The Extract-Transform-Load (ETL) system is the foundation of the data warehouse. A properly designed ETL system extracts the data from source systems, performs transformations and cleansing and delivers the data in a presentation ready format after which the data will be loaded to the ware house. The following figure is the schematic description of the ETL process.

The 4 steps of ETL process are explained below:

Extracting: In this phase, data from different types of source systems are fetched into the staging area. The source systems can be mainframe, production sources or any other OLTP sources. Source files can also be different. Data can be stored in relational tables as well as flat files (e.g. Notepad files). The first job of ETL is to fetch data from these different sources.

Cleansing: In most cases level of data quality in an OLTP source system is different from what is required in a data warehouse. To achieve those data quality, cleansing has to be applied. Data cleansing consists of many discrete steps, including checking for valid values, ensuring consistency across values, removing duplicates and checking whether complex business rules and procedures have been applied.

Conforming: Data conformation is required whenever 2 or more data sources are merged in the data warehouse. Separate data sources cannot be queried together unless some or all the textual labels in these sources have been made identical and unless similar numerical measures have been rationalized.

Delivering: The main motto of this step is to make the data ready for querying. It includes physical structuring the data into a set of simple, symmetric schemas known as dimensional models, or star schemas (we will discuss star schema and dimensional model later). These schemas are a necessary basis for building an OLAP system.

We are all familiar with the term “Database”. What is a Database? We can say that a database is a storage of some meaningful data specific to one’s business/personal need. A database can store any type of data. But if a database is storing the data then what’s the need of a Data Warehouse? So at first we have to know the basic difference between a Database and a Data Warehouse.

A Database is that which is storing only the most current data. In a more technical term, it is known as OLTP source. OLTP stands for Online Transactional Processing. But whenever we use Oracle/DB2/Teradata etc. to store historical data, it becomes a Data Warehouse. By the term Historical data, we mean “Snapshots” of data. That is data of same process taken at different instant of time. Technically its known as OLAP (Online Analytical Processing) system.  A simple example can be given at this context. Lets consider a bank. A database of the bank will store the latest transactional data only. But each day the bank have these types of data. So they need to archive these. So they are storing it in a daily basis, i.e. they are taking snapshots of data and consequently the are creating a data warehouse.

So am I able to draw the line clearly between a database and a data warehouse? Maybe I am ( thinking positively ). Now another question comes into the picture. So why do one have to maintain a data warehouse. Because maintaining a data warehouse is a costly job. Day by day the size of the warehouse will grow. The answer is Business. One have to maintain the historical data to analyse the trend of his business and making decisions based on those data. This decisions can be a big factor in case of the present and upcoming performance of his business.

The job of a data warehouse specialist can be in many phase. He/she has to extract the data from different OLTP source systems, apply the modifications or cleansing according to the requirements and then loading this data to the data warehouse. And in another phase he have to fetch the data from the data warehouse, analyse it and develop the report. The end users can see those reports and based on those he/she can make the business decisions.

Ok… lets end it here. I will discuss more about this in depth from the next post. Take care..see you soon friends.

The Difference between the FAT 32 and NTFS file syetems::

NTFS::

1. Allows access local to w2k w2k3 XP win NT4 with SP4 and later may get access for some file.
2. Maximum size of partition is 2 terabytes and more.
3. Maximum file size is upto 16TB.
4. File and folder encryption is possible only in NTFS.

FAT 32::
1. Allows access to win 95 98 Win Millenium Win2k XP on local partitions.
2. Maximum size of partition is upto 2TB.
3. Maximum file size is upto 4GB
4. File and folder encryption is not possible.

Hello everyone. It was a tough 3 months for me. Oh, I forgot, you don’t have a idea of my present status. I have joined Accenture on August and relocated to Bangalore. So my present location is Bangalore aka Bengaluru. The first 2 month was really a hectic one. It was tough to follow a daily schedule of 8-30 to 20-30 with exam after each couple of days. Many friends of mine were unable to sustain in this hectic procedure and some of them got unlucky and eventually  they have been sacked. I got lucky and finally after 2 months of “without food – without sleep” effort I have cleared the training procedure. I have been trained on Informatica, the ETL tool. Previously there was a fascination in my mind that someday I will be a successful programmer. But it was again proved that there is something called as destiny.

