My understanding of NoSQL -part1

Start with MongoDB

Ubuntu includes its own MongoDB packages.
Here are the few simple steps I followed to install mongodb on Ubuntu 14.

1. Import the public key : The Ubuntu package management tools (i.e. dpkg and apt) ensure package consistency and authenticity by requiring that distributors sign packages with GPG keys. Issue the following command to import the MongoDB public GPG Key:  sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv 7F0CEB10
2. Reload the local package database: sudo apt-get update
3. Install latest version of mongodb : sudo apt-get install mongodb-org
4. Issue the command to start mongod: sudo service mongod start

This was the basic installation of Mongodb on ubuntu. Will keep on posting as I explore ....

References

1. http://docs.mongodb.org/manual/tutorial/install-mongodb-on-ubuntu/ 

Change your username -UBUNTU

If you want to change your username

Restart in recovery mode and go to the root prompt shell

 ("Drop to root shell prompt")

1. First remount the root
1. mount -o remount,rw /
2.  change the username and home folder name

1. usermod -l <newname> -d /home/<newname> -m <oldname>
   

3. reboot
4. Resume normal boot

Configure IP of CentOS on virtual box

Once you installed CentOS on virtual box and it's not binded with any IP after issuing the command ifconfig.

Troubleshoot by issuing the following commands

ifdown eth0
ifup eth0
yum update

It will solve the problem.

Reference :

http://stackoverflow.com/questions/20816133/pycurl-error-6-couldnt-resolve-host-mirrorlist-centos-org

Troubleshoot- if alt-tab does not switch windows in UBUNTU

If alt-tab is not switching your screen, here is the solution .

• Open the terminal and install compizconfig-settings-manager
• sudo apt-get install compizconfig-settings-manager
• Or search for compizconfig-settings-manager in Software Center and install from there.
• Then go to system tools > preferences > compizconfig
• Go at the very bottom where it says windows management , Put a checkmark in application switcher.

Your problem with window manager is solved !! :)

Reference

http://askubuntu.com/questions/135685/alt-tab-does-not-switch

Install rabbitvcs, SVN client simillar to tortoiseSVN on Windows

If you are a UBUNTU fan and looking for a svn client, rabbitvcs is a solution. Although I faced some issue while trying to install directly from repository, the nautilus was not showing on right click, after some trial, finally I could set up and installed from the source code by following the steps mentioned below

1. sudo apt-get install python-nautilus python-configobj python-gtk2 python-glade2 python-svn python-dbus python-dulwich subversion meld gconf-edit
2. sudo apt-get install python-nautilus python-configobj python-gtk2 python-glade2 python-svn python-dbus python-dulwich subversion meld 
3. wget http://rabbitvcs.googlecode.com/files/rabbitvcs-0.15.2.tar.bz2
4. tar jxvf rabbitvcs-0.15.2.tar.bz2
5. cd rabbitvcs-0.15.2/
6. sudo python setup.py install --install-layout=deb
7. cd clients/nautilus-3.0
8. sudo cp RabbitVCS.py /usr/share/nautilus-python/extensions/

your are done now !!

Cron Job to take a daily backup of Database - Postgres

Cron job are used to schedule commands to be executed periodically. You can setup commands or scripts, which will repeatedly run at a set time.

• To edit your crontab file, type the following command at the UNIX / Linux shell prompt:

         $ crontab -e

• Syntax of crontab (Field Description) 

        Your cron job looks as follows for user jobs:

        1 2 3 4 5 /path/to/command arg1 arg2

        OR

        1 2 3 4 5 /root/backup.sh

        Where,

       1: Minute (0-59)

       2: Hours (0-23)

       3: Day (0-31)

       4: Month (0-12 [12 == December])

       5: Day of the week(0-7 [7 or 0 == sunday])

      /path/to/command - Script or command name to schedule

For  example if you want to take a daily backup of your postgres database you can follow the following steps:

• Make entry for user  USERNAME for database DATABASENAME as following in the file pg_hba.conf

          # "local" is for Unix domain socket connections only

• local   DATABASENAME       USERNAME                                  trust
• * make sure that the user has select permission on the database.

