All the processes in the digital world are the game of numbers. To manage all this process and providing the information is called theNumber System.

Most commonly used number system is the **Decimal Number **System (base 10). Which we have used in general life also. Other major number systems are the **Binary Number** System(base 2), **Octal Number** System(base 8), **Hexadecimal Number **System(base 16).

Remember, we have learned the first thing in our school was A to Z, अ, आ, इ, ई. Then we moved to words, sentences, paragraphs and so on.

It means to write any language we need a few standard basic symbols. These symbols or characters are collectively known as **Script or लिपि**. Like for the Hindi language was written in **देवनागरी** script. The same way for any number system there is a predefined script present which is known as the **base of the number system**.

## Decimal Number System

Decimal Number system has** **a** base** **10** number system. This includes **0 to 9 **digits. It means all the values written in the Decimal Number System would **contain 0 to 9 digits only**.

The value of these digits (0 to 9) will depend on the position of the digit. That’s why it is also known as a **positional value system**.

For example, consider three numbers *123, 213, 231*. Here we can see there are three numbers having the same digits but the value of these numbers are different.

**123:**the value of 1 is 100 (One hundred twenty-three)**213:**the value of 1 is 10 (Two hundred thirteen)**231:**the value of 1 is 1 (Two hundred thirty-one)

The value or weightage of each position can be understandable by the below image.

As we all know that in any computer system instructions have been passed through the electric signals. So while using Decimal Number System we have to 10 signals for single instructions, that is too complex. So, other number systems have been developed to make it easier to implement by **reducing the base**.

**Binary Number System**

The easiest way to resolve the above problem is by using the Binary Number System. Most of the technologies use this system. This number system works on **base 2**. Means only two numbers **0 and 1** used in this number system. That’s why it is called a Binary Number System.

- 0 = OFF
- 1 = ON

All the values would be defined using these two digits (0 and 1) in the Binary number system. Like the Decimal Number System, these are also using Positional Value System.

### Binary to Decimal

Suppose that any digital system received two signals like **101** and **010**. So we could get the actual value by using below method:

Each digit is called a unit of memory **bit** in Binary Number System. Computer memory is measured in terms of how many bits it can store.

### Decimal to Binary

## Octal Number System

Octal Number System has **base 8**. It contains digits from **0 to 7**. Likewise Decimal and Binary Number systems we can get decimal value from an Octal Value.

### Octal to Decimal

**Octal Value**: 672_{8}

672_{8} = (8^{2} x 6) + (8^{1} x 7) + (8^{0} x 2)

= 384 + 56 + 2

= 442_{10}

### Decimal to Octal

## Hexadecimal Number System

Hexadecimal Number System has **base 16**. It contains digits from **0 to 9** and **A to F**. Remember A=10, B=11, C=12 and so on.

### Hexadecimal to Decimal

**Hexadecimal Value**: 6F2_{16}

6F2_{16} = (16^{2} x 6) + (16^{1} x 15) + (16^{0} x 2)

= 1536 + 240 + 2

= 1778_{10}

### Decimal to Hexadecimal

## ASCII

Below are the complete set of letters and symbols used in any standard computer system.

- Lower Case Alphabets (a to z) : 26
- Upper Case Alphabets (A to Z) : 26
- Numeric Values (0 to 9) : 10
- Punctuation Marks(. , ; : – ” !) : 7
- Special Characters (like $ @ & etc) : approx 40

These computer systems are now used Globally all over the world. So, it is necessary that there should be a unique value assigned to each of the above letter or symbols.

As we know that all the data/information, instructions is stored on a computer in binary form. So, assigning a standard Binary Code to each of them has been done under the ASCII code. It stands for **American Standard Code for Information Interchange**.

