1 / 14

Hardware

Hardware. Software. Input. ?. Success. Failure. Output. Fault-Tolerant Programming. N-Version Programming. Recovery Blocks Scheme. +. Correct Result. Version 1. AT. -. Version 1. M Identical Outputs. +. Correct Result. Version 2. AT. Version 2. Correct Result. Voter. -. ….

rigel-burris
Download Presentation

Hardware

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. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Hardware Software Input ? Success Failure Output

  2. Fault-Tolerant Programming N-Version Programming Recovery Blocks Scheme + Correct Result Version 1 AT - Version 1 M Identical Outputs + Correct Result Version 2 AT Version 2 Correct Result Voter - … … + Version N Failure Correct Result Version N AT - Failure

  3. N-Version Programming Parallel Execution of Versions Consecutive Execution of Versions t1 t2 t1 t2 t3 t4 t5 t3 M=3 t4 t5 T T failure success voting

  4. Fault-Tolerant System Structure Software Running on Different Hardware Blocks Software Running on Single Hardware Block … … …

  5. Effect of Parallel Versions Execution 1 3 1 2 3 4 5 2 4 5 t1+t2+t3+t4 t1+t3 L=1 L=2 1 5 1 4 1 2 2 2 5 3 3 3 4 4 5 t1+t4 t3 t3 L=3 L=4 L=5

  6. Reliability/Performance Analysis Problem Characteristics of Version Characteristics of System Reliability Reliability Pr{ T < T* } Expected Execution Time E(T) Execution Time Conditional Expected Execution Time E(T) | T < T* Computational Resources

  7. Distributionof System Execution Time Q(k/n)=Pr{ k out of n first versions succeed } i1: {1…n-k+1} i2: {i1+1…n-k+2} Pj=Pr{ system succeeds after execution of version j } = rj Q(M-1/j-1)

  8. j first versions: UGF Approach Single version i: For j = M: PM Pj Pj-1

  9. For the entire system: UGF Approach For each component c: PcM , PcM+1 ,…, Pcn TcM , TcM+1 ,…, Tcn

  10. Effect of Versions Sequencing 3-out-of-5 system 5 3 1 3 4 2 2 4 5 1 t2+t4+t5 t1+t3 5 3 3 4 4 2 1 2 5 1 t1+t2+t5 t3+t4

  11. M=1 M=2 M=3 M=2 M=1 Parameters of Software System

  12. Optimal Version Sequences

  13. T* Software Structure Optimization R(T*) MAX |C < C*

  14. Optimal Fault-Tolerant System Structures

More Related