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Udi Dahan

@udidahan.com

1.9K followers 161 following 44 posts

Posts about Software Development, Design, and Architecture. Founder and CEO of NServiceBus. He/Him. udidahan.com twitter.com/UdiDahan hachyderm.io/@udidahan

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Udi Dahan @udidahan.com · 20/05/2026

> In the context of combined EDA and SOA, the word “service” is equivalent to a logical “thing” that can have a database schema, Web Services, and even user-interface (UI) code inside it.

Layered architecture diagram with User Interface, Business Logic, and Database layers - and colored vertical bars overlaid representing cross-functional services.

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Udi Dahan @udidahan.com · 08/04/2025

So, back to the ordering of bank transactions. It turns out the banks have been INTENTIONALLY reordering transactions to cause accounts to get overdrawn so that they can charge overdraft fees - and there was a lawsuit about that: www.schmidtandclark.com/bank-overdra...

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Udi Dahan @udidahan.com · 08/04/2025

It reminded me of an old blog post I'd written about Invariants, and how many developers often get them wrong. The business world isn't nearly as mathematical as developers would like to believe. For example: udidahan.com/2014/11/16/w...

Rules – not invariants
Employees can’t take more annual leave than they have.
… unless their manager approves.
… but that’s only up to 2 days.
… unless their manager is a VP, and then it’s up to 5 days.
… and that negative balance will be deducted from next year’s leave.
… Oh, and if the employee leaves the company before then, then the value of those negative days will be deducted from their final paycheck.

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Udi Dahan @udidahan.com · 16/03/2025

For those of you not wanting to go there, here's the summary: > There are probably several areas of sustainability for OSS but without a strong enough revenue/financing model, OSS that tries to expand its breadth of use may end up in unsustainable territory.

Spreadsheet with two columns - Breadth of use and Staffing level.
Going from "extra small" breadth of use with 1 person part time as a staffing level, through "medium" breadth of use with 2 to 4 full time and/or 6 to 10 part time staff, up to "extra large" with 40 to 100 full time staff.

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