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How Porsche hacked the financial system and made a killingYesterday

Adolf Merckle, one of the world’s richest men, committed suicide yesterday by throwing himself under a train, Bloomberg reports. Financial difficulties, and particularly great losses he suffered on Volkswagen stock, are being cited as the key reason he ended his life:

[Merckle's company] VEM was caught in a so-called short squeeze after betting Wolfsburg, Germany-based Volkswagen’s stock would fall. Merckle lost at least 500 million euros on the bets on VW stock, people familiar said on Nov. 18. VEM lost “low three-digit million euros” on VW stock, the company said in November.

A “short squeeze” sounds inconspicuous enough; you wouldn’t tell it by Bloomberg’s language, but Merckle’s Volkswagen bet lost out to one of the most masterful hacks of the financial system in history.

For those of us who don’t live and breathe finance, this is that story.

● ● ●

In 1931, Austro-Hungarian engineer Ferdinand Porsche started a German company in his own name. It offere

Rate limiting with memcachedYesterday

On Monday, several high profile “celebrity” Twitter accounts started spouting nonsense, the victims of stolen passwords. Wired has the full story—someone ran a dictionary attack against a Twitter staff member, discovered their password and used Twitter’s admin tools to reset the passwords on the accounts they wanted to steal.

The Twitter incident got me thinking about rate limiting again. I’ve been wanting a good general solution to this problem for quite a while, for API projects as well as security. Django Snippets has an answer, but it works by storing access information in the database and requires you to run a periodic purge command to clean up the old records.

I’m strongly averse to writing to the database for every hit. For most web applications reads scale easily, but writes don’t. I also want to avoid filling my database with administrative gunk (I dislike database backed sessions for the same reason). But rate limiting relies on storing state, so there has to be some kind of persistence.

Using memcached counters

I think I’ve found a solution, thanks to

C++ for Python Programmers: a CheatsheetYesterday

A fellow prof here at MSU, Rich Enbody, whipped up the following cheat-sheet for new programmers transitioning from Python (CSE 231) to C++ (CSE 232). He welcomes comments. Here's the link:

http://web.cse.msu.edu/~cse231/python2Cpp.html

Paranthetically, he and his cohort in crime, Bill Punch, will be giving a talk about using Python as the intro CS programming language at PyCon '09. They have some interesting stats on the effects of a mixed Python-C++ curriculum vs a C++-C++ course base for the first year of programming.

And folks... remember, this is for intro programmers who don't know C++ yet!

--titus

What's a good Python code base?Yesterday

A friend asks,

i'm going to be recoding <x> from scratch starting next week, in python. what codebase would you recommend as good to model after?

Any thoughts on a well-formed, reasonably sized (yet not huge), and simple Python code base?

There have to be some examples somewhere! I'd suggest something in the stdlib, but nothing is coming to mind right now -- and there are some real stinkers in there, too.

For now, I've pointed my friend towards PEP 8 and the Python Cookbook. Very unsatisfying.

--titus

Extending your C# application with IronPythonYesterday

Bernie Almosni looks at extending C# applications with IronPython. He shows how to use the DLR hosting API to create a 'rules engine' for the application - and example IronPython code for adding new rules.

• Extending your C# application with IronPython

I think that in almost every enterprise application project at some point you’ll come to the conclusion that you need extension points in the system. It can be a Rule Engine, a Workflow of some sort or a pluggable User Interface. So now you want to give someone else the ability to extend or modify the application’s behavior with a minimal effort and time. Of course it’s possible to achieve this with custom tools and code generators that compile and load at runtime, but these solutions are complex and time consuming. Utilizing the DLR as an embedded scripting engine is easy and for my opinion quite elegant.