Racks questions

Summary A simulation model in AnyLogic encountered issues with worker assignment and tracking box data in a racking system. Workers needed to be restricted to specific aisles, and box data (weight, volume, and ID) required tracking after storage. Root Cause Worker Assignment: Workers were not properly assigned to specific aisles, leading to inefficiencies. Data Tracking: … Read more

App Store Connect: Xcode Cloud Build Failing with Ad-hoc and Developer Distribution Errors

Summary This incident involved Xcode Cloud builds failing with Ad‑hoc and Developer Distribution errors (Error code 70) when attempting to upload an iOS app to App Store Connect. The local build and simulator runs succeeded, but the cloud pipeline consistently rejected the archive due to misaligned signing assets and incorrect distribution configuration. Root Cause The … Read more

Timezone Conversion Bug When Scheduling Across Day Boundaries Flutter

Summary A timezone conversion bug caused scheduling errors when crossing day boundaries, resulting in incorrect execution dates. The issue occurred due to improper handling of date adjustments during timezone conversions, leading to either a one-day delay or repetition of the same day. Root Cause Incorrect date handling: The conversion logic failed to account for day … Read more

UK Met Office migrating from DataPoint to DataHub

Summary This postmortem examines a common migration pitfall: moving from the Met Office’s legacy DataPoint API to the newer DataHub API and expecting identical data structures. The issue arises when teams assume that symbolic weather codes, descriptive strings, or visibility categories will be preserved across API generations. They are not — and this mismatch leads … Read more

What packages and CLI commands are required to add authentication to an existing ASP.NET Core MVC application?

Summary Adding authentication to an existing ASP.NET Core MVC application requires specific NuGet packages, .NET CLI commands, and configuration steps. This postmortem outlines the process, root causes of common issues, and best practices for implementation. Root Cause The primary issue arises from missing dependencies and incomplete configuration when integrating ASP.NET Core Identity into an existing … Read more

Why does CPU usage suddenly reach 100% on an AWS EC2 instance running a Next.js application?

Summary This incident describes a sudden and sustained 100% CPU spike on an AWS t3.micro instance running a Next.js application. After the spike, the Node.js process is killed, often without meaningful logs. This pattern strongly suggests resource exhaustion, runaway background tasks, or event‑loop blocking triggered by recent code changes. Root Cause The most common root … Read more

Question about Postmate Client tool for api testing

Summary Postmate Client, a VS Code extension for API testing, was evaluated as an alternative to banned tools like Postman and Thunder Client. Initial testing revealed performance bottlenecks and inconsistent request handling, leading to failed API tests and delayed deployments. Root Cause Inefficient request batching: Postmate Client grouped requests in suboptimal batches, causing timeouts. Lack … Read more

What Domain Name should I used

Summary Choosing the right domain name is critical for building credibility and personal branding. The decision to switch from .site to .com and potentially change from “Holo Integrated Ops” to “Holo Olagoke” requires careful consideration to avoid losing established credibility. Root Cause Lack of clarity on the purpose of the domain name (personal branding vs. … Read more

First Love2D Lua Program

Summary This postmortem analyzes a beginner Love2D Lua program that behaves correctly but contains several subtle issues common in early game‑loop code. The goal is to highlight why the code works, where it hides long‑term problems, and how senior engineers approach these patterns in real production systems. Root Cause The core issues stem from implicit … Read more

NASM bootloader: Protected mode jump to kernel at 0x00010000 shows nothing in VirtualBox

Summary A protected‑mode jump to a kernel loaded at 0x00010000 failed silently, leaving VirtualBox on a black screen. The root cause was a combination of incorrect segment usage, invalid far jumps, and loading the kernel to the wrong physical address relative to the GDT and protected‑mode setup. Root Cause The failure came from several interacting … Read more