Go Komura

Dark Mode and Contrast Themes in Windows Apps — DWM Dark Title Bars, System Theme Tracking in WinForms/WPF, and Drawing under High Contrast (archived 2026-09-07)

How to make WinForms/WPF apps follow the dark mode and contrast themes of Windows 11. Covers DWM dark title bars, SetColorMode and ThemeMode in .NET 9/10, detecting theme changes, and drawing with system colors under high contrast. Archived version of https://comcomponent.com/en/...

The Depths of Windows Virtualization (Part 1) — Where Is Your Windows Actually Running? The Hypervisor and Partitions (archived 2026-09-07)

When you enable Hyper-V, the host Windows itself runs as the root partition on top of the hypervisor. This article explains the foundations of virtualization, from VT-x and SLAT to VMBus. Archived version of https://comcomponent.com/en/blog/windows-virtualization-internals-hyperv...

The Depths of Windows Virtualization (Part 2) — Memory Even the Kernel Cannot See: How VBS, HVCI, and Credential Guard Work (archived 2026-09-07)

Enabled by default on a clean install to compatible hardware, VBS uses the hypervisor and SLAT to isolate beyond the kernel. Covers VTLs, the Secure Kernel, HVCI, and Credential Guard. Archived version of https://comcomponent.com/en/blog/windows-virtualization-internals-vbs-hvci-...

Declarative Configuration Management for Windows with DSC — Starting IaC with dsc.exe (archived 2026-09-07)

Move on from runbook scripts that break when re-run. DSC v3 (dsc.exe) declares Windows configuration in YAML and applies it idempotently, with drift detection. Archived version of https://comcomponent.com/en/blog/dsc-windows-declarative-iac/, as published on 2026-09-07. The live...

What Is an OLE Object? — How Embedding and Linking Work and the Pitfalls in Business Documents (archived 2026-09-07)

An OLE object is what embeds an Excel table in Word. Learn embedding vs. linking, compound files, In-Place Activation, broken links, bloat, and security. Archived version of https://comcomponent.com/en/blog/what-is-ole-object/, as published on 2026-09-07. The live article is main...

The "Same PC" Is Not the Same Execution Environment — The User Boundary That Separates AppData, HKCU, DPAPI, and Credentials (archived 2026-09-07)

Why an app that works on your desk breaks as a task or service: how the Windows user boundary separates AppData, HKCU, DPAPI, browser profiles, and credentials. Archived version of https://comcomponent.com/en/blog/windows-user-boundary-appdata-hkcu-dpapi/, as published on 2026-09...

The Depths of Windows Virtualization (Part 3) — Virtual Machines That Boot in Seconds: Why WSL2, Windows Sandbox, and Containers Are So Light (archived 2026-09-07)

Why WSL2 and Windows Sandbox boot in seconds and stay light: dynamic base images, direct map, dynamic memory allocation, and Hyper-V isolated containers explained. Archived version of https://comcomponent.com/en/blog/windows-virtualization-internals-wsl2-sandbox-containers/, as p...

Why Arguments Break — The Rules of Windows Command-Line Arguments (archived 2026-09-07)

Windows passes CreateProcess a single string that the receiver splits. Covers the CommandLineToArgvW, CRT, and .NET rules, ArgumentList, and building it in C++. Archived version of https://comcomponent.com/en/blog/windows-command-line-argument-rules/, as published on 2026-09-07....

The Win32 Thread Pool API — Concurrency That Does Not Create Threads, with CreateThreadpoolWork (archived 2026-09-07)

Calling CreateThread everywhere in native code? A primary-source guide to the Win32 thread pool API: the work, timer, wait, and io objects, cleanup groups, and callback rules. Archived version of https://comcomponent.com/en/blog/win32-thread-pool-api/, as published on 2026-09-07....

The Depths of Windows Memory (Part 2) — The Life of a Physical Page: Five Lists and the Truth About the Page File (archived 2026-09-03)

This article connects the PFN database, Standby, Modified, memory compression, and the page file to explain where a physical page goes after it leaves the Working Set. Archived version of https://comcomponent.com/en/blog/windows-memory-internals-page-lifecycle-pagefile/, as publi...

