Archive for category: Computer Science

My trip down memory lane leads me back to TOPS-10 and the PDP-10

May 17, 2011 | Computer Science | By: Mark VandeWettering

I’m going to be nostalgic for a few moments. If you are too young to have any sense of nostalgia, skip ahead to the bold text below. You were warned! A few days ago, I mentioned that I was having a bit of flashback, thinking of my first experience with time sharing computers back in […]

Magnetic core memory reborn… on an Arduino????

May 11, 2011 | Computer Science, electronics, Hacking, Hardware | By: Mark VandeWettering

I may have mentioned before, I’m kind of old. One measure of how old I am is the fact that I’ve actually programmed machines that used core memory. Real core memory. Little ferrite donuts on arrays of wires. Some time ago, I remember running across this awesome blog post from “Wayne’s Tinkering Page” which showed […]

Word squares…

May 4, 2011 | Computer Science, My Projects, Puzzles | By: Mark VandeWettering

I like to read the Programming Praxis website. Every post challenges you to write some simple programs to boost your skill, akin to finger exercises for a musical instrument. Today’s challenge was an interesting which intrigued Charles Babbage: creating word squares. I spent about 10 minutes writing one in Python that worked rather well: here […]

A small standalone homebrew computer: FIGnition by Libby8dev

May 1, 2011 | electronics, Hardware | By: Mark VandeWettering

I’m old. I learned to program as a teenager in the 1980s. Back then, we learned to program on small microcomputers. These machines weren’t very powerful, but they had a neat feature: they were self-hosted. In recent years, a large variety of small microcontrollers have become popular. Many of these have capabilities far in excess […]

Watermarking and titling with ffmpeg and other open source tools…

April 19, 2011 | Amateur Radio, Computer Graphics, Games and Diversions, My Projects, Video | By: Mark VandeWettering

I’ve received two requests for information about my “video production pipeline”, such as it is. As you can tell by my videos, I am shooting with pretty ugly hardware, in a pretty ugly way, with minimal (read “no”) editing. But I did figure out a pretty nice way to add some watermarks and overlays to […]

Code from the Past: a tiny real time raytracer from 2000

April 12, 2011 | Computer Graphics, My Projects | By: Mark VandeWettering

Back in 2000, I was intrigued by the various demos that I saw which attempted to implement real time raytracing. I wondered just what could be done with the computers I had on hand, without using any real tricks, but just a straightforward implementation of ray/sphere and ray/patch intersection. As I recall, I got two […]

Cool Hack O’ Day: real pixel coding

April 11, 2011 | Computer Graphics, Link of the Day | By: Mark VandeWettering

The problem with working some place with lots of intelligent people is that it is increasingly hard to maintain one’s sense of superiority. Today, I tip my hat to Inigo. He has a very cool demo here, where he creates a program by creating and editing a small image in photoshop, saving it as a […]

Neat article on William Friedman and Steganography

March 28, 2011 | Cryptography | By: Mark VandeWettering

William F. Friedman is a name that might not be familiar to you unless you are a bit of a cryptography nut. Of course, I am a bit of one: I have a couple of long technical notes that were authored by Friedman on the cracking of some complex WWI era ciphers. But I must […]

Demo of Enigma and the Turing Bombe at Bletchley Park

March 15, 2011 | Amateur Radio, Cryptography, My Photos, My Projects | By: Mark VandeWettering

Carmen and I just got back from a trip to London, and we had a blast. One of the geekiest things we did while there was to take a day trip by train out to Bletchley Park to see the site of the codebreaking efforts by the British during WWII. As any long time reader […]

Hershey Vector Fonts

February 28, 2011 | Computer Graphics, My Projects | By: Mark VandeWettering

Nearly thirty years ago, I remember hacking together some simple code to display graphics on a WYSE 35 terminal. The terminals supported the TEK 4014 graphics commands to draw vectors, and I found the original “Hershey Fonts”, created by A.V. Hershey at the U.S. National Bureau of Standards, and placed in the public domain. I’ve […]

A Neighborhood of Infinity: Quine Central

January 30, 2011 | Computer Science | By: Mark VandeWettering

Dan Piponi has a very cool article on nth degree quines on his blog. It’s much more understandable than his fascinating but mostly over-my-head postings which I read often, only to be struck by serious feelings of inadequacy. A Neighborhood of Infinity: Quine Central.

Colossus: The secrets of Bletchley Park’s code-breaking computers

January 15, 2011 | Books I Read, Cryptography | By: Mark VandeWettering

As long time readers of my blog might remember, I’ve been fascinated by old cryptographic machines. I spent quite a bit of time tinkering around with them back when I was working on Simon Singh’s cipher challenge in his book. In particular, I spent a considerable amount of time reading up on the German Enigma […]

The J1 Forth CPU, running on an FPGA

December 2, 2010 | FPGA, Hardware, My Projects | By: Mark VandeWettering

Tom showed me a link to The J1 Forth CPU, a very small processor which is coded in Verilog (only 200 lines!) and can run very fast on existing FPGA boards. It is quite an intriguing design. Forth is an intriguing if somewhat archaic programming language. In the bygone ages of my youth, I experimented […]

LatticeXP2 Brevia Development Kit, with a deal breaker

December 2, 2010 | electronics, FPGA, Hardware, My Projects | By: Mark VandeWettering

I’ve been playing with a BASYS2 FPGA development kit from digilentinc.com, and pondering the world of digital system design. I chose the BASYS2 because of its low price ($70) and because it included a reasonable number of LEDs, switches, a VGA interface and a connector for a PS/2 keyboard. Still, I’ve been looking for other […]

Somewhere… over the (simulated) rainbow revisited…

November 1, 2010 | Amateur Science, Computer Graphics, Math, My Projects | By: Mark VandeWettering

A couple of months ago, I did some simple simulations of light refracting through raindrops in a hope to understand the details of precisely how rainbows form. The graphs I produced were kind of boring, but they did illustrate a few interesting features of rainbows: namely, the double rainbow, and the formation of Alexander’s band, […]