Category Archives: Links

Links: 20 Sep

Technology

Other

> How about a sysctl that does “for the love of kbaek, don’t ever kill these
> processes when OOM. If nothing else can be killed, I’d rather you panic”?

An aircraft company discovered that it was cheaper to fly its planes with less fuel on board. The planes would be lighter and use less fuel and money was saved. On rare occasions however the amount of fuel was insufficient, and the plane would crash. This problem was solved by the engineers of the company by the development of a special OOF (out-of-fuel) mechanism. In emergency cases a passenger was selected and thrown out of the plane. (When necessary, the procedure was repeated.) A large body of theory was developed and many publications were devoted to the problem of properly selecting the victim to be ejected. Should the victim be chosen at random? Or should one choose the heaviest person? Or the oldest? Should passengers pay in order not to be ejected, so that the victim would be the poorest on board? And if for example the heaviest person was chosen, should there be a special exception in case that was the pilot? Should first class passengers be exempted? Now that the OOF mechanism existed, it would be activated every now and then, and eject passengers even when there was no fuel shortage. The engineers are still studying precisely how this malfunction is caused.

Remember measles? That old-timey disease we officially eliminated in the United States 13 years ago? Thanks to the wonder of inoculation, measles should be entirely nonexistent in this country, but yesterday the Center for Disease Control reported 159 cases from January through August of this year.

What’s unique about this year’s outbreak is that the CDC has finally admitted the spread of this “eliminated” disease is based on religious communities’ philosophical aversion to vaccines and reliance on divine healing through the Word of God. According to the report, 91 percent of the reported cases were in people who were unvaccinated, or didn’t know their vaccination status, and “of those who were unvaccinated, 79 percent had philosophical objections to vaccination.”

  • London Heathrow’s glissade timelapse:

 

 

Links: 4 Sep

Technology:

  • grep tricks: grep files recursively, show only filenames where matching string was/wasn’t found.
  • Did you know that:
    • $ less <directory> — shows directory listing
    • $ less <archive.zip> — shows archive content
  • Teacher’s rumblings “Kids can’t use computers“. Agree to a T.
  • Going back to iPhone [from Android]. Again having pretty much the same thoughts.
  • Reddit: Lessons Learned From Mistakes Made Scaling To 1 Billion Pageviews A Month
  • Start a Web Search in a GUI Browser from the Command Line on Mac OS X
  • Screen recording to an animated GIF on Mac OS X
  • How to know from a child process that its parent exited:
    • a pipe between parent and a child, child gets SIGPIPE when parent exits
    • if a child has not detached, PPID becomes 1 when parent exits
    • Linux-specific: a child can ask kernel to deliver a signal when parent dies by specifying option PR_SET_PDEATHSIG in prctl() syscall
  • Two talks from YAC which I liked:

rpmdb locking issues, notorious on RHEL4/5, manifest as hanging rpm command. To see active locks:

# cd /var/lib/rpm; /usr/lib/rpm/rpmdb_stat -CA

Normally there should be no locks, given no rpm command is running. In case there are stale locks, just remove __db.00* files.

Other:

Sunlight in Europe and the USA in hours per year.

Links: 16 Aug

Technology:

  • Cloud server showdown: Amazon AWS EC2 vs Linode vs DigitalOcean. AWS performance sucks, Linode winner.
  • Pull mode in orchestration’s rising star, Ansible. Check also out the web interface — AnsibleWorks AWX
  • Learning from other disciplines, nice quote:

    I’ve seen several college of engineering departments that have a sign that says the equivalent of, “If you cheat in engineering classes, you will kill people later”. We don’t have that mindset yet with IT, but I think we should because eventually, we’ll be responsible for infrastructure that will kill people if we get it wrong.

  • knockd — a port-knock server. It listens to all traffic on an ethernet (or PPP) interface, looking for special “knock” sequences of port-hits. A client makes these port-hits by sending a TCP (or UDP) packet to a port on the server. When the server detects a specific sequence of port-hits, it runs a command defined in its configuration file. This can be used to open up holes in a firewall for quick access.
  • Here’s the example of why LISA conferences rock: 2007 paper On Designing and Deploying Internet-Scale Services. Must read for sysadmins.
  • How to automatically setup and keep ssh tunnel up with autossh, available from macports

Social:

  • Steven Fry, one of my all-time favourite actors and activists, wrote an open letter petitioning for moving Winter Olimpics 2014 from Russia to elsewhere, because of wilful LGBT community oppressions. On a related note, sexual orientation forms during prenatal period, influenced by hormone levels, and is therefore inborn feature. Read about it in Russian.

 

 

 

Links: 3 Aug

Technology

English

Ghosting—aka the Irish goodbye, the French exit, and any number of other vaguely ethnophobic terms—refers to leaving a social gathering without saying your farewells. One moment you’re at the bar, or the house party, or the Sunday morning wedding brunch. The next moment you’re gone.

Republicans are also better, Democrats fear, at agreeing on a message and sticking to it. Frank Luntz, a Republican consultant, once said: “There’s a simple rule. You say it again, and you say it again, and you say it again, and you say it again, and you say it again, and then again and again and again and again, and about the time that you’re absolutely sick of saying it is about the time that your target audience has heard it for the first time.”

 

 

 

Links: 21 July

Technology

Education

My most favourite coursera course Algorithms by Kevin Wayne and Robert Sedgewick of Princeton is coming back with new session this autumn; my passionate recommendation to take it if you’re doing any kind of programming, either to improve your skills or just get a lot of fun:

Bootstrap-related

IT in Ukraine (in Russian)

Miscellaneous

Petit Fille, liked choreography a lot:

Links: 14 July

Technology

  • Three ways how to get Apache to automatically insert the Google Analytics script into every page on the fly.
  • SSL: Intercepted today, decrypted tomorrow — recently leaked documents appear to reveal that the NSA logs very high volumes of internet traffic and retains captured encrypted communication for later cryptanalysis. The reason […] is that if the SSL private key to the encrypted traffic later becomes available — perhaps through court order, social engineering, successful attack against the website, or through cryptanalysis — all of the affected site’s historical traffic may then be decrypted at once.
  • First 5 Minutes Troubleshooting A Server, great post, Russian translation is here.
  • Swagger is a specification and complete framework implementation for describing, producing, consuming, and visualizing RESTful web services.

English