Tuesday, March 15, 2011

Interesting Facts about India

  • India never invaded any country in her last 100000 years of history.
  • When many cultures were only nomadic forest dwellers over 5000 years ago, Indians established Harappan culture in Sindhu Valley (Indus Valley Civilization)
  • The name 'India' is derived from the River Indus, the valleys around which were the home of the early settlers. The Aryan worshippers referred to the river Indus as the Sindhu.
  • The Persian invaders converted it into Hindu. The name 'Hindustan' combines Sindhu and Hindu and thus refers to the land of the Hindus.
  • Chess was invented in India.
  • Algebra, Trigonometry and Calculus are studies, which originated in India.
  • The 'Place Value System' and the 'Decimal System' were developed in India in 100 B.C.
  • The World's First Granite Temple is the Brihadeswara Temple at Tanjavur, Tamil Nadu. The shikhara of the temple is made from a single 80-tonne piece of granite. This magnificent temple was built in just five years, (between 1004 AD and 1009 AD) during the reign of Rajaraja Chola.
  • India is the largest democracy in the world, the 7th largest Country in the world, and one of the most ancient civilizations.
  • The game of Snakes & Ladders was created by the 13th century poet saint Gyandev. It was originally called 'Mokshapat'. The ladders in the game represented virtues and the snakes indicated vices. The game was played with cowrie shells and dices. In time, the game underwent several modifications, but its meaning remained the same, i.e. good deeds take people to heaven and evil to a cycle of re-births.
  • The world's highest cricket ground is in Chail, Himachal Pradesh. Built in 1893 after leveling a hilltop, this cricket pitch is 2444 meters above sea level.
  • India has the largest number of Post Offices in the world.
  • The largest employer in India is the Indian Railways, employing over a million people.
  • The world's first university was established in Takshila in 700 BC. More than 10,500 students from all over the world studied more than 60 subjects. The University of Nalanda built in the 4th century was one of the greatest achievements of ancient India in the field of education.
  • Ayurveda is the earliest school of medicine known to mankind. The Father of Medicine, Charaka, consolidated Ayurveda 2500 years ago.
  • India was one of the richest countries till the time of British rule in the early 17th Century. Christopher Columbus, attracted by India's wealth, had come looking for a sea route to India when he discovered America by mistake.
  • The Art of Navigation & Navigating was born in the river Sindh over 6000 years ago. The very word Navigation is derived from the Sanskrit word 'NAVGATIH'. The word navy is also derived from the Sanskrit word 'Nou'.
  • Bhaskaracharya rightly calculated the time taken by the earth to orbit the Sun hundreds of years before the astronomer Smart. According to his calculation, the time taken by the Earth to orbit the Sun was 365.258756484 days.
  • The value of "pi" was first calculated by the Indian Mathematician Budhayana, and he explained the concept of what is known as the Pythagorean Theorem. He discovered this in the 6th century, long before the European mathematicians.
  • Algebra, Trigonometry and Calculus also originated in India.Quadratic Equations were used by Sridharacharya in the 11th century. The largest numbers the Greeks and the Romans used were 106 whereas Hindus used numbers as big as 10*53 (i.e. 10 to the power of 53) with specific names as early as 5000 B.C.during the Vedic period.Even today, the largest used number is Terra: 10*12(10 to the power of 12).
  • Until 1896, India was the only source of diamonds in the world
    (Source: Gemological Institute of America).
  • The Baily Bridge is the highest bridge in the world. It is located in the Ladakh valley between the Dras and Suru rivers in the Himalayan mountains. It was built by the Indian Army in August 1982.
  • Sushruta is regarded as the Father of Surgery. Over2600 years ago Sushrata & his team conducted complicated surgeries like cataract, artificial limbs, cesareans, fractures, urinary stones, plastic surgery and brain surgeries.
  • Usage of anaesthesia was well known in ancient Indian medicine. Detailed knowledge of anatomy, embryology, digestion, metabolism,physiology, etiology, genetics and immunity is also found in many ancient Indian texts.
  • India exports software to 90 countries.
  • The four religions born in India - Hinduism, Buddhism, Jainism, and Sikhism, are followed by 25% of the world's population.
  • Jainism and Buddhism were founded in India in 600 B.C. and 500 B.C. respectively.
  • Islam is India's and the world's second largest religion.
  • There are 300,000 active mosques in India, more than in any other country, including the Muslim world.
  • The oldest European church and synagogue in India are in the city of Cochin. They were built in 1503 and 1568 respectively.
  • Jews and Christians have lived continuously in India since 200 B.C. and 52 A.D. respectively
  • The largest religious building in the world is Angkor Wat, a Hindu Temple in Cambodia built at the end of the 11th century.
  • The Vishnu Temple in the city of Tirupathi built in the 10th century, is the world's largest religious pilgrimage destination. Larger than either Rome or Mecca, an average of 30,000 visitors donate $6 million (US) to the temple everyday.
  • Sikhism originated in the Holy city of Amritsar in Punjab. Famous for housing the Golden Temple, the city was founded in 1577.
  • Varanasi, also known as Benaras, was called "the Ancient City" when Lord Buddha visited it in 500 B.C., and is the oldest, continuously inhabited city in the world today.
  • India provides safety for more than 300,000 refugees originally from Sri Lanka, Tibet, Bhutan, Afghanistan and Bangladesh, who escaped to flee religious and political persecution.
  • His Holiness, the Dalai Lama, the exiled spiritual leader of Tibetan Buddhists, runs his government in exile from Dharmashala in northern India.
  • Martial Arts were first created in India, and later spread to Asia by Buddhist missionaries.
  • Yoga has its origins in India and has existed for over 5,000 years.

