Thursday, November 27, 2014

Resize video with Avidemux

Avidemux, a video editing tool is an open source software or GPL v2 licensed, and can be downloaded from for Linux, Mac OS and MS Windows. Currently I am using version is 2.6.8 on MS Windows 8.

Found a good reference Compressing with Avidemux by Bo be.

Need to try this out soon to prepare videos to be shared online (outside of youtube).

Points to note
General file size = bitrate * running time

Thursday, November 13, 2014

Howto set Default Account in Thunderbird

Mozilla Thunderbird is a widely used Email client that is fast, friendly and can be extended with many plug-ins available for Linux, OS X and MS Windows platform. Licensed with Mozilla Public License 2.0 it is an open source software (OSS) with an active list of developers. The current version being 31 and more information can be found at Mozilla website.
Mozilla Thunderbird

Many email accounts can be created within this email client and this makes it easy to see all emails from one screen. Emails can be composed by opening the Thunderbird email client or via links that user clicks to activate the email composer. In order improve efficiency, one of the accounts can be assigned as the default email account and this is normally indicated in bold. This allows all new emails to use this account and users do not need to choose the account. I have listed the steps tested for Thunderbird version 24 and 31 where the example shows account2 in bold as the default account and we want to switch the default to account1.

Step 1: Open Thunderbird account's setting.

Start Thunderbird and from its menu bar at the top (default), choose Tools ->Account Settings...
Identify the default account that is used to send out emails. This is in bold, for example "account2"

Step 2: Set the default account

Choose the account to be used as the default. In this case, its "account1". At bottom of the window, click Account Actions. Choose "Set as Default".

Click OK, notice that this email account will go to the top of the list and is in bold font. Ensure all email screens are closed and restart Thunderbird.

Thursday, October 9, 2014

Managing Firefox Sidetab

In the recent upgrade to Firefox version, the sidetab bar appeared when using the Delicious bookmarks addon. Steps shown are for disabling and enabling display of the sidebar.

So whats a sidebar? Its just displays and application/addon in a column next to the web pages being viewed. Delicious and Facebook are example of addon that uses Sidebars.

Disable the sidebar

Step 1. Disable sidebar
At the top of the sidebar, click on the gear.
Uncheck the "Show sidebar".

Enable sidebar
Step 1. Add Sidebar item to the Firefox menu.
Click on the Firefox menu, choose "Customize"
In the Additional Tools and Features window, drag "Sidebars" icon to the menu. Click "Exit Customize"

Step 2. Turn on Sidebar.
Click on Firefox menu, choose Sidebars.

Click on the Application available for Sidebars. In this case its the Delicious bookmarks.


Monday, September 29, 2014

Presenting ideas with Mind Map

Was on the internet today and saw a long time software, Freemind. How I miss working with Mind Map.

Mind mapping was traditionally used on sheets of paper or mahjong paper to present ideas and later it was also used for teams to work together to build an idea together. The mind mapping technique I learnt was something made popular by Tony Buzan, UK. Looks like branches from a tree, but from what I have also learnt, mind mapping was around long before Buzan and appears in many forms to pictorially describe an idea. Officially, I learnt a great deal of mind mapping during the courses at SMR.

Many of the mind mapping software subscribes to Buzan way of doing things. There are 2 software that is open source software; (1) Freemind is a Java Technology based mind mapping tool that allowed users to use data interchangeably on Linux and MS Windows. (2) XMind is considered one of the more popular tool in the Internet, but it didn't really stick with me. Note taking tools such as Evernote provided even more flexibility for mind mappers as it is integrated with XMind.

Saw good reviews on Mindomo, why not try it, as its advantage is that it is available on MS Windows, Mac and Android. That is if you don't mind installing Adobe Air.

Today, there is even a mind mapping tool built into Chrome web browser.


It saves the mindmap in Google Drive and I can access it pretty much any where.

Serious exploits in August and Sept 2014

These recent months have shown how the open source software model could handle (or is still handling) bugs that could be turned into an exploit of Linux servers. These are;

Shellshock (Sept 2014) - remotely take over a server.

Heartbleed (April 2014) - OpenSSL data could be intercepted.

