UK’s ICO Guide to GDPR

Information Commissioner’s Office (ICO) is the the UK’s independent authority set up to uphold information rights in the public interest, promoting openness by public bodies and data privacy for individuals.

They have published their own Guide to GDPR, which I find somewhat better than this one from the European Union.

Reading postmortems

Once in a while a seemingly straightforward article turns into a goldmine of links and resources. This happened to me today with this one – “Reading postmortems“.

Not only this article itself is a very nice roundup of common sources for system failures, but it also links to a couple of awesome references:

  • Simple Testing Can Prevent Most Critical Failures: An Analysis of Production Failures in Distributed Data-Intensive Systems. This is both a talk and a paper.
  • danluu/post-mortems – a GitHub repository with a collection of publicly available postmortems from a variety of organizations, like Google, Amazon, Facebook, NASA, GitHub, and more.

If you still have no idea what postmortem is, Wikipedia explains.

GraphViz dot: Format: “png” not recognized.

As I’ve mentioned many times, I’m a huge fan of GraphViz software suite in general, and the dot tool in particular. It’s super handy for generating graphs and diagrams out of plain text files.

Today though I came across a problem that I haven’t seen before. While trying to generate an updated PNG graph from a dot file that used to work just fine before, I got the following:

$ dot -Tpng source.dot -o destination.png 
Format: "png" not recognized. Use one of: canon cmap cmapx cmapx_np dot dot_json eps fig gv imap imap_np ismap json json0 mp pic plain plain-ext pov ps ps2 svg svgz tk vdx vml vmlz xdot xdot1.2 xdot1.4 xdot_json

That looks weird. I tried the same with a few other formats and none of them were working. A quick Google search around found the solution over at StackOverflow. All I had to do was:

$ sudo dot -c

After that, dot started working as always.

Cloud Diagrams & Notes

Jerry Hargrove – Cloud Diagrams & Notes is an excellent resource for (mostly Amazon AWS) cloud diagrams and notes. I’m sure I’ve seen some of these around, but never thought to visit the original site. To some degree, these are similar to the Julia Evans’ drawings, but are more subject specific.