Ganesh Swami

In the few months that this blog has been running, akismet (“the collaborative effort to make spam a non-issue”) has caught about 4000 spam comments.

Most sites use CAPTCHA to determine legitimate users. A friend recently told me about a new method that spammers are using to circumvent CAPTCHA. A site with high demand content (like free music or porn) harvests CAPCTCHA on demand from another site and displays it to a user. The user is able to decode the text and types in the correct text, which in turn is used to spam the site where the CAPTCHA is taken from.

This is incredible.

A more useful version of this technique is reCAPTCHA. Instead of posting spam, the user is presented with words from a book that is currently being digitized, some of it correctly recognized by software and some incorrectly. This is compared with what others have typed in, and if correct, your comment is posted and the words added back to the database.

I’m trying to figure out if the evil way or the good way was thought of first. I’m guessing evil.

Nvidia is coming out a massively multi-threaded GPU based architecture. Each GPU will have 128 processors per core providing upto 500 gigaflops of performance. Multiples of these can be connected to a host via PCI Express for more power. Their server solution at the high end gives you 2 teraflops peak performance.

Some selling points:

• Industry’s first massively multi-threaded architecture with a 128-processor computing core
• World’s only C-language development environment for the GPU
• A suite of developer tools (C-compiler, debugger, performance profiler, optimized libraries)
• Largest ISV development community for GPU Computing applications
• Seamlessly able to fit into existing HPC environments

One of the white papers available on Nvidia’s website claims a 240X performance increase for the molecular dynamics program NAMD.

If you’re interested in this kind of stuff, gpgpu is a good place to check.

The Crystal Weather Station from Oregon Scientific sports a kick-ass form factor. It has laser engraved 3D icons of sun, clouds and rain in crystal and a radio controlled digital clock. You can even change the display mode between the time and indoor temperature with a wave of the hand.