12/17/2007

Amazon SimpleDB: a database server for the internet

Filed under: — Aviran Mordo

Amazon has announced SimpleDB, the latest addition to what is becoming an extensive suite of web services aimed at developers. It is now in beta.

Why bother with SimpleDB, when seemingly every web server on the planet already has access to a free instance of MySQL?

Perhaps the main reason is scalability. If demand spikes, Amazon handles the load. Second, SimpleDB is universally accessible, whereas your MySQL may well be configured for local access on the web server only. If you want an online database to use from a desktop application, this could be suitable. It should work well with Adobe AIR once someone figures out an ActionScript library. That said, MySQL and the like work fine for most web applications, my blog being one example. SimpleDB meets different needs.

This is utility computing, and prices look relatively modest to me, though you pay for three separate things:

Machine utilization - $0.14 per Amazon SimpleDB Machine Hour consumed.

Data transfer - $0.10 per GB - all data transfer in. From $0.18 per GB - data transfer out.

Structured data storage - $1.50 per GB-month.

In other words, a processing time fee, a data transfer fee, and a data storage fee. That’s reasonable, since each of these incurs a cost. The great thing about Amazon’s services is that there are no minimum costs or standing fees.

Open source VirtualBox challenges VMware Workstation

Filed under: — Aviran Mordo

First, the particulars: VirtualBox is a cross-platform virtual machine management solution. It supports Windows (both 32- and 64-bit versions), Mac OS X, and various Linux distributions as hosts while providing a VMware-like laundry list of supported guest OSes. It maintains a consistent user interface across all of its host implementations, making it popular with users who multiboot between Windows, Linux, and/or OS X. VirtualBox is available free for noncommercial use, and there’s even a GNU-licensed version for those who might want to tinker with the source code.

With version 1.5.0, VirtualBox introduced a major new capability: seamless windows. Basically, it’s a knock-off of the Coherence feature of Parallels Desktop for the Mac. The VirtualBox implementation, however, represents the first time the capability has been available under Windows or Linux. The latter should be of special interest to Windows defectors who have been looking for a reason to go the Linux route versus Apple. And though it’s not as well integrated with the Linux host as Parallels is with OS X (for example, you can’t create shortcuts or file associations between the host and guest), it’s free and integrates well with leading desktop distributions such as Ubuntu.

Storing light with sound

Filed under: — Aviran Mordo

The information in a beam of light can be stored for a while by converting it into a sound signal, then reading it back out again as light, researchers have found. The process, which can be done in commercially-available optical fibres, could be used to help make computer processing more efficient in future.

Data can be sent great distances at speed in beams of light: modern optical networks, like those used to transmit information in the internet, can deliver 10 gigabits of information per second. But the information can’t be processed as quickly. To get around this, optical bits are turned into electric signals that can be stored for a short time and then turned back into optical signals to be read. But this process generates heat, and as more bits need to be moved around, more heat is going to be generated. In future, even greater speeds of information delivery mean that electronic processing will no longer be viable.
The sound of light

Researchers wondered whether they could get around this problem by turning the signal into sound instead. Daniel Gauthier, at Duke University in Durham, North Carolina, and his colleagues have demonstrated that this might be possible.

They first send optical data as a stream of light pulses into a short piece of standard optical fibre. Into the other end of the fibre they send a different short pulse: the ‘write’ pulse. When the two sets of pulses collide, they interfere, and an interference pattern is set up in the fibre with areas of high and low intensity. This interference pattern in turn affects the physical properties of the fibre, setting up an acoustic wave because of a phenomenon called electrostriction.

As the light pulse leaves the fibre, the acoustic wave with all its inherited information lags behind: the speed of light in the fibre, at some 200 million metres per second, far exceeds the more sluggish 5,000 metres per second of sound. “The acoustic wave is essentially stationary over the duration of our experiment,” says Gauthier, whose work is published in Science 1.

To get the information from the acoustic wave out again, a third light pulse, the ‘read’ pulse, is sent in. When it reaches the part of the fibre being affected by the acoustic wave, the light scatters in such a way as to regain the information that was left behind by the initial pulse. The newly-formed data pulse leaves the fibre, resuming the journey in the same direction as the original pulse, taking the same information with it.

In the tests done so far, a 2-nanosecond pulse could be held in the fibre for up to 12 nanoseconds.

“What is so cool about this process is that the original data stream is recreated with reasonable fidelity,” says Gauthier: the initial light pulse and the emerging one have nearly the same shape. In theory it is possible to have perfect fidelity. But this relies on a mass of certain conditions that haven’t yet been achieved.

Iran shuts down 24 cafes in Internet crackdown

Filed under: — Aviran Mordo

Iranian police have closed down 24 Internet cafes and other coffee shops in as many hours, detaining 23 people, as part of a broad crackdown on immoral behavior in the Islamic state, official media said on Sunday.

The action in Tehran province was the latest move in a campaign against fashion and other practices deemed incompatible with Islamic values, including women flouting strict dress codes and barber shops offering men Western hair styles.

“Using immoral computer games, storing obscene photos … and the presence of women wearing improper hijab were among the reasons why they have been closed down,” Colonel Nader Sarkari, a provincial police commander, said.

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