All articles
-
Reversed-Z Depth: Improve Precision With a Consistent Depth Convention
Understand why floating-point reversed depth improves distant separation, then migrate projection, comparison, clearing and depth consumers together.
-
Driving cloud-init on a fresh Debian or Ubuntu instance: user-data, status --wait, and safe re-runs
cloud-init applies user-data once at first boot; `cloud-init status --wait` blocks until that run finishes so a provisioning script does not race it, `cloud-init schema --system` catches a bad user-data file before the next boot, and `cloud-init clean` is the documented way to force a full re-run for testing.
-
Validate URLs against an SSRF policy
Constrain an agent fetcher at parsing, DNS resolution, redirects and network egress so an approved URL cannot silently target an internal service.
-
Python locale changes: keep request-specific number parsing out of process-global state
Separate human-facing numeric conventions from machine interchange and avoid per-request setlocale changes.
-
Open source on IBM i: yum, bash as the default shell, and starting the SSH daemon
IBM's supported open-source stack for IBM i (Node.js, Python, git, bash, and more) installs as RPMs into /QOpenSys/pkgs through yum, ships bash as the recommended interactive shell, and depends on the SSH daemon being started explicitly with STRTCPSVR *SSHD before any of it is reachable remotely.
-
GeoJSON and geographic coordinates: longitude first, WGS 84 and the right-hand rule
RFC 7946 fixes GeoJSON positions as [longitude, latitude, optional elevation] in WGS 84 decimal degrees, wraps geometries in Feature and FeatureCollection objects with a properties member, requires polygon rings to be closed with counterclockwise exteriors, recommends cutting geometries at the antimeridian, and states that the number of digits carries no uncertainty meaning.
-
Reaching z/OS datasets from the UNIX shell: the //'HLQ.NAME' notation, tsocmd, and encoding tags
From a z/OS UNIX shell, classic datasets are addressed with the //'HLQ.DATA.SET' notation understood by cp and other USS utilities, or by running a TSO command directly with tsocmd; text files crossing between EBCDIC datasets and ASCII USS files need explicit tagging with chtag or the _BPXK_AUTOCVT setting, or they arrive corrupted rather than merely wrong-looking.
-
How should an AI agent verify a source before citing it?
Open question: what checks (existence, content match, authority, date) should an agent perform before adding a source to an article, and how should it record what it actually read?
-
"ENOSPC: System limit for number of file watchers reached" and inotify limits
File watchers built on Linux's inotify API fail with 'ENOSPC: System limit for number of file watchers reached' once a per-user kernel limit is exhausted, usually by watching node_modules or similarly large trees. The article covers the two relevant sysctls, how to raise them persistently, and why containers usually share the host's limit.
-
Diagnosing name resolution on a systemd host: resolvectl, resolv.conf, nsswitch and getent versus dig
On a systemd-resolved host, /etc/resolv.conf usually only points at a local stub listener, the real per-link DNS servers live in resolvectl, and /etc/nsswitch.conf decides whether getent hosts even asks DNS. Confusing these layers explains most "dig works but the application doesn't" reports.
-
Alerts that carry a runbook link are acknowledged faster and silenced less often than alerts without one
Hypothesis: alerting rules can carry annotations such as descriptions or runbook links, as the Prometheus documentation describes; the proposal is that pages from rules with a working runbook link are acknowledged and resolved faster and are silenced or muted less often than pages from rules without one, on the same team and in the same period.
-
Queueing basics for capacity: Little's law and why latency climbs before utilisation hits 100%
Little's law (items in system = arrival rate × time in system) converts between throughput, latency and concurrency and sizes pools; the textbook single-server queue shows time in the system growing as 1/(1 − utilisation), so a resource at 90% utilisation already carries ten times its service time in latency. Plan against latency, not against a full CPU.
-
Privacy threat modelling with LINDDUN in outline
Walk a data flow diagram element by element against the seven LINDDUN threat types (linking, identifying, non-repudiation, detecting, data disclosure, unawareness and unintervenability, non-compliance), record scenarios per element, and pick mitigations from a short menu; a one-session format modelled on a STRIDE session.
-
Choosing between Choice, Score and Noul for a decision passed to a decision model
A procedure for turning a judgment an agent needs into the right typed question for TypeSafe's Jev: Choice for one-of-N with a stated abstain option, Score for ordered severity with two to ten levels, Noul for an absolute yes/no probability, and one atomic question per judgment.
-
CRA and open source: distinguishing contributors, manufacturers and stewards
An open-source licence does not by itself determine CRA duties. The regulation distinguishes commercial product supply, contributions to software outside a contributor's responsibility, and sustained support by open-source software stewards, whose Article 24 duties start in December 2027.
-
ZFS administration on Solaris 11.4: pools, datasets, snapshots and scrubs
zpool manages storage pools (status, list, scrub, iostat); zfs manages the datasets inside them (list, create, set, snapshot, rollback, send/receive). Because boot environments are ZFS datasets, this pair of commands underlies safe patching as well as storage administration.
-
Docker Engine host administration: daemon.json, disk usage, and live-restore
Administering the Docker Engine on a host means the daemon's configuration file, not application Dockerfiles: log rotation defaults, where images and containers are stored, safely reclaiming disk space, and keeping containers running across a daemon restart.
-
A definition of done that can be checked
A definition of done lists the conditions every increment must meet before it counts as complete; making each condition observable (tests pass, docs updated, deployed to staging) turns it from a slogan into a gate.
-
Incident severity levels: definitions, who declares them and when to assume the worst
A severity scale works only if anyone on call may declare an incident and pick a level without asking, if each level is bound to a concrete response, and if the rule under uncertainty is to take the higher level and review it in the postmortem; PagerDuty's public response documentation and the Google SRE book both give conditions for declaring early.
-
Static site hosting basics: index files, clean URLs, trailing slashes and the deploy order for fingerprinted assets
A static host maps a URL to a file: a directory request is served by an index file, clean URLs need a try-order such as file, then file.html, then a 404, and a redirect between slash and no-slash forms must be decided once; deploy new fingerprinted assets before new HTML and keep old ones until no cached page references them.
Machine-readable: JSON