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Welcome to my blog, which was once a mailing list of the same name and is still generated by mail. Please reply via the "comment" links.

Always interested in offers/projects/new ideas. Eclectic experience in fields like: numerical computing; Python web; Java enterprise; functional languages; GPGPU; SQL databases; etc. Based in Santiago, Chile; telecommute worldwide. CV; email.

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Lepl parser for Python.

Colorless Green.

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SVG experiment.

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Calibration of seismometers.

Data access via web services.

Cache rewrite.

Extending OpenSSH.

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The Quest for Randomness; Chat Wars; Real-life Financial Co Without ACID Database...; Flexible Muscle-Based Locomotion for Bipedal Creatures; SQL Performance Explained; The Little Manual of API Design; Multiple Word Sizes; CRC - Next Steps; FizzBuzz; Update on CRCs; Decent Links / Discussion Community; Automated Reasoning About LLVM Optimizations and Undefined Behavior; A Painless Guide To CRC Error Detection Algorithms; Tests in Julia; Dave Eggers: what's so funny about peace, love and Starship?; Cello - High Level C Programming; autoreconf needs tar; Will Self Goes To Heathrow; Top 5 BioInformatics Papers; Vasovagal Response; Good Food in Vina; Chilean Drug Criminals Use Subsitution Cipher; Adrenaline; Stiglitz on the Impact of Technology; Why Not; How I Am 5; Lenovo X240 OpenSuse 13.1; NSA and GCHQ - Psychological Trolls; Finite Fields in Julia (Defining Your Own Number Type); Julian Assange; Starting Qemu on OpenSuse; Noisy GAs/TMs; Venezuela; Reinstalling GRUB with EFI; Instructions For Disabling KDE Indexing; Evolving Speakers; Changing Salt Size in Simple Crypt 3.0.0; Logarithmic Map (Moved); More Info; Words Found in Voynich Manuscript; An Inventory Of 3D Space-Filling Curves; Foxes Using Magnetic Fields To Hunt; 5 Rounds RC5 No Rotation; JP Morgan and Madoff; Ori - Secure, Distributed File System; Physical Unclonable Functions (PUFs); Prejudice on Reddit; Recursion OK; Optimizing Julia Code; Cash Handouts in Brazil; Couple Nice Music Videos; It Also Works!; Adaptive Plaintext; It Works!; RC5 Without Rotation (2); 8 Years...; Attack Against Encrypted Linux Disks; Pushing Back On NSA At IETF; Summary of Experimental Ethics; Very Good Talk On Security, Snowden; Locusts are Grasshoppers!; Vagrant (OpenSuse and IDEs); Interesting Take On Mandela's Context; Haskell Cabal O(n^2) / O(n) Fix; How I Am 4; Chilean Charity Supporting Women; Doing SSH right; Festival of Urban Intervention; Neat Idea - Wormholes Provide Entanglement; And a Link....; Simple Encryption for Python 2.7; OpenSuse 13.1 Is Better!; Little Gain...; More Details on Technofull Damage; Palmrest Cracked Too....; Tecnofull (Lenovo Support) Is Fucking Useless; The Neuroscientist Who Discovered He Was a Psychopath; Interpolating Polynomials; Bottlehead Crack as Pre-amp; Ooops K702!; Bottlehead Crack, AKG K701; Breaking RC5 Without Rotation; Great post thank you; Big Balls of Mud; Phabricator - Tools for working together; Amazing Julia RC5 Code Parameterized By Word Size; Chi-Square Can Be Two-Sided; Why Do Brits Accept Surveillance?; Statistics Done Wrong; Mesas Trape from Bravo; European Report on Crypto Primitives and Protocols; Interesting Omissions; Oryx And Crake (Margaret Atwood); Music and Theory; My Arduino Programs; Elliptic Curve Crypto; Re: Licensing Interpreted Code; Licensing Interpreted Code; ASUS 1015E-DS03 OpenSuse 12.3 SSD; translating lettuce feature files into stub steps files; Re: translating lettuce feature files into stub steps files

© 2006-2013 Andrew Cooke (site) / post authors (content).

