Started Reviewing Liferay Beginners Guide By Packt publication

Since last one year, i am working with liferay projects. I was looking for some good startup book on liferay. There are lots of companies are moving towards Liferay. And at developer stand, it is really good to learn liferay. According to me why i like liferay, as such some of the built in tool are stable and good. and allmost with all of the java library and other library like php, .net, there is integration possible. So as a developer you are limitless to provide integration support for your application.

In Book Liferay Beginners Guide, at the first look found that contents are well arranged, it contains little theory first and then example. So if person follows complete book.  He can learn liferay easily. I appreciate efforts by Cignex Datamatics Team. Good efforts.

Good content in Book

•  For starting, learning and setting up liferay this book is the first choice.
• Contains enough examples and exercises(Time for action contents)
• In built portlet knowledge.
• Contains initial setup and requirements related information.

Lackings:

• No development information, how to develop portalet with liferay.
• Integration support is not added.
• Liferay 6.1 is on a way, and as such it is paper print, so no information within book. And for older release also no information.
• I may expect advance version of the book.

I will add more summary and reviews for the book in between of reading and completing reading book.

Create/Edit iso image in linux

It’s rather trivial task to make some changes into already burned installation or live CD. It may be performed to add some files to this CD or edit files on it. In any case it’s impossible to loop mount .iso file and then save it as iso9660 filesystem is read-only.

So, just mount your CD or iso image to some directory by commands:

sudo mkdir /mnt/image
sudo mount /dev/cdrom /mnt/image


or


sudo mount /path/to/your.iso /mnt/image -o loop

then copy it’s contents to some directory:

mkdir /tmp/newiso
cp -r /mnt/image /tmp/newiso


After this you can modify any files in /tmp/newiso, add files, delete them. After modifications are done, create new ISO image to be burned onto CD (or kept somewhere for a rainy day):

cd /tmp/newiso

and

sudo mkisofs -o /tmp/new.iso -b isolinux/isolinux.bin -c isolinux/boot.cat -no-emul-boot -boot-load-size 4 -boot-info-table -J -R -V “new iso name” .

After mkisofs is finished new ISO file will be created at /tmp directory.

Tomcat Change Default Web Application

Today i came to know how to set default webapplication. I mean that when you install tomcat in your system. When you open your-machine-ip:8080 then tomcat application is displayed but to configure your application on first page is really easy.

It is actually loading root application which comes with your tomcat free.

Just add following in your tomcat-dir/conf/server.xml

Search for host tag and put following lines in between.(search <host )

……
<Context path=”" docBase=”iview” debug=”0″ reloadable=”true”>
</Context>
………….

Now one more thing new tomcat(above v5.x) is preserving session between tomcat restart but to stop that you can change tomat-dir/conf/context.xml and un-comment following tag.

<Manager pathname=”" />

You can also change default port for your tomcat. Just change port attribute value to your custome port number in connector tag in server.xml. And you are done.

Apache Linux Tomcat configuration

Sharing here link only and not real content. Some times i am having problem to configure tomcat and apache. Each time i need to google but today i thought to put link for it.

HOWTO : Installing Web Services with

Linux / Tomcat / Apache / Struts / Postgresql / OpenSSL / JDBC / JNDI / DBCP

Apache 2.x + Tomcat 4.x + Load Balancing Tutor

About OS install on USB pen Drive

After long time i am back with the Operating System on USB or pen drive. See i am not forcing you to install the linux on pen drive. But some times it is very helpful to you to have Any OS handy on your hand. Just put your usb in any machine and your likely OS is ready to use.

Today let me instroduce one software which works with both linux and windows to install iso to your pendrive. Really very nice tool and very user friendly also. I am looking for such tool from long time. One more thing this is open source.

http://unetbootin.sourceforge.net/

UNetbootin allows you to create bootable Live USB drives for a variety of Linux distributions from Windows or Linux, without requiring you to burn a CD. You can either let it download one of the many distributions supported out-of-the-box for you, or supply your own Linux .iso file if you’ve already downloaded one or your preferred distribution isn’t on the list.

And one more thing i am currently studying debian OS named Backtrack 4, which includes tool for hacking. If you are interested get it from the net and work with again USB and enjoy Hacking and not cracking. and know your network activity.

–Narendra Shah.

About Linux (fedora) usb install

This time i am being late to put blog. Today i am came with the concept that install linux on pen drive. 

Now the question stays that why to install linux on usb pen drive ?

I have seen many people who dont want to experiment new OS on their laptop/computer harddisk. because generally afraid of hard disk failure.  And that is one reason that linux is not used. 

Some users think it is difficult to install linux on haddisk ….. multi boot and removal problem and many more, so not play with it. Frankly speaking I am also with them. 

Now days USB cost very low approximately 2GB @ Rs 250 / $4 and 8 GB @ Rs 750 / $6 with good brand name. It is better to use any of them other then using your own hard disk.

