Computer Information

Thursday, August 2, 2018

CENTRAL PROCESSING UNIT August 02, 2018

System Bus

A bus is a path through which data is transferred from one component to other inside system. System bus connects CPU and memory and other components inside system.

A bus is data communication path over which information is transferred a byte or word at a time. System bus connects the central processing unit to main memory on the motherboard. The majority of system buses are made up of 50 to 100 distinct lines for communication. The system bus consists of three types of buses. The system Bus consists of three types of buses.

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1. Data Bus

2. Address Bus

3. Control Bus

A bus is a path through which data is transferred from one component to other inside system. System bus connects CPU and memory and other components inside system. A bus is data communication path over which information is transferred a byte or word at a time. System bus connects the central processing unit to main memory on the motherboard. The majority of system buses are made up of 50 to 100 distinct lines for communication. The system bus consists of three types of buses. The system Bus consists of three types of buses.

Data Bus

A type of Bus that is used to transfer data from memory to CPU and I/O device to memory is called Data Bus.

Data bus is the bidirectional bus. It can communicate in two ways, but in one direction at a time. It handles the transfer of data and instructions. The data bus is used to transfer instructions from memory to the CPU for execution. It carries data (Operands) to and from the CPU and memory as required. It is also used to transfer data between memory and I/O devices during input output operations. A typical data bus is 32-bits wide. This means that up to 32-64 bit data buses and even more.

Address Bus

A type of Bus that is used to carry the address (not data) is called Address Bus. It carries address between memory and CPU (central processing unit) and between memory and I/O devices.

Address bus carries addresses not data. An address is defined as a label, symbol, or other set of characters used to designate a location or register where information is store. Before data or instructions can be written into or read from memory by the CPU or I/O sections, an address must be transmitted to memory over the address bus. The number of lines on the bus determines the number of addressable memory elements. For example an 8-bit bus can represent 2⁸for example 256 unique addresses. A 16-bit bus can address 65536 unique addresses.

Control Bus

Control Bus is a type of bus that carries control instructions to run operates hardware.

The Control Bus is used by the CPU (central processing unit) to direct and monitor the actions of the other functional areas of the computer. It is used to transmit a variety of individual signals (read, write, interrupt, acknowledge) and coordinate the operations of the computer. The size of control bus is from 8 to 16 bits.

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Wednesday, August 1, 2018

CENTRAL PROCESSING UNIT August 01, 2018

Types of Register

Special purpose Register
General Purpose Register

General Purpose Register

The type of register that hold data and addresses is called general purpose register.

General purpose register are used to arithmetic (+,-,*,/) and logic (<,>,=) operations.

Typically theses register are 8-32 bit registers.

Following are the commonly used purpose registers

1. Accumulator (AX)

2. Data Register (DX)

3. Base Register (BX)

4. Counter Register (CX)

Accumulator (AX)

Accumulator is general purpose register and is used by CPU (Central processing unit) for performing arithmetic and logic operations and to hold the result of those operations. The accumulator is initially set to zero, and then each number in turn is added to the value in the accumulator. It consists of two 8-bit register (AH and AL) which can be combined together and used as a one 16-bit register.

Base Register (BX)

The base register can perform arithmetic and data movement and it has some special addressing abilities. Base Register can hold a memory address that points to another variable. It usually contains a data pointer. It consists of two 8-bit register (BH and BL) which can be combined together and used as a one 16-bit register.

Counter Register (CX)

The counter register acts as a counter for repeating or looping instructions. The instructions given are automatically repeated and will decrement the value of counter register and quits when it is equal to 0. It consists of two 8-bit registers (CH and CL) which can be combined and used as 16-bit register counter register.

Data Register

Data register has a special role in multiply and divide operations. It works like a buffer and holds anything that is copied from the memory ready for the processor to use it. It also consists of two 8-bit register (DH and DL) and can register can used as port number.

Special Purpose Registers

These register hold the state of a program. They include program counter, instructions register, memory address register and memory buffer registers. These are used by control the operations of Central processing unit and by the operating system programs to control the executions of the programs.

