I am a Unix system developer from Cambridge. I work on BIND9 at the Internet Systems Consortium ( isc.org ) .
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This week I was in Rotterdam for a RIPE meeting . On Friday morning I gave a lightning talk called where does my computer get the time from? The RIPE meeting website has a copy of my slides and a video of the talk; this is a blogified low-res version of the slides with a rough and inexact transcript.
A couple of years ago I wrote about tolower() in bulk at speed using SWAR tricks . A couple of days ago I was interested by Olivier Giniaux’s article about unsafe read beyond of death , an optimization for handling small strings with SIMD instructions, for a fast hash function written in Rust.
I commented on Lobsters that /tmp is usually a bad idea , which caused some surprise. I suppose /tmp security bugs were common in the 1990s when I was learning Unix, but they are pretty rare now so I can see why less grizzled hackers might not be familiar with the problems.
DNS servers often have to convert DNS names to their canonical lower case form. BIND has to do so a bit more than most because it tries to preserve the case of DNS names rather than canonicalizing them.
For reasons beyond the scope of this entry, I have been investigating elliptical and ovoid shapes. The Wikipedia article for Moss’s egg has a link to a tutorial on Euclidean Eggs by Freyja Hreinsdóttir which (amongst other things) describes how to construct the “four point egg”. I think it is a nicer shape than Moss’s…
There are a couple of version control commands that deserve wider appreciation: SCCS what and RCS ident . They allow you to find out what source a binary was built from, without having to run it – handy if it is a library! They basically scan a file looking for magic strings that contain version control metadata and…
Following my previous post on rate limiting with GCRA, leaky buckets without the buckets , I reviewed my old notes on rate limiting for Exim . I thought I should do a new write-up of the ideas that I hope will be more broadly interesting.