Wandering Thoughts

Link: X Window System Basics

X Window System Basics (via) is an interactive walk through of the basic elements of X, starting with windows themselves and various things to do with them. This is a topic that's very relevant to me since I deal with old X programs and an old X window manager that have things like old fashioned iconification of windows. Fiddling around with the interactive demos (which require Javascript) is a great way to see in a concrete way how the nuts and bolts work.

Link: USB, Thunderbolt, Displayport & docks

USB, Thunderbolt, Displayport & docks (via, also) is a high density 'overview' of the technology of all of these things, or at least the technology of the connectors and connections involved. Since it gets down to the level of the number of lines and lanes (and their speed) involved in USB signaling and so on, it's an overview only from a certain perspective.

Although I read it through once and absorbed some things, I think of it more as a reference work that I can consult for fairly low level details if and when I need to understand some aspect of the entire USB mess (and it is a mess) at some depth. There is certainly a lot there.

Link: The MGR Window System

The MGR Window System (via) is a brief introduction to MGR, an interesting and under-mentioned Unix windowing system, including a screenshot. I once used MGR myself and have reasonably fond memories of it, so it's nice to see more writing about it on the Internet.

(And looking at my old entry I see that I linked to this article there in HTTP version. Still, I encourage you to read about MGR. It's a path not taken in Unix window systems.)

Link: An opinionated list of best practices for textual websites

An opinionated list of best practices for textual websites by Rohan Kumar is what it says in the subject. I'm not sure I agree with everything in it (and I certainly don't do everything there), but I think it has useful information and it's certainly given me things to think about.

(Since this entire blog is a textual website, I have a decided interest in this area and some opinions of my own.)

Link: Histograms in Grafana (a howto)

Histogram evolution: visualize how a distribution of values changes over time (via) has the article URL slug of 'grafana histogram howto', and the slug is quite accurate. It's a step by step walkthrough of how to do this for a native Prometheus counter histogram metric, which most of them are. It includes copious screenshots, which is especially useful since you have to do all of this through Grafana's GUI and describing GUI actions in text is not necessarily ideal. I've slogged through heatmaps and histograms in Prometheus and Grafana, and this article still taught me something quite useful that I hadn't realized (the 'exclude zeros' setting; I agree with the author that this should be the Grafana default).

PS: Contrary to what the article suggests, heatmap legends aren't always useful, at least in current versions of Grafana. I tried putting a legend on some disk IO latency heatmaps that have very small latencies and the result was not all that readable or clear.

Link: Eric Rescorla's "DNS Security, Part II: DNSSEC"

Eric Rescorla's DNS Security, Part II: DNSSEC (via) is a pretty even handed overview of DNSSEC. Rescorla is respected by Thomas Ptacek, even if they disagree (I think) about DNSSEC.

(Rescorla also has a Part I: Basic DNS for people who need that.)

Related to this is Ptacek's fascinating A Brief, Inaccurate History of DNSSEC (via). This goes with Ptacek's Against DNSSEC (from 2015; this debate has been going on for a while).

Link: Examining btrfs, Linux’s perpetually half-finished filesystem

Ars Technica's Examining btrfs, Linux’s perpetually half-finished filesystem (via) is not very positive, as you might expect from the title. I found it a useful current summary of the practical state of btrfs, which is by all accounts still not really ready for use even in its redundancy modes that are considered "ready for production". There's probably nothing new for people who are actively keeping track of btrfs, but now I have something to point to if people ask why we're not and won't be.

Link: "a2d<C-V>3gE: Vim normal mode grammar

"a2d<C-V>3gE: Vim normal mode grammar (via) presents an interesting way of thinking about how Vim normal mode commands are structured. It gave me some things to think about and also taught me a few Vim things I didn't know.

Link: Taking This Serially

j. b. crawford's Taking This Serially (via) is about the history of serial connections and RS-232, including the various connectors used and the complications that ensued with actually connecting things serially. I have a certain amount of history with serial connections, so I found this interesting.

(Also, looking at the article's pinouts for DE9/DB9 serial connectors made me realize something, but that's another blog entry.)

Link: What was the original reason for the design of AT&T assembly syntax?

This quite informative answer to a Stackoverflow question (via) answers the question, or at least provides a great deal of context that I didn't know. It turns out that the reason AT&T syntax puts the destination register second (instead of first, the way Intel syntax does) almost certainly stretches all the way back to how PDP-11s encoded instructions.

(The AT&T assembly syntax, commonly used on Unix systems but not uncommonly disliked (via), is a cross-platform general syntax that AT&T and Unix mostly used on a range of platforms. The specific x86 version of AT&T syntax is yet another adaptation of this general syntax. More information on the difference between AT&T and Intel syntax for x86 can be found on, eg, Wikipedia.)