Monday, December 19, 2011

How to mount a VirtualBox shared folder in Ubuntu guest

1. Click on VirtualBox VM Devices and Shared Folders... to create a shared folder, named it SharedFolder, for example.
2. On Ubuntu guest machine, open Terminal
3. Type sudo mkdir /mount/vboxshared
4. Type sudo mount -t vboxsf SharedFolder /media/vboxshared to mount the VirtualBox shared folder as read. To make it read/write, use this command: sudo mount -t vboxsf -o uid=1000,gid=1000 SharedFolder /media/vboxshared

If the shared folder is a permanent share and auto mount, make sure your user id in group vboxsf. To add a user id to group vboxsf, using command: sudo usermod -a -G vboxsf linuxuserid


Sunday, November 20, 2011

Apple iPad 2 vs. Toshiba Thrive vs. Acer Iconia Tab vs. Samsung Galaxy Tab vs. Motorola Xoom

There is no question that Apple iPad 2 is a leading table. Let compare it with other 16GB Wi-Fi tablets.

Tablet Apple iPad 2 Toshiba Thrive Acer Iconia Tab A500 Samsung Galaxy Tab Motorola Xoom Family Edition
Operating System (OS) Apple iOS 4, 5 Google Android 3.1, 3.2 Google Android 3.1 Google Android 3.1 Google Android 3.1
Screen Size 9.7-inch 10.1-inch 10.1-inch 10.1-inch 10.1-inch
Screen Resolution 1024x768 1280x800 1280x800 1280x800 1280x800
Processor 1GHz dual-core Apple A5 1GHz Dual-core 1GHz Dual-core NVIDIA® Tegra™ 2 1GHz Dual-core NVIDIA® Tegra™ 2 1GHz Dual core
Memory (RAM) 512MB 1GB DDR2 1GB DDR2 1GB 1GB
Storage (ROM) 16/32/64 GB 8/16/32 GB 8/16/32 GB 16 or 32 GB 16GB
Expandable memory None Full-size SD Card slot. Up to 128GB SDXC microSD, microSDHC None Up to 32 GB microSD card
Back Camera 1MP. Video recording, HD (720p) 5MP with auto-focus, 720p video capture 5MP with auto focus and single LED flash 3MP auto-focus camera with LED flash. HD(720p) Video recording 5MP auto-focus camera with LED flash. 720p video capture
Front Camera 0.3MP VGA 2MP 2MP 2MP 1.3MP
Microphone Yes Yes Yes
HDMI No Yes Yes No Yes
USB No Mini USB 2.0 port, Full-size USB 2.0 port 1 USB 2.0 No Micro USB
Wi-Fi 802.11a/b/g/n 802.11b/g/n 802.11b/g/n 802.11 a/b/g/n Dual-band (2.4GHz, 5GHz) 802.11b/g/n
Battery 10 hrs 11 hrs 8 hrs 9 hrs 10 hrs
Weight 1.33 lbs 1.60 lbs 1.69 lbs 1.25 lbs 1.43 lbs
Flash support Yes Yes Yes
Price $500/$600/$700 $380/$400/$480 $350/$450/$500 $500/$600 $400

Saturday, November 5, 2011

How to remove exif tag

Each time we take a picture from a digital camera or smart phone, the exif tag and other photographic meta data are include in these pictures. These meta data contain info about your camera or your phone, GPS location,... To protects your privacy or reduce the picture size before publish the pictures on the web, you should remove exif data.

On Ubuntu: Using GPS Correlate
In the terminal:
To show the exif tags: gpscorrelate -s *.jpg
To remove the exif tag: gpscorrelate -r *.jpg

On Windows: Using a free software called IrfanView

Sunday, October 30, 2011

How to completely disable Google Web History?

Google Web History records your key search and web activity after you log in to Google Account. When you create a Google Account at, you're given the option to enable Web History with your account. Visit Google Web History for more detail.

Many people choose to NOT enable Web History for privacy reason. However, when you activate Google+ service, you may accident enable Web History. For more information, read "Think You’ve Disabled Google’s Web History Tracking? Check Again" posted at TechCrunch.

