Why did the server go down?
A server stops at 9 am. The boss asks why. The answer is not one thing. The power failed and the battery was flat.
Experts use named tools to follow a problem back to its causes, or forward to its effects. You will meet four.
By the end of this lesson
Note
I can say what fault tree analysis, FMECA, CRAMM and FAIR are used for.
Key words
| Word | What it means |
|---|---|
| Fault tree analysis | a diagram that works back from a failure to its causes |
| Scope | to decide what is included in a job and what is left out |
| Top event | the failure at the top of a fault tree |
| AND gate | a join where every cause must happen |
| OR gate | a join where any one cause is enough |
| FMECA | failure mode, effects and criticality analysis: a method that lists what can fail and what it would do |
| CRAMM | CCTA Risk Analysis and Management Method: a three stage method that ends with advice on counter measures |
| FAIR | Factor Analysis of Information Risk: a model for working out cyber risk |
The cells students fill in are left blank in this preview.
Starter
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Starter
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.
Fault tree analysis works backwards
Put the failure at the top. This is the top event. Below it, draw its causes.
An AND gate means all the causes must happen together. An OR gate means one cause is enough.
The tree shows which causes to fix first.
Check
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Check
3 questionsYour answers are marked here and are not kept. A college account keeps every student’s marks.