Hot Backup and a Cold Backup

Cold Backup- We can take the Backup while DB(eg. Oracle) is down. 
Hot Backup-We can take the Backup while DB(eg. Oracle) is running. 

Cold backup is a physical backup. During a cold backup the database is closed and not available to users. All files of the database are copied (image copy). The datafiles do not change during the copy so the database is in sync upon restore. 
Used when: Service level allows for some down time for backup 


Hot backup is a physical backup. In a hot backup the database remains open and available to users. All files of the database are copied (image copy). There may be changes to the database as the copy is made and so all log files of changes being made during the backup must be saved too. Upon a restore, the changes in the log files are reapplied to bring the database in sync. Used when:A full backup of a database is needed Service level allows no down time for the backup

Package and Language?

Package:

It is a well defined program used to manipulate the data. Eg. Ms- Office

Language:

Using language we can create package as well as other application programs.

Eg. Java, C++...

Computer Organization and Computer Architecture

Computer Organization is how operational attributes are linked together and contribute to realise the architectural specifications.
Computer architecture is the architectural attrributes like physical address memory,CPU and how they should be made and made to coordinate with each other keeping the future demands and goals in mind.
Computer Architecture comes before computer organiation.Its like building the design and architecture of house takes maximum time and then organisation is building house by bricks or by latest technology keeping the basic layout and architecture of house in mind.  

DBMS and Data warehouse

A DBMS is a Database management System, it consists of the tools needed to access or build a database. A Data Warehouse is merely a collection of data from one or more sources collected together to enhance the the activities of data mining, which is performed with a DBMS or a RDBMS*.

Information Systems and Information Technology?

Information Systems is a large umbrella referring to systems designed to create, store, manipulate, or disseminate information. Example of an information system is a pencil and a piece of paper. The two objects themselves are just tools, but together they create a system for writing (information). The term Information systems has been around a lot longer than the computer, or the term information technology. These days the two are sometimes thought to be synonymous, but that, in most cases is a misconception. 

Information technology falls under the information systems umbrella, but has nothing to do with systems per say. IT deals with the technology involved in the systems themselves, e.g. an information system like wiki.answers.com contains many information technologies. Servers, server operating systems, web-server software (IIS, Apache, et al), and code written for the web-server software (PHP, C#, VB, PERL, Ruby, et al). Even your computer and browser make up part of this information system. Like the pencil and paper example, each one of the mentioned parts of this information system in itself is an information technology. 

That being said, most people in the profession no longer make a distinction. Moreover, companies call their IS/IT department a wide range of titles based on more on culture and tradition than anything else.

Understand Ranges in Microsoft Excel

Two Types of Range

There are two types of ranges in Excel -- contiguous and noncontiguous. These are described below:

Contiguous Range -- A contiguous range is a simple connected rectangular group of one or more cells.

Noncontiguous Range -- A noncontiguous range consists of two or more non-connected contiguous ranges.

Range Addresses

Single Cell Range Address-- A single cell range address consists of a column address followed by a row address. For example, the range address D16 means the cell at column D and row 16.

Multi-Cell Range Address-- A multi cell range consists of the starting corner of a range, followed by a colon, and then the ending corner of a range. It typically defines a rectangle in multiple rows and multiple columns, but it could be just a portion of a row or a portion of a column. See the examples below:

A1:C3 is an example of a typical multi-row multi-column range; it defines a 3 x 3 connected group of cells that extends from cell A1 to cell C3 inclusive.

A1:J1 is an example of a single-row multi-column range; it defines a 10 x 1 connected group of cells that extends from cell A1 to cell J1 inclusive.

A1:A10 is an example of a typical multi-row single-column range; it defines a 1 x 10 connected group of cells that extends from cell A1 to cell A10 inclusive.

Range Address Including Sheet -- Both single cell and multi-cell range addresses can contain a sheet name. If the sheet name is not included, the range is assumed to refer to the current sheet. Examples follow:

Sheet3!D16is an example of a single cell range that is located on worksheet 3.

Sheet3!A1:C3 is an example of a multi-row multi-column range that is located on worksheet 3.

Noncontiguous Range Addresses -- Noncontiguous range addresses consist of a comma separated group of range addresses. An example follows:

Sheet1!A1:C3, Sheet2!A1:C3, Sheet3!A1:C3 is an example of a noncontiguous range address that consists of the cells in the range A1:C3 on each of Sheet1, Sheet2, and Sheet3.

Selecting a Range

There are several ways to select a range. Descriptions follow:

-- Click on a cell, hold the left mouse button down, and drag to select a range.
-- Select a cell, press [F8], and use the arrow keys to select the range.

Selecting a Noncontiguous Range

To select a noncontiguous range, select the first part of the range with the mouse, then hold down the[Ctrl] key and select the second group of cells in the range. Repeat until you have selected all portions of the range.

Summary

This article defined the different types of ranges in Excel, gave some examples, and described basic methods for selecting ranges.

Glossary

Glossary

(Chapter-11)

Algorithm

A series of instructions or procedural steps for the solution of a specific problem.