By the way, though the training is a tough one, somehow It was also enjoyable. At least we have to think like that. The services provided in the Accenture premises are excellent. And also I have to mention about the building structure. The skyscrapers are really eye catching.

          Accenture(Bang6), Divyashree Tech Park                                     Accenture(Bang4), Eco Space SEZ

Accenture (Bang3), Bannerghata Main Road, Dairy Circle

Above are some of the pictures of the Accenture offices in Bangalore. Presently I am working at Bang4 at Eco Space SEZ.

Now lets come to the technical stuff. So in the training period I was allocated Data warehousing as a stream. At first I thought it would be boring and conceptual one. But later on I am in love with this subject and specially the tool Informatica. The subject is totally inline with the present market needs and consumer goods and productions. Anyone can think of many practical scenarios in which the subject will be applicable.

Presently I am working on MicroStrategy, a reporting tool ( a reporting tool is necessary to create reports on the basis of data available in data warehouse).

So if all goes well then in the coming years I am gonna have some competency in Data warehousing field. Lets pray for that. Oh, one more thing. The upcoming posts will contain more about Informatica, Business Objects, MicroStrategy and other concepts of Data warehousing. So Hasta luego.

Following are the steps to configure a switch port to work in promiscuous mode.

1. Connect to console port (using hyper terminal [port com1, speed 9600 bps]).
2. Run the following commands:

   # configure terminal.
   

   # no monitor session 1.
   

   # monitor session 1 source interface fastEthernet 0/1.
   

   # monitor session 1 destination interface fastEthernet 0/24.
   

   # encapsulation dot1q.
   

   # end
   

   # show monitor session1.
   

    

   [Note: Promiscuous mode refers to the special mode of Ethernet hardware, in particular network interface cards (NICs), that allows a NIC to receive all traffic to the network, even if it is not addressed to this NIC. In a wider sense, promiscuous mode also refers to network visibility from a single observation point.]

1. Format the Linux partitions to create unallocated space, if you haven’t already. You can find a walkthrough on how to do this under External Links listed below.
   
2. Change the BIOS so that your computer boots your CD drive first.
   
3. Insert the Windows XP disc and reboot. It may take a few minutes to load.
   
4. Select ‘Recovery Console’ by pressing ‘r’.
   
5. Select the Windows system to log on to. The default option is ‘1′.
   
6. Press enter to bypass the administrative password prompt.
   
7. Type fixboot and press enter.
   
8. Type fixmbr and press enter.
   

   Hope these will fix the MBR. J
   

What is an Generic Host process for Win32:

Generic Host Process for Win32 Services or svchost.exe is a legal and essential component of Windows which is used to host services which run from dynamic-link libraries (DLLs). Multiple instances of Svchost.exe can run at the same time. So it is not a problem in most cases if you see five or six or even more copies of svchost.exe running in your services because they host different groups of DLLs. However, there are several known spyware and trojans that pretend to be legal svchost.exe. They usually have the same name or one of the following names: svchost.exe, svchosts.exe (which often causes svchosts.exe page faults), Generic.exe, svcchost.exe and several others. Please note that legal svchost.exe should reside in Windows\System32 folder and should not appear in startup list.

Fixing Generic host Win32 Error:

Step1:

1. Hop to ‘Run’ and open ‘Regedit’
2. Navigate to:
   HKEY_LOCAL_MACHINE > SYSTEM > CurrentControlSet > Services > Browser > Parameters
3. Find the Key
   Name: IsDomainMaster
   and set
   Data: False
4. Restart Your PC

Step2:

1. Go to ‘Run’ and open ‘cmd’
2. Type ‘netsh’ in command console then press enter
3. Then type ‘winsock’ and press enter and then type reset
4. Restart Your PC

Step3:

1. Open ‘cmd’
2. type regedit and press enter. This will lead you to the registry editor.
3. Find the following key: HKEY_LOCAL_MACHINE\System\CurrentControlSet\Services\NetBT\Parameters
4. In the right-hand window pane you will find an option called TransportBindName.
   Double click onTransportBindName and delete the existing default value and click Ok (This gives TransportBindName a blank value)
5. Close Port 135: Navigate to the following registry key:
   HKEY_LOCAL_MACHINE\Software\Microsoft\Ole
6. In the right hand window pane you will see an option called EnableDCOM. Double-click EnableDCOM and change the Y to an N and click Ok. Close the Registry Editor and restart your computer.

