Tyvek is a material made of high-density polyethylene fibers flashspun and bonded into a paper-like sheet. This lightweight and highly breathable plastic resists tearing, moisture, and chemicals, but can be folded and cut like paper. Tyvek is often used in protective clothing, backpacking groundcloths, CD sleeves, and mailing envelopes. It can also be used to make weather-resistant pouches for electronic devices. In this case, Tyvek from a used USPS Priority Mail envelope was engineered into a T-Mobile G1 smartphone pouch.
Archive for January 2009
This semester of physical chemistry deals with quantum chemistry, so naturally we discussed some of the philosophical aspects of science. My professor said that nobody really understands quantum mechanics…
Professor: … even Feynman said so in his famous lecture. It has also been said that “if you are not completely confused by quantum mechanics, you do not understand it.” (Wheeler)
Me: Surely, Feynman understood the technical aspects of quantum mechanics; what he didn’t understand was the metaphysics. But that has an explanation so simple and so elegant that not even science could express it.
Professor: And how would you explain it?
Me: Floating point numbers have a large but limited dynamic range. When we approach the extremely large or the infinitesimally small, we run into problems. Quantum mechanics is simply an out-of-bounds error in God’s pocket calculator of the universe.
Professor: Of course you are free to speculate about these things, but when we’re in a science classroom…
Me: … we talk about science. On the astronomical scale, we have anomalies such as dark matter. On the subatomic scale, we have quantization of time, space, matter, energy, and everything. These are clearly manifestations of an inability to represent the very large or the very small…
… perhaps when God designs version 2.0 of His universal software He’d use bignums instead of floats. Now wouldn’t that make the world a better place?
Insects are a ubiquitous part of our lives. Some of the most versatile insects belong to the order blattodea. Cockroaches are amazingly quick and hardy critters. They can run a meter a second and change directions 25 times a second. Their small size and sleek form factor make them easy to work with and difficult to capture. Their tough exoskeletons allow them to survive harsh environmental conditions and their muscular limbs allow them to carry weighty loads. In other words, this lean little beast is a perfect platform for robotics.
Imagine a tiny harness containing measurement and remote control mechanisms that can be strapped onto a cockroach, turning it into a remote-controlled probe. Now let’s scale the scenario up to tens, hundreds, or thousands of mobile units. Each unit carries a tiny camera and can be directed to any location via radio signals. Together with a computer control center, the swarm could be used to rapidly map out areas that humans would be loathe to investigate. This is just one of the many applications of such technology. But how can such a system be designed?
The Market cache has been a source of grievance for many Android/G1 users. Applications under Android store data in caches that are cleaned up when memory is running low. The G1 has an unimpressive amount of onboard memory, and the Market browser has a cache that cannot be manually cleared. This has lead to many individuals performing factory data resets on their phones just to reclaim the sequestered memory.
The factory data reset is not the best approach. In fact, I would say that the best approach is to do nothing at all about the problem. By virtue of Android’s memory manager, caches are cleared automatically when memory is needed. For example, if the foreground task needs to do something memory-intensive and there are some background tasks and caches, some of the tasks could be killed or caches could be cleared to make room. So… the problem solves itself.
One does not need to manually reclaim the memory, but what’s wrong with doing it anyway? I mean, it does get rid of the low-memory warnings that are so distressing to some. However, the biggest problem with clearing caches is the act itself. Caches perform the useful function of storing objects so that they need not be computed or fetched again, saving processor, networking, and power resources. One can even say that memory exists mainly for the purpose of caching. Therefore, it would be optimal to fill the memory as much as possible with cache. The system that Google set up is almost perfect — it allows the memory to fill with cached data, clearing bits at a time only when needed for a foreground task.
But why isn’t it perfect? Well, I had mentioned the low-memory warnings earlier. When the average user sees one of these, he/she thinks that the phone is about to explode. It’s not; rather, it’s a sign that the memory manager is doing its job. The psychological aspect of the problem can be resolved by either removing this warning or making it appear more benign, reserving the real warning for when the memory is really running out.
In the interim, I’m going to hang onto my caches and encourage you to do the same. There is no harm in taking the need-based memory management approach. Remember, unused memory is wasted memory.
Support for the EXT4 filesystem started appearing in the Ubuntu 9.04 daily development images just a few days ago, and early adopters have been experiencing the speed and efficiency of this new format. Compared to EXT3, EXT4 shows marked performance improvements and pulled far ahead of the competition in many respects. Phoronix’s article on Ubuntu’s EXT4 support contains some technical benchmarks.
But what does this mean for us regular users? For one, we’ll now be able to store gargantuan files on the scale 16TB. While that feature would not be useful to most users, the faster read/write speeds would allow most applications to start and work faster. In particular, Softpedia reports a noticeable boot time improvement of 9 seconds, yielding a 21.4-second boot. While this may not seem very much, let’s remember that Ubuntu and the EXT4 module are still full of debugging code. Once that’s gone and everything else is stabilized, the system would work even better.
Due to popular demand and the ensuing server overload, Microsoft has postponed the Windows 7 public beta and removed its download links. And it’s no wonder — weighing in at 3.2GB apiece, these DVD images aren’t exactly small downloads.
Microsoft will be posting the links again when they have sufficient infrastructure to handle the load, but the resourceful fellows over at [H] Enthusiast have found the original links still functional. Here they are:
These are direct links to the English version. I’d recommend using wget rather than your browser. Wouldn’t it have been so much easier and cost-effective to use Bittorrent?
Update: Apparently… the official links are back! The direct links still work, but you could now sign in to obtain licenses for activating your Windows 7 setups.
According to Android_Dave over at Android Community, a conversation with a T-Mobile UK representative revealed the existence of a big OTA software update on Friday, January 9th. Though this hasn’t been confirmed, the representative was apparently pretty confident that the update would occur and that it would include video messaging, Java, and Flash. Naturally, this sparked a discussion on whether this is indeed the imminent “cupcake” update.
We speak not of the tasty treat, but of a development branch of the Android operating system. It’s a work-in-progress collection of changes since the Android 1.0 release, and has recently been merged into the master branch. There will be a large update this quarter followed by smaller updates along the “cupcake” track.
Because this update will contain numerous bugfixes and enhancements, people are naturally quite excited about it. Is the Friday update the first in the series of “cupcake” updates, and would it occur in the United States as well?
At this point, nobody knows for sure… but at least something is happening.
Says Bratag, an anonymous but reliable source has indicated a pre-cupcake update this month. Apparently, the OTA should be pushed out as early as Sunday, January 11th according to Michael Martin and as late as Thursday, January 15th according to kareem. Well, the 11th had come and gone and we still have no cupcake. Let’s hope for the 15th, then?