Monday, March 14, 2011

Company Names

Yahoo!

The word was invented by Jonathan Swift and used in his book Gulliver's Travels. It represents a person who is repulsive in appearance and action and is barely human. Yahoo! founders Jerry Yang and David Filo selected the name because they considered themselves yahoos.

Xerox

The Greek root "xer" means dry. The inventor, Chestor Carlson , named his product Xerox as it was dry copying, markedly different from the then prevailing wet copying.

Sun Microsystems

Founded by four Stanford University buddies, Sun is the acronym for Stanford University Network.

Sony

From the Latin word 'sonus' meaning sound, and 'sonny' a slang used by Americans to refer to a bright youngster.

SAP

"Systems, Applications, Products in Data Processing", formed by four ex-IBM employees who used to work in the 'Systems/Applications/Projects' group of IBM.

Red Hat

Company founder Marc Ewing was given the Cornell lacrosse team cap (with red and white stripes) while at college by his grandfather. He lost it and had to search for it desperately. The manual of the beta version of Red Hat Linux had an appeal to readers to return his Red Hat if found by anyone!

Oracle

Larry Ellison and Bob Oats were working on a consulting project for the Central Intelligence Agency (CIA). The code name for the project was called Oracle (the CIA saw this as the system to give answers to all questions or something such).

Motorola

Founder Paul Galvin came up with this name when his company started manufacturing radios for cars. The popular radio company at the time was called Victrola.

Microsoft

It was coined by Bill Gates to represent the company that was devoted to MICROcomputer SOFTware. Originally christened Micro-Soft, the '-' was removed later on.

Lotus

Mitch Kapok got the name for his company from the lotus position or 'padmasana.' Kapok used to be a teacher of Transcendental Meditation of Maharishi Mahesh Yogi.

Intel

Bob Noyce and Gordon Moore wanted to name their new company ' Moore Noyce' but that was already trademarked by a hotel chain, so they had to settle for an acronym of INTegrated ELectronics.

Hewlett-Packard

Bill Hewlett and Dave Packard tossed a coin to decide whether the company they founded would be called Hewlett-Packard or Packard-Hewlett.

Hotmail

Founder Jack Smith got the idea of accessing email via the web from a computer anywhere in the world. When Sabeer Bhatia came up with the business plan for the mail service, he tried all kinds of names ending in 'mail' and finally settled for Hotmail as it included the letters "html" - the programming language used to write web pages. It was initially referred to as HoTMaiL with selective upper casings.

Google

The name started as a jockey boast about the amount of information the search-engine would be able to search. It was originally named 'Googol', a word for the number represented by 1 followed by 100 zeros. After founders - Stanford graduate students Sergey Brin and Larry Page presented their project to an angel investor, they received a cheque made out to 'Google

Cisco

The name is not an acronym but an abbreviation of San Francisco . The company's logo reflects its San Francisco name heritage. It represents a stylized Golden Gate Bridge .

