https://jhlimlab.com I build things, test them, and leave notes. ko Tue, 13 Oct 2026 00:00:00 GMT https://jhlimlab.com/notes/a-random-hexagram-on-purpose https://jhlimlab.com/notes/a-random-hexagram-on-purpose Tue, 13 Oct 2026 00:00:00 GMT Sketched a framework that reads one problem twice — once by ordinary analysis, once through the sixty-four hexagrams — then argues the two readings against each other. One of the four hexagrams is drawn at random, and that is the point. AI THOUGHTS framework reasoning bias iching idea https://jhlimlab.com/notes/the-caption-disagreed-with-the-curve https://jhlimlab.com/notes/the-caption-disagreed-with-the-curve Fri, 25 Sep 2026 00:00:00 GMT The caption under a chart said one pair of numbers. The curve above it drew another. The words were typed by a person and the line was drawn by code, and nothing made them agree. EDUCATION EXPERIMENT chart teaching honesty skill data https://jhlimlab.com/notes/i-ignored-my-own-rule https://jhlimlab.com/notes/i-ignored-my-own-rule Fri, 25 Sep 2026 00:00:00 GMT The drawing skill said the default line was a hand-drawn sketch, meant for rough concepts. It had been drawing finished equipment diagrams that way the whole time. I wrote that rule. EXPERIMENT EDUCATION claude-code skill diagram drawing tooling https://jhlimlab.com/notes/where-the-skills-live https://jhlimlab.com/notes/where-the-skills-live Wed, 23 Sep 2026 00:00:00 GMT Claude Code reads skills from only three places, and none of them is shared across repositories. So one repo became a warehouse. Here is the whole structure, and the two things that kept not working. AI EXPERIMENT claude-code skill plugin tooling recipe https://jhlimlab.com/notes/what-the-crawlers-actually-got https://jhlimlab.com/notes/what-the-crawlers-actually-got Tue, 22 Sep 2026 00:00:00 GMT Search engines and AI crawlers do not open a page the way a person does. Four times in seven months, the file they were handed was not the page I thought I had built. EXPERIMENT THOUGHTS geo seo crawler prerender llms-txt semifab https://jhlimlab.com/notes/did-you-press-the-button https://jhlimlab.com/notes/did-you-press-the-button Wed, 16 Sep 2026 00:00:00 GMT The wafer transfer trainer had fifteen chapters and every one of them ended at "did you press the button". Five graded drills became twenty-nine, and one of those five turned out to be unwinnable two percent of the time. EDUCATION SIMULATION simulator robot teaching grading verification https://jhlimlab.com/notes/four-games-replaced-in-eleven-days https://jhlimlab.com/notes/four-games-replaced-in-eleven-days Sun, 06 Sep 2026 00:00:00 GMT Eleven days, four games swapped out — including the one that drew the most attention. The invite mechanic is what made a game nobody would forward impossible to keep. EXPERIMENT game byeolbyeol pivot content https://jhlimlab.com/notes/it-only-works-if-two-people-play https://jhlimlab.com/notes/it-only-works-if-two-people-play Thu, 03 Sep 2026 00:00:00 GMT Built a travel-compatibility game for youdam.com. Eight questions, two minutes, four travel types. Alone you get half of it — the other half only opens when someone you invite finishes theirs. EXPERIMENT game invite share byeolbyeol no-server https://jhlimlab.com/notes/search-thought-i-was-another-company https://jhlimlab.com/notes/search-thought-i-was-another-company Mon, 31 Aug 2026 00:00:00 GMT An answer engine folded my brand together with a semiconductor company whose name looks like mine. The fix was not writing more pages. It was filling in what this is, and what it is not. THOUGHTS EXPERIMENT geo seo entity brand structured-data semifab https://jhlimlab.com/notes/the-door-did-more-than-the-prompt https://jhlimlab.com/notes/the-door-did-more-than-the-prompt Mon, 31 Aug 2026 00:00:00 GMT Plugged the MCP in and ran it end to end. Handing over the tools was not enough. It only felt like a fab once there was a door between inside and out — and it cost speed. AI SIMULATION ai agent mcp semifab llm https://jhlimlab.com/notes/the-dashed-line-ran-backwards https://jhlimlab.com/notes/the-dashed-line-ran-backwards Sun, 30 Aug 2026 00:00:00 GMT Stood up the equipment technology book, then built a gas panel you operate instead of read. The flow animation ran backwards on one line only, and the cause was not direction. It was speed. SEMICONDUCTOR EDUCATION simulator hmi diagram equipment teaching https://jhlimlab.com/notes/white-text-on-white https://jhlimlab.com/notes/white-text-on-white Sat, 29 Aug 2026 00:00:00 GMT The fab is one dark shell with process modules plugged into it. A bright module inherited the shell colour and went white on