper bound on reliability
Upper Bound on Reliability
  • If structure is too complicated - derive upper and lower bounds on Rsystem
  • An upper bound - Rsystem 1 -  (1-Rpath_i)
    • Rpath_i - reliability of modules in series along path i
    • Assuming all paths are in parallel
  • Example - the paths are ADF, BEF and ACEF
  • Rsystem 1 -(1-RARDRF)(1-RBRERF)(1-RARCRERF)
  • If RA=RB=RC=RD=RE=RF=R then
  • Upper bound can be used to derive the exact expression: perform multiplication and replace every occurrence of by
lower bound on reliability
Lower Bound on Reliability
  • A lower bound is calculated based on minimal cut sets of the system diagram
  • A minimal cut set: a minimal list of modules such that the removal (due to a fault) of all modules will cause a working system to fail
  • Minimal cut sets: F, AB, AE, DE and BCD
  • The lower bound is
  • Rsystem (1-Qcut_i)
    • Qcut_i - probability that the minimal cut i is faulty (i.e., all its modules are faulty)
  • Example - RA=RB=RC=RD=RE=RF=R
example comparison of bounds
Example – Comparison of Bounds
  • Example - RA=RB=RC=RD=RE=RF=R
  • Lower bound here is a very good estimate for a high-reliability system