To complete disable Google Web History, after login to Google Account, type this URL:
(Source: Alex at Google Web Search Community)

Sunday, October 23, 2011

Upgrade to Ubuntu 11.10 (Oneiric Ocelot)

I upgraded my Ubuntu 11.04 Natty Narwhal to Ubuntu 11.10 beta 2, code name Oneiric Ocelot, on Oct. 12, before official release few days. Here are my own experience:
  1. Make sure you know the admin password for PhpMyAdmin, if installed, before you upgrade. I forgot this password and it took me almost half hour to get out the infinite loop :(
  2. An hour for download and another hour to install.
  3. Remote desktop 'tsclient' was removed. Used 'RDesktop' or 'Remmina' instead. After using Remmina Remote Desktop client, I liked it. It's better than 'tsclient'
  4. Somehow the trash icon in launchpad associated with VLC media. Uninstalled VLC resolve this issue.

Saturday, October 15, 2011

How to upgrade VirtualBox 4.0.12 to 4.1.4 on Ubuntu 11.04

Oracle released VirtualBox 4.1.4, a maintenance release of VirtualBox 4.1 which improves stability and fixes regressions, on Oct 3rd, 2011. Using 'sudo apt-get update' and 'sudo apt-get upgrade' will not upgrade your Oracle VirtualBox ( from 4.0.12 to 4.14. To upgrade:
  1. Backup your virtual machine by press <ctrl>-E to export appliance
  2. Go to Ubuntu Software Center to uninstall current version
  3. Install new version Oracle VM VirtualBox 4.1.4
  4. Install Oracle VM VirtualBox Extension Pack
  5. Run virtual machine and apply new version of Oracle VM VirtualBox Guest Addition 4.1.4r74291

Saturday, October 8, 2011

Steve Jobs

Steve Jobs, the mastermind behind Apple's iPhone, iPad, iPod, iMac and iTunes, passed away on Wednesday, Oct. 5, 2011. Jobs was 56.

Apple said in a statement on its website: "Apple has lost a visionary and creative genius, and the world has lost an amazing human being. Those of us who have been fortunate enough to know and work with Steve have lost a dear friend and an inspiring mentor. Steve leaves behind a company that only he could have built, and his spirit will forever be the foundation of Apple."

Well said, I have nothing to add. But I would like to share "one more thing". One of the things I learn from Steve Jobs in WWDC 1997: “And you know the hardest thing is, when you think about focusing right, you think well focusing is about saying yes. No. Focusing is about saying no. Focusing is about saying no. And you got to say no no no. And when you say no, you piss off people… and the result of that focus, is going to be really great products, where the total is much greater than the sum of the parts.

Rest In Peace, Steve.

Sunday, September 25, 2011

The Pencil Analogy

This article written by Brad Wallace posted on SQL Server Central on Aug. 18, 2011. It was a great editorial. After reading, I wondered who is at fault? The CEO or the contractor.

"The Pencil Analogy" reminded me of my own painful experience almost 25 years ago. As the requirements kept changing, little by little, I ended up working for nothing. I did not make enough money to keep my roof over my head. I closed my first startup business and went to work for others.

Sunday, September 18, 2011

How long 2011 Developer Conferences Sold Out?

Microsoft BUILD conference occurred in Anaheim, California from Sept. 13 to Sept 16, 2011. In this developer conference, Microsoft introduced Windows 8. How long did it take Microsoft to sell out? Two months. ( and

Three months ago, Apple Worldwide Developers Conference (WWDC) 2011 ran from June 6 to June 10, 2011 in San Francisco.  Steve Jobs introduced IOS 5 at this event. How long did it take to sell out? 10 hours. (

Earlier this year, Google I/O 2011 from May 10 to May 11 also took place in San Francisco, California. The ticket to this developer event sold out in record time, not days, not hours but in minutes : 59 minutes. (

Thus, we know which technology is most attractive to developer.

Saturday, August 20, 2011

HP TouchPad Liquidation

Last night, I read from TechCrunch "HP Issues TouchPad Liquidation Order – Get Yours Now For $100". Wow. Is that's true? I would like get one for $99 and use it for browsing, reading, listening music and watch video. I don't need other apps.

I do some more research. It looks like that price for Canada only.

But for BestBuy in USA, it still $399

Even I cannot click thru the link at, I check the special return policy for HP TouchPad

So I will stop by at BestBuy to check it out. If it's $99, I will buy it.

Saturday, August 13, 2011

Is Free Software Open Source?

No. Some software or applications are free to use but they are not open source. For example, Microsoft Security Essentials is free to use on licensed Microsoft Windows operating system but you can not get the source code. LibreOffice is the power-packed free and open source personal productivity suite for Windows, Macintosh and GNU/Linux. You can download LibreOffice's source code to look at, modify, build and run.

