Difference between Binary Coded Decimal (BCD) and Binary Number System

Binary Coded Decimal (BCD) Vs. Binary:

BCD		Binary
1	BCD is a coding system.	Binary is a number system.
2	Its base is 4.	Its base is 2.
3	It needs more bit to represent a number.	It needs fewer bits to represent a number.
4	It is easy to construct.	It is difficult to construct.
5	Example: BCD of 15 is 00010101.	Example: Binary of 15 is 1111.

Unicode Code

Unicode:

Unicode means Universal Code. Unicode is standard for representing the characters of all the languages of the world. Unicode uses 16 bits per character to represent 65,536 (2¹⁶) unique characters. One the major advantage of Unicode is the first 256 codes is same as ASCII codes.

BCD Code

BCD:

BCD stands for Binary Coded Decimal. A number representation where a number is expressed as a sequence of decimal digits and then each decimal digit is encoded as a 4- bit binary number.

EBCDIC Code

EBCDIC:

EBCDIC stands for Extended Binary Coded Decimal Interchange Code. It is an 8- bit code that defines 2⁸= 256 symbols. EBCDIC is still being used in IBM’s, mainframes and midrange computers.

ASCII Code

ASCII:

ASCII is short for American Standard Code for Information Interchange, and is a 7 bit encoding of characters on computers. There are 128 values ranging from 0 to 127, of which 95 are printable characters and 33 are not visible but used for control characters.

There are several larger character sets that use 8 bits known as ASCII-8, which gives them 128 additional characters. The extra characters are used to represent non English characters, graphics symbols, and mathematical symbols. 

Code

Code:

A number, letter, character, symbol or any combination thereof, used to represent a item is known as code.

There are different types of codes. They are as follows:

1. ASCII
2. BECDIC
3. BCD
4. Unicode, etc.

2’s complement

2’s complement:

The 2’s complement of a binary number can be obtained by first complement each bit of the number to get 1’s complement. Add 1 to this number to get 2’s complement.

For example, consider the number 14 whose binary representation is 1110. 1’s complement is 0001. Now, adding 1 to this number gives 0010 which is 2’s complement representation of -14. 

1’s Complement

1’s Complement:

The 1’s complement of a binary number can be obtained by subtracting each digit of the number from 1 which is same as replacing 1 by 0 and 0 by 1. 

For example, 1’s complement of 110101 is 001010.

Complement

Complement:

Subtraction of two numbers in a computer complicated and expensive in terms of circuit, especially for repeated borrowing from one column to another. Complements can be used to reduce from subtraction to addition. It avoids the possibility of repeated borrowing from one column to another and hence, borrow circuits are eliminated and cost is reduced.  

There are two types of complements:

1. 1’s Complement.
2.  2’s Complement. 

Reasons for use of Binary system in the design of Computer

Reasons for use of Binary system in the design of Computer:

The reasons of using binary system by the computer are:

1. Electronic components naturally operate in a binary mode. A core is magnetized in anticlockwise (0 state) or clockwise (1 state); a switch is either open (0) or closed (1); electrical pulses are either absent (0) or present (1).
2.  With the use of any two states, the circuit design is simplified, cost is reduced and reliability is improved.
3. Finally, the binary system is used because everything that can be done with a base 10 can be done in binary. 

Hexadecimal Number System

Hexadecimal Number System:

The hexadecimal number system consists of sixteen digits: 0, 1, 2, 3, 4, 5, 6, 7, 8, 9, A, B, C, D, E, and F. Since the system uses sixteen digits, its base is 16 and each position in a hexadecimal number represents a power of the base 16. Thus the hexadecimal number D3E0 can be expressed in decimal equivalent as

Octal Number System

Octal Number System:

The octal number system consists of eight digits: 0, 1, 2, 3, 4, 5, 6, 7. Since the system uses eight digits, its base is 8 and each position in an octal number represents a power of the base 8. Thus the octal number 7312 can be expressed in decimal equivalents as

Binary Number System

Binary Number System:

