Time has a profound impact on the complexity of the systems we build.

A significant amount of this software complexity comes from either an inability to recall previous states or the inability to understand how a state was arrived at.

From the foundations of AI, LISP and functional programming [1], to causality in distributed systems [2], to the more grungy practices of immutable infrastructure, or the unreasonable effectiveness of fact-based approaches to large scale data systems; the ability to adequately cope with time, and the change and conflict it inevitably creates, is a common thread to being able to build and reason about these systems.

This talk looks at the impact of time on system design. We will walk through examples of large-scale systems and their battles with complexity. At the end of the talk, the audience should start to see the common spectre of time and have an appreciation of how understanding time is fundamental to maintaining clarity, correctness and reliability in systems.

[1] Situations, Actions, and Causal Laws
John McCarthy
http://www.dtic.mil/dtic/tr/fulltext/u2/785031.pdf

[2] Times, Clocks and the Ordering of Events in a Distributed System
Leslie Lamport
https://amturing.acm.org/p558-lamport.pdf

Building on the earlier two introductions to functional programming with types, property based testing is the extra verification technique you need to ensure working software. We will work through the patterns of property based testing, starting with simple functions, working up to verification of a larger program.

By the end of this workshop participants will have a better understanding of the advantages of property based tests over example based tests, as well as acquiring the skills and confidence to start applying property based testing techniques to their current work.

This workshop has the same requirements as Tony's introduction, and will require a recent clone of the workshop repository available at https://github.com/markhibberd/property-based-testing-workshop.

Time has a profound impact on the complexity of the systems we build.

A significant amount of this software complexity comes from either an
inability to recall previous states or the inability to understand
how a state was arrived at.

From the foundations of AI, LISP and functional programming [1], to
causality in distributed systems [2], to the more grungy practices of
immutable infrastructure, or the unreasonable effectiveness of
fact-based approaches to large scale data systems; the ability to
adequately cope with time, and the change and conflict it inevitable
creates, is a common thread to being able to build and reason about
these systems.

This talk looks at the impact of time on system design. We will walk
through examples of large-scale systems and their battles with
complexity. At the end of the talk, the audience should start to see
the common spectre of time and have an appreciation of how
understanding time is fundamental to maintaining clarity, correctness
and reliability in systems.

[1] Situations, Actions, and Causal Laws
John McCarthy
http://www.dtic.mil/dtic/tr/fulltext/u2/785031.pdf
[2] Times, Clocks and the Ordering of Events in a Distributed System
Leslie Lamport
https://amturing.acm.org/p558-lamport.pdf

Data is a powerful tool. Data-driven systems leveraging modern analytical and predictive techniques can offer significant improvements over static or heuristic driven systems.

The question is:

• How much can you trust your data? Data collection, processing and aggregation is a challenging task.
• How do we build confidence in our data? Where did the data come from?
• How was it generated? What checks have or should be applied?
• What is affected when it all goes wrong?

This talk looks at the mechanics of maintaining data-quality at scale. Firstly looking at bad-data, what it is and where it comes from. Then diving into the techniques required to detect, avoid and ultimately deal with bad-data. At the end of this talk the audience should come away with an idea of how to design quality data-driven systems that ultimately build confidence and trust rather than inflate expectations.

Data is a powerful tool. Data-driven systems leveraging modern analytical and predictive techniques can offer significant improvements over static or heuristic driven systems.

The question is:

• How much can you trust your data? Data collection, processing and aggregation is a challenging task.
• How do we build confidence in our data? Where did the data come from?
• How was it generated? What checks have or should be applied?
• What is affected when it all goes wrong?

This talk looks at the mechanics of maintaining data-quality at scale. Firstly looking at bad-data, what it is and where it comes from. Then diving into the techniques required to detect, avoid and ultimately deal with bad-data. At the end of this talk the audience should come away with an idea of how to design quality data-driven systems that ultimately build confidence and trust rather than inflate expectations.