Reload the database.

• Write a script as following  (vi scriptname.sh )

       mkdir PATH/bkp-$(date '+%Y-%m-%d')

       PATH TO POSTGRES/bin/pg_dump  -U USERNAME DBNAME  > PATH FOR BACKUP            FOLDER/$(date '+%Y%m%d')-bkp.sql

• Create a cron job (Take a daily backup at 5 pm)

      crontab -e
     0 17 * * * /PATH TO SCRIPT/scriptname.sh

About Patents search - India

If you want to search the current patents filed in India, you can search using diffrent keywords on the following website

http://ipindiaservices.gov.in/patentsearch/search/index.aspx

It provides an exhaustive list of granted patents, published applications, Application status etc.

For other details you can also check

http://ipindia.nic.in/ipr/patent/patents.htm


Happy Patenting :)

Android on virtual box

If you want to run Android on you PC, you can install Android ISO in Virtual box. Once installed you can use Android enviornment on your machine install apps on it.

You need to install virtualbox first, which can be downloaded from https://www.virtualbox.org/wiki/Linux_Downloads (I tried it for UBUNTU 12.04)

Then download Android x-86 ISO from http://www.android-x86.org/download 

 I have tested it for the following settings

• Operating System: Linux – Linux 2.6
• Memory Size: 512 MB
• Hard Drive Size: 3 GB or More

Here is the snap shot of adding Android on virtual box.

After Installation is complete, reboot it go to devices > CD/DVD Devices remove disk from virtual drive so as to boot normally inplace of getting booted from ISO.

"xournal" an excellent pdf editor for UBUNTU

I was looking for a pdf editor in linux and  found xournal. This is excellent pdf editor and easy to use.
you can install it by command

• sudo apt-get install xournal

After it is installed open the pdf file which you want to edit, after you are done you can also export it into pdf.

My experience - "Member of the panel discussion" at an International Conference

It was two day Conference on 12th-13th June 2013, at Sofitel Hotel, BKC on "The Global high on Cloud summit". It was related to cloud computing and we have recently started a research activity on "Mobile Cloud Computing", so our group head suggested to attend this and get an insight about how the industry is adopting cloud and what issues and challenges are they facing.
On the morning of 13th the session started and I entered into the conference room, looking for a comfortable place to get seated and settled, the moderator of panel discussion had already initiated a panel discussion and this time members were not preplanned, as a Prof of class he started calling up the delegates randomly, my colleague and me were sitting at the last seat, in the age,experience and designation we were the junior most barely having 6+ years of total experience and months of experience in the field of cloud computing, while mostly the CIO's, CTO's, Executive Directors, MD's and all exalted dignitaries that everyone aspire to get added with his name, were present from renowned Industries like IBM, Oracle, Hero Moto Corp, Maruti Suzuki India Ltd, Essar, Sify etc .
Suddenly the moderator asked me to join the panel at the stage "oh No"  I whispered as it used to be in the MBA classes (no not me ;)), but this was not the class, I could not say NO I am not prepared or how can I join with u all luminaries, I had to suppress my nervousness and get up with confidence.
I got seated at the Dias with 5 other panelist the Director New India Insurance,  Executive Director – IT, JM Financial Services Ltd etc etc. Fortunately they did not asked me to initiate the discussion and one of the member started with what challenges are they facing, which are the issues need to be addressed and issues related to continuity, disaster recovery, availability and security while two of them were talking I got some time to prepare my speech, had a deep breath and gear up. As soon as the second guy finished the moderator said "Let us have the privilege to hear something from the lady ".
After my introduction I started with "As you  rightly said about the mobile reaching right up-to the "Paanwala", I would like to continue from there, the mobile has reached to masses but computer has not reached yet, we are looking forward for a solution that can bridge this gap and this is possible with the help of "Mobile Cloud Computing", So the vision is to allow everyone to use their mobile  as if they are using a computer system and the solution should be intelligent enough to identify the kind of device, bandwidth, network connectivity etc and scalable enough to match the capacity of the cloud, dynamically call the services of the cloud on to the mobile and  on the top of that it has to act like a plugin so as to become convenient for the user to install on his device, be it a low end mobile or high end tablets, For example I should be able to access all the features of Microsoft Power point from my mobile/ tablet itself in the way it works on desktop/laptop" . I brought a lot of questions to be answered and was counter argued by the other members as most of them were having their own cloud set up and they were trying to relate with the client server or thin client kind of architecture for mobile, then I had to convince them how different and usable it would be from client server, definitely a market need to be identified for this but every concept has some niche at the beginning.
Don't know what shape this idea is going to take in future but definitely I am happy that I was able to express my self, could remember something which my group head used to discuss and those exhaustive and difficult research paper from Berkley university had left some impression into my mind :)