The Open Source Definition:
1. Free Redistribution
2. Source Code
3. Derived Works
4. Integrity of The Author's Source Code
5. No Discrimination Against Persons or Groups
6. No Discrimination Against Fields of Endeavor
7. Distribution of License
8. License Must Not Be Specific to a Product
9. License Must Not Restrict Other Software
10. License Must Be Technology-Neutral

Sunday, July 24, 2011

Disable Mousepad on Dell Inspiron 1545 with Ubuntu 11.04

After upgraded to Ubuntu 11.04, I could not use the command 'sudo modprope psmouse -r' to disable. Executed that command cause my laptop hung.

This discussion "Ubuntu 11.04 with Gnome on Dell 6510: cannot disable touchpad" on offered me a solution. Here, what I did on on my computer:

user@vn-software:~$ xinput list
⎡ Virtual core pointer id=2 [master pointer (3)]
⎜ ↳ Virtual core XTEST pointer id=4 [slave pointer (2)]
⎜ ↳ Logitech USB Receiver id=10 [slave pointer (2)]
⎜ ↳ Logitech USB Receiver id=11 [slave pointer (2)]
⎜ ↳ ImPS/2 ALPS GlidePoint id=13 [slave pointer (2)]
⎣ Virtual core keyboard id=3 [master keyboard (2)]
↳ Virtual core XTEST keyboard id=5 [slave keyboard (3)]
↳ Video Bus id=6 [slave keyboard (3)]
↳ Power Button id=7 [slave keyboard (3)]
↳ Sleep Button id=8 [slave keyboard (3)]
↳ AT Translated Set 2 keyboard id=12 [slave keyboard (3)]
↳ Dell WMI hotkeys id=14 [slave keyboard (3)]
↳ Integrated Webcam id=9 [slave keyboard (3)]

Device ID for my mousepad is 13. Let find out what properties on device 13 are:

user@vn-software:~$ xinput --list-props 13
Device 'ImPS/2 ALPS GlidePoint':
Device Enabled (127): 1
Coordinate Transformation Matrix (129): 1.000000, 0.000000, 0.000000, 0.000000, 1.000000, 0.000000, 0.000000, 0.000000, 1.000000
Device Accel Profile (250): 0
Device Accel Constant Deceleration (251): 1.000000
Device Accel Adaptive Deceleration (252): 1.000000
Device Accel Velocity Scaling (253): 10.000000
Evdev Axis Inversion (254): 0, 0
Evdev Axes Swap (256): 0
Axis Labels (257): "Rel X" (137), "Rel Y" (138)
Button Labels (258): "Button Left" (130), "Button Middle" (131), "Button Right" (132), "Button Wheel Up" (133), "Button Wheel Down" (134), "Button Horiz Wheel Left" (135), "Button Horiz Wheel Right" (136)
Evdev Middle Button Emulation (259): 0
Evdev Middle Button Timeout (260): 50
Evdev Wheel Emulation (261): 0
Evdev Wheel Emulation Axes (262): 0, 0, 4, 5
Evdev Wheel Emulation Inertia (263): 10
Evdev Wheel Emulation Timeout (264): 200
Evdev Wheel Emulation Button (265): 4
Evdev Drag Lock Buttons (266): 0

The Device Enabled property for device #13 (Touchpad) is 127 and it set to 1. Let turned it off.

user@vn-software:~$ xinput set-prop 13 127 0

It worked! I loved it.

So, to enable the touchpad, I will using this command "xinput set-prop 13 127 1" on my computer. Please note: The device ID and device enabled property for the touchpad on your computer may not same as mine. You need to find out yours by using commands 'xinput list' and 'xinput --list-props' as describe above.

Updated Aug. 13, 2011: Make sure you check device number by using command "xinput list" before disable your touchpad. Otherwise, you may disable the wrong device.

Sunday, July 17, 2011

Upgrade to Eclipse Indigo (3.7) from Eclipse Helios (3.6) on Ubuntu 11.04

I'm using Eclipse IDE for Java EE Developers to develop Android applications on Ubuntu Linux 11.04. The latest version Eclipse in Ubuntu Software Center is Galileo (3.5). To install or upgrade new version of Eclipse IDE:
1. Download 64-bit Linux package from Please select the approriate version for your machine: Mac OS, MS Windows, 32-bit, 64-bit.
2. Extract the downloaded zip file: eclipse-jee-indigo-linux-gtk-x86_64.tar.gz
3. Rename Eclipse folder in my home directory to Eclipse-Helios
4. Move the Eclipse folder from Downloads directory to home folder.
5. Re-install ADT Plugin for Eclipse Indigo (3.7)
6. After Eclipse restart, check, and enjoy new version Eclipse

Monday, July 4, 2011

Free Internet Fax

Which one is the best to send free fax from computer using online service without fax machine? I don't like any fax service with monthly fee. I don't like to provide my credit card number for a free trial. I like these below fax services because they are free. So, what is the catch?

