Download pdf - Fault tolerant 4_5

EVA Community Ji-won Kim([email protected]) 2013.8.24

Intent : People make mistakes and are slow; to minimize downtime the system should take care of itself, without human intervention.

2

50%~

25%

25%

The cause of failures

Human

Hardware

Software

(From a study of the US telephone network[Kuh97])

Recognition/Report

Fix/Modification Analysis Destruction

Test/ PlanningOperation

5Network

ComputingMachine

Math

Switch

Human is not a machine

AlwaysIdentical ProceduralSoftware&Hardware

Become Bored, inattentive with routine, monotonous tasks

http://dory.mncast.com/mncHMovie.swf?movieID=10055055020071201145315&skinNum=1

Control

Self Recovery

Automatic Error-HandleDetection->Processing

http://www.google.co.kr/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=cKiIjaCl9DOtsM&tbnid=TpAo8zavU3MCvM:&ved=0CAUQjRw&url=http://dia3.gamemeca.com/board/view.php?gcode=dia3_usernews&gid=20923&ei=qyoYUv7KGs3TkAXfz4DgDw&bvm=bv.51156542,d.dGI&psig=AFQjCNGMjcyiC-AhmOelq-0VYB1BNLzFFQ&ust=1377401852395896

http://www.google.co.kr/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=JTX7w_V3ww_pjM&tbnid=o8L0bsuXonA_SM:&ved=0CAUQjRw&url=http://blog.naver.com/PostView.nhn?blogId=luciferlml&logNo=60129559917&ei=EisYUpHaDci9kQWFw4AI&psig=AFQjCNEc-wE8wk_ubnAxIFppoxpOAjRvuA&ust=1377401949088295

http://www.google.co.kr/url?sa=i&rct=j&q=&esrc=s&frm=1&source=images&cd=&cad=rja&docid=q5PAZaTPHozQtM&tbnid=0RQ24qkWIrhtWM:&ved=0CAUQjRw&url=http://yibumsuk.tistory.com/882&ei=uisYUsrnNov9lAXA0YDYDA&psig=AFQjCNE5YxcVHH_gvg4FXeg1J5peg5zL_Q&ust=1377402132908299

7

The risk of Procedural Errors

Incorrect system from imperfect Human’s

Requirements

Operator

Whole System

8

Fault Observer

Monitoring System

Component1 Component2

Component3

Fault Observer

Fault Observer

RecoverySystem

Operator

From Book, originally from©iStockphoto.com/Don Bayley

Minimize Human

Intervention

Detection

• Fault Observer

• Audible Alarm

Recovery

• Recovery Blocks

• Error Handlers

• Maximize Human Participation

Management

• Maintenance Interfaces

• IO Triage

Prevention

& Correct

• Reintegration

• Revise Procedure

Helpful Patterns :An Input and Output Pattern Language [HS00]