Windows Time Synchronization (w32time) and Business Systems — Solving "The Log Timestamps Don't Match" from the Mechanism Up (archived 2026-09-03)

Why do timestamps drift between a device and a PC? This article explains it from the mechanics of the Windows Time service (w32time): the default behavior in domain hierarchies and workgroups, diagnosis with the w32tm commands, the caveats around high-accuracy time and virtual ma...

What Website Clients Should Know Too — Using IPA's 'How to Secure Your Website' as a Checklist (archived 2026-09-03)

What standard should you use to check your company website's security against? This article explains the 11 vulnerabilities and countermeasures covered in IPA's 'How to Secure Your Website,' in language that makes sense to clients and site operators, and shows how to use it when...

What Is OpenHarmony? — Sorting Out How It Differs from HarmonyOS and HarmonyOS NEXT (archived 2026-09-03)

OpenHarmony and HarmonyOS are not the same thing. This article works systematically through the relationship between the open source OS run by the OpenAtom Foundation, Huawei's commercial OS, and HarmonyOS NEXT onwards with its Android compatibility removed — all based on primary...

Fable Is Gone — Don't Give Up: OpenRouter Fusion + Chinese LLMs + Review Layer (archived 2026-09-03)

How to set up opencode with OpenRouter Fusion and five Chinese LLMs (DeepSeek, Kimi, more), plus a GPT review layer — full opencode.json config included. Archived version of https://comcomponent.com/en/blog/2026/06/14/000-opencode-fusion-chinese-llms/, as published on 2026-09-03....

The Depths of Windows Memory (Part 2) — The Life of a Physical Page: Five Lists and the Truth About the Page File (archived 2026-09-03)

This article connects the PFN database, Standby, Modified, memory compression, and the page file to explain where a physical page goes after it leaves the Working Set. Archived version of https://comcomponent.com/en/blog/windows-memory-internals-page-lifecycle-pagefile/, as publi...

What Do the Eight Digits of an Insurer Number Tell You? — Law-Type Numbers, Prefecture Numbers and Check Digits Read from a Receipt Computer's Implementation (archived 2026-09-03)

The insurer number on a Japanese health insurance card is made up of a 2-digit law-type number, a 2-digit prefecture number, a 3-digit per-insurer number and a 1-digit check digit. Taking the Ministry of Health, Labour and Welfare's setting guidelines as the primary source, this...

Where Do Downcoding and Returned Claims Actually Happen? — Taking Apart Receipt Checking Logic Using ORCA's Source Code and Public Documents (archived 2026-08-30)

Where do downcoding and returned claims actually happen? From ORCA's data check function and its check masters, through the rece-den data check, to the computer checks, cross-matching review and longitudinal review performed by the claims review and payment bodies — this article...

Should That Batch File Move to PowerShell? — Auditing cmd/bat Assets and Making the Migration Call (archived 2026-08-30)

A decision table for working out whether the batch files still running your business should move to PowerShell: how cmd and VBScript differ in status, bat's structural weaknesses such as not stopping on errors, how to write during the mixed period, a command rewrite reference tab...

Registered Information Security Specialist Exam, Spring 2024 (Reiwa 6) PM Q1 Commentary — JWT alg=none, API Authorization, and Interim WAF Mitigation (archived 2026-08-30)

Using the Registered Information Security Specialist Examination's Spring 2024 (Reiwa 6) PM Q1 as a case study, this article explains JWT's alg=none, API authorization, Mass Assignment, brute-forcing a four-digit authentication code, and interim mitigation with a WAF. Archived ve...

The Depths of Windows I/O (Part 2) — Synchronous and Asynchronous I/O: What OVERLAPPED Really Means (archived 2026-08-30)

Part 2 of a series explaining Windows synchronous and asynchronous I/O (overlapped I/O) with diagrams. It covers what FILE_FLAG_OVERLAPPED means, the four ways completion is reported, the conditions under which supposedly-asynchronous I/O completes synchronously, how to cancel pr...