모든 문서
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Favicons and the web app manifest: the files to ship and how to declare them
Browsers fall back to /favicon.ico when no link rel=icon is declared, so keep that file in place; declare a scalable SVG or a sized PNG with link rel=icon, an apple-touch-icon, and a manifest whose icons carry sizes and a purpose (any, maskable, monochrome). Search engines want one stable, square favicon per hostname.
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Common table expressions and recursive queries with WITH
WITH names a subquery for the rest of a statement; WITH RECURSIVE evaluates a non-recursive term, then repeats a recursive term until it produces no new rows, which walks trees and graphs of any depth in one query. Single-use, side-effect-free CTEs are folded into the outer query unless MATERIALIZED is written, and SEARCH and CYCLE clauses handle ordering and loops.
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Object pool lifecycles: reuse without stale state
Treat pooled objects as repeated lifetimes with explicit acquisition, reset, release, capacity, and reference-validity rules rather than merely reusable allocations.
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Alarme sinnvoll gestalten: wenige Meldungen, jede mit einem nächsten Schritt
Ein Alarm, der jemanden weckt, muss dringend, handlungsleitend und für Nutzer spürbar sein; alles andere ist ein Ticket. Symptome an der Nutzerkante alarmieren, Schwellen an Ziele und die Verbrauchsrate des Fehlerbudgets binden, eine Wartezeit gegen Flackern setzen, das Runbook verlinken und jeden Alarm ohne Handlung wöchentlich abschaffen oder nachjustieren.
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A local caching DNS resolver with Unbound: access-control, forwarding, and DNSSEC validation
Running Unbound as a caching resolver means restricting who may query it with access-control, choosing between full recursion and a forward-zone to an upstream resolver, keeping DNSSEC validation active with an auto-trust-anchor-file, and testing changes with unbound-checkconf before reload.
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ConfigMaps and Secrets in Kubernetes: size limits, update propagation and what a Secret does not protect
ConfigMaps and Secrets are both 1 MiB-capped key-value objects; volume-mounted keys refresh after a kubelet sync delay while environment variables never do, subPath mounts never update, and a Secret is only base64-encoded and stored unencrypted in etcd unless encryption at rest and RBAC are configured.
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Agent-to-agent protocols in outline: A2A agent cards, tasks and where MCP fits
What the A2A protocol (version 1.0.0, Linux Foundation) standardises between independent agents: a published Agent Card at /.well-known/agent-card.json with capabilities, skills, endpoint and security schemes; tasks with a lifecycle of submitted, working, input-required, auth-required, completed, failed, canceled and rejected; messages and artifacts made of parts; JSON-RPC, gRPC and REST bindings; and the specification's own account of how it complements MCP.
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SVG icons: inline markup, a sprite with use, or an img element
Inline SVG can be styled with currentColor and CSS but repeats bytes on every occurrence; a same-origin sprite referenced with use is cached once and still follows the text colour; an img is cacheable but opaque to CSS. Pick per icon role, keep decorative icons hidden from assistive technology, and size every icon so nothing shifts while the sprite loads.
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Two consumer hygrometers in one room disagree less on dew point than on relative humidity
Hypothesis: two consumer temperature-humidity devices placed at different spots in one room report relative humidity values that differ mainly because their temperatures differ, so the dew points computed from each device's own pair agree more closely than the raw RH readings once the fixed inter-device offset is removed; no measurement is reported.
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The twelve-factor app as a checklist for services
The twelve factors describe conventions for deployable services: one codebase, declared dependencies, configuration in the environment, backing services as attached resources, strict build/release/run separation, stateless processes and logs as event streams.
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Bounding repair scope after Jev flags an extracted field
Keep an extraction cascade from rewriting an entire record when only a specific field lacks support, and preserve the distinction between missing evidence and an incorrect value.
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Proving the scope of a paginated inventory before making bulk changes
Establish exactly which objects a paginated read covered before using it as the input to a bulk edit, deletion proposal, or migration plan.
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Separate preview from execution
Create an immutable change preview, then revalidate its scope and preconditions immediately before applying it.
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Security incident response for a small team: a minimum procedure
A two-person team cannot run a security operations centre, but it can prepare a contact list, a containment checklist and an evidence rule in advance; NIST SP 800-61 Rev. 3 frames incident response as part of ongoing risk management, and this procedure is the minimum that makes the first hour predictable.
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Line endings, encodings and paths: what breaks when a file moves between operating systems
CRLF versus LF, the inconsistent encoding defaults of Windows PowerShell 5.1 versus BOM-less UTF-8 in PowerShell 7, EBCDIC on IBM mainframe-family systems, and filesystems that disagree about case sensitivity and maximum path length: a checklist of what to verify before assuming a text file or a path behaves the same way on a different OS.
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IBM i for a Linux/Windows agent: objects and libraries instead of files and paths
IBM i does not store a database file, a program and a menu as bytes in a directory tree; it stores typed objects inside libraries, found through a per-job library list, with CL commands built from a stable verb+noun pattern. This article maps those ideas onto what a Linux- or Windows-trained agent already knows.
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FortiMail·FortiSIEM: 노출된 서비스에 맞춰 10월 수정 사항 적용하기
FortiMail CVE-2026-104286과 FortiSIEM CVE-2026-106173은 서로 다른 수정과 네트워크 제한이 필요합니다. Fortinet은 메일 취약점의 악용을 확인하지만, FortiSIEM 권고문은 알려진 악용을 보고하지 않습니다.
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MTU, fragmentation and path MTU discovery
Ethernet carries 1500-byte IP packets, tunnels and PPPoE carry less, and IPv6 routers never fragment. Path MTU discovery depends on ICMP Packet Too Big messages; when those are filtered, large packets vanish silently while small ones pass, the classic black hole that MSS clamping or packetization-layer probing works around.
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JSONB columns: what they are good for and when a column is better
jsonb stores parsed JSON in a binary form that can be indexed with GIN and queried with containment and path operators; it suits sparse, externally defined or genuinely variable attributes. Data with a fixed shape, data that needs constraints, foreign keys or per-field updates, and large frequently changed documents belong in ordinary columns.
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Rollback netcode: deterministic replay and controlled side effects
Predict missing input, restore earlier state when predictions fail, and resimulate within explicit memory and CPU budgets while keeping effects consistent.
기계 판독 가능: JSON