Letter | ASCII Code | Binary | Letter | ASCII Code | Binary | |

a | 97 | 1100001 | A | 65 | 1000001 | |

b | 98 | 1100010 | B | 66 | 1000010 | |

c | 99 | 1100011 | C | 67 | 1000011 | |

d | 100 | 1100100 | D | 68 | 1000100 | |

e | 101 | 1100101 | E | 69 | 1000101 | |

f | 102 | 1100110 | F | 70 | 1000110 | |

g | 103 | 1100111 | G | 71 | 1000111 | |

h | 104 | 1101000 | H | 72 | 1001000 | |

i | 105 | 1101001 | I | 73 | 1001001 | |

j | 106 | 1101010 | J | 74 | 1001010 | |

k | 107 | 1101011 | K | 75 | 1001011 | |

l | 108 | 1101100 | L | 76 | 1001100 | |

m | 109 | 1101101 | M | 77 | 1001101 | |

n | 110 | 1101110 | N | 78 | 1001110 | |

o | 111 | 1101111 | O | 79 | 1001111 | |

p | 112 | 1110000 | P | 80 | 1010000 | |

q | 113 | 1110001 | Q | 81 | 1010001 | |

r | 114 | 1110010 | R | 82 | 1010010 | |

s | 115 | 1110011 | S | 83 | 1010011 | |

t | 116 | 1110100 | T | 84 | 1010100 | |

u | 117 | 1110101 | U | 85 | 1010101 | |

v | 118 | 1110110 | V | 86 | 1010110 | |

w | 119 | 1110111 | W | 87 | 1010111 | |

x | 120 | 1111000 | X | 88 | 1011000 | |

y | 121 | 1111001 | Y | 89 | 1011001 | |

z | 122 | 1111010 | Z | 90 | 1011010 |

### ISCII

The same way ISCII (Indian Standard Code for Information Interchange) has been developed to support Devanagari, Tamil, Bangla, Gujarati**, **etc.

## Microprocessor

Microprocessor is like a brain of Computer. It controls entire system on a single chip. The design and functioning on the microprocessors are different depending upon the machine type.

While selecting any computer system, be careful about below characteristics of Microprocessors:

- Clock Speed
- Word Size
- Instruction Set

### Clock Speed

Clock Speed defines the **speed of the microprocessor** at which it executes the instructions. Speed of any microprocessor depends on how many electric **signals can be transferred per second**. That’s why Clock Speed is measured in **MHz(Mega Hertz)** or **GHz(Giga Hertz)**.

- 1 MHz = 1 Million cycle per second
- 1 GHz = 1 Billion cycle per second
- Cycle = 1 electric signal

### Word Size

Word Size refers to the **number of bits**, that can be processed in a single instruction. The first microprocessor was a **4-bit processor**. This processor has 4 input pins and 4 output pins. It means 4-bit data can be processed in a single go.

Nowadays, **32-bit and 64-bit** microprocessor available in the market.

### Instruction Set

Instructions are the **commands to perform an action/operation** on the given set of Data.

There are few pre-defined instructions are present in the Microprocessor. These instructions are in Machine Language. All these instructions are known as Instruction Set. Few of them are mentioned below:

- Data Transfer: share data, transform into information, etc.
- Arithmetic Operations: Basic Calculations
- Logical Operations: Decision making
- Control Flow: Handling Memory, Processes, etc.
- Input/Output and Machine Control

Related Links:

- Computer Basics -1 || Introduction and Structure of Computer.
- Computer Basics -2 || Types of Computers and Usage.
- Computer Basics -3 || What are the different types of Software?
- Computer Basics -4 || Importance of Operating System(OS).
- Computer Basics -5 || Understanding of Number System.
- Computer Basics -6 || Understanding MS-DOS Commands.
- Computer Basics -7 || Important Features of MS-Word.
- Computer Basics -8 || Let’s learn the usage of MS-Excel.
- Computer Basics -9 || Understand and Implement Data Validation in Excel.
- Computer Basics -10 || How to apply Filter in a data set in Excel?
- Computer Basics -11 || Using Charts in place of Data Tables in Excel.
- Computer Basics -12 || Advantages of PivotCharts over Simple Charts in Excel.
- Computer Basics -13 || Creating pivot charts/tables in Excel.
- Abbreviations to Full-Forms in Computer Basics.

TestNG:

