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Why Your Server Is Slow #2: More Memory Didn't Help — Page Cache, Swap, Working Set
Tracking down why adding memory left performance unchanged. Covers what available really means, how spare memory already works as page cache, judging swap by movement rather than usage, sizing the working set, and the container limits and application heaps that upgrades never reach.
Practical Git Workflows #2: rebase vs merge — Decision Criteria and the Golden Rule
See through diagrams how rebase re-applies commits as brand-new ones, and build criteria for choosing between rebase and merge. Includes the structural reason you must never rebase a shared branch.
Why Your Server Is Slow #1: Low CPU Usage but Still Slow — Run Queue, I/O Wait, Lock Contention
Tracking down why a server is slow while CPU usage stays low. Covers run queue and scheduling delay, the iowait trap, lock contention and off-CPU waits, and steal time in the cloud — a diagnostic order for finding the waiting that utilization graphs miss.
Git Basics #6: GitHub and Your First Pull Request
Create a repository on GitHub, connect your local repository, and follow a first Pull Request end to end — from branching through review feedback to merging and cleanup. The final part of the Git Basics series.
Practical Git Workflows #1: Branching Strategies — GitHub Flow and Trunk-Based
Compare the structure and prerequisites of Git Flow, GitHub Flow, and trunk-based development, and build criteria for choosing one based on team size and release cadence.
Git Basics #5: Undoing Changes — restore, reset, and revert
Discarding edits, unstaging files, amending commits, undoing commits, and reverting pushed commits. A three-areas map of when to reach for restore, reset, or revert.
Git Basics #4: Remotes — clone, fetch, pull, push, and What origin Really Is
We organize the flow of cloning a repository and exchanging work with a remote through fetch, pull, and push. Along the way we pin down what origin and origin/main actually are.
Git Basics #3: Branching and Merging — Fast-forward and 3-way
From the fact that a branch is a lightweight pointer to a commit, through the difference between fast-forward and 3-way merges, to reading conflict markers and resolving them.
Git Basics #2: add, commit, status — What the Staging Area Means
Read the untracked, modified, and staged states from real git status output, and record your first snapshot with add and commit. Why the staging area exists, the two kinds of diff, and what .gitignore keeps out of history.
Git Basics #1: What Git Is — the Snapshot Model and the Three Areas
From why version control exists to the snapshot model, the .git directory that git init creates, and the three areas — working directory, staging area, and repository. The mental picture to build first when learning Git.
LLM App Operations #7: Capstone — Taking the Document Q&A Bot to Production
We tie the five pillars of this series into an operations checklist and apply it to the document Q&A bot. Turning on instrumentation, routing, caching, batching, reliability, and security one by one, we watch how per-request cost and stability change, and close out the AI track that spans four series.
How Does Your Phone Count Your Steps? Accelerometers and the Pedometer
Your phone counts steps all day from inside a pocket and the battery barely notices — here is why. How the accelerometer senses tilt and motion, how steps are picked out of the rhythmic bounce of walking, the filtering that keeps bus vibrations and hand-waving from counting, the dedicated low-power chip that watches sensors while the main processor sleeps, and why every step app shows a different number — explained for non-developers.