The binary number system consists of only two digits, namely 0 and 1. Since the system uses only two digits, its base is 2 and all the numbers in the system are written as a string of 0's and 1's. Thus the binary number 10101 can be expressed in decimal equivalent as                                                 

Types of number systems (positional) with Base and Symbols

Different types of number systems (positional) with Base and Symbols:

Types of Number System: Non-Positional and Positional

Types of Number System:

1. Non-Positional System
2. Positional System

Non-Positional Number System:

In the non-positional system, the characters used are I for 1, II for 2, etc. and are of position invariant, i.e. each symbol represents the same value regardless of its position in the number. Since it is very difficult to perform arithmetic calculations with such a number system, positional number systems were developed.

Positional Number System:

In positional number system, there are only a few symbols called digits, and these symbols represent different values depending on the position they occupy in the number. The value of each digit in such a number is determined by three considerations:

1. The digit itself,

2. The position of the digit in the number, and

3. The base of the number system.

Base of a number system

Base of a number system:

The total number of digits, that is used to represent number, in any number system, is known as the base of that number system.

Number System

Number System:

A number system consists of a set of symbols and rules for representing any number.

Types of Microcomputer: Desktop, Laptop, Workstation and Handheld

Types of Microcomputer:

Microcomputer is a kind of computer that deals with single use. The brain of a microcomputer is the microprocessor. It computes all the operation. A micro computer system is formed by adding input/ output capability and memory to the microprocessor.

There are four types of microcomputers, such as:

1.  Desktop

2.  Laptop

3.  Workstation

4.  Handheld

·         Desktop:

It is small computer based on a microprocessor and it is non-portable, general-purpose computer that fits on a normal office table.

Generally used by one person at a time, supports multitasking. It designed to meet personal computing needs of individuals.

Types of Computers Based on Capacity: Macrocomputer, Minicomputer, Mainframe Computer and Supercomputer

Types of Computers Based on Capacity:

Capacity of computer refers to the volume of data that a computer system can process.

There are four types of computer based on capacity.

1. Macrocomputer.

2. Minicomputer.

3. Mainframe Computer.

4. Supercomputer.

• Microcomputer:

Microcomputer is kind of computer that deals with single user. Thebrain of a microcomputer is the microprocessor. It computes all the operation. A micro computer system is formed by adding input/ output capability and memory to the microprocessor. It is also known as personal computer. Example: IBM PC, Apple power PC.

Difference between Analog Computer and Digital Computer

Analog Computer Vs. Digital Computer:

Analog computer		Digital computer
1	It works using continuous varying device.	It works using two different voltage levels.
2	It is measuring device	It is a counting device.
3	It takes temperature, pressure etc. as input.	It takes character, digit etc. as input.
4	Results are represented by meters, oscilloscopes etc.	Results are presented by printer, monitor etc.
5	It is cost and provides less precise information.	Digital computer is cheap and reliable.
6	It doesn’t have the ability of digital computers to store data in large quantities.	It can store data of large volume.

Types of Computer Based On Working Principal: Analog, Digital and Hybrid Computer

Types of Computer Based On Working Principal:

• Analog computer
• Digital computer
• Hybrid computer

• Analog Computer: 

  An analog computer is a form of computer that uses the continuously changeable electric signal is used rather than letter or digit which is represented by “0” and “1”. Since it uses any vector or scalar quantity directly, input data does not take conversion like digital computers. It does not need memory to store data.

Difference between General-purpose Computer and Special-purpose Computer

General-purpose Computer Vs. Special-purpose Computer:

General-purpose		Special-purpose
1	It is designed to perform variety or task.	It is designed for a specific application
2	It is more versatile.	It is less versatile.
3	It is less efficient.	It is more efficient.
4	Programs are temporarily stored in memory.	Instruction permanently programmed into the memory.
5	It is comparatively slower than special purpose computer.	It is comparatively faster than general purpose computer.
6	Example: microcomputer.	Example: to control traffic lights.