Apple Computers

Favourite fruit of founder Steve Jobs. He was three months late in filing a name for the business, and he threatened to call his company Apple Computers if the other colleagues didn't suggest a better name by 5 o'clock.

Apache

It got its name because its founders got started by applying patches to code written for NCSA's httpd daemon. The result was 'A PAtCHy' server - thus, the name Apache.

Adobe

The name came from the river Adobe Creek that ran behind the house of founder John Warnock

Wednesday, February 2, 2011

Datastructures(1)


1. What is data structure?
·          A data structure is a way of organizing data that considers not only the items stored, but also their relationship to each other.
·          Advance knowledge about the relationship between data items allows designing of efficient algorithms for the manipulation of data.

2. List out the areas in which data structures are applied extensively?
1.     Compiler Design,
2.     Operating System,
3.     Database Management System,
4.     Statistical analysis package,
5.     Numerical Analysis,
6.     Graphics,
7.     Artificial Intelligence,
8.     Simulation

3. What are the major data structures used in the following areas : RDBMS, Network data model and Hierarchical data model.
1.     RDBMS = Array (i.e. Array of structures)
2.     Network data model = Graph
3.     Hierarchical data model = Trees

4. if you are using C language to implement the heterogeneous linked list, what pointer type will you use?
·          The heterogeneous linked list contains different data types in its nodes and we need a link, pointer to connect them.
·          It is not possible to use ordinary pointers for this. So we go for void pointer.
·          Void pointer is capable of storing pointer to any type as it is a generic pointer type.

5. Minimum number of queues needed to implement the priority queue?
Two. One queue is used for actual storing of data and another for storing priorities.

6. What is the data structures used to perform recursion?
Stack. Because of its LIFO (Last in First Out) property it remembers its 'caller' so knows whom to return when the function has to return. Recursion makes use of system stack for storing the return addresses of the function calls.
Every recursive function has its equivalent iterative (non-recursive) function. Even when such equivalent iterative procedures are written, explicit stack is to be used.

7. What are the notations used in Evaluation of Arithmetic Expressions using prefix and postfix forms?
Polish and Reverse Polish notations.

8. Convert the expression ((A + B) * C - (D - E) ^ (F + G)) to equivalent Prefix and Postfix notations.
1.     Prefix Notation: ^ - * +ABC - DE + FG
2.     Postfix Notation: AB + C * DE - - FG + ^

9. Sorting is not possible by using which of the following methods? (Insertion, Selection, Exchange, Deletion)
Sorting is not possible in Deletion. Using insertion we can perform insertion sort, using selection we can perform selection sort, using exchange we can perform the bubble sort (and other similar sorting methods). But no sorting method can be done just using deletion.

10. What are the methods available in storing sequential files ?
1.     Straight merging,
2.     Natural merging,
3.     Polyphase sort,
4.     Distribution of Initial runs.

TESTING - The W-Model of Testing

- Introduced by Paul Herzlich in 1993.

- Attempts to address shortcomings in V-model.

- Rather than focus on specific dynamic test stages (V-Model), W-Model focuses on the development product themselves.

- Everyday development activity that produces a work product is “showed” by the test activity.

- Purpose to test whether the objectives of the development activity has been met and deliverables meets its requirements.

- W-Model focuses specifically on the product risks of concern at the point where testing can be most effective.

W-Model and Static Test Techiniques:

- There is wide range of techniques available for the products of the left hand side.

W-Model and Dynamic test technique:

Tuesday, February 1, 2011

Relational Data Base Management Systems (RDBMS)(4)


1.       What are different Types of Join?

  1. Cross Join A cross join that does not have a WHERE clause produces the Cartesian product of the tables involved in the join. The size of a Cartesian product result set is the number of rows in the first table multiplied by the number of rows in the second table. The common example is when company wants to combine each product with a pricing table to analyze each product at each price.
  2. Inner Join A join that displays only the rows that have a match in both joined tables is known as inner Join. This is the default type of join in the Query and View Designer.
  3. Outer Join A join that includes rows even if they do not have related rows in the joined table is an Outer Join. You can create three different outer join to specify the unmatched rows to be included:
    1. Left Outer Join: In Left Outer Join all rows in the first-named table i.e. "left" table, which appears leftmost in the JOIN clause, are included. Unmatched rows in the right table do not appear.
    2. Right Outer Join: In Right Outer Join all rows in the second-named table i.e. "right" table, which appears rightmost in the JOIN clause are included. Unmatched rows in the left table are not included.
    3. Full Outer Join: In Full Outer Join all rows in all joined tables are included, whether they are matched or not.
  4. Self Join This is a particular case when one table joins to itself, with one or two aliases to avoid confusion. A self join can be of any type, as long as the joined tables are the same. A self join is rather unique in that it involves a relationship with only one table. The common example is when company has a hierarchal reporting structure whereby one member of staff reports to another. Self Join can be Outer Join or Inner Join.