Are they reliable and secure? How about the privacy of our faxes?
MyFax Free lets you send a fax for free to over 40 countries. This free faxing service is provided by Protus IP Solutions.
* Please note that existing MyFax® customers cannot use this free Service.
MyFax® is a trademark of j2 Global Communications, Inc. and its affiliates.
Free Fax
Ad on the cover page
Fax 1 document — max 3 pages
Max 2 free faxes per day
Send a Free Fax
No Setup Fee
Free Outbound Faxing
No Credit Card Required
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Free fax cover page, No Ads
3 pages per fax maximum
2 free faxes per day maximum

Friday, June 17, 2011

Free Fast Public DNS

If you experience a slow internet response, your DNS (Domain Name System) may have outage. You can use the follow free fast public DNS below to improve the speed and more security.

Google Public DNS:

* OpenDNS:

Level-Three GTEI Public DNS:

* Norton DNS by Symantec:

* ScrubIT DNS:

DNS Advantage:

* In additon to block the bad sites that are potentially harmful to your computer, OpenDNS, NortonDNS and ScrubIT DNS allow you to set your owm content filtering policy.

Friday, June 10, 2011

Install WordPress 3.1.3 on Ubuntu 11.04

WordPress is web application you can use to create a beautiful blog or website. This is an open source software. You can get it free at . Before you install WordPress on Ubuntu 11.04 (Natty Narwhal), make sure you already install on your Linux machine: Apache, MySQL and PHP (LAMP).

1. Unzip to a specified.

2. Make the virtual path for Apache web server:
sudo gedit /etc/apache2/httpd.conf
add a new line:
Alias /wordpress /home/yourusername/wordpress
restart sudo /etc/init.d/apache2 restart

3. Type on your browser to read some instruction.

4. Create MySQL database and user for WordPress

mysql -u root -p
mysql> use mysql;
mysql> create database wordpress;
mysql> INSERT INTO user (Host,User,Password) VALUES('localhost','wpuser',PASSWORD('wppass'));
mysql> grant all privileges on wordpress.* to wpuser@localhost;
mysql> flush privileges;
mysql> exit;

5. chmod -c 777 -R ~/wordpress

6. Type to install.
If you got this error message: "Error establishing a database connection", make sure user name and password are correct. It took me almost an hour to figure it out. For some reason, my MySQL password for wpuser@localhost is empty instead of a specified password that I set when I create a MySQL user account.

Wednesday, June 1, 2011

Running on Ubuntu 11.04 using Apache 2 web server

1.1 Install the mod_mono packages:
sudo apt-get install libapache2-mod-mono mono-apache-server2

1.2 Install the mono development tools packages:
sudo apt-get install mono-devel (optional)

2. Enable the Apache module:
sudo a2enmod mod_mono_auto

3. Restart Apache: sudo /etc/init.d/apache2 restart

To test your setup, you can create a test page with the following content anywhere that Apache can see (i.e. /var/www/test.aspx)


Saturday, May 14, 2011

Git on Microsoft Windows

For source code control, I used StarTeam and Microsoft Visual SourceSafe. Now, I would like to phase out Microsot Visual SourceSafe to use an Open Source source code control. After some research, I pick Git instead of Subversion SVN. CVS was out-of-date. Many well known companies, orgranizations using Git. I would like to put a Git repository on Microsoft Windows Server that can access by Git client on Windows and Ubuntu. How?

Setting Up Git Repository on Remote Windows Server?

Hosting Git Repository in Windows

An Illustrated Guide to Git on Windows

What is the Best Git GUI (Client) for Windows?

Git For Windows Developers – Git Series – Part 1

Hosting a Git server under IIS7 on Windows


Setting up a Msysgit Server with copSSH on Windows

Setting up a Git server with Windows Server 2008

Everyday GIT With 20 Commands Or So:

Develop with Git on a Google Code Project

git vs Subversion - pros and cons

Svn vs Git

Pro Git professional version control

Wednesday, May 4, 2011

How to install thinkorswim Software in Ubuntu 11.04

1. Make sure you have Sun Java Runtime Environment (JRE) or Sun Java Development Kit installed on your machine. If not, using Ubuntu Software Center, search for sun java, to install sun-java6-jre or sun-java6-jdk
2. Download
3. Change the to execute mode
4. Install to your home folder /home/username/opt/thinkTDA

Monday, April 25, 2011

Getting Start with Android

Repost from old blog (Nov. 5, 2009) with some updates.

