Configure Ubuntu login window appearance and behavior

By default, when you boot up Ubuntu Linux, you will first reach the GDM login window whereby you'll have to provide your username and password in order to login and use the system. Do you know that you can easily configure and personalize this login window with the Login Window Preferences? You can even enable automatic login so that you can directly reach your Desktop, bypassing the login process, good for single-user computer.

To configure your Ubuntu login window appearance and behavior, go to System > Administration > Login Window.



Among the configurable items in Ubuntu Login Window Preferences are:

• Hide/show visual feedback (the "***") in password entry. By hiding the visual feedback, no asterisk will appear when you key-in your password, which is more secured.
  
• Enable/disable multiple login for single user
• Change the theme. There are a few preloaded themes available, to download and install more themes, please read on...
• Hide/show the Action Menu, which consist options to shutdown, restart, select XDMCP, etc.
• Customize the greeting welcome message.
• Enable/disable remote login of X-Window.
• Configure the style for remote login window.
• Enable/disable accessible login.
• Customize the music played when login screen ready, upon successful login and/or when login failed.
• Enable/disable automatic login without asking for password.
• Enable/disable timed login. This will automatically try to login the selected user after inactivity of defined seconds in the login screen.
• Allow/deny local and/or remote system administrator login directly into the system.
• Allow/deny TCP connection to the XServer. It should be denied for security reason. Denying TCP to XServer doesn't affect the XDMCP function.
  
• Include/exclude user in the face browser listing of the login window.
  
• Some other security related settings.
  

You can download and install more themes and artworks from the GNOME Artwork Server by using the Ubuntu Art Manager. Just access to System > Preferences > Art Manager.

To download and install the themes for Login Manager, go to Art > Other Themes > Login Manager in the Ubuntu Art Manager. The Art Manager will then download the information of available themes from the GNOME Artwork Server, including the name, snapshot, description and author, and list them in the selection box as shown below.

From LCD TV to LED TV to OLED TV

I notice that there is a new species of flat panel television called LED TV available in the electrical shops nowadays. Here are some of the fact finding.

Pioneered by Samsung, LED TV is in fact a LCD TV using Light-Emitting Diodes (LED) as its backlight, contrasting to the Cold-Cathode Fluorescent Lamps (CCFL) backlight of normal LCD TV. This innovation has made Samsung to receive a prestigious award from European Image and Sound Association (EISA) in 2006, for its premium display technology in terms of true colour representation with a 46% larger colour gamut and the industry's highest contrast ratio of 10,000:1 by then.

According to Samsung, their LED TV provides improvements in 3 distinct areas:

1. Breakthrough picture quality with higher contrast, sharper motion and enriched colour.

2. Ultra slim design at only 1.2" deep with lighter weight.

3. Environmental friendly with 40% electric power savings than normal LCD TVs, produce less heat, and also lead and mercury free.

It is also claimed that the LED light source can double the TV panel life compared to the CCFL panels.

Beside Samsung, other manufacturers such as Sharp, Sony, LG, Panasonic, etc. have also produced their own series of LED TV. Of course, you will expect the price of LED TV to be higher than LCD TV of the same size.

Meanwhile, the television technology keeps on progressing, and the next generation will be a true LED TV called Organic LED TV (OLED) using the Active-Matrix Organic Light-Emitting Diodes (AMOLED) technology, this time to be led by Sony.

The primary benefit of OLED displays over the LCDs is that OLEDs do not require a backlight to function, and consume even less power. This technology also enable the panel to be ultra-slim, weight even lighter, and more robust. Of course, better quality display can also be expected.

On the other hand, we can notice that the plasma TV gradually step down from the TV technology warfare, following the CRT TV, as there is not much technology breakthrough and also less R&D investment allocated by the major manufacturers.

Database synchronization/replication with SymmetricDS

SymmetricDS is an open source, feature rich, web-enabled, database independent, data synchronization/replication software. It is written in Java 5 and released under GNU Lesser General Public License (LGPL) version 3.

It uses web and database technologies to replicate tables between relational databases in near real time. The software was designed to scale for a large number of databases, work across low-bandwidth connections, and withstand periods of network outage. By using database triggers, SymmetricDS guarantees that data changes are captured and atomicity is preserved.

Supported databases including:

• MySQL version 5.0.2 and above

• Oracle version 8.1.7 and above

• PostgreSQL version 8.2.5 and above

• Sql Server 2005

• HSQLDB 1.8

• H2 1.1

• Apache Derby 10.3.2.1 and above

• IBM DB2 9.5

• Firebird 2.0 and above

SymmetricDS allows for 2-tier and even n-tier synchronization, which can be configured to push data (trickle-back) or pull data (trickle-poll) at an interval, as illustrated below:



The software is installed either standalone, as a web application in a Java application server or can be embedded into another Java application.

SymmetricDS will be useful for data synchronization between a central database and multiple remote databases. This kind of requirement is often in:

• HQ and branches
  
• General office and retail outlets
• Police HQ and stations
  
• Ministry of education and schools
• Ministry of health and hospitals & clinics
• etc.

Click here for more information about SymmetricDS.