Tuesday, February 24, 2009

Your computer is the plug

Marvell has produced a new Linux server that plugs into a wall socket. Essentially, what Marvell has created is a small Linux appliance. Others have gone this direction. What I like about this one is that it plugs directly into a wall socket and is designed to run all the time. One potential use for this computer is a host for a web camera. Internet ready web servers can cost quite a bit and they actually include a web server in their hardware. By using a computer with a low-end web camera, you get both the camera and the server, but you control the mix of the two.

This unit could also be used to run a continuous presentation in the school lobby or some other place that a full size computer would not work.


Kindle Two Arrives Today -- what it means to you

Amazon's new Kindle is launching today. The first model was a big success and the second model has been getting even better reviews.

It's $350 price is not so bad if one considers the lifetime wireless connection and the savings of e-books over paper books. The unit could pay for itself in less than a year. My hope is that Amazon can get the school textbook publishers to convert their text books to Kindle-ready formats. Not only would it save a huge amount of weight on our students' developing backs, but content could be updated on the fly. The Kindle and those that will follow will be our future. The only question is whether the publishers will participate fully or be dragged into the 21st century.


Thursday, February 19, 2009

Anyone who has purchased a fully functional calculator knows they don't come cheap. You also cannot use the calculator that Microsoft or Apple supplies. SpeedCrunch is an open source project that matches the features of a top-end calculator and then adds some features that only a computer interface allows. With the new nettop computers, it may not be much of a difference between an expensive calculator and nettop computer in terms of expense. SpeedCrunch runs on all major OSes.


Thursday, February 12, 2009

Viruses cannot do what you cannot do

I've long held that one of the best methods of stopping viruses and other attacks is to refrain from using accounts with administrative privileges. What most people miss about virus attacks is that while a virus does things that you don't want to have done, but it does these unwanted actions as you. The computer operating system, in other words, believes that the requests from the virus is coming from you. Just another example of how computers don't "think" like a person. The idea of "why would anyone want to do that?" does not come into play with a computer.

If you are using a computer that cannot delete/create/modify applications, it is very unlikely that a virus would be able to do so, as well. Both OS X and Windows Vista deal with this issue by running in a standard -- limited -- mode and asking for permission. Of course, if you're one of those people who automatically clicks on permission pop-up windows, this security system does little good.

Beyondtrust has just released a report that documents that removing administrative rights on a Windows computer can protect it from over 90% of common security vulnerabilities. This is higher than even I was thinking it would be but it does confirm the notion that restricting user rights is a great security strategy.


Wednesday, February 11, 2009

OpenDNS for Internet filtering

I've been using OpenDNS for quite some time and recently started using their filtering system.

First, DNS is the system by which URLs, such as abc.com, become the IP addresses ( that the Internet actually uses to get from one place to another. While DNS is an open source application, OpenDNS is not so much open because of DNS being open but rather that it is not tied to any given ISP. Most users on the Internet use either their company's DNS server or one supplied by their Internet Service Provider. ISPs didn't always spend a lot of money making their DNS servers fast and reliable. In come OpenDNS with their DNS servers. They have great up-time and the look-up speed getting the URL turned into something meaningful has been great.

OpenDNS makes it money mostly by displaying advertisements on the error pages it presents when the user mistypes a URL. You're going to get an error page -- and your ISP is probably going to have ads too -- so that's not a big deal. They also route Google searches via their server. I assume this is the type of revenue system that FireFox uses to get money from Google for any Google search performed from the FireFox search window. FireFox makes millions a year off that search box. And, I'm glad that they do make money. It's not loss to me and I am able to support a service that benefits me.

OpenDNS is a nice addition to a school's ability to block bad sites. The way this works is being creating an account with OpenDNS and telling them that you want searches from your site to be filtered. You can select differing levels of protection from nothing to very tight. Any student trying to reach a bad site either intentionally or unintentionally will get an OpenDNS block page.

The system is not a perfect solution. If you want your staff to have open access from the same network as the students, the same restrictions would apply. I don't think this is a huge concern given that even the most restrictive filter setting does not appear to block anything truly useful.

Another problem with using only OpenDNS to block bad sites is that it obviously cannot help you if your student knows the IP address of a site they want to reach. OpenDNS would not be involved. It would not be a lot of fun for the student to get around the system in this way, but it is technically possible.

And, some schools may have issues with ads being displayed. I don't think there is a work-around for this issue. Given all the ads that are in school materials and on vending machines, I would think these ads are no worse, but don't assume you're okay until you have asked.

I would recommend using OpenDNS as one element -- a free one -- as part of an overall Internet safety system. You should also tell the students' parents to use it at home.


Tuesday, February 10, 2009

The eyes have it: How we see web pages

Google's official blog has an interesting story on how users of their search results page move their eyes over the page. A "heat map" showing the intensity of where users' eyes tracked can be seen to the left. These maps are created by having a camera look at the user's eye as they look at the screen. The camera can tell which part of the screen is being looked at.

In the case of Google, the users' eyes were looking at the parts of the page with the most relevant information. This occurrence is not always the case. Frequently, web designers toss in lots of eye candy to pretty up the page. If you have something that is attracting the eye from what the user actually should be reading, then your site is probably going to be less satisfying to use.

This map is also telling in that it shows that people then to pop from place to place. Certainly, one would not expect to see this pattern with a book. This means that web designers need to create pages that are suitable for quick scanning. Use of font sizes, titles, icons, and graphics are as important as the content of the page. Well-written prose is not useful if people see it as a big block of dense text to be avoided.


Wednesday, February 04, 2009

$40 Smart Board using Wii Remote

Johnny Lee, of CMU, has created a very useful hack of the common Wii remote to effectively replace the need for a smart board. Here is a video showing him demonstrate his technology. The system is based on the fact that the Wii remote is a high quality infrared camera. By connecting the Wii remote to a PC/Mac via Blue Tooth -- rather than to the Wii game console -- the camera can now be used to track infrared sources. Because many people have Wii remotes and Blue Tooth enabled computers, the only thing they need is an infrared source. A number of devices are now being produced. I have a customized key chain light, but a commercially sold version can be had for a few dollars. There are other versions, but I like this one because it does not require the person press on the surface to activate the light. That's important to me because I use LCD TVs to display. Pressing on the surface could cause damage. If you know that you are going to be using a firm surface, such as a white board, you can use a light pen that turns on as it is pressed to the surface. That can be lot better than having to remember to press a button every time you start to write.

The Wii sees where the infrared light is positioned on the surface -- which can be anything flat -- and relays that position back to the computer via Blue Tooth. The combination of the light pen and the Wii emulates a mouse. You can move, write, click, etc. as you could with a normal mouse.

The key to making this work is the software Johnny Lee created and the versions that have subsequently taken his code to the next level. The most sophisticated on the ones I found was Smoothboard. There is a cross-platform version that also works nicely. It's less feature-rich, but could be a good option for schools with Linux and Mac systems.

One thing I learned from my tests is that it's a good idea to use two Wii remotes. The reason is that when I'm writing I can inadvertently block the light of the pen from the Wii. Things are improved when I put the Wii remote to one side of the screen, but two units would certainly help.

The possibilities of this system is great. You could project on a brick wall via a LCD projector or view your computer via a large TV screen. The Wii will work with both.

Give it a try. It's a lot of fun and it could save you a great deal of money.