Type of Computer Based On Purpose

Type of Computer Based On Purpose:

1. General-purpose Computer;
2. Special-purpose Computer;

• General-purpose Computer:

• These types of computers are used to handle a variety of tasks.
• Programs are temporarily stored in memory. Once stored in memory, the program can be executed.
• After the completion of the execution of one program, another program can be used for some other tasks.
• Some hardware can be used for many different programs.

As for example: micro computer.

• Special-purpose Computer:

• These types of computers are designed for a specific application.
• Many such computers, have instruction permanently programmed in to the memory, are designed to perform only one major function.

As for example: special purpose computers are used to control traffic lights.

Type of Computer

Type of Computer:

Computer can be classified in many different ways. Such as:

• On the basis of purposes.
• On the basis of signals.
• On the basis of capacity.

Types of Computer

Computer Expansion Bus Architecture

Expansion Bus:

The Expansion Bus connects external devices, peripheral devices, expansion slot, I/O ports and drive connections to the rest of the computer. It allows for the expansion of computers capabilities. It is generally slower than the system bus.

There are various types of expansion bus. Such as:

• VESA (video Electronics Standard Association)
• PCI (Peripheral Component Interconnect)
• USB (Universal Serial Bus)
• VESA: A kind of expansion bus which carries video storage to the video signal is called VESA.

Computer System Bus Architecture

System Bus Architecture: 

The system buses connect the different component such as the CPU, system memory, and all other components on the motherboard.

System Bus can be classified into three types, as:

• Data Bus.
• Address Bus and
• Control Bus.

• Data Bus: A kind of system bus that carries only data from system components to the memory and from the memory to the system components is called data bus. It directional. It may be 8 bit, 16 bit, 32 bit and 64 bit. It means, it can carry up to 2n bit.
• Control Bus: A kind of system bus which carries control signal from the processor to other devices is called control bus. It is also directional. It connects all the devices with processor.

Computer Bus Architecture

Bus Architecture:

The desired arrangement of buses in the computer for proper propagation of all sorts of data and signal is called bus architecture.

Computer Bus:

A bus is a set of wires that allow information to travel between components inside or outside of a computer. Computer bus can be divided into two different types as:

1. Internal/ System Bus and
2. External/ Expansion Bus.

Computer Bus Architecture

Basic Computer Organization with details

Basic Computer Organization:

Computer systems perform the following four basic operations.

• Input unit: It takes data and instructions as the input and then converts those inputs in machine read-able from and supplies the converted data to the computer system for further processing.
• Processing Unit: It manipulation the data to make useful information. Its two parts are: The arithmetic logic unit and the control unit. They are jointly known as the central processing unit (CPU).

Computer Organization or system

Computer Organization/ system:

A system or organization is a group of integrated parts, which have the common purpose of achieving some objectives.

A computer is often referred to as a computer system or organization, because it is made up of integrated components, which works together to perform the steps called for in the program being executed.

An expanded computer system

An expanded computer system:

There are several methods for getting data into the computer, called the input. Getting data out from the computer, called the output. The functional units of an expanded system are:

An expanded computer system

• Input unit: It takes data and instructions as the input and then converts those inputs in machine read-able from.

A simplest computer system

A simplest computer system:

The most simple computer system has the following functional units:

1. Input unit.
2. Processing unit.
3. Output unit.

• Input unit:  It takes data and instructions as the input and then converts those inputs in machine read-able from.
• Processing unit: It manipulates the data to make useful information. The basic operations of processing units are arithmetic, logical, shift, controls etc.
• Output unit: It converts the machine read-able results into human read-able from and displays the result in soft copy from or in hardcopy from.

The computer Generation

The computer Generation:

“Generation” in computer talk is a step in technology. Originally, the term “generation” was used to distinguish between varying hardware and software technology.

There is five generation of computer until now. They are:

• First generation:

• Generation period: 1942-1955
• Hardware technologies:
• Vacuum tube.
• Electromagnetic relay memory.
• Punch card secondary memory.
• Software technologies:
• Machine and assembly language.
• Mostly scientific applications.
• Other features:
• Bulky in size.
• Unreliable.
• Limited commercial use.
• Difficult to use.

Example: IBM 701, ENIAC etc.