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2008.01.27

What I'd Say to Bill Gates

Bill Gates is visiting Athens tomorrow. In his short stay he'll inaugrate Microsoft's so-called innovation center, which is provided as an offset for a deal Microsoft signed with the Greek government for the purchase of 70.000 licenses, and he'll also give a talk on Microsoft's vision for the future of technology. As a prelude to this event the Sunday newspaper Eleftherotypia inset Epsilon has invited a few Greek open-source advocates to give in a few sentences what they would say to Bill Gates during his visit.

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2008.01.23

The Mysterious TreeMap Type Signature

For my lecture notes on file handling I wrote a small Java program to display the number of characters that fall in each Unicode block, and got bitten by an unexpected runtime error. Angelika Langer, a wizard of Java Generics, kindly provided me with an explanation of the JDK design, which I'd like to share.

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2008.01.13

Rational Metaprogramming

Metaprogramming, using programs to manipulate other programs, is as old as programming. From self-modifying machine code in early computers to expressions involving partially applied functions in modern functional-programming languages, metaprogramming is an essential part of an advanced programmer’s arsenal.

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2008.01.07

The Relativity of Performance Improvements

Today, after receiving a 1.7MB daily security log message containing thousands of ssh failed login attempts from bots around the world, I decided I had enough. I enabled IPFW to a FreeBSD system I maintain, and added a script to find and block the offending IP addresses. In the process I improved the script's performance. The results of the improvement were unintuitive.

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2008.01.04

Curing MIDlet Bluetooth Disconnects

Over the last few days I've been writing a MIDlet to collect GPS coordinates and cell identifiers. I'm doing this in an effort to look at what algorithms might be needed in order to implement something similar to Google's My Location service. Here is a Google Earth example of the data I'm collecting. Yesterday, I reached a point where I was collecting all the information I needed, but the program was often plagued by random disconnections of the Bluetooth link to the GPS.

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Unless otherwise expressly stated, all original material on this page created by Diomidis Spinellis is licensed under a Creative Commons Attribution-Share Alike 3.0 Greece License.