Following are the special purpose registers.

1. Instruction Register (IR)

2. Memory Address Register (MAR)

3. Memory Buffer Register (MBR)

4. Program Counter (PC)

Instruction Register (IR)

Instruction register is a part of control unit, which stores the instructions currently being executed. Each instruction to be executed is loaded into the instruction register. It is also known as current instruction register (CIR) because it holds the current instruction being executed.

Memory Address Register (MAR)

Memory Address Register holds the memory address, the memory address from which data will be provided to the Central processing unit or will have the address to which data will be send and then stored. It basically holds the memory location of data that needs to be accessed. When reading from memory, the data addressed by MAR is fed into the MDR (memory data register) and then is used by the Central processing unit. When writing to memory, the CPU writes data from Data register to the memory location whose address is stored in Memory Address Register. So, in both data is to be read or stored.

Memory Buffer Register (MBR)

The Memory Buffer Register actually holds the contents of the memory which are to be moved from memory to other components or from components to the memory. In order to store a word it must be transferred to Memory Buffer Register and then allowing the processor and memory units to act independently.

Program Counter (PC)

Program Counter is also known as instruction Pointer. It is a register in a computer processor that contains the address (Location) of the instruction being executed at the current time. As each instruction gets fetched, the program counter increases its stored value by 1. After

each instruction is fetched, the program counter points to the next instruction in the sequence.

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Tuesday, July 31, 2018

INSIDE SYSTEM UNIT July 31, 2018

Computer Casing

A Computer Case also known as computer chassis, box, tower, enclosure, Housing, system unit or simply case is the enclosure that contains most of the components of computer system. Cases are usually constructed from steel or aluminum. Plastic and other materials such as wood or Lego are also used.

There are two types of computer Casing.

1. Desktop Casing

2. Tower Casing

Desktop Casing

Desktop Casing is the old type of computer casing. These are designed to keep on desk and usually monitor is kept over it kept over it.

In Desktop casing the system unit is kept horizontally.

Tower Casing

Tower Casing is the modern type of system casing. It is more attractive then desktop casing. Normally monitor is kept side by side with tower casing.

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INSIDE SYSTEM UNIT July 31, 2018

Central Processing Unit( CPU) and system unit

Central Processing Unit (CPU) and system unit

Sometimes people erroneously refer the system unit as Central Processing Unit but these are two different things. A computer system unit is the case with motherboard and all the other parts while CPU is the central processing unit, a chip on the motherboard that does all the processing.

The CPU (central processing unit) chip is installed in a slot on motherboard which is placed inside the casing of system of the unit.

System Unit

A system Unit is a box or case that contains motherboard and other important component of system. Such as Hard Disk, CD(Compact discs)or DVD (Digital Versatile Disc) Power supply etc.

System Unit is also called Computer casing, Housing, Box, or system tower.

CPU (Central Processing Unit)

Central Processing Unit is a chip that is attached to computer. It is a small size device that performs the overall function of computer. It is consider to be the brain of computer. Central Processing Unit is used for processing of computer. Central Processing Unit is the integral part of any computer system. It is the brain of computer system. Just like human brain which controls all the activities of human body, the Central Processing Unit controls all the operations of the computer. Central Processing Unit is connected to all parts of computer. Central Processing Unit not execute instructions but also controls the storage of data, input output activates and functions of different devices attached. Central Processing Unit is also called microprocessor or processor.

