charles's blog

SETI@Home

Carl Sagan made a compelling argument for the existence of life elsewhere in the universe. And, as Douglas Adams said, "Space is Big. Really Big." For years, the SETI (Search for Extra-Terrestrial Intelligence) folks at UC Berkeley have been scanning the skies and collecting radio telescope data from locations such as the Arecibo Observatory. Unfortunately, they collect more data than they can process wither their available computer resources.

My latest idea for an art project that I can complete in a fairly short period of time involves the animation of still images. My first thought was to go for a walk and take pictures every so often, holding the camera at approximately the same level each time, pointed forward. When spliced together into a movie at, say, 10fps, you'd get a really choppy video where each image was visible for just long enough to register but not long enough to absorb much detail.

When taking a site live onto a production server, it's always tempting to rush the last few steps, especially if you're under a launch deadline, or if you've been working on the same site so long that you're sick of it. At this point it's important to sit back, take a breath, and be sure to go through the following pre-flight checklist:

1. Check for broken links
2. Disable any debugging lines in your code
3. For PHP-based sites, set error_reporting to NONE. Errors should be redirected to a log file.

MD5 is an algorithm for generating a digital signature from a message of indeterminate length. It can be used as a form of encryption but is also useful for ensuring data has not been corrupted during transmission.

Under Mac OS X, the "md5sum" terminal command allows the generation and verification of md5 checksums. An md5 checksum file will typically have a ".md5" extension. To verify data integrity from an existing md5 file, issue the following terminal command:

$ md5sum -c 

Apache 2 offers many improvements over Version 1.3 that comes with Mac OS X 10.4. That's probably why it comes with Mac OS X 10.5! For those of you who are just hankering for Apache 2 but not quite ready for the move to Leopard, here's how it's done. Roll up your sleeves, boys & girls...

Disable Apache 1.3

The first thing you have to to is disable the Apache 1.3 web server. In the "System Preferences" app, go to "Sharing", and turn off "Personal Web Sharing".

Download & Install

Occasionally when I eject a CD or DVD using the normal Mac OS X methods (either pressing the "eject" button on the keyboard or dragging a volume to the trash", the volume disappears, but the disc doesn't come out. Every time this happens, I browse the usual troubleshooting sources (eg., macosxhints.com), and find the unhelpful procedure using the Terminal "hdiutil" utility. This only works if the volume is mounted.

This document is an excerpt from the Apple Knowledgebase

FireWire is the Apple Inc. name for the IEEE 1394 interface which operates at a bandwidth of 400Mbps. Since it supported a much higher bandwidth than USB 1.1, it was well suited for applications requiring large amounts of data transfer (scanners, disk drives).

FireWire interfaces first appeared in the PowerMac G3 (Blue & White), the iMac 350MHz (3rd generation), PowerBook G3 "Pismo", and second-generation iBook "clamshell" models.