A cell

Compile C programs in Ubuntu Linux using GCC

2015-12-03T08:09:00.000+00:00

If you would like to compile your first C program on an Ubuntu Linux, it might not work out of the box. Needless to say, I was disappointed.

Versions I have:

GCC gcc version 4.8.4 (Ubuntu 4.8.4-2ubuntu1~14.04)

Ubuntu 14.04

To solve this, all you need to do is install "build-essential"

sudo apt-get install build-essential

Then you should be able to compile your code using gcc, (for example):

gcc bruteforce1.c -o bruteforce1 -std=c99

And of course, you will run the executable created:

./bruteforce1

Seems simple now, but I wish some things should work out of the box.

Does idle mode need relations?

2013-11-11T14:04:00.003+00:00

Short Answer: No. Since the mobile device is not connected, there is no need to handover.

Do I need an IRAT relation for CSFB

2013-11-10T23:23:00.002+00:00

Short answer: No. There is no need for a handover relation to exist if you want to do circuit switched fallback in LTE.

How to convert an XML file to DOM in Java

2013-07-28T15:18:00.000+01:00

Create a org.w3c.dom.Document reference to the xml file, using this method:

public static Document filepathToDocument(final String filepath){

Document doc = null;

File file = new File(filepath);

DocumentBuilderFactory dbFactory = DocumentBuilderFactory.newInstance();

DocumentBuilder dBuilder;

try {

dBuilder = dbFactory.newDocumentBuilder();

doc = dBuilder.parse(file);

} catch (ParserConfigurationException | SAXException | IOException e) {

e.printStackTrace();

}

return doc;

}

Then, you can pretty much do anything like use XPath to navigate or simply get the list of Nodes:

XPath xPath = XPathFactory.newInstance().newXPath();

NodeList nodeList = (NodeList) xPath.compile("//"+elemName).evaluate(doc, XPathConstants.NODESET);

// or

NodeList nodeList = doc.getElementsByTagName(elemName);

// see www.w3schools.com to learn how to write xpath syntax.

How much is one degree latitude in kilometers

2013-07-26T20:11:00.001+01:00

111.189 kilometers
Distance between the poles (20,014 kms) divided by 180 degrees.

What is a Tracking Area in LTE?

2013-01-06T12:24:00.001+00:00

Tracking area is a large area defined by the cellphone operator (say, Vodafone) to keep track of where approximately each phone is.

Imagine that the battery on your phone drained out and the phone switches off. You charged it and just turned it on. It is in the interest of Vodafone to know where are you in case someone wants to call you. Where should the operator look for you? Your town, your county/state, or the entire country?

This is an example of where it is nice for Vodafone to remember where you were before your phone switched off. This way, they don't have to look for you in the entire country.

You can be sneaky and turn off your phone, travel the length of your country and then turn on your phone at the other end :) In that case, Vodafone does not find you in your last known Tracking Area, and has to look in the entire country to find your new location.

What are PDPs?

2012-11-30T14:12:00.001+00:00

PDP in telecom stands for Packet Data Protocol. Wikipedia has a nice entry for it.
http://en.wikipedia.org/wiki/Packet_Data_Protocol#PDP_Context

But what if someone uses PDP with a number; like, "Vodafone has an average of 1 million PDPs"? What they actually mean is 1 million PDP contexts; or in simple words: 1 million devices accessing data.

How to open Iomega LPHD-UP3

2012-11-25T01:45:00.001+00:00

I learnt it the hard way, damaging the casing. You don't have to repeat my mistakes.

Open the outside 2 screws with a Philips screwdriver
The black outside plastic cover should come off easily
Next a silver metal plate should come off easily as well
Holding the outside metal body in one hand, push the black inner plastic away (along the length of the hard drive enclosure
The inner plastic holding should slide out of the other end of the enclosure, and you're done!

Mobile networks user experience - Vodafone Germany

2012-10-16T11:59:00.001+01:00

I have travelled to most major cities in Europe and US, and hands down Vodafone in Germany has been my best experience for mobile data access. For example, if you buy a 1GB data bundle valid for a month, you do get fast speeds, and if you end up using all of the 1GB before the month is over, you won't be left without internet access. They will gracefully degrade your service to 64kbps. Happy days!