Sometimes people erroneously refer the system unit as Central Processing Unit but these are two different things. A computer system unit is the case with motherboard and all the other parts while CPU is the central processing unit, a chip on the motherboard that does all the processing. The CPU (central processing unit) chip is installed in a slot on motherboard which is placed inside the casing of system of the unit. System Unit A system Unit is a box or case that contains motherboard and other important component of system. Such as Hard Disk, CD(Compact discs)or DVD (Digital Versatile Disc) Power supply etc. System Unit is also called Computer casing, Housing, Box, or system tower. CPU (Central Processing Unit) Central Processing Unit is a chip that is attached to computer. It is a small size device that performs the overall function of computer. It is consider to be the brain of computer. Central Processing Unit is used for processing of computer. Central Processing Unit is the integral part of any computer system. It is the brain of computer system. Just like human brain which controls all the activities of human body, the Central Processing Unit controls all the operations of the computer. Central Processing Unit is connected to all parts of computer. Central Processing Unit not execute instructions but also controls the storage of data, input output activates and functions of different devices attached. Central Processing Unit is also called microprocessor or processor.

System Unit with other important components

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Monday, July 30, 2018

CENTRAL PROCESSING UNIT July 30, 2018

Basic Components of CPU (Central Processing Unit)

Basic Components of CPU

CPU Consists of the following basic Components.

1. Arithmetic and logic Unit (ALU)

2. Control Unit (CU)

3 Register

4. Cache

5. Internal Buses

Arithmetic and Logic Unit(ALU)

Arithmetic logic unit is the main processing unit of CPU. It performs arithmetic and logic operation on data. Arithmetic means addition, subtraction, multiplication, division and logical operation is the comparison between two data items. Arithmetic and logic Unit processes the data and then give back the results. The Result of an operation Are stored in register (temporary storage location). Now a day’s Central Processing units (CPU) have more than one Arithmetic and logic Units that can do the calculation simultaneously in order to improve the efficiency of computer system.

Control Units (CU)

Control unit manages the functions performed by different parts of the computer. It Coordinates and controls and the overall computer system, just like the brain controls the human body. It executes instruction, controls and directs the input, informs ALU (Arithmetic and logic Unit) for processing, arranges the storage and directs the data to the output device.

Control unit is responsible for directing the flow of instruction and data within control signals. The control signals. The control unit contains the necessary logic to interpret instructions and to generate the signals necessary for the execution of those instructions. The descriptive words “fetch” and “execute” are used to describe and a read control to unit. It fetches an instruction at by sending an address and a read command to the memory unit. The instruction at that memory address is transferred to the control unit for decoding. It then generates the necessary signals to execute the instruction.

Registers

Registers are small memory devices available in the CPU. These are used to store data temporarily. CPU register are at top of the memory hierarchy, and provides the fastest way for a cpu to access data. Each register is designed for a special purpose and the size of each varies. Register are measured ny the number of bits they can hold, like 8-bitsm 16 bits or a 32 –bits register. Processor contains different kinds of register and is classified according to their content or instruction.

CPU register are divided into two main types

General purpose register

Special purpose register

Cache Memory

It is the small amount of memory located between main memory and processor. Cache memory is also known as high speed buffer or a chip memory. The microprocessor stores a copy of most frequently used data and instructions in the cache memory. The microprocessors when desires and data its first look and to the cache memory, if not found their then it will ask for the same from the main memory. This will result in the better efficiency of the microprocessor speed and its usage.

There are different levels of cache memory

Level 1(L1) Cache memory resides inside the microprocessor and is very fast from the other memories Microprocessor first checks the level 1 cache memory.

Level 2 (L2) cache memory lies just outside the microprocessor, it is slow as instruction not found in level 1 cache memory the microprocessor will look in to level 2 cache memory.

Now a day’s modern microprocessor has level3 cache in the motherboard.

It is the small amount of memory located between main memory and processor. Cache memory is also known as high speed buffer or a chip memory. The microprocessor stores a copy of most frequently used data and instructions in the cache memory. The microprocessors when desires and data its first look and to the cache memory, if not found their then it will ask for the same from the main memory. This will result in the better efficiency of the microprocessor speed and its usage. There are different levels of cache memory Level 1(L1) Cache memory resides inside the microprocessor and is very fast from the other memories Microprocessor first checks the level 1 cache memory. Level 2 (L2) cache memory lies just outside the microprocessor, it is slow as instruction not found in level 1 cache memory the microprocessor will look in to level 2 cache memory. Now a day’s modern microprocessor has level3 cache in the motherboard.

