Tuesday, October 23, 2012

Exploring the Mandelbrot set in real time

This is truly a beautiful hack! From Hack-a-day.

Exploring the Mandelbrot set in real time:

The Mandelbrot set – the fractal ‘snowman turned on its side’ seen above – has graced the covers of magazines, journals, and has even been exhibited in art galleries. An impressive feat for what is nothing more than a mathematical function, and has become something of an obsession for [Chiaki Nakajima].

Even on modern computers, generating an image of a portion of the Mandelbrot set takes a good bit of time. When [Chiaki] discovered this fractal in the mid-1980s, the computers of the day took hours to generate a single, low-resolution image. Real-time zooming and scrolling was impossible but [Chiaki] made the best of what he had on hand and built Pyxis, a Mandelbrot set generator made entirely out of TTL logic chips (Google Translate here).

The original Pyxis connected to a desktop computer via a breakout box. while a special program toggled the bits and registers inside the Pyxis to generate pictures of the Mandelbrot set a thousand times faster than the CPUs of the day could muster.

Time marches on, and the original logic chip Pyxis is can be easily surpassed by even the slowest netbooks. There is, however, another way to build a hardware Mandelbrot set generator: FPGAs.
A few years ago, [Chiaki] began work on the Pyxis2010 (translation), an FPGA-based Mandelbrot set generator able to dynamically zoom and pan around the world’s most popular fractal. Built around an Altera Cyclone III FPGA he picked up from Digikey for $600 (no, not a dev board, just a bare chip), [Chiaki] began deadbugging his circuit directly onto the pins of the hugely expensive FPGA. A man with a steady hand and no fear if there ever was one.

Instead of connecting his Mandelbrot generator to a computer and using it as a co-processor, [Chiaki] decided he wanted something more portable. He found an old Sony PSP, removed the LCD screen, and integrated it into his circuit. After a careful bit of dremeling and fabrication, [Chiaki] had a hand-held Mandelbrot generator that is able to display images of the world’s most famous fractal faster than any desktop computer.

It goes without saying this build is incredible. The technical skill to build an insanely fast Mandelbrot generator on an FPGA is astonishing, but basing it off a logic-chip based build reaches into the realm of godliness. You can check out a video of this amazing build after the break.
Props to [Ian Finder] for sending this one in.

Filed under: hardware, misc hacks

Tuesday, October 16, 2012

John the Ripper rules!

And I mean that both as a verb and as a noun. For those who don't know, John the Ripper is a password cracking program. It supports various formats natively and the community-enhanced version brings it to an insane level.

It can run attacks based on the login name itself, a wordlist and variations (called "rules") and, last resort, a brute force.

Here are a few rules I usually add:

# Try with 2 prefixing digits
l ^[0-9]^[0-9]
# Try prefixing with possessives
l A0"My"
l A0"Your"
l A0"His"
l A0"Her"
l A0"Our"
l A0"Their"
# Try with 1, 2, 3 and 4 digits at the end, and the same with punctuation
l $[0-9]
l $[0-9]$[0-9]
l $[0-9]$[0-9]$[0-9]
l $[0-9]$[0-9]$[0-9]$[0-9]
l $[0-9]$[(){},?;.:/=+<>%$*-_]
l $[0-9]$[0-9]$[(){},?;.:/=+<>%$*-_]
l $[0-9]$[0-9]$[0-9]$[(){},?;.:/=+<>%$*-_]
l $[0-9]$[0-9]$[0-9]$[0-9]$[(){},?;.:/=+<>%$*-_]
# Try with 1 or 2 digits and 2 punctuations symbols
l $[0-9]$[(){},?;.:/=+<>%$*-_]$[(){},?;.:/=+<>%$*-_]
l $[0-9]$[0-9]$[(){},?;.:/=+<>%$*-_]$[(){},?;.:/=+<>%$*-_]

If you have your own killer rules, feel free to drop the URL in the comment section.

Saturday, October 13, 2012

Bananas have gone nuclear!

So it seems that potassium-40 (40K) is naturally occurring in bananas and that it can undergo a disintegration, emitting a positron in the process. This positron can then interact with an electron, emitting 2 photons around 511 keV, in the gamma ray portion of the EM spectrum. This is of course assuming that the pair electron-positron have a low kinetic energy.

As said, bananas have gone nuclear!