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The Simplex Noise (or Improved Perlin Noise) algorithm uses a somewhat mysterious "skew factor" of 3-12. I did not find any really satisfactory explanation for this factor in the descriptions of Simplex Noise that I read. But I managed to work it out nevertheless, which I thought was a fun exercise and worth a quick write-up.

Simplex noise is constructed by assigning random values to each point in a simplex grid. The simplex grid is a tiling of the plane using rhombuses, each rhombus consisting of two equilateral triangles. See the figure on the right.

Given a point (x,y) (expressed in normal rectangular coordinates), we …

I feel a sense of pride when I think that I was involved in the development and maintenance of what was probably the first piece of software accepted into Debian which then had and still has direct up-stream support from Microsoft. The world is a better place for having Microsoft in it. The first operating system I ever ran on an 08086-based CPU was MS-DOS 2.x. I remember how thrilled I was when we got to see how my friend’s 80286 system ran BBS software that would cause a modem to dial a local system and display the application as if it were running on a local machine. Totally sweet.

When we were living at 6162 NE Middle in the nine-eight 292, we got an 80386 which ran Doom. Yeah, the original one, not the fancy new one with the double barrel shotgun, but it would probably run that one, too. It was also …

1. OMG Text -- a plugin for CSS framework Compass for directional text shadows. (via David Kaneda)
2. Build a Cheap Bitcoin Mine -- some day it will be revealed that the act of generating a bitcoin token is helping the Russian mafia to crack nuclear missile launch codes and Afghan druglords built the Bitcoin system to destabilize the US dollar.
3. Polycode -- a free, open-source, cross-platform framework for creative code. You can use it as a C++ API or as a standalone scripting language to get easy and simple access to accelerated 2D and 3D graphics, hardware shaders, sound and network …

I’m sure that most people have at least one of the tools listed in Ronald Bradford’s article: Monitoring MySQL Options. Many of these tools, such as Nagios and Cacti, also monitor the operating system. However, in the same way that a quick look at sar‘s output can give you some insight on the OS, with MySAR you can do the same for the MySQL server. This is especially useful when  it is not possible to access a monitoring tool’s graphic interfaces.

What Was Going On Around 2:30pm?

This is a question a customer asked us. To answer it we ran MySAR for a few days and queried the results for analysis. Looking at the data, we determined that the number of INSERT operations was significantly higher than any …

Some of you have noticed Kickfire, a new sponsor at this year’s MySQL Conference and Expo. Like Keith Murphy, I have been involved with them for a while now. This article explains the basics of how their technology is different from the current state of the art in complex queries on large amounts of data.

Kickfire is developing a MySQL appliance that combines a pluggable storage engine (for MySQL 5.1) with a new kind of chip. On the surface, the storage engine is not that revolutionary: it is a column-store engine with data compression and some other techniques to reduce disk I/O, which is kind of par for the course in data warehousing today. The chip is the really exciting part of the technology.

The simplest description of their chip is that it …

The following is what i wrote on “43people.com” about the boss. I thought it was worth keeping in my own archives, since it’s actually a story about my life as it pertains to Mr. Bezos.

Back a few years ago, I was taking some classes down in Edmonds. The one I’m thinking of in particular was on the care and feeding of unix. We were using red hat linux 6.0 or some crufty version that wasn’t so crufty at the time.

Anyway, the prof didn’t require that we buy any books, but he made some suggestions. And he also suggested that we buy them on this new fangled “Internet” thing through a few of his friends down south in Seattle at this place called Amazon.com.

And thus was my introduction to O’Reilly and Associates. I soon thereafter bought a book called “ …