Now let me come to the point. I found very easy way to install fedora linux on usb drives.  Not to say more about fedora. It is very nice OS and used by many people. I also like it. 

To intall you just need to download liveusb-creator which is compatible with windows(8.9MB) and linux(183kb).

https://fedorahosted.org/liveusb-creator/wiki

Get it from the site and follow the step given by him. and your Fedora Linux is ready. And you can use it when ever you like on your laptop / computer, without any problem. 

Come out of that costly Windows and have one look over how is linux ? And then decide which one is better. 

I hope you will try it now. 

Verify your java script

When we design Java script, we are missing many things. So now onwards if you want to check your java script code then test it in the following URL.

You just need to copy your java script function and click on JSLint. It shows possible error.

http://www.jslint.com/

More info. about it is in below given link.

http://www.jslint.com/lint.html

Stop stealing your laptop

According to various surveys, 90% of laptops in India are stolen during travel. Worldwide, a laptop gets stolen every 12 seconds. These figures are obviously alarming, and will only go up as laptop sales increase. But then the good thing is that the IT industry doesn’t leave any opportunity unexplored…so enter solutions that track stolen laptops. They provide a small ray of hope to those unfortunate souls who’ve lost their laptops. Some more good news is that if something is launched in the commercial world today, the Open Source world doesn’t sit quietly for long either. So, there are both commercial and Open Source solutions to track stolen laptops, and Adeona is one such Open Source solution. It enables you to map out your stolen laptop. All you need to do is install this software on your laptop, and if your laptop gets stolen, wait for the thief to connect it to Internet. The software continuously monitors current the location of the laptop and sends updates to the Adeona server. These updates contain information such as, IP address of the laptop, nearby routers and name of the Wireless AP (if connected through a wireless connection). It uses OpenDHT storage service to store locations of your laptop sent by Adeona client. The laptop owner can retrieve an update from the last IP and contact the appropriate law enforcement agency with the details.How to use?
Installing Adeona is easy. During installation it will ask for a password. Remember this password carefully as it will be required when you try to retrieve position of your laptop. Once installed Adeona will automatically start a background service. By default, the client sends update at randomly defined time, -usually an update every 30 mins. As the installation finishes it places an ‘.ost’ file on the desktop. This is the file you will need, to determine the location of your laptop. It’s recommended to backup up this file at a secure location away from your laptop, like on a CD or you can just email it to yourself.

Update results retrieved from Adeona server. Here it shows internal as well as external IP address of the laptop and name of the AP. It also shows details of nearby routers.

Now to determine the location of the laptop, you would need to run Adeona recovery tools. These tools are by default installed with the client, and can also be installed separately. Once you run this tool, it will ask for the ‘.ost’ and password for the file. If authentication is successful, it will now connect to its server and try to retrieve the last IP address from which Adeona client had sent the update. Once it has retrieved the details, it will automatically save them on the desktop in a text file format. This will include the last IP address and names of nearby routers if available.

Cache Memory

Every one which is from IT industry is some how knows about Cache Memory. Then also let me introduce about it with little bit different way as explained in HOWSTUFFWORKS, it is some how related librarirain meance non technical.

E.g In any library(not online), there is person with post Librarian(i.e CPU, Harddisk etc.).His job is to issue and take back books(data digital data). What he will do when ever any user comes, he goes to libarary store room take the book required by user and issue him. When some other user comes for submitting book, he will put that book back to library. Think about the time required by libararian to put and take book from Library.

As such he knows that every one is generally coming for requirement of very known book, why he will go to store and come back. Rather when any use submit book then he will put that in the Rack(CACHE) itself. If any one comes to take book he will return that book from the Rack itself. This is very popular solution which generally many libararian are following.

Now coming to our computer world, with coming of Dual core and Core 2 Duo processor, they do have cache which will store frequently used operation in the cache. and it will make that processor being faster than any other CPU which do have higher clock rate. and Performance hikes. Now intel is thinking only for cache to increase speed of his CPU. So he is now ahead of AMD. AMD do have processor which are much more faster in clock speed then also, Intel chip will give more performance because he have cache. And now intel wins.

When you think about writing cache for your application then you will get the performance difference of your own application.

Let me show you how? In many application we do have databases, why dont we cache the connection in connection pool. Why dont we design a cache architecture which will store frequently used database operation will be on database as well as on cache also. When you write in frequently used table then write it in cache and database both. So when ever any operation requested by your application from table it will return from Cache itself and not from table. So decrease I/O read from Harddisk.

Same is true for file operation also.

There are some thing before incorporating cache with your application like if you have good RAM then your application goes faster. But if it is not then it is not good to use it.

Inside iPhone SDK

Here is the detail insight on iPhone SDK

http://arstechnica.com/articles/culture/iPhone-SDK.ars

Enjoy !!!