2004 Mercedes Benz E200K W211 Atuomatic Elegance Problems

2012-10-10T23:40:00.001+01:00

I drive a 2004 Mercedes Benz E200K W211 Atuomatic Elegance. Nice car (everyone knows), but not without problems. Let me list them here:

(Sometimes) the remote central locking does not lock the driver side door (worn out spring?). [Updt 30/Nov/2012]Ordered the 'lock repair kit' from eBay. [Updt: 29/Dec/2012] Repair kit solution installed today, and now the car is fault-free!
While driving, there is an absolutely tiny little squeak that comes from the rear passenger overhead lights
Oh, and one of the gaskets on the engine has to be replaced. I sensed the problem before it did major damage. There was loss of power when you try to speed up after slowing down. Also, you could hear some knocking sounds at sub 1000 rpm. [Updt: 11/Oct/2012]: The garage informed me that it was a problem of faulty workmanship by the previous garage (who forgot to put in a gasket!). Now I have observable increase of power :)
A major repair at 159,000 Kms: replaced timing chain and tensioners. (Oil and oil filter changed while at it).
The Air Flow Meter (Sensor) needed cleaning/replacement. Ordered 2nd hand which works perfectly :)
[Updt: 07/Mar/2013] Front coil spring on the driver-side (right) broke. Could have been dangerous if it had happened all of a sudden in traffic.
[Updt: 07/Oct/2013] The in-tank fuel pump failed.

Tyre size description 225/55 R16 95V

2012-08-28T19:13:00.000+01:00

How to read this size:
225mm width of the tyre
55 is % of height to width ratio [height of tyre from the rim to tread]
R is for Radial
16 inches is the diameter of the rim of the wheel
95 is the load bearing capacity 690 Kg
V is for max speed 149 mph

Galaxy Note GT-N7000 firmware update Aug 2012

2012-08-09T10:14:00.001+01:00

I received an update this morning (though Kies) for the Galaxy Note:
PDA:LR6 / PHONE:LR1 / CSC:LR2 (INU)

Updt 22 Aug: This version of firmware has remarkably improved the battery life of the Note. I went 5 days without plugging in, and the battery went from 100% to 35%. The following parameters should be considered:

I don't have a Task Killer
wifi, data traffic, bluetooth and GPS are switched off most of the time
I did not turn on power-saver mode
total voice-calls were less than 20 minutes
very light overall usage (that means screen was mostly off)

Nevertheless, this improvement is astounding.
Pressing *#1234# on the keypad gives me:

Java Applet Security Issue - java.io.FilePermission

2012-08-08T10:14:00.002+01:00

A while ago I ran into this issue where an applet was used to upload files.

Security manager class: sun.plugin2.applet.AWTAppletSecurityManager

Exception in thread "Thread-45" java.security.AccessControlException: access denied (java.io.FilePermission ...)

The solution is to create a .java.policy file and explicitly give the applet permissions to access your file system.
Path in Windows Vista: C:\Users\<username>\.java.policy

grant {
permission java.security.AllPermission;
permission java.io.FilePermission "file://C:/Users/username/Documents/special/*", "read, write";
};

Here, you will need to replace the path to something of your choice.

Cheapest New Car in Ireland 2012

2012-07-24T23:15:00.001+01:00

A Renault Twizy is the cheapest car (?) in Ireland at the moment. It is a 2-seater electric vehical. The cheapest version costs 7,800 EUR.

The Skoda Citigo is a proper fossil-fuel burning, 4-seater car. The cheapest version costs 9,995 EUR.

Updt Aug 2012: The Seat Mii priced at 9,895 EUR will beat the Citigo.

DOS sleep command for batch files

2012-07-20T10:15:00.002+01:00

If you have windows Vista or later installed, you can use use the 'timeout' command instead of the old sleep command.

Wireless cable TV (Sky) using a Dreambox

2012-07-09T00:38:00.002+01:00

Objective
How to avoid buying a TV :)

Background
My wife wanted a 2nd TV installed in the bedroom since the house is wired for multi-view Sky cable TV. But I did not want to spend money buying a 2nd TV, given that I have 3 laptops and a desktop in the house.

I began with searching a way to convert SCART to SVGA, but found no convincing solution on the web. There are boxes made in China available on ebay for 40 USD, but I did not want to risk a loss of $40 if their video did not match up with the 16:9 LCD monitor.

So the techie in me started thinking of a zero-cost solution.

Apparatus

Dreambox ($60, I knew about a spare DM500-S lying around at a friend's)
Wireless router ($25, I had a free router lying around)
Ethernet wire (I had a 2 of these as well)
Windows computer (may work on Linux as well, but I have not tried it)

Procedure

Plug in the feeder cable to the Dreambox.
Connect the ethernet cable from the router to the Dreambox
Install VLC media player version 0.8.6i on your computer. If you have a different version of VLC media player installed, uninstall that first. Choose the advanced install option and make sure that you check the activeX checkbox.
Find out the IP address that the router has allocated to the Dreambox.
Next, open IE on the computer and type in the IP address of the Dreambox. There is a webserver running there. It will ask for a username and a password. The defaults are 'root/dreambox'.
Now you should see the admin console. Click on 'Providers' and choose an open channel. Check that the vpid and apid entries above the list of channels is not 'null'.
Click on x-webview link. A new window should launch and the video and audio should stream to the vlc activeX content of the window.

