--- title: The computer at the bottom of a canal | daily.dev description: A deep dive into the Rekursiv, a 1988 processor built by Scottish hi-fi company Linn Products that implemented hardware memory safety, silicon-level garbage... canonical: https://daily.dev/posts/the-computer-at-the-bottom-of-a-canal-0zdxsba7o twitter:card: summary_large_image twitter:site: @dailydotdev og:type: website og:site_name: daily.dev og:title: The computer at the bottom of a canal | daily.dev og:description: A deep dive into the Rekursiv, a 1988 processor built by Scottish hi-fi company Linn Products that implemented hardware memory safety, silicon-level garbage... og:url: https://daily.dev/posts/the-computer-at-the-bottom-of-a-canal-0zdxsba7o og:image: https://api.daily.dev/og/posts/0ZdXsba7O.png og:image:alt: The computer at the bottom of a canal 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. # The computer at the bottom of a canal **[Hacker News](https://daily.dev/sources/hn)** · 15 min read · 2 upvotes · 0 comments ## Summary A deep dive into the Rekursiv, a 1988 processor built by Scottish hi-fi company Linn Products that implemented hardware memory safety, silicon-level garbage collection, a single-level persistent object store, and a loadable instruction set. Despite being technically visionary, it was killed by the commodity microprocessor performance curve. The piece argues all four of its core architectural ideas have since been vindicated: CHERI capability hardware ships in Arm silicon today, GC algorithms from Azul's custom hardware now run in software, persistent object stores persist in IBM i, and domain-specific silicon (TPUs, AI ASICs) is now mainstream. The key lesson drawn is that ideas embedded in an abstraction layer (like ARM's ISA or IBM's TIMI) outlive ideas welded into specific gate arrays. The author connects this to a broader thesis about technology cycles and their own venture studio's investment thesis around contrarian silicon. ## Full article daily.dev links to this article rather than hosting it. Read it at the original source: ## Questions this post answers ### What is CHERI and how does it relate to hardware memory safety? CHERI is a capability-based hardware architecture developed by Robert Watson and colleagues at Cambridge and SRI since 2010, in which every pointer carries hardware-enforced bounds, permissions, and an unforgeable validity tag. Arm shipped CHERI in its Morello prototype boards in 2022 under the UK's Digital Security by Design programme, and a lighter version, the Memory Tagging Extension, ships in Android phones. Microsoft's security team concluded in 2020 that CHERI would have deterministically mitigated at least two thirds of the memory-safety vulnerabilities it patched in 2019. _Engineers weighing capability hardware against software mitigations can track CHERI and Morello developments on daily.dev._ ### What was the Rekursiv processor and why did it fail commercially? The Rekursiv was a custom object-oriented processor built by Scottish hi-fi company Linn Products, shipping in 1988 after four years of development. It checked type and bounds of every memory access in hardware, garbage-collected its own heap in silicon, and treated memory and disk as one persistent object store. It failed because commodity microprocessors improved roughly 52% a year from 1986 to 2003, making the bespoke architecture obsolete by the time it reached silicon, and only twenty to thirty boards were ever built, mostly going to universities rather than Linn's own production line. _Anyone researching failed but prescient hardware bets can follow silicon architecture history on daily.dev._ ### Why did IBM's System/38 succeed with persistent single-level store ideas while the Rekursiv failed with similar concepts? IBM put its single-level store, persistent objects, and capability semantics into a virtual instruction set called the Technology Independent Machine Interface (TIMI), then translated it to whatever processor ran underneath, so when the platform moved to PowerPC in 1995 customer applications didn't even need recompiling. Linn instead welded the same semantics directly into four specific gate arrays, so the abstraction outlived the hardware for IBM but the Rekursiv's gate arrays lasted only about five years. _Developers deciding whether to target an abstraction layer or bare silicon can compare architecture trade-offs on daily.dev._ ## Similar posts on daily.dev - [A Third World Embedded Engineer Responds to "RISC-V: They Should Have Known