Data replication with Postgresql and Slony using pgAdmin

1. Slony-I – introduction:

      Slony-I is a "master to multiple slaves" replication system for PostgreSQL supporting cascading        (e.g. - a node can feed another node which feeds another node) and failover.

     The big picture for the development of Slony-I is that it is a master-slave replication system that     includes all features and capabilities needed to replicate large databases to a reasonably limited number   of slave systems. Slony-I is a system designed for use at data centers and backup sites, where the   normal mode of operation is that all nodes are available.

2. Tools: Postgres-9.2, PgAdmin 1.16, slon version 2.0.7 on UBUNTU 12.04
   
3. Database setup
   The data will be replicated from database source ,public schema with table emp_details to to target databse,public schema and emp_details table.
   User is postgres, host=localhost both the database are on the same machine (same host and port)
   
   
4. Replication Process with PgAdmin
   Create to database “source” and “target” .
   Create a schema-only dump of the source database, and load it into target.
   Everything has to be done into the Replication items inside the two newly created databases. The two replication objects need references to each other .

   1- Create base replication objects

For the Master :

• Right click on source > Replication and choose "New Slony-I Cluster"
• Join existing cluster : Do not check this !
• Cluster name : choose a name, here it is : REP_CLUSTER
• Local Node Left : 1
• Local Node Right : master_node
• Admin Node Left : 99
• Admin Node Right : admin_node
• Press OK.
  

For the Slave :

• Right click on target > Replication and choose "New Slony-I Cluster"
• Join existing cluster : Has to be checked
• Server : localhost
• Database : source
• Cluster name : REP_CLUSTER (should be automatically recognized)
• Local Node Left : 10
• Local Node Right : slave_node
• Admin Node : 99 - admin_node
• Press OK.
  

2 – Create path setup

For the Master :

• Right click on master_node Path and choose New path
• Server : 10 - Slave Node
• Connect Info : host=localhost port=5434 user=postgres password= “” dbname=target
• Conn retry : 10
• Press OK.
  

For the Slave :

• Right click on slave_node > Path and choose New path on target
• Server : 1 - master_node
• Connect Info : host=localhost port=5434 user=postgres password=”” dbname=source
• Conn retry : 10
• Press OK.
  

Similarly create path for each node (slave on source and master on target)

3 – Define replication set on source

• In the Db source > REP_CLUSTER create a Replication Sets and choose new Replication Set
• ID : 1
• Comment : Replication Set 1
  

Now we choose the table we want to be replicated from source to target .

• In the Replication Set 1 choose New tables
• Table : Any table of your choice e.g public.details (You will have to select table from the list that you want to replicate.)
• ID : 1
• Index : Auto filled when choosing table. That’s important to have a unique constraint on the table you want to replicate (primary key for instance).
• Comment : a nice comment
• Press OK.
  