Hope this will solve your problem.

The following steps should help you to get updates from WSUS server:–

1. Login as Administrator.

2. Goto Start –> Run –> type gpedit.msc and then press OK.

3. In the left pane of the window under local Comuter Policy, thee should be two subgroups as “Computer Configuration” and “User Configuration”. Click ‘+’ left to Computer Configuration and then click ‘+’ left to Administrative Templates and then click ‘+’ left to Windows Cmponents. Finally click on Windows Update.

4. In the right pane, double click on the setting “Configue Automatic Updates”. Make it enabled and select 3-Auto Download and notify for install in the drop down menu. Then click the next setting menu.

5. Make it enabled and type http://wus (it should b the path of your WSUS server) in the both places. Then click Next setting button.

6. Make it enabled and type PERSONAL (it can vary depending on users choice). Then click the Next setting button.

7. Make it enabled and type the startup time as yu want. Then click Next setting button.

8. Leave this settings as not configured and then click Next seting button.

9. Make it enabled and type the time duration between each updation. Then click OK.

You have done necesary settings to recieve the windows update from a WSUS server. Now close the window and restart the pc. After restarting the pc, you will be prompted certain updates in the taskbar. The updates are required for your pc depending upon the windows software you had installed. Install the updates. You may be prompted to restart the pc.

Computer data storage, often called storage or memory, refers to computer components, devices, and recording media that retain digital data used for computing for some interval of time. Computer data storage provides one of the core functions of the modern computer, that of information retention. It is one of the fundamental components of all modern computers, and coupled with a central processing unit (CPU, a processor), implements the basic computer model used since the 1940s.

a DDR-2 RAM or RANDOM ACCESS MEMORY

Last day, I’d ended on the basic structure of the C Programming Language. Today, we shall start to do real programming. It is really fun.

Ok. Lets do a small program to print your name:

This program will give you output like:

Now, we shall move to DATA Types.

As we know, there are many types of data in our real world. For example, the Integers, the Floating point numbers, Characters etc.

In case of C, there also exist all of them. In case, we want to use them, we need to “INITIALIZE” them to the Compiler. The method is like this:

Here we can see, “int a” declares an integer called ‘a’ without any value. But, “int b = 5″ declares an integer called ‘b’ with a value 5 assigned in it. Similarly for floating point numbers, ‘float’ is used and for characters, “char” is used. All these ‘int’ or ‘float’ or ‘char’ are called “keywords” in C.

We shall look further more keywords in C:

All these keywords have their own meanings and jobs to do. We shall look them further, while we will need them in future.

Now, there is a question. I know, I can use int as a keyword to mean the integers. But, how long that integer can be? Int x = 1234567891011121314151617…..??? There should be a limit of this.

char     => a single byte, capable of holding one character in the local character set

int        => an integer, typically reflecting the natural size of integers on the host machine

float     => single-precision floating point

double =>  double-precision floating point

In addition, there are a number of qualifiers that can be applied to these basic types. short

and long apply to integers:

short int sh;

long int counter;

The word int can be omitted in such declarations, and typically it is. The intent is that short and long should provide different lengths of integers where practical; int will normally be the natural size for a particular machine. short is often 16 bits long, and int either 16 or 32 bits. Each compiler is free to choose appropriate sizes for its own hardware, subject only to the the restriction that shorts and ints are at least 16 bits, longs are at least 32 bits, and short is no longer than int, which is no longer than long.  The qualifier signed or unsigned may be applied to char or any integer. unsigned numbers are always positive or zero, and obey the laws of arithmetic modulo 2n, where n is the number of bits in the type. So, for instance, if chars are 8 bits, unsigned char variables have values between 0 and 255, while  signed chars have values between -128 and 127 (in a two’s complement machine.) Whether plain  chars are signed or unsigned is machine-dependent, but printable characters are always positive.  The type long double specifies extended-precision floating point. As with integers, the sizes of floating-point objects are implementation-defined; float, double and long double could represent one, two or three distinct sizes.