By User:Salimfadhley (Own work) [GFDL ( or CC-BY-SA-3.0 (], via Wikimedia Commons

4-way TCP handshake and firewalls

Jarek Siembida wrote “This is one of those pieces that you keep in your head for ages but never get around to write up. Tcpdumping I was doing of late brought it back so here it is. We all know the 3-way handshake in TCP: SYN + SYN/ACK + ACK and voila! But this is not the end…”


Tom Parker wrote “Over the last couple of years I’ve been reading and talking about a lot of things related to distributed systems. This is a common train of thought around here, and after working on this on and off for the past 18 months or so (the version you’re seeing here is in fact version 3 having repeatedly changed…”

By Engineers11 (Own work) [CC BY-SA 3.0 (], via Wikimedia Commons

Scripting vs. Engineering

Ian Rogers wrote “I’ve come to the conclusion that the terms like “programming”, “coding” etc. have become horribly ambiguous which has enabled: organisations to offer courses on html/css editing as “coding” people to make claims like “nodejs is more productive than java” (which is a nonsense statement either way) various arguments along the lines of “is X a…”

Docket: Fun with Todoist and Beeminder APIs

Tom Parker wrote “So, I recently changed over my todo list usage to use Todoist. However, now I had a chunky amount of my phone screen chewed up with both a display of that and my existing Beeminder list, and I wondered if I could somehow merge the two. Also, because my Beeminder emergency days are one of the significant sources…”

Scrutiny: Github permissions audit and backup tool

Tom Parker wrote “These days we’ve all got an awful lot of our code in Github, and so we really need both a backup (so we can cope with them having a catastrophic failure) and a permissions auditing mechanism (so we know who’s getting access). For the latter, some of you may be saying “just use the audit…”

Talky Jukebox bot

Tom Parker wrote “Previously I talked about our soon-to-be-new Jukebox (which is currently blocked on going live due to a Mopidy bug). At the bottom of that post, I mentioned Slack support, but hadn’t figured out what sort of form this support would take. The Mopidy search interface is perfectly good, but having something that notifies our #jukebox Slack channel…”

Yet Another Jukebox

Tom Parker wrote “LShift has for a significant part of it’s history (at least 9 years, according to the blog post in 2006 about an earlier version) had an in-office jukebox. When I arrived here to begin with in 2010, there was the aforementioned earlier version, written in Erlang, and I have anecdotal reports of predecessors to that.…”

Raspberry Chef

Tom Parker wrote “Last month I wrote about temperature monitoring, and how I ended up using Raspberry Pi’s. I’m still fiddling around with their configuration, and I ran into a few problems. For starters, if I brought them home, they knew how to talk to the work WiFi, but not my home system, and vice versa (although this is…”

Kitten videos: an engineering approach

Tom Parker wrote “A little while ago one of my colleagues put up a kitten video feed on one of the spare monitors in the office. This was liked, but as we rapidly found out there was a few problems. Biggest of which is that kittens have a fairly well known failure state: they fall asleep. Sleeping kittens are…”

Waveform Necklace as a Service

Tom Parker wrote “I’m generally quite fond of laser cutters and cute crafting things done with them, so when I saw a Waveform Necklace Instructable the other day, I had to give it a go. Basic idea is that you take a sound recording’s waveform and reduce it’s waveform down to a level where it can be reasonably represented…”