- TestNG – 1 || Introduction and benefits of TestNG Framework.
- TestNG – 2 || Installation process and a sample program of TestNG.
- TestNG – 3 || Create and execute multiple Test Cases.
- TestNG – 4 || Let’s understand @Test Annotation and attributes.
- TestNG – 5 || Understand Assertion in TestNG.
- TestNG – 6 || Use of @BeforeMethod and @AfterMethod.
- TestNG – 7 || Use of @BeforeClass and @AfterClass.
- TestNG – 8 || Creation and execution of Test Suites.
- TestNG – 9 || Let’s move deep into the Test Suites.
- TestNG – 10 || Use @BeforeTest and @AfterTest Annotations.
- TestNG – 11 || Groups attribute with @Test Annotation.
- TestNG – 12 || Use of @BeforeGroups & @AfterGroups.
- TestNG – 13 || Use of @BeforeSuite & @AfterSuite.
- TestNG – 14 || DataProvider annotation & attribute.
- TestNG – 15 || DataProvider with parameters.
- TestNG – 16 || Access data from Excel sheet using DataProvider.
- TestNG – 17 || Passing multiple Parameters in testng xml.
- TestNG – 18 || Multiple Browser and Parallel Execution in TestNG.
- TestNG -19 || Concept of Parallel Execution.
- TestNG – 20 || Run TestNG Program using main() method.

Java Basics:

- Basic Java – 1 || Understand Java before start learning JAVA.
- Basic Java – 2 || Variables and Data Types used in JAVA.
- Basic Java – 3 || Understanding Class, Objects, Methods in Java.
- Basic Java – 4 || More on methods(Return Type and Parameters)
- Basic Java – 5 || Methods- Call by Value and Call by Reference in Java.
- Basic Java – 6 || Understanding of Constructor and Destructor in JAVA.
- Basic Java – 7 || Static Variables and Methods.
- Basic Java – 8 || Lets learn about Arrays in Java.
- Basic Java – 9 || Performing multiple operations using Java Operators.
- Basic Java – 10 || Conditions (If and Switch) in JAVA.
- Basic Java – 11 || for and for-each in Java. (Loops Part-1)
- Basic Java – 12 || Alternate looping concepts while and do-while. (Loops Part-2)
- Basic Java – 13 || Decimal values v/s Octal base(8) values in JAVA.
- Basic Java – 14 || Learn about String literals in Java.
- Basic Java – 15 || Runtime User Input using Scanner Class (Part-1).
- Basic Java – 16 || Runtime User Input using BufferedReader Class (Part-2).
- Basic Java – 17 || Runtime User Input using Console Class (Part-3).
- Basic Java – 18 || Difference between break and continue keywords.
- Basic Java – 19 || Sending Email using Java (Part-1).
- Basic Java – 20 || Sending Email with attachment using Java (Part-2).
- Basic Java – 21 || Stack memory and Heap memory in Java.
- Basic Java – 22 || Let’s learn more about String.

**Java File Handling:**

- File Handling | Reading data from word document(.doc or .docx) in JAVA.
- File Handling | Reading data from Excel files (.xls or .xlsx) using JAVA.
- File Handling | Writing data into an Excel(.XLSX or .XLS) File.
- File Handling | Implement formatting in Excel using Java.
- File Handling | Copy existing data from one workbook to another workbook in Java.
- File Handling | Reading data from PDF file using JAVA.
- File Handling || Traverse folders and subfolders in Java.
- File Handling || Reading and Writing data from a text file.
- File Handling || Multiple file creation using template based input data.
- Framework || Simple example of Key Driven Framework using excel sheet in Selenium(JAVA).

**OOPs Concept:**

**Java Question And Answer:**

- QnA | Difference between Integer and int keywords.
- QnA | Can main method be overloaded?
- QnA | How do I reverse a String/Sentence in Java?
- QnA | Perform Multiplication and Division without * or / or % operators.
- QnA | How do I get the default value of data type?
- QnA | How to split String if it contains period symbol (.) in between?

**Java Programs:**

- Different ways to Reverse a String in Java.
- Copy formatting & style of cells from one sheet to another.
- Getting IP address and Hostname using InetAddress Class.
- User inputs via Command Prompt using arguments of main() method of a class.
- Program for List and ArrayList in Java.
- Useful methods and implementation under Scanner Class.
- Swapping two variable values without using any third variable.
- Difference between int x= 10 and y=010 in Java.
- Parameterized Constructors v/s Setter and Getter function in JAVA.
- Override a Static Method.

**Excel:**

- Computer Basics -13 || Creating pivot charts/tables in Excel.
- Computer Basics -12 || Advantages of PivotCharts over Simple Charts in Excel.
- Computer Basics -11 || Using Charts in place of Data Tables in Excel.
- Computer Basics -10 || How to apply Filter in a data set in Excel?
- Computer Basics -9 || Understand and Implement Data Validation in Excel.
- Computer Basics -8 || Let’s learn the usage of MS-Excel.