--- title: Systems and Delays | daily.dev description: A reflection on a key insight from the book 'Thinking in Systems' by Donella Meadows, illustrated through a car dealership inventory simulation. The post... canonical: https://daily.dev/posts/systems-and-delays-5cgsr0rup twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Systems and Delays | daily.dev og:description: A reflection on a key insight from the book 'Thinking in Systems' by Donella Meadows, illustrated through a car dealership inventory simulation. The post... og:url: https://daily.dev/posts/systems-and-delays-5cgsr0rup og:image: https://api.daily.dev/og/posts/5cgsR0rUP.png og:image:alt: Systems and Delays og:image:width: 1200 og:image:height: 630 og:locale: en --- > ## Documentation Index > Fetch the complete documentation index at: https://daily.dev/llms.txt > Use this file to discover all available pages before exploring further. # Systems and Delays **[Hacker News](https://daily.dev/sources/hn)** · 7 min read · 0 upvotes · 0 comments ## Summary A reflection on a key insight from the book 'Thinking in Systems' by Donella Meadows, illustrated through a car dealership inventory simulation. The post explores how delivery delays and response delays interact in a feedback system, showing counterintuitively that reducing a response delay can cause greater oscillations and instability, while increasing it (responding more slowly) can actually stabilize the system. The author built an Elm-based simulator to model the scenarios and encourages acting on data rather than intuition when tuning system parameters. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Community take How the wider developer community reacted, aggregated from 3 discussions and 29 comments across lobsters, hackernews (as of 2026-07-26). **TL;DR:** Commenters find the post a genuinely interesting illustration of how feedback delays cause oscillations in supply-chain (and software) systems, connecting it to control theory, the bullwhip effect, and the Beer Game. A minority push back on the model's simplifying assumptions, but most treat those as beside the point of the broader principle. **Sentiment:** 55% positive · 35% mixed · 10% skeptical **The case for** - The post's core insight maps cleanly onto established control-theory results — a commenter derived the exact stability condition (r > 2τ/π) from delay-differential equation theory, validating the examples. - The principle generalises usefully beyond supply chains, e.g. autoscaling systems that cause outages by overcorrecting after a DDoS attack has already ended. - The counterintuitive takeaway — that adding delay (dampening) can stabilise a system — is seen as a valuable mental model worth carrying into 2026 and beyond. **The pushback** - The modelled system is criticised for assuming stock should track immediately preceding demand, whereas real inventory management uses lead times, seasonal history, and multi-month observation windows. - The 'response delay divisor' parameter is arguably mislabelled — it controls signal amplification/dampening, not delay per se, which may confuse readers. - Control-theory formalisms for systems design lack an industry-standard reference (like DDIA for distributed systems), limiting practical adoption. **By community** - lobsters (positive): Lobsters commenters engaged most technically, deriving the exact stability bound from delay-differential equation theory and asking good follow-up questions about model extensions. - hackernews (mixed): Hacker News broadly appreciated the post as a clear illustration of oscillation and its real-world analogues, while a vocal minority questioned the realism of the model's assumptions and the framing of its parameters. **Hottest debate:** Whether the simplified inventory model's assumptions (tracking only immediate demand, daily ordering) are too unrealistic to be instructive, versus the view that the simplification is precisely what makes the emergent oscillation legible. **Open questions** - Is there an industry-standard formalism for applying control theory to distributed systems design, analogous to DDIA? - How does the system behave if in-transit (ordered-but-not-delivered) inventory is counted in the feedback signal? - What other fields beyond control/system theory study the relationship between data-sampling rate and system stability? **Highlights** > > I’d be interested in learning what, mathematically, makes these oscillations inevitable Say you model your inventory as df/dt = −f(t − τ) / r Where τ is the delay, and r is the response delay divisor, like your post. A standard result is that the first-order delay differential equation dx/dt = −ax(t − τ) is stable when aτ < π/2. (e.g. see corollary 3.3 in Stépán's Retarded Dynamical Systems, https://www.mm.bme.hu/~stepan/mm/book/retarded_dynamical_systems.pdf) With a = 1/r that gives τ/r < π/2, i.e., r > 2τ/π Applying that to your examples, if τ = 5, you need r > 10/π ~ 3.18 So the system ends up stable when r = 6, but not with r = 2 or r = 1. > — [typesanitizer on lobsters · 5 points, 1 comments](https://lobste.rs/s/yia0pc/systems_delays_2026#c_zpqlum) > It applies to software engineering too in things like autoscaling. I’ve seen many DDOS outages caused not by the attack itself but the wave of autoscaling that takes things down (often well after the actual attack ended). > — [wonnage on hackernews](https://news.ycombinator.com/item?id=49055185) > It’s a simplified example of a broader principle. This structure shows how oscillation can emerge from a very simple system and how it can be remedied by adjustments of the delays. Oscillating systems are very much a thing and this explains why. By the way, what you said about stock levels is correct, of course, but doesn’t necessarily avoid oscillations. See, all of these metrics are feedback-based as well. With a delay. How much history do we take into account? Are account lead times influenced by delivery times. This is a classic problem in system dynamics: where do we draw the system boundary? Since everything is connected to everything, the right thing to do is to model the entire universe. Since this is not practical, we draw a line _somewhere_. _Where_ exactly does not matter much as long as the resulting model is useful. > — [belZaah on hackernews](https://news.ycombinator.com/item?id=49055344) > I think the source of confusion is that the "response delay divisor" isn't a delay at all. This parameter is the inverse of amplification. If you dampen a signal more then it will oscillate less. > — [skybrian on hackernews](https://news.ycombinator.com/item?id=49054343) **Source threads** - [lobsters](https://lobste.rs/s/yia0pc/systems_delays_2026) · 21 points · 3 comments - [hackernews](https://news.ycombinator.com/item?id=49053382) · 40 points · 26 comments - [hackernews](https://news.ycombinator.com/item?id=49046932) · 3 points · 0 comments ## Similar posts on daily.dev - [Six Systems That Save You Months](https://daily.dev/posts/six-systems-that-save-you-months-cnxmykwr6) · Khalil Stemmler · 0 upvotes · 0 comments - [Your Software Delivery Is Broken and More AI Won’t Fix It](https://daily.dev/posts/your-software-delivery-is-broken-and-more-ai-won-t-fix-it-csilhkemg) · IT Revolution · 4 upvotes · 0 comments --- Tags: [#elm](https://daily.dev/tags/elm) [View this post on daily.dev](https://daily.dev/posts/systems-and-delays-5cgsr0rup) ```json {"@context":"https://schema.org","@graph":[{"@type":"Organization","@id":"https://daily.dev/#organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180},"sameAs":["https://twitter.com/dailydotdev","https://github.com/dailydotdev","https://www.linkedin.com/company/daily-dev-ltd"]},{"@type":"WebSite","@id":"https://daily.dev/#website","url":"https://daily.dev","name":"daily.dev","publisher":{"@id":"https://daily.dev/#organization"},"potentialAction":{"@type":"SearchAction","target":{"@type":"EntryPoint","urlTemplate":"https://daily.dev/search?q={search_term_string}"},"query-input":"required name=search_term_string"}}]} {"@context":"https://schema.org","@type":"TechArticle","headline":"Systems and Delays","url":"https://daily.dev/posts/systems-and-delays-5cgsr0rup","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/systems-and-delays-5cgsr0rup"},"datePublished":"2026-07-26T04:07:58.359Z","dateModified":"2026-07-26T16:22:20.213Z","description":"A reflection on a key insight from the book 'Thinking in Systems' by Donella Meadows, illustrated through a car dealership inventory simulation. 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