--- title: Who Checks the Assumptions of a Simulation? | daily.dev description: Functional simulators for embedded systems work by detaching software logic from hardware timing, not by perfectly mimicking the hardware itself. Documenting... canonical: https://daily.dev/posts/who-checks-the-assumptions-of-a-simulation--umrgs8jg5 twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: Who Checks the Assumptions of a Simulation? | daily.dev og:description: Functional simulators for embedded systems work by detaching software logic from hardware timing, not by perfectly mimicking the hardware itself. Documenting... og:url: https://daily.dev/posts/who-checks-the-assumptions-of-a-simulation--umrgs8jg5 og:image: https://api.daily.dev/og/posts/UMRgS8JG5.png og:image:alt: Who Checks the Assumptions of a Simulation? 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. # Who Checks the Assumptions of a Simulation? **[Embedded Artistry](https://daily.dev/sources/embedded-artistry)** · 5 min read · 0 upvotes · 0 comments ## Summary Functional simulators for embedded systems work by detaching software logic from hardware timing, not by perfectly mimicking the hardware itself. Documenting the assumptions behind interfaces and data inputs turns them into a shared spec that hardware drivers, mocks, and playback modules can all be tested against. Confidence can grow by recording real bus traffic and replaying it through the simulator to expose bad assumptions. The piece also argues that hardware prototypes and demos have the same problems as simulations, since the author rarely sees system assumptions checked on hardware either. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### How do you validate that a software simulator accurately represents real embedded hardware behavior? Ground the simulator in recorded reality by collecting raw data from real hardware, such as I2C or SPI bus traffic or radio bits, and playing it back through the simulator. Document assumptions about interfaces and data inputs as a specification, then build automated tests that check hardware drivers, mock drivers, and playback modules against that same spec. _Teams weighing simulator trust against hardware testing can track this reasoning on daily.dev._ ### What's the difference between a functional simulator and simulating hardware timing exactly? A functional simulator detaches software logic from hardware rather than reproducing hardware timing precisely. It runs the same production code with as much functionality preserved as possible but without real-time fidelity, treating the hardware as a set of abstracted data inputs that the software components consume. _Developers deciding how to structure embedded test environments can follow this distinction on daily.dev._ ## Similar posts on daily.dev - [The Regression Tests Nobody Writes: Capturing How Software Actually Behaves](https://daily.dev/posts/the-regression-tests-nobody-writes-capturing-how-software-actually-behaves-oemkxrld2) · Stack Overflow Blog · 0 upvotes · 0 comments - [Test, don't \(just\) verify](https://daily.dev/posts/test-don-t-just-verify-xttcataah) · Hacker News · 2 upvotes · 0 comments - [Black Box Testing APIs in Microservices: Why Your Tests Pass but Your System Still Fails](https://daily.dev/posts/black-box-testing-apis-in-microservices-why-your-tests-pass-but-your-system-still-fails-egkisgycd) · Cloud Native Now · 0 upvotes · 0 comments --- Tags: [#testing](https://daily.dev/tags/testing), [#embedded](https://daily.dev/tags/embedded) [View this post on daily.dev](https://daily.dev/posts/who-checks-the-assumptions-of-a-simulation--umrgs8jg5) ```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":"Who Checks the Assumptions of a Simulation?","url":"https://daily.dev/posts/who-checks-the-assumptions-of-a-simulation--umrgs8jg5","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/who-checks-the-assumptions-of-a-simulation--umrgs8jg5"},"datePublished":"2026-10-29T15:31:34.824Z","dateModified":"2026-10-29T15:36:20.546Z","description":"Functional simulators for embedded systems work by detaching software logic from hardware timing, not by perfectly mimicking the hardware itself. 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Document assumptions about interfaces and data inputs as a specification, then build automated tests that check hardware drivers, mock drivers, and playback modules against that same spec. Teams weighing simulator trust against hardware testing can track this reasoning on daily.dev."}},{"@type":"Question","name":"What's the difference between a functional simulator and simulating hardware timing exactly?","acceptedAnswer":{"@type":"Answer","text":"A functional simulator detaches software logic from hardware rather than reproducing hardware timing precisely. It runs the same production code with as much functionality preserved as possible but without real-time fidelity, treating the hardware as a set of abstracted data inputs that the software components consume. Developers deciding how to structure embedded test environments can follow this distinction on daily.dev."}}]} ```