Thursday, April 12, 2007

Windows User Tips


  1. Backup! Backup! Backup!


  2. Upgrade to Windows Vista as soon as possible.


  3. Do not login as administrators.




Thursday, April 5, 2007

Language Recognition

Here, language recognition refers to distinguishing English from Spanish, etc..

Recognition of Languages seems not a big deal, but why should many translating tools asking users to select the languages.

Online translation websites like Babel Fish and Google Translate both have a language selection box.

One solution, which is quite straight forward, is to recognize the words or characters of different languages. Those words with a high frequency are very good clues. Different encoding also helps recognize languages.

Friday, March 16, 2007

Real Time Search

When I was reading on reader, I found it quite not up to date. There might be two reasons. One is that reader did not get the latest feed, while the other is the feed itself is not updated.

As information explodes, a huge number of bytes were generated day by day, hour by hour. With newspaper, we know what happened yesterday; with TV, we know what happened today; with Internet, we could know what happened just now. However, these are all limited to public concerned events. They are not what we are most interested in.

When search engine came up, we were able to find what we want by typing some keywords. When searching, we got what was being. The information we searched on was crawled by robots days or even months ago.

One approach to solve time critical problem is subscription and notification. In this way, every subscriber is notified whenever an event happened. It is better than "publishing and waiting till someone sees it" method. But still, there are problems. One is that the subscription and notification server would become a bottleneck. Another is that we could not know what to subscribe before it happened. To solve the former one, a more powerful hardware or smarter software on cooperated computers might do. To the latter, only can we believe there is a wizard.

So, here comes the necessity of existence of real time search.

Wednesday, March 14, 2007

Recovery Oriented Computing

Mr Patterson, UCB, introduced Recovery Oriented Computing. In the article, Recovery-Oriented Computing (ROC): Motivation, Definition, Techniques, and Case Studies, an undoable email system was presented. This reminds me of Gmail which is the only one that I know, that provides a 'undo' function.

Recovery Oriented Computing is not a new idea. Things like checkpoints do just the same. Reliability or Dependability is quite important on High Performance Computers. However, it is equally hard to implement a fully reliable system that meets the performance requirements. Then checkpointing and rollback is an option. Recovery Oriented Computing showed why it is necessary and how to implement it.

On the other hand, Gmail is a new technology based product. Many big ideas like tagging, search not sort, dialog, combining with IM and AJAX were added to help improve performance, flexibility and change the way that emails were used. Compared to old plain text email system, which I believe was still used on many Unix systems, Gmail has countless advantages.

Either you do things ahead, or you do them faster. Theories are often ahead of times. They lead the technology. Theories, especially in engineering, require the support of experiments. Such experiments might be very difficult or costly. Thus supporting is somewhat important. Technology makes use of theory. The sooner you make use of advanced technology, the more you will benifit. Racers running faster reach the finishing line earlier than those slowers starting at the same line.

Wednesday, March 7, 2007

Distributed Hash Table

Distributed hash table, or DHT in short, has become more and more popular in P2P networks.

Refer to
http://blog.csdn.net/Crazy_Dreamer/archive/2007/01/06/1475413.aspx

Friday, January 19, 2007

Event Listener, a Java Pattern

The book, Java Threads, describes 'event listener' as a standard Java pattern. Has anyone heard of it?

Tuesday, January 16, 2007

Web Service Containers

In web services, request and response are common. However, a stateless web service (actually, should it be called static web pages?) could not provides something as easy as a counter that most websites have (or should they hide the counter for certain reasons). You might be familiar with dynamic pages or PHP, ASP etc. They are just the front end of a stateful web service, or to be more precise, connectors. They connect customers' requests to containers.

What is the relationship among containers, resources and services?

A service provides an entry to certain resources, and services and resources are all in containers. A typical container is Tomcat. Sometimes, standalone makes it easier for installation, but confuses terms. A standalone Tomcat seems more than just a container. It provides what a typical web server provides, at least.

Apache web server (Apache httpd) accepts modulars like PHP modular. Then, could PHP modular be called a container? The motive of PHP is to provides a flexible way to generate dynamical web pages.