white; the sweep found twenty-one more in the diagrams. EDUCATION EXPERIMENT semifab ui contrast audit https://jhlimlab.com/notes/the-one-line-that-says-what-this-site-is https://jhlimlab.com/notes/the-one-line-that-says-what-this-site-is Fri, 28 Aug 2026 00:00:00 GMT Wrote an llms.txt for the arcade so answer engines could quote it. The top line got rewritten three times — and each rewrite was a different answer to what the site actually is. EXPERIMENT THOUGHTS geo llms-txt seo byeolbyeol positioning https://jhlimlab.com/notes/a-hundred-and-twenty-ghost-seats https://jhlimlab.com/notes/a-hundred-and-twenty-ghost-seats Fri, 28 Aug 2026 00:00:00 GMT Deleting a class did not delete its seats. The leftovers kept counting, and the numbers the staff read were wrong. EDUCATION EXPERIMENT semifab operations data failure https://jhlimlab.com/notes/one-qr-code-sixty-seats https://jhlimlab.com/notes/one-qr-code-sixty-seats Wed, 26 Aug 2026 00:00:00 GMT Handing out sixty codes at the start of a class wastes the first ten minutes. One code on the projector, and everyone gets their own seat. EDUCATION EXPERIMENT semifab onboarding qr classroom https://jhlimlab.com/notes/deleting-a-year-of-work https://jhlimlab.com/notes/deleting-a-year-of-work Wed, 26 Aug 2026 00:00:00 GMT Deleted the entire EduAtlas application and started over. 47 files, 11,419 lines gone in one commit. THOUGHTS lab notes rebuild eduatlas https://jhlimlab.com/notes/a-general-ai-now-runs-the-fab https://jhlimlab.com/notes/a-general-ai-now-runs-the-fab Wed, 26 Aug 2026 00:00:00 GMT The gateway works. A general AI can list the flows, read parameter ranges, open the equipment panel, and run the process itself. AI SIMULATION ai agent mcp semifab tool https://jhlimlab.com/notes/zero-and-null-are-different-facts https://jhlimlab.com/notes/zero-and-null-are-different-facts Tue, 25 Aug 2026 00:00:00 GMT KOH crystal-plane etching is outside what the model covers. Declared the boundary instead of implementing a guess. SEMICONDUCTOR SIMULATION minifab etch physics verification https://jhlimlab.com/notes/swap-the-brain-keep-the-hands https://jhlimlab.com/notes/swap-the-brain-keep-the-hands Mon, 24 Aug 2026 00:00:00 GMT Moved Bandi onto a different brain. The hands — the action bus, the eyes, the console wiring — stayed exactly where they were. AI SIMULATION bandi minifab ai architecture https://jhlimlab.com/notes/ai-operations-manager https://jhlimlab.com/notes/ai-operations-manager Mon, 24 Aug 2026 00:00:00 GMT An assistant that proposes actions for staff to approve. Then I made it watch what happened after — and stop suggesting things that cannot reach anyone. AI EDUCATION ai agent semifab operations https://jhlimlab.com/notes/replacing-a-blog-with-an-arcade https://jhlimlab.com/notes/replacing-a-blog-with-an-arcade Sun, 23 Aug 2026 00:00:00 GMT Wiped the blog off youdam.com and put a web game arcade there instead. No sign-up. Three minutes per game. Retargeted it three days later. EXPERIMENT game byeolbyeol codex arcade https://jhlimlab.com/notes/using-it-myself-three-were-broken https://jhlimlab.com/notes/using-it-myself-three-were-broken Thu, 20 Aug 2026 00:00:00 GMT Sat down and used the etching simulator like a student would. Three things were not working. Then a textbook check found HBr half-built. SEMICONDUCTOR SIMULATION simulator etch physics teaching verification https://jhlimlab.com/notes/forty-thousand-random-checks https://jhlimlab.com/notes/forty-thousand-random-checks Wed, 19 Aug 2026 00:00:00 GMT A build passing does not mean the numbers are right. Built a physics invariant check and threw forty thousand random inputs at it. SIMULATION SEMICONDUCTOR simulator physics verification testing https://jhlimlab.com/notes/bypassed-by-a-tone-of-voice https://jhlimlab.com/notes/bypassed-by-a-tone-of-voice Sat, 15 Aug 2026 00:00:00 GMT Two weeks after wiring the verified-recipe warehouse in front of the model, one phrasing walked straight past it. "다층 배선해줘" fell through to invention. AI SIMULATION westworld bandi llm verification minifab https://jhlimlab.com/notes/semifab-visual-content-engine https://jhlimlab.com/notes/semifab-visual-content-engine Sat, 15 Aug 2026 00:00:00 GMT Built a SemiFab-specific visual content engine on top of the video factory. A still-first pipeline cut the cost of one iteration by 25x. SEMICONDUCTOR VIDEO AI video semifab automation pipeline cost https://jhlimlab.com/notes/the-simulator-taught-the-opposite https://jhlimlab.com/notes/the-simulator-taught-the-opposite Thu, 13 Aug 2026 00:00:00 GMT Checked every theory tab against the literature rather than against the code. Two modules were