IntelliJ Idea

From: "andrew cooke" <andrew@...>

Date: Sat, 31 Mar 2007 23:54:17 -0400 (CLT)

I am switching from Eclipse to IntelliJ Idea.  I have no idea whether this
will work out, but I was tired of Eclipse crashing and Codehaus have a
licence for Idea.

First impressions are that the two are generally quite comparable.  While
running checkstyle doesn't crash Idea like it does Eclipse, it does
occasionally fail on a stupid classloader problem.

However, there is one significant advantage to Idea which has impressed me
- its default analysis of code is intelligent and useful.  It flags real,
important issues rather than "nitpicking details".  In other words it
focuses more on semantics and less on syntax - it's like having an
intelligent code reviewer.  The intelligence doesn't extend to
architectural issues, but it does "understand" basic logic and flow

I'm using the preview releases available from http://www.intellij.net/ -
they have a free 30 day trial licence, low price academic and free
opensource licences.


PS It is only after writing this (I promise!) that I realise this
"intelligent analysis" may be why it's called "IntelliJ"...

Maybe Intelligent is the Wrong Word

From: "andrew cooke" <andrew@...>

Date: Sun, 1 Apr 2007 10:01:23 -0400 (CLT)

Hmmm.  My previous post was rather enthusiastic.  The advice is not
particularly "intelligent" - it's just based on simple static analysis. 
Maybe what *is* intelligent is the interface design, or the selection of
warnings.  Somehow it is useful, rather than annoying.

Another nice feature - maybe this was possible in Eclipse - is that I can
configure code highlighting in some detail.  So my text is simple black
(keywords in bold), but with mutable state (class and instance variables,
and also reassigned local variables or parameters) highlighted.


IntelliJ Idea uses some odd ports...

From: "andrew cooke" <andrew@...>

Date: Mon, 2 Apr 2007 21:22:07 -0400 (CLT)

Don't like this much.  Idea is using the following ports:

tcp :::63342              :::*               LISTEN
tcp :::2864               :::*               LISTEN
tcp :::6942               :::*               LISTEN
udp         :::*
udp :::9876               :::*
udp :::2863               :::*
udp :::2863               :::*

where and are local addresses to my server.

Surreally, connecting via HTTP to gives an empty page with
the title "Dick's Sporting Goods Bragging Board" (see related address

And port 2863 regularly broadcasts "Anybody out there" to other odd

The established link is Jabber - my machine (the editor) is making a
series of "Jabber Request" messages.


In related news, SuseFirewall doesn't block outgoing connections, and
Novell's AppArmour scares me.


How to block IntelliJ Idea on SUSE (and Linux in general)

From: "andrew cooke" <andrew@...>

Date: Mon, 2 Apr 2007 21:56:21 -0400 (CLT)

OK, so on SUSE you need to go to the sysconfig editor in Yast (System
menu) and edit the firewall setting FW_CUSTOMRULES to include the custom
rules file.  Then edit that file to include the following in the first
function (fw_custom_before_antispoofing).

For other Linux distros, the same iptables commands apply but you need to
work out how best to set them.

# mess with intellij

iptables -A OUTPUT -p tcp --dport 5222 -j LOG --log-level warn \
  --log-prefix "BLOCKING INTELLIJ: "
iptables -A OUTPUT -p tcp --dport 5222 -j DROP

iptables -A OUTPUT -p tcp --dport 2864 -j LOG --log-level warn \
  --log-prefix "BLOCKING INTELLIJ: "
iptables -A OUTPUT -p tcp --dport 2864 -j DROP

iptables -A OUTPUT -p tcp --dport 6942 -j LOG --log-level warn \
  --log-prefix "BLOCKING INTELLIJ: "
iptables -A OUTPUT -p tcp --dport 6942 -j DROP

iptables -A OUTPUT -p udp --dport 2863 -j LOG --log-level warn \
  --log-prefix "BLOCKING INTELLIJ: "
iptables -A OUTPUT -p udp --dport 2863 -j DROP

iptables -A OUTPUT -p udp --dport 9876 -j LOG --log-level warn \
  --log-prefix "BLOCKING INTELLIJ: "
iptables -A OUTPUT -p udp --dport 9876 -j DROP

Note that the backslashes are not valid syntax - I added them above to
make the lines shorter in this email.  It's not clear to me that all the
above are needed, and I am assuming that you already block *incoming*
connections, but the above is the right idea (and does block several
outgoing connection attempts on my machine).


re: IntelliJ Idea

From: "andrew cooke" <andrew@...>

Date: Wed, 16 May 2007 20:13:58 -0400 (CLT)

---------------------------- Original Message ----------------------------
Subject: re: IntelliJ Idea
From:    "Alexandre Paterson" <alexandre_paterson@...>
Date:    Mon, May 14, 2007 8:12 pm
To:      compute@...

