WINDOWS-BATCH FILE

Windows batch file is nothing but a line by line collection of commands that are executed in command prompt.To create a batch file open the notepad and type the commands line by line and save as of type .bat.For example consider the following example
cd c:\\images
del a.gif
and save the file as example.bat.
When you double click the above created batch file a.gif in the images folder is deleted.

TRACE THE ORIGIN OF YOUR EMAIL

When you receive a email saying it come from London or USA you will be confused whether it really came from that location.The best way to verify it is to check with the IP from which it is was received.To know the IP from which the email is received use the following steps.

GMAIL
In gmail open the message and click the inverted triangle above the message and click show original.You can see the IP from which the email is received.

YAHOO
In yahoo click the see full header option to see the IP from which it is received.

Using the IP just search it with google to see the location or goto the url http:\\www.whatismyipaddress.com and click IP lookup to see the location.

EDITING THE SYSTEM FILES IN WINDOWS VISTA AND WINDOWS 7

When you are previously using windows xp and upgraded to windows vista or 7 you may have faced this situation.For example in windows vista and 7 when you open some system or administrative files such as c:\windows\system32\drivers\etc\hosts file in notepad for testing some tricks you are not able to save the edited file which is not a matter in XP.To edit such files drag that file to another location such as desktop and then edit and save.After saving move the file back to the original location then done.

DIFFERENCE BETWEEN BLOG AND WEBSITE

Though the blog and website are seem to be same there are many important differences between them.The main difference that differentiate the two is STATIC PAGES.The blog doesnt contain any static pages because it was initially invented to share the personal ideas of a person with his friends and relatives which is updated frequently.Also the blog doesnt contain the storage space and as a result it should provide external link for downloading of files.On the other hand websites contain static pages and also the storage space.The search engines will give high priority for blog compare to website as it is updated frequently.As a result the commercial organisation will employ both blog with a link to its website for better results.

KNOW THE IP ADDRESS OF A WEBSITE

As i have said in earlier posts that every website have an unique IP address and it is named only for our convenience.Sometimes you want to know the IP address of a particular site to hack or to make fool your friends.To satisfy your needs i tell the way to find the IP of a site from windows connected to internet.For example when you want to know the IP of google.com then goto run and type "cmd" the command prompt will open here type the following command.

ping google.com

and press ENTER.

Now you will see the a number of lines indicating the status of connection including the IP address of the site.You com find the IP of any site by using this method when you are currently connected to the internet.

GOOGLE Search Techniques and Query Optimization

Google supports several syntax and optimisation for the queries by which the user can get the desired output.I summarize some important features.


1.There are certain circumstances when you require result from only a certain site excluding result from another sites.At that time try the following format using (site:) command.
For ex[site:foolishengineers.blogspot.com prakash]

Try the above query without the brackets and see the result.


2.Another important feature provided by google is built in calculator which performs mathematic operations.Try the following queries.


1+100
2*5

3.When you want to know the meaning of certain word then try the following query.
ex.[define word]
Use the above query by replacing the word with word you want to know the meaning without the bracket.


4.When you want to know the time of a certain city then use the following query.

ex.[time Chennai]

5.Google provides inbuilt unit conversion from one unit to another by simply providing a query in the following format.

ex. [60kg to gram]

Google supports many types of such a conversion from one unit to another.


Apart from this it provides many services especially for U.S such as fligt status etc.

Static ip vs Dynamic ip

When an ip address is assigned to you that enables you to connect to global network which doesnt change with time then it is STATIC IP.By doing so there is insufficiency in the number of ip addressed as the number of net users increase exponentially with time.To avoid this unfavourable situation DYNAMIC IP was introduced which dynamically assigns address to the client when requested.The dynamic addressing concept is based on the fact that the number of users online at any time is very less than the total number of net users.The ISP maintains a large pool of addresses from which one address is assigned to a host when requested and get back into the pool when that host is disconnected.This can be done by DHCP(Dynamic Host Configuration Protocol)which provides dynamic ip to a host.Check your ip address before and after(i.e different sessions)your ip will definitely vary.To overcome this type of problems ipv6 was introduced and the world is slowly migrating to it.Japan has completely implemented IPv6.