On the eve of the launch of Motorola Droid by Verizon Wireless, I started working on Android. I picked Android because its huge potential market. Second, I can utilized my current tools to develop mobile apps without spending more money. With this current economy, I need to save for the rainning days. I can use my existing Windows system to develop an Android app. On the other hand, I need to spend thousand dollar more to purchase a MacBook for iPhone development.

System Requirements ( need to install in order
1. First thing first, download and install JavaTM Platform, Standard Edition Development Kit (JDKTM) if it's not exist in your system. For Ubuntu Linux, using Ubuntu Software Center to install and configure Sun Java(TM) Development Kit 6 sun-java6-jdk package.
2. Download and extract Eclipse IDE for Java EE Developers to your root (C:\) in Microsoft Windows or your home folder in Linux. For Ubuntu Linux, the current version in Software Center is not up to date and you may forgot to install other required development plug-ins like eclipse-pde, eclipse-jdt in addition to Eclipse Integrated Development Environment, so just download the latest version from site and extract to your home folder.
3. Download and extract Android SDK to your root (C:\) in Microsoft Windows or your home folder in Linux.
For Microsoft Windows, update system variables path=%path%;C:\android-sdk-windows\tools if necessary according to
4. Download and configure ADT Plugin for Eclipse per instructions at
5. Adding SDK Components

Finally, working with the first simple sample project: "Hello, World"

Sunday, April 17, 2011

Compare 3G, 4G,Wi-Fi, WiMAX, and Ethernet (Wired)

Summary from Wikipedia and other places in internet:

3G is a generation of standards for mobile phones and mobile telecommunications services fulfilling specifications by the International Telecommunication Union. Application services include wide-area wireless voice telephone, mobile Internet access, video calls and mobile TV, all in a mobile environment.

4G is the fourth generation of cellular wireless standards. It is a successor to 3G and 2G families of standards. A 4G system is expected to provide a comprehensive and secure all-IP based solution where facilities such as ultra-broadband (giga-bit speed such as 1000+ MiB/s) Internet access, IP telephony, gaming services, and streamed multimedia may be provided to users.

Wi-Fi is a trademark of the Wi-Fi Alliance. It is not a technical term. However, the Alliance has generally enforced its use to describe only a narrow range of connectivity technologies including wireless local area network (WLAN) based on the IEEE 802.11 standards, device to device connectivity.

WiMAX (Worldwide Interoperability for Microwave Access) is a telecommunications protocol that provides fixed and fully mobile Internet access. The current WiMAX revision provides up to 40 Mbit/s with the IEEE 802.16m update expected to offer up to 1 Gbit/s fixed speeds.

Ethernet is a family of frame-based computer networking technologies for local area networks (LANs).  Ethernet is standardized as IEEE 802.3. The combination of the twisted pair versions of Ethernet for connecting end systems to the network, along with the fiber optic versions for site backbones, is the most widespread wired LAN technology. It has been used from around 1980 to the present.

Data transfer rates in order from low to high speed:

  • 3G:  128Kbps to 384Kbps
  • 10BASE-T Ethernet (Wired) 802.3: 10Mbps
  • Wi-Fi 802.11b: 11MBps (Max)
  • Wi-Fi 802.11g: 54MBps (Max)
  • 100BASE-T Fast Ethernet (Wired) 802.3u: 100 Mbps
  • Wi-Fi 802.11n: 300MBps  (Max)
  • 4G: 100Mbps (mobile) to 1GBps (fixed)
  • WiMax 802.16m: 40Mbps to 1Gbps
  • 1000BASE-T Fast Ethernet (Wired) 802.3: 1GBps

4G and Wi-Fi have almost the same bandwidth. The difference between them is in range. Wi-Fi is targeted to cover low range networks, while 4G was designed to replace high range mobile networks.

Sunday, March 27, 2011

Git vs Subversion (SVN)

Git and Subversion (SVN) are free and open source version control software. I'm planning to replace Microsoft Visual SourceSafe in Microsoft Windows system. I need a modern open source version control system can use in both platform Linux and Microsoft Windows.

Which one is better?

Tuesday, March 1, 2011

Hello World!

This is my first post at I'm trying to import my blog in BlogML format to Blogspot unsuccessful. I got this error message "Sorry, the import failed due to a server error. The error code is bX-3zfghs". How do I fix this?

Update: Work around by import it to WordPress see