Posts Tagged ‘reliability’
Let’s distinguish between systems where the hazards of failure are material (critical) and those that are not. If it bugs don’t matter, they don’t matter. As the question (posed in a LinkedIn forum) asks about safety and security, we’re talking about critical systems.
There is a long standing debate in reliability engineering…
Read MoreWe don’t need a miracle cure for rogue algorithms. More regulation will not prevent them. Proven software engineering and testing will.
Read MoreEvery time I read about another high profile system outage, I wonder what was missed during development and testing.
For example, although an unusual natural disaster triggered the recent Amazon cloud services outage, the root cause was a lurking bug that could have been revealed with a testing strategy that I (and others) have…
Technical Equity is the value that accrues when a software system is well-formed. Instead of burdening you with unnecessary excess cost, your codebase works for you. Technical equity pays dividends: you avoid wasted effort and the consequences of buggy releases, and gain the advantage of releasing sooner and/or with more features,…
Read MoreThis post covers part four of my 2010 talk on testability. White box testability refers to specific programming practices and components that can improve or hinder testability.
Since Dykstra’s 1968 note “Go To Considered Harmful,” practices for producing clean, well-structured, readable, and maintainable software have been the subject of extensive discussion,…
I think’ve finally found a good visual metaphor for model-based testing. In Aliens, Ellen Ripley uses the power lifter suit to battle the Alien Queen. Model-based testing is like the power lifter suit. It has to be driven with intelligence and skill, but it’s your only hope against the super bugs that…
Read MoreThe FDA has just published a new draft of guidance about mobile technology in FDA-regulated systems. This guidance is open for comment and isn’t binding yet.
So, what does this mean for testing FDA-regulated products with mobile technology?
The draft guidance defines when mobile platforms are considered as part of a regulated system or not. The criteria for inclusion…
A Chicago Tribune article recounts how a software bug in an infusion pump lead to brain-death for a patient in 2009 (“Medical Industry Taking Hard Look at Software Faults,” Christine Mai-Duc, Chicago Tribune, August 31, 2011, p. 19)
It reports that the US Food and Drug Administration (FDA), which regulates and…
This post covers part three of my 2010 talk on testability.
Aren’t the dancing hamsters a stitch?
Not so funny if you have to test code whose stability or controllability makes you feel like you’re wearing the hula-hoop.
To reveal a bug, a test must:
Reach the buggy code
Trigger the bug
Propagate the incorrect result to an observable interface
Incorrect…
What makes a software system easier or harder to test?
The general aspects are controllability and observability.
This post covers part two of my 2010 talk on testability.
Controllability determines the work it takes to set up and run test cases and the extent to which individual functions and features of the system under test…
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