An Introduction to Residuality Theory - Barry O'Reilly - NDC Oslo 2023

Residuality theory is a revolutionary new theory of software design that aims to make it easier to design software systems for complex business environments. Residuality theory models software systems as interconnected residues - an alternative to component and process modeling that uses applied complexity science to make managing uncertainty a fundamental part of the design process.
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[@Abhothra]

Utterly fascinating, great talk well done.

[@LarsKemmann]

Excellent presentation! I've seen this concept go by the name volatility-based decomposition (Juval Lowy), and as an approach it dates back to a famous paper on the criteria for decomposing a system into modules by David Parnas (1972), but it's great to see it presented in a fresh way and with the well-defined tie-in to complexity theory to help support it. I'd love to see a follow-up to this presentation that relates the theory more explicitly to some of those prior findings in the software architecture field to show the consistency.

[@Barry-ru9kf]

These are completely different concepts. Both Parnas and Volatility Based Decomposition are referenced in the academic papers on residuality - and both these methods assume an ability to predict what will change and encapsulate it. This is not considered possible hence the need for complexity theory.
Neither of these techniques address the key architectural question on non-functional requirements and are instead focused on use case analysis. In particular there is a focus on pattern based approaches for encapsulating volatility.
Thus on a deeper level residuality has a very different philosophical approach that avoids the pitfalls of structural thinking that inform these two approaches. However, Parnas was right in pointing out the anti-patterns in decomposition. The extension of deterministic thinking to social systems is where the ideas part ways.

[@edencandelas]

A perfect talk for our actual business status. Kudos.

[@alonsocantu8196]

Taking notes...😅

[@lautarojayat7914]

A really interesting approach to systems design

[@shanefisher4451]

This looks alot like things that have been done in supply chain management over the last couple of decades, "Supply Chain Resilience".

[@pauldv69]

Brilliant

[@kwisin1337]

Great talk. Nice to see a more detailed and educational approach to one way I tend to think things through when I approach a process. It's a great way to annoy the partner when approaching the questions she asked you aswell..😅

[@brujua7]

Great talk and great theory. I find hard to imagine working with the matrix for the systems I've worked with in the past due their size. Lots of columns and rows.
How would one tackle handling a significantly larger system? I guess that bounded contexts are important to manage the size but even then...

[@Barry-ru9kf]

This is done by partitioning the system, bounded contexts is a common way to do this. Any hyperliminal coupling across contexts can then be investigated in more detailed matrices. Even at the system level this can be used to get a picture across an entire company, but you shouldn’t have that many components rattling around without clear boundaries that it becomes impossible! In that case you need the matrices more than anyone…

[@stevie_mac]

Where can we track this ongoing research? Is there a site with guides for practitioners?

[@KZGonZa]

A-M-A-Z-I-N-G

[@BugTrampler]

Man im at 43:20, completely mind blown by the insights into this mans head and all of a sudden i see that those two shadows of the spot lights make him look like an angel :D Haha this ist so funny i can't but giggle all the time he moves :D :D