The sheer number of Linux servers affected means that it is a serious threat and is wide spread. In Heartbleed, its patched but Shellshock is yet to have a patch to fully resolve the bug.

Interesting technical discussion on Shellshock is found at stackexchange.

How do you know if your shell is vulnerable? Hackernews recommends to run the following command in all the shell being used;

env X="() { :;} ; echo shellshock" /bin/sh -c "echo completed"
env X="() { :;} ; echo shellshock" `which bash` -c "echo completed"

If you see the text output "shellshock", please find a patch.

Chris, a contributor at Buzzfeed News, provided a good material on how 2 persons maintained the OpenSSL package, Steve Marquess and Stephen Henson. The commercial entity for this is known as OpenSSL Software Foundation.

Now doesn't it make you wonder who is responsible of bash shell and is it the same package for every Linux distro?

Tuesday, September 9, 2014

What is FTP?

FTP or File Transfer Protocol
"... is a standard network protocol used to transfer computer files from one host to another host over a TCP-based network, such as the Internet. FTP is built on a client-server architecture and uses separate control and data connections between the client and the server."

One reason why this is being replaced by other network protocol is in its exposure of the user password in plain text for a traditional FTP server. SSH and encrypted FTP sessions have replaced almost all new implementations these days.

Which ports are used by this service?
Standard ports used are port 20 (data) and 21 (command) but this may change depending on the server's settings. On the client FTP site, free standard ports higher than number 1023  is used.

This service by the FTP Server can provide active or passive connection and sometimes both. A simplified explanation in entitled "Active FTP vs. Passive FTP, a Definitive Explanation" is a good read.

Typically, on the FTP server in Passive mode will require connection to several higher standard ports and this allows larger number of connections. In Active mode, limitation on the server is to how many connections can be done over that one port 20.

How to determine if its in Passive more?
After login to FTP server, type
quote PASV

How to establish connection to an FTP server?
Use an FTP client and enter the FTP server's URL. E.g. on Linux, to connect to the FTP server



Friday, September 5, 2014

Microsoft's Windows Defender

It was time to uninstall the McAfee antivirus that came pre-installed with the Windows 8 laptop. Just by doing that I noticed that the bubble appear to say that I am no longer protected and to click it. This is when Windows Defender application started, which makes me wonder if its good enough to replace the previous antivirus.

Doing an update to virus and spyware definition version 1.183.1668.0 on 5th Sept 2014. Will continue to run this with Basic membership setting where this means almost anything could be sent to Microsoft.

Tuesday, August 26, 2014

Quick start to Mozilla Firefox OS 1.x

For those of you who were looking for a new smart phone, it might be good to also look at Firefox OS. This is being developed by Mozilla and will be a game changer.

Quick notes:

  1. Initially known as B2G (Boot to Gecko) in the Mozilla Project and initially demonstrated in 2012
  2. Has a Linux based operating system
  3. Target for smart phones, tablets and smart TV.
  4. Among the first adopter was ZTE Open phone
  5. Its has 4 software layers. I.e. Gonk (Linux kernel), Gecko (application services), XUL Runner (Application run-time) and Gaia (User interface system)
  6. Supports HTML5
  7. Website at
  8. Apps can be found at the Firefox marketplace.
Current development is at Firefox OS 1.3 (Stable) and Firefox OS 2.1 (Unstable)  and you can try it out via a simulator.

Following are steps to install and run a simulator:
Requirements: Firefox version 30+

Step 1. Install the simulator.

Open Mozilla Firefox web browser and access "App Manager add-ons" by typing in the URL

Click "Install Firefox OS 1.3 Simulator (Stable)" or which ever version pleases you.

When the Pop-up appears, Click "Allow" then wait till the download starts (There isn't any indicator onscreen) and when the Software Installation box appears, click "Install Now".

Click "Firefox OS 1.3 Simulator has been installed successfully."

Step 2:  Check installation

To determine if its installed, open Mozilla Firefox web browser and enter URL as

You should see "Firefox OS 1.3 Simulator ...."

Step 3: Start up the App Manager

In Mozilla Firefox web browser enter URL as

At bottom of the  App Manager click "Start Simulator"
The Firefox OS Simulator will appear as a new Firefox Window. now have access to the latest Smartphone OS.