Hi Andrew,

I was very happy to find your message
about IntelliJ using some strange ports...
At first I thought my machine was compromised.
However at it is a strenghtened Unix machine
behind several firewalls (the machine as its own
firewall in addition to another firewall... And it is
NATted behind a router) so I would very surprised
if it was compromised.

The UDP on port 2863 is a multicast on the LAN:


It may be followed by TCP access on 2864 and up, depending
on how many IDEA machines you have.

I was baffled too then by the attempt to connect to

A reverse IP shows that "intellijoin.org" shares that IP.


Things get stranger:

 $ telnet intellijoin.org 80
Connected to intellijoin.org.
Escape character is '^]'.
GET / HTTP/1.0\nAccept: */*\n\n

HTTP/1.1 503 Service Temporarily Unavailable
Date: Tue, 15 May 2007 00:03:04 GMT
Server: Apache/2.0.52 (Red Hat)
Last-Modified: Tue, 05 Sep 2006 15:38:54 GMT
ETag: "269405-31c-a7f01f80"
Accept-Ranges: bytes
Content-Length: 796
Connection: close
Content-Type: text/html; charset=UTF-8

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">

<title>Dick's Sporting Goods - Bragging Board</title>

But if you type www.intellij.org in your browser everything
is fine: you get to a site obviously belonging to JetBrains.

I'll post a message in the IntelliJ IDEA forum asking
what is going on.

Anyway... Instead of blocking things I want to be blocked,
my system is configured to REJECT everything, even
access to

Then I allow what I consider to be legitimate trafic.

For example, if I want IntelliJ to be able to access my
LAN Tomcat server (that has some html Javadocs,
for example), I do:

iptables -I OUTPUT -p tcp -d --dport 80
-m owner --uid-owner 1007 -j ACCEPT

Same for SVN, CVS, JProfiler, etc.

I do it this way so closed-source programs emitting
spooky trafic are blocked in a user account (that can't
even communicate on

This is painful with some dumbly-written plugins and
utilities that thinks that they can appropriate a great
many ports but all in all it poses no problem.

Anyway, it takes some time to set it up at first but
I honestly think it's worth it.

"Everything that is not specifically allowed is denied"


Besides that upon hitting your blog (I was googling
on "63.236.202 jabber" IIRC) I recognized your blog
instantly :  I *love* your gallery.

I saw it quite some time ago and saved a few pictures.


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Fwd: on blocking incoming trafic

From: "andrew cooke" <andrew@...>

Date: Wed, 16 May 2007 20:14:49 -0400 (CLT)

---------------------------- Original Message ----------------------------
Subject: on blocking incoming trafic
From:    "Alexandre Paterson" <alexandre_paterson@...>
Date:    Mon, May 14, 2007 8:21 pm
To:      compute@...


you wrote:

> Note that the backslashes are not valid
> syntax - I added them above to make the
> lines shorter in this email.  It's not
> clear to me that all the above are needed,
> and I am assuming that you already block
> *incoming* connections, but the above is
> the right idea (and does block several
> outgoing connection attempts on my machine).
First in a Bash shell script where you put all your iptables
rules the backslash is actually a perfectly correct syntax:
it's the one I'm using for my long iptables rules ;)

Then on a stateful firewall, you usually block *new*
incoming connections, not RELATED or ESTABLISHED

Usually people have :

iptables -I INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT

which may be a problem when a rogue program decides
to establish the connection from your computer: no matter
how much you block incoming stuff, if you allow RELATED
and ESTABLISHED trafic in (which is usually how iptables
is configured), you're hosed.

To me the real best option is to "deny everything that
is not specifically allowed".

Thanks again and talk to you one of these days,

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