Algorithm Code
A system of coding data by the use of combination of letters to represent item of information.


Alphanumeric Code
Pertaining to character set or field of data in which the coded characters may represent numerals or letters of the alphabets.


Analog Computers
Analog computers are machines designed to perform arithmetical functions upon numbers where the numbers are represented by some physical quantity.

Introduction to Windows Operating System

Introduction to Windows Operating System

(Chapter-10)

Windows Desktop
Windows “Desktop” is like a working surface of a desk. Desktop is where your applications, folders and shortcuts are located. Desktop contains the following items.
1. Icons
2. Taskbar
3. Start Button
The function of these desktop items is given below:


1. Icon
An icon is a small colourful graphical picture that represents an object like a file, folder, program or any hardware components of the computer. Every icon has a lable, which identifies it. The labels can be changed.

Computer Software

Computer Software

(Chapter-9)

Machine Language
Machine language is the only language that a compute understands directly without any translation, it is the binary language. It is the language of 0’s and 1’s . It consists of strings of binary numbers.
The binary codes are very difficult to memorize for human beings that is why a machine language is cumbersome for a user.


Difference Between a High-Level Language and Low-Level Language
High-Level Languages
High-Level language are more suitable for human use than machine languages and enable the programmer to write instructions easily using English words and familiar mathematical symbols. These symbolic languages are called High-Level languages. These high-level languages consist of simple English sentences, which are very easy to understand and memorize for human being.

Boolean Algebra

Boolean Algebra

(Chapter-8)

Boolean Algebra
The Boolean algebra was developed by the English mathematician George Boole; it deals with statements in mathematical logic, and puts them in the form of algebraic equations. The Boolean algebra was further developed by the modern American mathematician Claude Shannon, in order to apply it to computers. The basic techniques described by Shannon were adopted almost universally for the design and analysis of switching circuits. Because of the analogous relationship between the actions of relays, and of modern electronic circuits, the same techniques which were developed for the design of relay circuits are still being used in the design of modern high speed computers. Thus the Boolean algebra founds its applications in modern computers after almost one hundred years of its discovery.
Boolean algebra provides an economical and straightforward approach to the design of relay and other types of switching circuits. Just as an ordinary algebraic expression may be simplified by means of the basic theorems, the expression describing a given switching circuit network may also be reduced or simplified using Boolean algebra.

Data Representation

Data Representation 

(Chapter-7)

Data
The word data is derived from Latin language. It is plural of Datum (But Data is usually used as a singular term.) Datum (singular) – Data (plural). Data is any collection of facts of figures. The data is the raw material to be processed by a computer.
Example
Names of students, marks obtained in the examination, designation of employees, addresses, quantity, rate, sales figures or anything that is input to the computer is data. Even pictures, photographs, drawings, charts and maps can be treated as data. Computer processes the data and produces the output or result.

Storage Devices

Storage Devices 

(Chapter-6)

Primary Storage Devices

The names of some computer’s primary storage devices are as follows:
1. Random Access Memory (RAM)

• DRAM
• SRAM

2. Read Only Memory (ROM)

• EPROM
• PROM

3. Memory
4. Cache Memory

Computer Components

Computer Components

(Chapter - 5)

Central Processing Unit – CPU

The central processing unit (CPU), also called the microprocessor, the processor or central processor is the brains of the computer. The CPU is housed on a tiny silicon chip. This chip contains millions of switches and pathways that help your computer make important decisions. The switches control the flow of the electricity as it travels across the miles of pathways. The CPU knows which switches to turn on and which to turn off because it receives its instructions from computer programs. Programs are a set of special instructions written by programmers that control the activities of the computer. Programs are also known as software.

Programming and Basics

Programming and Basics

(Chapter-4)

LOOP

While writing a program it is necessary to repeat a part of a program for a number of times. The best solution for this is to use a loop it is a method which executes a part of the program repeatedly as specified by the programmer.

TYPES OF LOOPS

a) Pre-Test Loop
b) Post-Test Loop

Input and Output Devices

Input and Output Devices

(Chapter-3)

Printer
A computer peripheral that puts text or a computer generated image on paper or on another medium, such as a transparency. Printer can be categorized in several ways the most common distinction is IMPACT and NON-IMPACT.


Impact Printing
Is the method used by the conventional type writers. In some type of impact printing a metal “hammer” embossed with a character strikes a print ribbon, which presses the characters image into paper. In other types the hammer strikes the paper and presses it into the ribbon characters created through impact printing can be formed by either a solid font or dot matrix printing mechanism.

Data Processing

Data Processing

(Chapter-2)

Data Processing
Data processing often referred as D.P is a process of collecting the data together and converting the data into information. The method used for collecting the data may be manual, mechanical or electronic.
Data processing is a term mostly associated with business and commercial work. Since computers are being used in the processing of data the term “electronic data processing” may also be used.