2.       What are primary keys and foreign keys?

·         Primary keys are the unique identifiers for each row.
·         They must contain unique values and cannot be null.
·         Due to their importance in relational databases, Primary keys are the most fundamental of all keys and constraints.
·         A table can have only one Primary key.
·         Foreign keys are both a method of ensuring data integrity and a manifestation of the relationship between tables.

3.       What is User Defined Functions? What kind of User-Defined Functions can be created?

·         User-Defined Functions allow defining its own T-SQL functions that can accept 0 or more parameters and return a single scalar data value or a table data type.
·         Different Kinds of User-Defined Functions created are:
1.       Scalar User-Defined Function A Scalar user-defined function returns one of the scalar data types. Text, ntext, image and timestamp data types are not supported. These are the type of user-defined functions that most developers are used to in other programming languages. You pass in 0 to many parameters and you get a return value.
2.       Inline Table-Value User-Defined Function An Inline Table-Value user-defined function returns a table data type and is an exceptional alternative to a view as the user-defined function can pass parameters into a T-SQL select command and in essence provide us with a parameterized, non-updateable view of the underlying tables.
3.       Multi-statement Table-Value User-Defined Function A Multi-Statement Table-Value user-defined function returns a table and is also an exceptional alternative to a view as the function can support multiple T-SQL statements to build the final result where the view is limited to a single SELECT statement. Also, the ability to pass parameters into a TSQL select command or a group of them gives us the capability to in essence create a parameterized, non-updateable view of the data in the underlying tables. Within the create function command you must define the table structure that is being returned. After creating this type of user-defined function, It can be used in the FROM clause of a T-SQL command unlike the behavior found when using a stored procedure which can also return record sets.

4.       What is Identity?

·         Identity (or AutoNumber) is a column that automatically generates numeric values.
·         A start and increment value can be set, but most DBA leave these at 1.
·         A GUID column also generates numbers; the value of this cannot be controlled.
·         Identity/GUID columns do not need to be indexed.

5.       What is Data Warehousing?

  1. Subject-oriented, meaning that the data in the database is organized so that all the data elements relating to the same real-world event or object are linked together;
  2. Time-variant, meaning that the changes to the data in the database are tracked and recorded so that reports can be produced showing changes over time;
  3. Non-volatile, meaning that data in the database is never over-written or deleted, once committed, the data is static, read-only, but retained for future reporting.
  4. Integrated, meaning that the database contains data from most or all of an organization's operational applications, and that this data is made consistent.

Sunday, January 30, 2011

TESTING (Cont.)

Incremental Testing:

- Disciplined method of testing the interfaces between unit-tested programs as well as between system components.

- Involves adding unit tested programs to a given module or component one by one and testing each result and combination.

- Two type – Top Down and Bottom Up.

Thread Testing:

- Often used during early integration testing.

- Demonstrates key functional capabilities by testing a string of units that accomplish a specific function in the application.

- Thread and incremental are usually utilized together.

Regression Testing:

- Conducted during all stages of testing introduced to application or downstream application after a change is made.

- Three type:

· Unit Regression Testing – retesting a single program or component after a change is made.

· Regional Regression Testing – retesting modules connected to the program or component has been changed.

· Full Regression Testing – retesting the entire application after a change has been made.

V – Model Approach:

- Illustrates the sequence in which testing should occur.

- Life Cycle Testing involves continuous testing of the system during the developmental process.

- The results of the development process are inspected to test the correctness at predetermined points.

- These inspections identify defects at the earliest possible point.

- Unless a formalized software development life cycle has been incorporated, life cycle testing cannot occur.

- The life cycle testing becomes ineffective when the information service personnel has discretion to determine the order which normally increases cost.

- The life cycle testing can be best by formation of a test team.

- The members must use formal testing methodology.

- Without a specific structured methodology, the test team concept is ineffective.

An 11 – Step Software Testing Process example: