News and other tidbits that Chad Cloman finds interesting enough to share
First flip-phones, and now transparent aluminum—Star Trek is getting better and better at predicting new technologies. Apparently this stuff is superior to regular (and bullet-proof) glass in nearly every manner except price. If they can get the cost down to reasonable levels, we may see it become ubiquitous.
The following is from an email newletter I receive (reprinted with permission).
How are recordable CDs burned?
By Kim Komando
CDs are a great example of how fast technology moves. Ten years ago, CDs were high technology. I remember buying an expensive computer just to get a CD player (CD-ROM). Today, we burn CDs at the drop of a hat, to play in our cars. But it’s still good to know how this stuff works. The technology is pretty cool.
Digital information, including music, is stored in binary (1’s and 0’s). To represent all those 1’s and 0’s, a CD contains tiny spots that are highly reflective or poorly reflective. A laser is used to read the sequence of spots. The sequence can then be interpreted as sounds.
A CD-R disc has two important layers of material sandwiched between plastic. One is a layer of metal, typically aluminum. In front of that is the other layer, a special dye. The aluminum layer is highly reflective. The dye is mostly transparent, so overall the disc is completely reflective. But the dye can be changed by the laser in your CD-R drive.
The laser heats and burns tiny spots on the dye layer. The burned spots become nontransparent. They block light from reaching the aluminum layer. So a finished CD-R ends up with both highly reflective and poorly reflective spots. These are the 1’s and 0’s, respectively.
Your CD-R drive uses a strong laser to burn a disc’s dye layer. Typically, CD-Rs have a second, weaker laser, used for playing. It is too weak to affect the dye’s transparency. CD-ROMs also have only a weak laser.
The chemicals used for the dye layer eventually degrade, ruining the disc. Disc manufacturers use various dye formulas, some sturdier than others. But the cheapest last only a couple years. And price tag aside, it’s difficult to discern the quality of CD-R brands. I always buy name brands.
Rewritable discs use a layer of crystallized material instead of a dye. A CD-RW drive’s laser melts tiny spots of the layer. The spots cool too fast to re-crystallize; that makes them opaque. Those spots are 0’s, because they do not reflect light. Crystallized spots, which are transparent, are 1’s.
When data is erased on a CD-RW, the spots are melted again. But they’re heated to a lower temperature and cool slowly enough to re-crystallize.
Commercially produced discs like software or music albums (and my books) are not burned. They use tiny bumps or dips to represent 1’s and 0’s. The dips and bumps are molded directly into a disc’s plastic. The sequence is then coated by a layer of metal, usually aluminum. These discs can last for decades.
Copyright © 2005 WestStar TalkRadio Network. Subscribe to Kim Komando’s free e-mail newsletters at: www.komando.com
A company named Nantero has created a 10-gigabit RAM chip based on nanotube transistors.
Nanotube RAM (NRAM) uses carbon nanotube transistors instead of conventional silicon transistors. It is non-volatile, like flash memory, but does not degrade over time as is the case with flash. It is also ten times faster and uses substantially less power than flash. In addition, NRAM is “highly resistent to heat, cold, and magnetism”.
The technology is currently not a viable replacement for flash memory in gadgets like iPods because it is too large—the 10Gb wafer is 13cm (5in) in diameter. It is not clear whether Nantero expects the size to decrease in the future, but I wouldn’t be surprised if this was the case. At the very least, they could make the chip more 3-dimensional, thus converting a flat, thin wafer into more of a cube.
Solid-state memory is much faster than mechanical hard drives, and this technology has the potential to replace conventional hard drives completely. There is already some headway in this direction, and I expect NRAM to join the movement.
UPDATE: The nature.com article has become subscription-only, so you won’t be able to read it unless you (or your library) have a subscription to Nature.
The DARPA Grand Challenge is a government-sponsored competition to see if robotic vehicles can successfully navigate a great distance (approximately 150 miles) without human intervention. The race course includes obstacles such as tunnels, ditches, and berms. The initial prize was $1 million, with each successive race worth more until someone wins.
The first race in March 2004 was a fiasco, with the best entry covering only 7 miles of the 142-mile course. This year’s race, however, saw five vehicles complete the 131-mile course, with Stanford University winning the $2 million prize. This increase in performance over a mere 19 months is pretty impressive and bodes well for the future of robotic intelligence.