4 – Create a new Subscription (screen caps below)

• Source >Replication Set > Subscription and choose New subscription.
• Origin : write “1”
• Provider : Choose “1 - Master Node”
• Receiver : Choose “10 - Slave Node”
• Can forward : Keep it unchecked
• Press OK.
  

Now check path and listen are same in source and target of admin node .If not add master_node (slave_node), slave_node(slave_node) in the target as well .

Start the replication

Go to slon path

/usr/lib/postgresql/9.2/bin bin (or any other location depending on your linux flavour and / or Postgresql installation path). Check that slon is there in the path. This is the slony daemon you will start twice : one for the MASTER(source), the other for the SLAVE (target).

slon syntax :

slon [Options] [ClusterName] [ConnexionInfos]

For the Master :

• ./slon -d 1 REP_CLUSTER "dbname=source user=postgres host=localhost port=5434"
  

For the Slave :

• ./slon -d 1 REP_CLUSTER "dbname=target user=postgres host=localhost port=5434"
  

Refer to the sample output of source and target .

Test the Replication

Add some data in the details table of source database and check whether it is replicated at the target.

Reference:

http://open-bi.blogspot.in/2010/05/data-replication-with-postgresql-and.html

Upgrading pgadmin3 from 1.14 to 1.16

The Ubuntu 12.04 package manager will install pgadmin3 version 1.14 which does not support PostgreSQL 9.2.

Warning:
The server you are connecting to is not a version that is supported by this release of pgAdmin III.
pgAdmin III may not function as expected.
Supported server versions are 8.2 to 9.1.

Remove the current pgAdmin version

sudo apt-get remove pgadmin3

---

Install pgAdmin version 1.16 using a ppa

sudo apt-add-repository ppa:voronov84/andreyv
sudo apt-get update
sudo apt-get install pgadmin3

Solving the problem of browser and open office after upgrading UBUNTU 12.04 FROM 11.10

After upgrading UBUNTU 11.10 to UBUNTU 12.04

I was getting following error while opening any browser and open office


Error: in load: file "/usr/share/uim/lib/sigscheme-init.scm" not found
Error: in load: file "/usr/share/uim/lib/sigscheme-init.scm" not found

To rectify the issue I installed the following package 

sudo apt-get install --reinstall libuim-data

Troubleshhoting while upgrading UBUNTU 11.10

While trying to update to UBUNTU 11.10 I was getting following error:

W:Failed to fetch http://archive.ubuntu.com/ubuntu/dists/dapper/main/source/Sources

All I did I opened /etc/apt/sources.list and commented the following lines :

deb-src http://archive.ubuntu.com/ubuntu dapper main multiverse
deb-src http://archive.ubuntu.com/ubuntu dapper-updates main multiverse
deb http://archive.canonical.com/ lucid partner
deb-src http://archive.canonical.com/ lucid partner

Then System >Administration >UpdateManager 

Click Upgrade.Follow the on-screen instructions.

Upgrade pgadmin ubuntu

You can upgrade pgadmin to it's latest version by using following command.

sudo apt-add-repository ppa:flexiondotorg/postgres
sudo apt-get update
now you can upgrade from synaptic or use sudo apt-get install pgadmin3 to install the latest version.

Gnome: System Monitor Application To Kill a Process

To start System Monitor GUI, click on System menu > Select Administration > System Monitor. Alternatively, open a command-line terminal (select Applications > Accessories > Terminal), and then type:
$ gnome-system-monitor



































now select the process you want to kill and End Process.


To kill from command line option 


 $ ps aux | grep program_name

 ps - report a snapshot of the current processes.

To end a process, enter:


$ kill -s 15 PID

Type in Hindi and other Indian languages using yudit

If you want to type in Hindi ,you can use yudit which is a free software can be downloaded from http://www.yudit.org/download.html.

Yudit is a simple Unicode editor, has Opentype font support for Devanagari, Malayalam & other
indic languages. Inscript & phonetic keymaps are available for typing in Indic.