Notes

If you need help through any of these steps, try to google the issue, and if you are still stuck, ask a question though comments.

How to Run a Java application as a Windows Service or a UNIX Daemon

2012-03-20T11:34:00.000+00:00

There is a wrapper by Tanuki Software, that allows you to run any Java application (including servers like Jboss/Tomcat) as a windows service or a Unix daemon.

This is pretty cool if...

you have applications that depend on other services to be stopped and started in conjunction
you like a single place from where you can control all your services

Where is my android market?

2012-03-20T10:29:00.002+00:00

Recently, I lost the android market on my phone. This was quite an unpleasant moment and I spent half an hour looking of what the hell happened. It turns out that the market was still there, but now called 'Google Play'. They even gave a new icon to the Market app.
Bad move Google! I am sure that there were other users who were confused how they 'lost' the market app.
The transition should have taken place in 2 phases. Change the name, then the icon, or the other way round.

Anyway, duly noted, Android Market is now called Google Play.

How to find out the version of Jboss

2012-03-14T13:43:00.000+00:00

Open jboss/jar-versions.xml in an editor
Look for jboss.jar
the implVersion attribute gives you the Jboss version.

My favourite Java Decompiler

2012-03-07T13:50:00.000+00:00

For years I have used frontend plus with JAD to decompile class files. But since it is not a supported product since circa 2001, i decided to move on.
I found this http://java.decompiler.free.fr/ to be a free software that does the job to a good standard.
Comes in 2 variations: stand-alone (no installation necessary) and as an Eclipse plug-in.

Thanks to Canadian Mind Products for the recommendation.

App42 Cloud API

2012-03-07T11:00:00.000+00:00

If you ever thought of using the cloud for your apps, go ahead give these guys a try apps.shephertz.com. This is lighter than cloudfoundry.com.

To each, his own
Case 1: If I have a project like a mobile app that pulls data from your central source. I do not need a full server. I just need a data source that is reliable (up-time and speed). For such a situation, I should go to Shephertz.

Case2: If I need a full-blown web-server that I can tune and configure, that hosts multiple apps that talk to other parts of the Internet, then I would prefer Cloudfoundry.

How to type in Hindi with an English keyboard

2012-02-28T18:24:00.002+00:00

Microsoft Indic Language Input Tool

Samsung Galaxy Note Review - N7000

2012-02-21T19:31:00.006+00:00

I've moved from an HTC Desire S to this phone. Here are some finer points that you will not see on regular reviews (gsmarena).

After upgrading to Android 4.0 (ICS), I found that the battery drains at almost twice the speed. So, what I will do is try the 2 tips mentioned on this page:
http://androidforums.com/samsung-galaxy-s2-international/540699-android-os-battery-drain-since-ics-upgrade.html

Pros:

Huge screen: makes excellent web browsing in landscape mode
Music player: access it even when the screen is locked ;)
Good quality headphones, with volume control and play/pause buttons
Ability to decline an incoming call with a text message like, "I'll call you later"
An excellent radio interface

Cons:

The Note UI can learn from HTC's Sense, which I find very user friendly!
Sometimes the tip of the S-pen can become statically-charged, and then the screen starts responding if the pen's tip is near the screen (not actually touching). This can be fun and annoying at the same time.
I have a front screen cover integrated with the back panel (manufactured by Samsung). Some of the locking bits of the back panel come off once every few days and have to be pushed back in to click into place.
One shortcoming that (I suppose) is common to all smartphones web-browsers, is that if a webpage has a sliding control, you press your finger (or stylus) on that control and try to move it, the browser starts scrolling the page. This makes the sliding-control unusable.

(image courtesy: www.carzone.ie)

2012-02-06T23:51:00.000+00:00

About memory profiling in Java... First, use the tool jvisualvm that ships with Java SE to connect to your local vm.

For remote VMs, see here

To analyse memory, you will need to generate hprof memory dump files.
I am using Java 1.5.0_14, therefore I do not have the tools available in Java 6 and 7 that allow you generate hprof files on-demand.

For local VMs, firststep is to add -XX:+HeapDumpOnOutOfMemoryError as a VM-arg. This means that when your program runs out of memory, a core dump will be generated.

Once you have a hprof file, install MAT (Memory Analysis Tool) in your Eclipse and open the hprof file using MAT perspective.
See their excellent introduction: http://wiki.eclipse.org/index.php/MemoryAnalyzer

SonyEricsson Experia X8

2011-07-29T17:32:00.000+01:00

We just received these new smartphones from our company to replace the deskphones:

Pros:

The thing that captivates is the audio quality.

Cons:

The UI is a bit slow to respond.
And once it goes off to sleep, it gets sleepy and does not wake up easily.

But hey, its free.