Simplicity is the art of hiding complexity
Rob Pike, "Simplicity is Complicated", dotGo 2015


Disabling the Group Policy Client Service in Windows

  • You are an administrator on your machine.
  • Your machine is either:
    • In a Windows Domain, and you don't want the domain admins messing with it.
    • Not in a Windows Domain, and you just don't want useless services running.
In this case, what you probably want to do is prevent the Group Policy Client Service from running on your machine.  Unfortunately, that's not a straightforward task to accomplish, because if you go to "services" and try to stop or disable this service, Windows doesn't let you.

Here is how to do it.

These instructions have worked for me on Windows 7; they might also work on other versions of windows.  If there is anything in these instructions that you don't quite understand, what it means is that these instructions are not for you;  don't try to follow them, you are going to wreck things.  Ignore this post, move on.
  1. Using regedit go to HKLM\SYSTEM\CurrentControlSet\services\gpsvc and:
    1. Change the owner to yourself.
    2. Grant Administrators (not just you) full control.
    3. Change the value of “Start” from “2” to “4”.
  2. Now go to HKLM\SYSTEM\CurrentControlSet\Control\Winlogon\Notifications\Components\GPClient and:
    1. Change the owner to yourself.
    2. Grant Administrators (not just you) full control.
    3. Delete the entire key. (Possibly after exporting it so as to have a backup.)
  3. Restart your machine.


My notes on "Greg Young - The Long Sad History of Microservices"

Greg Young - The Long Sad History of Microservices
From the "Build Stuff" event of April 2017.

Talk begins at 9:45.

Highlights of the talk:
27:00 Placing a network between modules simply to enforce programmer discipline 
29:05 There is other levels of isolation I can go to. I can run a docker container per service. That's the coolest stuff right? What that means is I can make it work on my machine so I send my machine to production. 
29:52 Now, one thing that's very useful is I don't necessarily want to make this decision up front. And I don't necessarily want to make the same decision in dev as in production. I may want in dev to have a different way that we run things, why? because bringing up 19 docker containers on your laptop is not very much fun. I may prefer to host everything inside a single process to make debugging and such a lot easier when I am running on dev in my laptop. Whereas in production we may go off to multiple nodes. 
34:16 If you have maintenance windows, why are you working towards getting rid of your maintenance windows? Is this a business drive or is this you just being like C.V. driven development? 
My notes:

Unfortunately his shrieky voice makes him sound like he is bitching about things, which in a sense he is, but it would help his cause to deliver his criticism in a more palatable tone. Also, in order to make his point about microservices being nothing new he seems to disregard statelessness.

Resources referenced in the talk:




Leslie Lamport - Time, Clocks, and the Ordering of Events in a Distributed System
(available on the interwebz)

C.A.R. Hoare - Communicating Sequential Processes
(available on the interwebz)


Dear recruiter...

If you are a recruiter wishing to contact me with regards to some job opportunity, please read this.


Migrating a project from java 8 to java 9

Now that Java 9 is out, I decided to migrate to it my pet project, which is around 120K lines of java.

The first step is to just start compiling and running against jdk9, without using any of its features yet.

This is an account of the surprisingly few issues that I encountered during this first step and how I resolved them.

Issue #1: Object.finalize() has been deprecated.


A Hacker's Tale (With a Human Side)

Screenshot of Borland Turbo Debugger found on the interwebz, possibly the same version that I was using back then.

This is a hacking story from my University years. It ends with a nice bit about human qualities. 


Grumpy Posts

Besides the delicate grumpiness which is gratuitously scattered throughout this blog like the golden rays of light in a gentle sunset, there exist a few blog posts which have been written with the express purpose of venting out some major grumpiness.

Here is a list of them:


Rich Hickey - Simple Made Easy

"Simple Made Easy" presentation by Rich Hickey from the InfoQ Software Development Conference, recorded at Strangeloop 2011

(the slideshow plays alongside with the video.)

My notes on the presentation:

"Simplicity is prerequisite for reliability" - Edsger W. Dijkstra

Simple vs. Complex, Easy vs. Hard


What is wrong with UUIDs and GUIDs


Universally Unique Identifiers (UUIDs) otherwise known as Globally Unique Identifiers (GUIDs) are 128-bit numbers that are often used to identify information. In its canonical representation, a UUID looks like this: 2205cf3e-139c-4abc-be2d-e29b692934b0.

The Wikipedia entry for Universally Unique Identifier () says that they are for practical purposes unique and that while the probability that a UUID will be duplicated is not zero, it is so close to zero as to be negligible. Wikipedia then does the math and shows that if 103 trillion UUIDs are generated, the chance of duplication among them is one in a billion.

Despite the infinitesimally small chances of receiving a duplicate UUID, there exist programmers out there who are afraid of this actually happening, and who will not hesitate to suspect duplicate UUIDs as being responsible for an observed malfunction rather than first look for a bug in their code. Clearly, these folks do not understand the meaning of infinitesimally small chance, so let me try to explain it:

Infinitessimally small chance means practically impossible to happen, and the practically part is only mentioned for scientific correctness: practically, you can disregard the word practically and consider it as simply impossible to happen.

Great. Now, let me tell you why I hate UUIDs.


6 videos from TechSummit Amsterdam 2017 (Jun 1st)

A couple of weeks ago some of us went to the TechSummit conference organized by LeaseWeb.  Here is a list of the talks that I attended, along with a short description for each.

The first presentation was “Shaving my head made me a better programmer” by Alex Qin, which was about what it is like to be a woman, and specifically a programmer, in the U.S. tech industry.  (And in the University before that.)  She talked about the inequality, the sexism, and the harassment.   She mentioned that she once gave a talk in a really big conference about accessibility in the U.S., and afterwards she was asked “How do I talk to women at bars?”  The head-shaving part refers to how changing her appearance resulted in being taken more seriously.  It was quite an interesting talk, though I suspect that in Amsterdam, she was to a large extent preaching to the choir.