Difference between read and write permission in windows

Whenever you are currently using a file(e.g. playing an audio or video file) check the properties before and after the usage by right click or pressing Alt+Enter) when the file is highlighted.You can notice that the read only property of that file is automatically marked and you are not able to delete that file at that time but still you can copy it to USB etc. and also you can open it with other application this is because copy or play option requires only read permission but delete operation requires write permission which is not available when read only is marked.Therefore you are not able to delete a file when it is currently in use and most of the viruses uses this concept to make the virus file undeletable.At that time you can change the properties of a specific file from the command prompt using attrib command to change the permission and delete that file.

Revealing Wikipedia

Most of the student and teaching community will opt for Wikipedia as the primary source of information.But most of us dont know many amazing facts about this fabulous site.The articles in this site are created and edited by billions of contributor like us around the world.
Due to the above fact it suffers from vandalism(i.e some persons will utilize it for publishing their ads and make a link to anonymous site)and some of its articles contain fake and unverified information.Therefore some persons will not accept the references from Wikipedia.

Despite of criticism and controversies by many experts around the world some of its features marked it apart.
1)Wikipedia is the fifth most viewed website in the world.This may be due to google which gives highest priority to Wikipedia in its search results.
2)It is non commercial which doesnt support ads of any kind in its pages.A survey discovered that when this site supports ads it will earn many billions per year.It will ask for voluntary donation once in a year for its expenses.
3)It is available in more than 200 languages and contains more than billion articles on almost every topic and it is ever increasing.
Last but not least it employs less than 35 persons for maintaining such a large site.
Wikipedia has taken many steps to ensure the reliability of its contents which includes the inclusion of talk page and history page for contributors which is capable of rollback to previous states when it is damaged by vandals.

DIFFERENCE BETWEEN PUBLIC IP AND PRIVATE IP

In ipv4 addressing ambiguity arises in deciding whether a given ip is assigned through ICANN(International Council for Assigned Name and Number)to connect to global network or it is assigned by the user locally for LAN.To avoid this confusion ICANN allocated certain set of address exclusively for private use.They are
1)10.0.0.0 to 10.255.255.255
2)172.16.0.0 to 172.31.255.255
3)192.168.0.0 to 192.168.255.255

we can use the above ip ranges without any permission from ICANN for local connection. The IP addresses which doesnt lie in the above category are called public IP obtained from ISP for connecting to global network and hence the name public IP.But most of the ISP will provide you a private IP due to insufficiency of addresses and this is possible due to NAT(Network Address Translation).

STEGANOGRAPHY

Steganography is defined as the art of hidden way of writing whereas the cryptography is the secret way of writing.By using cryptography the third person will know something is crypted.The major advantage of Steganography over cryptography is that it is almost impossible to know that something is hidden.We know that every image is made up of several bits.The data to be hidden is also a series of bits. Steganography replaces the least visible bits in the image by the data bits which is unidentified by the human eyes.The bits to be replaced is generated by an algorithm shared by sender and receiver.The receiver user the same algorithm to generate the bits where his message is hidden.The message is usually compressed and then encrypted before hiding inside a image.As the terrorists extensively use this method for conspiracy the government has involved in extensive research in this field to counteract the terrorists.

VIRTUAL PRIVATE NETWORK

Large organisation will usually have to employ two types of network.
1.PRIVATE NETWORK
2.GLOBAL NETWORK

PRIVATE NETWORK
This type of network doesnt require internet connection and it is used only to share information between the computers in a organisation.These organisation which have branches all over the world have to be connected through wires which constitute a WAN.

GLOBAL NETWORK
This internet connection is required for connecting to external world.

HYBRID NETWORK
To accomplish the above two needs the organisation employs two routers one to connect to the private and another to connect to external world.

NEED FOR VPN
The above method has major disadvantage that using a private network with WAN is very costly since it requires connection to branches in all parts with wires.Also the global network requires monthly payment.To integrate both the cost ICANN introduced VPN which provides both the private and global connection with a single connection.The data packets destined for private computer is encapsulated with IPsec such that it will be deciphered only by private computer.This process is called tunneling.As the network seem to be private it is not but it make use of global line for communication.Thats why the name VIRTUAL PRIVATE NETWORK.