Better"](https://daily.dev/posts/a-third-world-embedded-engineer-responds-to-risc-v-they-should-have-known-better--1bh7jvqtz) · Lobsters · 2 upvotes · 0 comments - [Small Things Retro](https://daily.dev/posts/small-things-retro-yps3c9exj) · Hacker News · 0 upvotes · 0 comments - [Computers that I never had: the Acorn A3020](https://daily.dev/posts/computers-that-i-never-had-the-acorn-a3020-hspqvpdsc) · Two Stop Bits · 4 upvotes · 1 comments - [Memory ordering in CPUs](https://daily.dev/posts/memory-ordering-in-cpus-ynhh3zoic) · Ryg blog · 0 upvotes · 0 comments - [He Comes To Bury Segmented Memory, Not To Praise It](https://daily.dev/posts/he-comes-to-bury-segmented-memory-not-to-praise-it-7q7ra33ui) · Hackaday · 0 upvotes · 0 comments --- Tags: [#architecture](https://daily.dev/tags/architecture), [#hardware](https://daily.dev/tags/hardware) [View this post on daily.dev](https://daily.dev/posts/the-computer-at-the-bottom-of-a-canal-0zdxsba7o) ```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":"The computer at the bottom of a canal","url":"https://daily.dev/posts/the-computer-at-the-bottom-of-a-canal-0zdxsba7o","mainEntityOfPage":{"@type":"WebPage","@id":"https://daily.dev/posts/the-computer-at-the-bottom-of-a-canal-0zdxsba7o"},"datePublished":"2026-07-18T13:56:47.051Z","dateModified":"2026-09-14T08:02:19.777Z","description":"A deep dive into the Rekursiv, a 1988 processor built by Scottish hi-fi company Linn Products that implemented hardware memory safety, silicon-level garbage...","image":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/5f5bfa11b1db5de96e93bbd85d78c565?_a=AQAEuop","thumbnailUrl":"https://media.daily.dev/image/upload/f_auto,q_auto/v1/posts/5f5bfa11b1db5de96e93bbd85d78c565?_a=AQAEuop","isAccessibleForFree":true,"articleSection":"Hacker News","inLanguage":"en","publisher":{"@type":"Organization","name":"daily.dev","url":"https://daily.dev","logo":{"@type":"ImageObject","url":"https://daily.dev/apple-touch-icon.png","width":180,"height":180}},"author":{"@type":"Organization","name":"Hacker News","logo":"https://media.daily.dev/image/upload/t_logo,f_auto/v1/logos/hn","url":"https://daily.dev/sources/hn"},"commentCount":0,"discussionUrl":"https://daily.dev/posts/the-computer-at-the-bottom-of-a-canal-0zdxsba7o","interactionStatistic":[{"@type":"InteractionCounter","interactionType":{"@type":"LikeAction"},"userInteractionCount":2},{"@type":"InteractionCounter","interactionType":{"@type":"CommentAction"},"userInteractionCount":0}],"keywords":"architecture,hardware","timeRequired":"PT15M"} {"@context":"https://schema.org","@type":"BreadcrumbList","itemListElement":[{"@type":"ListItem","position":1,"name":"Home","item":"https://daily.dev"},{"@type":"ListItem","position":2,"name":"Hacker News","item":"https://daily.dev/sources/hn"},{"@type":"ListItem","position":3,"name":"The computer at the bottom of a canal"}]} {"@context":"https://schema.org","@type":"FAQPage","@id":"https://daily.dev/posts/the-computer-at-the-bottom-of-a-canal-0zdxsba7o#faq","mainEntity":[{"@type":"Question","name":"What is CHERI and how does it relate to hardware memory safety?","acceptedAnswer":{"@type":"Answer","text":"CHERI is a capability-based hardware architecture developed by Robert Watson and colleagues at Cambridge and SRI since 2010, in which every pointer carries hardware-enforced bounds, permissions, and an unforgeable validity tag. 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It failed because commodity microprocessors improved roughly 52% a year from 1986 to 2003, making the bespoke architecture obsolete by the time it reached silicon, and only twenty to thirty boards were ever built, mostly going to universities rather than Linn's own production line. Anyone researching failed but prescient hardware bets can follow silicon architecture history on daily.dev."}},{"@type":"Question","name":"Why did IBM's System/38 succeed with persistent single-level store ideas while the Rekursiv failed with similar concepts?","acceptedAnswer":{"@type":"Answer","text":"IBM put its single-level store, persistent objects, and capability semantics into a virtual instruction set called the Technology Independent Machine Interface (TIMI), then translated it to whatever processor ran underneath, so when the platform moved to PowerPC in 1995 customer applications didn't even need recompiling. Linn instead welded the same semantics directly into four specific gate arrays, so the abstraction outlived the hardware for IBM but the Rekursiv's gate arrays lasted only about five years. Developers deciding whether to target an abstraction layer or bare silicon can compare architecture trade-offs on daily.dev."}}]} ```