Install yudit :
You can follow the steps given at the following URLto install yudit.

1. http://www.yudit.org/download/binary
2. if you have downloaded the zipped folder.Unzip it and go to the folder 

     1. cd yudit

     2.configure --prefix=/usr/local

     3. make

     4. make install

Binary RPMs and Windows version is also available.To type in any indian language, you need to only install the font and set the keymap.Yudit only works with Unicode or Opentype fonts.
For Hindi/Marathi download Gargi devanagari opentype font.



To install the font :
Either copy it into .yudit/fonts in your home directory.
$ cd
$ cp Gargi-1.1.ttf .yudit/fonts
or globally in /usr/share/yudit/fonts.
# cp Gargi-1.1.ttf /usr/share/yudit/fonts/
You dont need to do any ttmkfdir/mkfontdir stuff.
Yudit configuration is stored in ~/.yudit/yudit.properties.
Global one is in /usr/share/yudit/config/yudit.properties
In yudit.properties look for line starting with
yudit.font.TrueType=

And add the font file name (eg Gargi-1.1.ttf) to the line, like below
yudit.font.TrueType=Gargi-1.1.ttf,Sampige.ttf,arial.ttf,kochi-gothic.ttf, gulim.ttf,
tsckanna.ttf:tscii, dc-font.ttf,code2000.ttf, code2001.ttf:unicode:RL, cyberbit.ttf,yudit.ttf
Using Yudit http://www.indlinux.org/doc/yuditguide.html


Next you need to set the keyboard input. Start yudit ,
You will get a Window like below.














Font (with "A" icon ) : This should be set to TrueType ( Shift - F2 does it )
Input (right of Font ): Clicking this brings up a dialog as shown below.
The Available list contains list of all supported input methods.
For Indic inscript and phonetic keymaps are defined , of the name lang-inscript or lang-phonetic
where lang is 3 letter code for the language eg Devanagari - dev, Kannada - kan , Telugu - Tel

You can assign one input method to each Function key.
Leaving F1 as straight ( ie english ) you can set you language by , selecting the input map
and funtion key to bind to and click the arrow.


















On Windows
If you are using Yudit on windows, assuming you have installed in say C:\Yudit
Your configuration will be in C:\Yudit\config\yudit.properties
And Fonts in C:\Yudit\fonts
Rest all you can follow steps as above.


Snapshot from yudit

References:

1. http://www.indlinux.org/doc/yuditguide.html 
2. http://www.yudit.org/download/binary/

Setting up Android development enviornment on UBUNTU

Downloading the Source Tree

Installing Repo

Repo is a tool that makes it easier to work with Git in the context of Android
To install, initialize, and configure Repo, follow these steps:

• Make sure you have a bin/ directory in your home directory, and that it is included in your path:
  

  $ mkdir ~/bin
  $ PATH=~/bin:$PATH

• Download the Repo script and ensure it is executable:
  

  $ curl https://dl-ssl.google.com/dl/googlesource/git-repo/repo > ~/bin/repo
  $ chmod a+x ~/bin/repo

• For version 1.17, the SHA-1 checksum for repo is ddd79b6d5a7807e911b524cb223bc3544b661c28
  

Initializing a Repo client

After installing Repo, set up your client to access the android source repository:

• Create an empty directory to hold your working files. If you're using MacOS, this has to be on a case-sensitive filesystem. Give it any name you like:
  

  $ mkdir WORKING_DIRECTORY
  $ cd WORKING_DIRECTORY

• Run repo init to bring down the latest version of Repo with all its most recent bug fixes. You must specify a URL for the manifest, which specifies where the various repositories included in the Android source will be placed within your working directory.
  

  $ repo init -u https://android.googlesource.com/platform/manifest

  To check out a branch other than "master", specify it with -b:
  

  $ repo init -u https://android.googlesource.com/platform/manifest -b android-4.0.1_r1

• When prompted, please configure Repo with your real name and email address. To use the Gerrit code-review tool, you will need an email address that is connected with a registered Google account. Make sure this is a live address at which you can receive messages. The name that you provide here will show up in attributions for your code submissions.
  