teaching the exact opposite of the truth, and the test that should have caught a third was comparing the code to itself. SIMULATION SEMICONDUCTOR simulator physics verification teaching audit https://jhlimlab.com/notes/process-replay-and-learning-gate https://jhlimlab.com/notes/process-replay-and-learning-gate Wed, 12 Aug 2026 00:00:00 GMT Every scenario deliberately leaves one step out. The student has to notice what is missing instead of following a recipe to the end. AI SIMULATION semifab bandi sem replay teaching https://jhlimlab.com/notes/not-an-llm-judge https://jhlimlab.com/notes/not-an-llm-judge Tue, 11 Aug 2026 00:00:00 GMT How do you test a layer that is not deterministic? Not by asking another model. By comparing against what the fab can see. AI SIMULATION bandi llm verification ai https://jhlimlab.com/notes/landing-page-as-a-dse-demo https://jhlimlab.com/notes/landing-page-as-a-dse-demo Sat, 08 Aug 2026 00:00:00 GMT Replaced the blog landing with an interactive SemiFab DSE demo — HBM physics packs, quantum fabrication tracks, decision gates. SEMICONDUCTOR SIMULATION semifab hbm quantum dse https://jhlimlab.com/notes/a-board-that-costs-nothing-to-watch https://jhlimlab.com/notes/a-board-that-costs-nothing-to-watch Tue, 04 Aug 2026 00:00:00 GMT The operations assistant answers when asked, and every answer costs a call. So the always-on view got built without any model at all. AI EDUCATION semifab operations dashboard cost https://jhlimlab.com/notes/a-console-for-the-instructor https://jhlimlab.com/notes/a-console-for-the-instructor Tue, 04 Aug 2026 00:00:00 GMT Built the instructor side. What the class is doing, where they are stuck, and what Bandi did about it — all reported into one place. EDUCATION AI minifab lighthouse operations teaching bandi https://jhlimlab.com/notes/a-safety-net-without-the-tutor https://jhlimlab.com/notes/a-safety-net-without-the-tutor Thu, 30 Jul 2026 00:00:00 GMT Not every institution will run the AI tutor. Built a deterministic status board that watches the process and says nothing more. SIMULATION EDUCATION minifab teaching verification bandi https://jhlimlab.com/notes/warehouse-first https://jhlimlab.com/notes/warehouse-first Tue, 28 Jul 2026 00:00:00 GMT If a well-known process is asked for, hand over a verified golden recipe before the model gets a chance to invent one. AI SIMULATION westworld bandi llm verification minifab https://jhlimlab.com/notes/bandi-basic-mode https://jhlimlab.com/notes/bandi-basic-mode Tue, 28 Jul 2026 00:00:00 GMT Finished the basic mode of Bandi, the AI tutor. It reads the live process state — etch depth, sidewall angle, contamination — and helps from there. AI SIMULATION semifab bandi ai tutor https://jhlimlab.com/notes/fuzzing-the-renderer https://jhlimlab.com/notes/fuzzing-the-renderer Mon, 27 Jul 2026 00:00:00 GMT Hand-written tests only catch what you thought of. Built fuzzers that sweep the render space from many angles and report a coverage cloud. SIMULATION SEMICONDUCTOR westworld verification sem minifab testing https://jhlimlab.com/notes/lighthouse-dashboard https://jhlimlab.com/notes/lighthouse-dashboard Thu, 23 Jul 2026 00:00:00 GMT Built an operations assistant for the people who run the classes. It borrowed the tutor's shape — same chat, same cursor, different job. EDUCATION semifab dashboard operations teaching https://jhlimlab.com/notes/it-said-it-ran-but-it-didnt https://jhlimlab.com/notes/it-said-it-ran-but-it-didnt Tue, 21 Jul 2026 00:00:00 GMT Let students talk Bandi into running the equipment. It lied about having run it. Killed the whole path the next day. AI SIMULATION bandi ai agent teaching https://jhlimlab.com/notes/content-reliability-sweep https://jhlimlab.com/notes/content-reliability-sweep Tue, 21 Jul 2026 00:00:00 GMT Rebuilt the topic modules as an actual library — shelves, spines, a reading room. Then swept every deck for the errors the redesign exposed. SEMICONDUCTOR EDUCATION semifab physics textbook quality https://jhlimlab.com/notes/three-layers-of-verification https://jhlimlab.com/notes/three-layers-of-verification Sat, 18 Jul 2026 00:00:00 GMT Westworld became the control and setup center. Declared the three layers of verification, and made measurement honesty a permanent gate. SIMULATION EDUCATION westworld verification minifab bandi teaching https://jhlimlab.com/notes/rules-decide-when-the-model-decides-what https://jhlimlab.com/notes/rules-decide-when-the-model-decides-what Sat, 18 Jul 2026 00:00:00 GMT Split Bandi in two: rules choose the moment to speak, the model chooses the words. Canned lines became the fallback. AI bandi llm ai architecture tutor