Electronic Data Processing
Data processing means transformation of data into more meaningful results for carrying out scientific, business activities. The result of data processing is called “information”. The transformation of data consist of a sequence of operations. The sequence is called “procedure”.
Input -> Processing -> Output

Introduction to Computers

Introduction to Computers

(Chapter-1)

Computer
A Computer is an automatic electronic, calculating device which can process a given input in a prescribed manner to produce a desired output, at a very high speed with remarkable accuracy. It can also perform all arithmetic and logical functions according to instructions given in a systematic order to solve any problem and produce processed information.


Advantages of Computers


Speed
Since Computer is an electronic machine and electrical pulses travel at the rate of passage of electric current. This speed enables the computer to perform millions of calculations per second.


Storage
A computer has too much storage capacity. Once recorded, a piece of information can never be forgotten.

Glossary

Acidity

The acidity of a base is defined as the number of ionizable hydroxyl groups in its molecule.


Anode
It is an electrode through which electrons enter the external circuit.


Alpha Rays
There are positively charged particles emitted from a radioactive substance. They carry two positive charges and are called helium nuclie.


Analytical Chemistry
It is the branch of chemistry which discusses the analytical methods forgetting information about chemical compounds and chemical processes.

Differences

Metals and Non Metals

Metals
1. Metals have luster shine surface.
2. Metals reflect heat and light.
3. Metals conduct heat and electricity
4. Metals are ductile and can be drawn into wire.


Non-Metals
1. Non-Metals have no luster.
2. Non-Metals usually don’t reflect heat and light.
3. Non-Metals do not conduct heat and electricity.
4. Non-Metals are non ductile and cannot be drawn into wire.
5. Non-Metals are non-malleable and can not form sheets.

Electro-Chemistry

Electro-Chemistry

(Chapter – 7)

Electro-Chemistry
The branch of chemistry which deals with the study of chemical energy to electrical energy or electrical energy to chemical energy is called electro-chemistry.


Conductors
Those substances through which electric current can pass are called conductors. For example all metals are conductors.


Non-Conductors
Those substances through which electric current cannot pass are called non-conductors. For example plastic, wood are non-conductors.

Solution and Suspension

Solution and Suspension

(Chapter-6)

Solution
A homogeneous mixture of different chemical substances which has uniform chemical composition through out and shows uniform physical properties is called solution. For example dissolve a small amount of copper sulphate in water the water will become blue. If this blue liquid is filtered, it will pass through the filter paper without leaving any solid. The mixture thus prepared is called a solution.


Binary Solution
A solution which is formed by mixing two substances is called binary solution. For example solution of glucose and water.

States of Matter

States of Matter

(Chapter-5)

States of Matter
Matter has three states:
1. Gas
2. Liquid
3. solid
These are physical states of matter. The three states of one matter may have different physical properties while their chemical properties are same. Water exists in three physical states solid (ice), liquid and gas(steam) has same chemical properties.

Periodicity of Elements & Periodic Table

Periodicity of Elements and Periodic Table

(Chapter – 4)

Definitions
Periodic Table
A table of elements obtained by arranging them in order of their increasing atomic number in which elements having similar properties are placed in the same group is called Periodic Table.


Group
The vertical column of elements in the periodic table are called Groups.


Period
The horizontal rows of elements in the periodic table are called Periods.


Periodicity
The repetition of physical and chemical properties of elements periodically is called Periodicity of Properties.

Atomic Structure

Atomic Structure

(Chapter-3)

Dalton’s Atomic Theory
The important postulates of Dalton’s atomic theory are:
1. All elements are composed of atoms. Atom is too small so that it could not be divided into further simpler components.
2. Atom cannot be destroyed or produced.
3. Atoms of an element are similar in all respects. They have same mass and properties.
4. Atoms of different elements combine in a definite simple ratio to produce compounds.


Discovery of Electron
A discharge tube is a glass tube. It has two electrode, a source of electric current and a vacuum pump.
(Diagram)
Sir William Crooks (1895 performed experiments by passing electric current through gas in the discharge tube at very low pressure. He observed that at 10-4 (-4 is power to 10) atmosphere pressure, shining rays are emitted from cathode. These rays were named cathode rays. Cathode rays are material particles as they have mass and momentum.

Chemical Combination & Chemical Equation

Chemical Combinations & Chemical Equation   
(Chapter-2)

Laws of Chemical Combinations
There are four laws of chemical combinations these laws explained the general feature of chemical change. These laws are:
1. Law of Conservation of Mass
2. Law of Definite Proportions
3. Law of Multiple Proportions
4. Law Reciprocal Proportions 


Antoine Lavoiser has rejected the worn out ideas about the changes that take place during a chemical reaction. He made careful quantitative measurements in chemical reactions and established that mass is neither created nor nor destroyed in a chemical change. 

Introduction to Chemistry

Introduction to Chemistry

(Chapter-1)

Chemistry
The branch of science which deals with the study of matter,its composition and structure, changes in matter and laws and principles which govern these changes.

Matter
Anything that has mass and occupies space is called matter.For example,gases,air and water etc.

Branches of Chemistry
Some main branches of chemistry are as follows:

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