Notes

SQLite is an embedded database that holds a SQL database in a single file. It is one of the most frequently chosen options for local storage in desktop and mobile apps.

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cmd.exe is the command processor on Windows NT-family systems. It debuted in 1993 with Windows NT 3.1 and ships with every Windows release. Since PowerShell arrived, cmd's role as an entry point for new code has shrunk,…

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iOS app builds go through similar steps to Android (compile → bundle resources → sign → package), but the tools, distribution channels, and policies look quite different. The biggest difference is that macOS and the App…

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The trend of running large language models directly on personal computers has taken hold rapidly since 2023. Where there used to be only cloud APIs, the combination of quantization formats like GGUF, inference runtimes…

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Even with the same language and the same code, the basics like paths, line endings, shells, and permissions shift once the operating system changes. Linux falls on the macOS side of this split (both are Unix-flavored).

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An embedding is the result of mapping text (or images · code) to fixed-dimensional real-valued vectors. On top of the assumption that semantically close items sit close in the vector space, search · clustering · classif…

Whether a subnet is "public" or "private" is decided by routing, not by labels. Once we understand how Internet Gateway (IGW), NAT Gateway, route tables, and VPC endpoints combine, the meaning of subnet design becomes c…

When a service is in its early stage, it is often most reasonable to bring everything up on a single VPS with docker compose. Operational cognitive load is small and costs are predictable. How far this model goes, when…

The trend of combining large language model responses with external knowledge has settled under the name RAG (Retrieval-Augmented Generation). At its core sits vector similarity search, and PostgreSQL's pgvector extensi…

When writing an HTTP API, the code around the handler body (auth, validation, logging, error translation, rate limiting) often outweighs the body itself. Where and how this cross-cutting code lives decides consistency a…

TypeORM was once a representative ORM in the Node camp and was widely used alongside NestJS. Its position has shifted somewhat as new ORMs appeared, but it still runs in many codebases.

Supabase appeared in 2020 with the slogan "open source Firebase." If Firebase is one giant managed box with its own NoSQL · Auth · Storage, Supabase took the path of placing Postgres at the center and stacking small com…

> The multi-emulator paths and commands below are an architectural example, not a claim about a particular repository. Select only the providers and cost envelope you actually need.

The shell most often encountered on Unix-flavored systems is bash. Its roots trace back to sh (Bourne shell).

In Python web backends, frameworks rarely enforce a folder layout, so it falls to team agreement. A well-organized layout shortens onboarding for new members; without it, the same patterns get scattered everywhere.

State management in React apps creates confusion because there are many libraries. The biggest fork, however, is not the library choice but whether the state belongs to the client or to the server.

The training-data cutoff of an LLM never quite matches the latest. Library docs and API specs change often, and the model answers with old information confidently. MCP servers and services that expose docs in an LLM-fri…

Spring carries two web stacks side by side. The older Spring MVC (Servlet-based, synchronous and blocking) and the relatively newer Spring WebFlux (Reactor-based, asynchronous and non-blocking).

Frontend bundlers have branched out rapidly over the past decade or so.

Systems that handle external data reduce to similar steps everywhere. Fetch the data, clean it, store it, and expose it.

Untrusted input arrives at the edges of the system. HTTP body, query, headers, environment variables, external API responses, file contents. Letting that input flow into the inner code blurs both type and meaning, and s…

Choosing a data store is often a burden. NoSQL, distributed SQL, graph DBs, time-series DBs all line up. Yet for many projects, PostgreSQL alone is enough for a long time at the start.

When several Spring applications live in a single repository, we have to settle the location of shared code, the build unit, and the direction of dependencies. Gradle's multi-project build is the standard tool for handl…

The three areas of human writing (text in images), human speech (sound), and the reverse of synthesized voice run on different stacks but are often bundled together inside an app.

As AI coding assistants multiplied, the convention "write the project rules and context in a single file" took root. Tools differ slightly in name and location, but the intent is similar.