Ganesh Swami

Wow, feels like just yesterday that Intel announced new SSE4 instructions. AMD today announced new SSE5 instructions. The new instructions include:

• Fused multiply accumulate (FMACxx) instructions
• Integer multiply accumulate (IMAC, IMADC) instructions
• Permutation and conditional move instructions
• Vector compare and test instructions
• Precision control, rounding, and conversion instructions

The Fused-Multiply Accumulate instruction is the most interesting. Architectures like PowerPC and Itanium have had these instructions for a long time. The Itanium processors do the fmac in the same number of cycles as an addition or multiplication. Here’s a paper that describes some elementary functions that can be computed using fmac.

Download the instruction set manual from AMD.

(via insidehpc)

Gear6 is a Silicon Valley startup that just came up with an incredible product — a machine “CACHEfx” that uses standard computer RAM as storage cache. They come in blocks of 250 or 500 GB, and the operating system will virtualize it into a single pool of upto 5 TB.

The box plugs into a standard Gigabit Ethernet link and caches frequently used files. CACHEfx has a latency of less than 500 microseconds. They also have a handy tool to assess the speedup that you’ll gain by using their product.

If my lab had some more money and the need, we could get one of these. Currently, runs of fluidmatch can generate outputs of upto half a gigabyte. Multiply this by a hundred, and simple things like moving or copying files needs to be scheduled for overnight.

Neuroscientists are trying to figure out how different parts of the hippocampus are responsible for identifying previously visited places. Quoting from the Science summary, “Where am I?” by André A. Fenton:

The collective discharging of place cells allows us to predict the rat’s location by, in a sense, reading its mind. Knowing a rat’s location from the activity of its neurons is astonishing given that rats, like people, have no specific spatial sense organs analogous to, for example, the visual or auditory systems. Somehow spatial knowledge is assembled by the brain.

This is interesting to me because there’s a lot of work being done on analyzing deformations in the hippocampus to distinguish between Alzheimer’s and normal dementia. Being able to distinguish between the two in a blind setting is extremely valuable.

The official TED blog makes a list of 100 websites that you should know and use. I know what I’ll be doing when I have time to spare.

The Web is constantly turning out new and extraordinary services many of us are unfamiliar with. During TED University at this spring’s TED2007 in Monterey, Julius Wiedemann, editor in charge at Taschen GmbH, offered an ultra-fast-moving ride through sites in many different areas, from art, design and illustration, to daily news, blogs and curiosity. Now, by popular demand, here’s his list of 100 websites you should know and use.

Here’s the deal:

• Google lists the post on my favorite wordpress plugins as the second hit for my name.

• Spammers target this highly visible post for all the spam (about 90% on just this post.) Fortunately, akismet blocks almost all of them.

• I have a plugin installed that organizes the dates in my sitemap by the most recent updates. The amount of spam causes the last modified date on the post to be updated regularly.

• Google uses this information to repeatedly crawl the aforementioned post, thinking it’s a highly active page.

• Positive feedback ensues.