The free-lunch guide to idea circularity

by Holly Cummins

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Holly Cummins IBM The free-lunch guide to idea circularity March 18, 2026 QCon London

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The Palace of Westminster prior to the embankment of the Thames, Westminster, 1860s

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The Palace of Westminster prior to the embankment of the Thames, Westminster, 1860s

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the great stink

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Michael Faraday “Near the bridges the feculence rolled up in clouds so dense that they were visible at the surface”

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Benjamin Disraeli “reeking with ineffable and intolerable horrors”

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Crossness pumping station, by k7hpn on fl ickr

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“cistern chapel” Crossness pumping station, by k7hpn on fl ickr

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history rhymes

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throughput

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poo throughput

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pooput

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sewage trade-offs

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sewage trade-offs

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sewage trade-offs

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centralised stink and disease distributed stink and disease

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Robert Heinlein, The Moon is a Harsh Mistress “TANSTAAFL”

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grid

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cloud

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nothing is new under the sun

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“maybe let’s not wreck our home”

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being sustainable optimise for short-term

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Sources: https://www.greenit.fr/wp-content/uploads/2019/11/GREENIT_EENM_etude_EN_accessible.pdf https://ourworldindata.org/ghg-emissions-by-sector the digital world creates more carbon emissions than aviation

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Lighter area represents high and low estimates, where available. Sources: https://www.iea.org/fuels-and-technologies/data-centres-networks https://ourworldindata.org/grapher/electricity-demand?tab=table&country=USA~GBR~FRA~DEU~IND~BRA data centres use as much electricity as a medium country

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Itaipu dam, Brazil, photo by Deni Williams, reative Commons Attribution 2.0 Generic license

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days are now 0.06 µsec longer three gorges dam

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earth’s axis tilted 2 cm three gorges dam

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- LightSwitchOps - efficient software

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LightSwitchOps architect things to be turned o ff and on often

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quarkus makes java apps more efficient

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capacity Source: John O’Hara Setup: • REST + CRUD • large heap • RAPL energy measurement Assumptions: carbon as a function of load (single instance)

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capacity Source: John O’Hara Setup: • REST + CRUD • large heap • RAPL energy measurement Assumptions: carbon as a function of load (single instance) longer line means higher max throughput

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capacity Source: John O’Hara Setup: • REST + CRUD • large heap • RAPL energy measurement Assumptions: carbon as a function of load (single instance) longer line means higher max throughput lower line means better carbon footprint

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Setup: • REST + CRUD • large heap • RAPL energy measurement • multiple instances to support high load Assumptions: • US energy mix Source: John O’Hara carbon as a function of load

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“let’s decide everything at runtime” why a duck? duck typing!

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dynamic pre-decided

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lazy eager

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“distribute all the things, all the time”

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microservices hyper-distributed

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amazon prime video reduced costs by 90% by moving to a monolith 2023

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latency complexity infra cost computing power resilience independent lifecycles

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git github

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data centre ai

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data centre ai vs distributed ai

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hype cycles

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grid internet of things digital twin model-driven-development low code cloud native kubernetes microservices

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the morning after the technology before

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the lunch was not free

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– Meredith Whittaker

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– Meredith Whittaker

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– Meredith Whittaker “It’s not simply that one piece of technology is overhyped, it’s that hype is a necessary ingredient of the current business ecosystem of the tech industry.”

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grid internet of things digital twin model-driven-development low code cloud native kubernetes microservices

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grid internet of things digital twin model-driven-development low code cloud native kubernetes microservices ai

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venture capital

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baby company

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baby company

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baby company

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