A successful initialization will end with a message stating that Repo is initialized in your working directory. Your client directory should now contain a .repo directory where files such as the manifest will be kept.

Getting the files

To pull down files to your working directory from the repositories as specified in the default manifest, run

$ repo sync

The Android source files will be located in your working directory under their project names. The initial sync operation will take an hour or more to complete. For more about repo sync and other Repo commands, see Version Control.

Using authentication

By default, access to the Android source code is anonymous. To protect the servers against excessive usage, each IP address is associated with a quota.
When sharing an IP address with other users (e.g. when accessing the source repositories from beyond a NAT firewall), the quotas can trigger even for regular usage patterns (e.g. if many users sync new clients from the same IP address within a short period).
In that case, it is possible to use authenticated access, which then uses a separate quota for each user, regardless of the IP address.
The first step is to create a password from the password generator and to save it in ~/.netrc according to the instructions on that page.
The second step is to force authenticated access, by using the following manifest URI: https://android.googlesource.com/a/platform/manifest. Notice how the /a/ directory prefix triggers mandatory authentication. You can convert an existing client to use mandatory authentication with the following command:

$ repo init -u https://android.googlesource.com/a/platform/manifest

Building the System

The basic sequence of build commands is as follows:

Initialize

Initialize the environment with the envsetup.sh script. Note that replacing "source" with a single dot saves a few characters, and the short form is more commonly used in documentation.

$ source build/envsetup.sh

or

$ . build/envsetup.sh

Choose a Target

Choose which target to build with lunch. The exact configuration can be passed as an argument, e.g.

$ lunch full-eng

The example above refers to a complete build for the emulator, with all debugging enabled.

Build the Code

Build everything with make. GNU make can handle parallel tasks with a -jN argument, and it's common to use a number of tasks N that's between 1 and 2 times the number of hardware threads on the computer being used for the build. E.g. on a dual-E5520 machine (2 CPUs, 4 cores per CPU, 2 threads per core), the fastest builds are made with commands between make -j16 and make -j32.

$ make -j4

Run It!

You can either run your build on an emulator or flash it on a device. Please note that you have already selected your build target with lunch, and it is unlikely at best to run on a different target than it was built for.

Emulate an Android Device

The emulator is added to your path automatically by the build process. To run the emulator, type

$ emulator

Trouble Shooting

I got the following error while building

make: *** [out/host/linux-x86/obj/EXECUTABLES/adb_intermediates/adb] Error 1

I fixed it by installing following package:

sudo apt-get install lib32ncurses5-dev
sudo apt-get install libncurses5-dev

Before running the emulator change the permission of file

chmod 777 /home/surabhi/Android/out/target/product/generic/system.img

More details can be found at the following Link :

http://source.android.com/source/building.html

How do I reset a lost Administrative(root) password?

To do this you need to boot into recovery mode.
Boot up the machine, and after the BIOS screen, hold down the left Shift key. You will then be prompted by a menu that looks something like this:

Hit the down arrow until you select the 2nd entry from the top (the one with the recovery mode in the description) and then hit Enter.

Using the arrow keys scroll down to either root or netroot (doesn't matter in this case) and then hit Enter.
You should now see a root prompt, something like this:

root@ubuntu:~#

Now we can set the user's password with the passwd command. (In this example I will usesurabhi as the example, you need to substitute whatever the user's username is):

passwd surabhi
Enter new UNIX password:
Retype new UNIX password:
passwd: password updated successfully
root@ubuntu:~#

Type in what you want the new password to be at the prompt. After it's successful reboot the machine and the user will be able to log in with their new password.
It worked for me.

Reference http://askubuntu.com/questions/24006/how-do-i-reset-a-lost-administrativeroot-password