Internal Buses

Bus

Data travels, inside the system through a communication path. These path are drawn on motherboard and joined different components of computer inside system.

Bus is a data communication pathway through which data travels from are components to other, inside system.

Buses are used to carry data between CPU (central processing unit) and memory

Bus can be

Serial Bus

Parallel bus

Serial Bus

A type of bus that carries data through a single channel, is serial bus. In serial bus bit follows each other on single on a single channel.

Parallel Bus

A type of bus that carries data (bits) through multiple channel

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Saturday, July 21, 2018

SYSTEM DEVELOPMENR LIFE CYCLE July 21, 2018

What is a system? Where exactly the testing activities begins in SDLC?

System:

The term system is originated from the Greek term “Systema” which means to “place
together”. It can be defined as a set of inter-related components having a clear boundary that
work together to achieve a common set of objectives.

Testing Activities in SDLC:

In SDLC the testing activity takes place after the coding phase where the software is evaluated.
The given outputs are compared with the required outputs. Thus a decision is made about the
validity of developed product. If any problems found they are removed and the new product
undergoes again this testing procedure.
One of the software testing principle say that “Start testing early” in the SDLC. It has been
observed that most of the errors introduced in the requirement or design phase. Defects identified
later in SDLC are expensive to fix than defects identified in early stage. So testing should start
early to the introduction of defects in the early phase. So start testing early in the software
development would solve the problem, as the earlier you find a bug, the cheaper it is to fix it.

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PROGRAMMING LANGUAGE July 21, 2018

Structure of C++Program &declaration,Initialization of Variable

Structure of C++ Program with declaration&initialization of variable

Declaration & Initialization of variable in C++ Program:

In order to use a variable in C++, we must declare it, first. The process of specifying the variable name and its data type is called Variable Declaration.

The syntax of declaring a variable is: data type variable;

Example: int a; float b; char c;

Many variables of the same data type can be declared in a single line. In this case following syntax is used.

data type variable1, variable2, variable3, …, variable_n;

Example: int a, b, c,d;

[Note: "Semi-colon; must be placed at the end of the variable declaration."]

Variable initialization in C++ Program:

The process of assigning a value to a variable at the time of declaration is called variable initialization. The = (equal to) sing is used to initialize a variable.

Example: int a=5; float b= 1.6; char c= ‘a’ ;

Define Structure of C++ Program:

The format of writing C++ program is called its structure. The structure of C++ program consists of following parts:

Pre-processor directives,
Header file,
Main function,
Program Body, and
Statements.

Now we will explain each of the above one by one.

1. Pre-Processor Directives:

Pre-processor directive is an instruction given to compiler before the execution of an actual program. These are executed before the compilation process. The compiler resolves all these directives before any code is actually generated. This directive gives instruction to a compiler to perform certain tasks before the compilation process. Almost every C++ program contains a pre-processor directive.

The pre-processor directives start with a # symbol. These directives are written at the start of the program. “#include” is most commonly used pre-processor directive. It is used to include the Header File in the program. There are many other preprocessor directives in C++.

2) Header File:

A header file is also called “include file”. A header file is a file that contains the definition of different predefined functions and objects/terms. Header files contain definitions of Functions and Variables. The meaning and purpose of different predefined functions and objects are stored in header files. Header file has an extension "h".

The programmer just uses the pre-defined function but does not explain the meaning and purpose of them to a computer. This task is done by the header file. Thus this saves our precious time and effort. There are different header files in C++. Each contains the definition of a set of some predefined functions. The name of a header file is written in angle brackets < >. E.g. <conio.h>

3. Main function:

The main function is the starting point of a C++ program. When the program runs, the controls enter in main function and stars executing its statements. Each program must contain a main function. If a program does not contain the main function it can’t be executed. Method of writing the main function is: int main ( ) or void main( )

4. Program Body:

After the main function, the body of a program starts. The program body begins with opening brace { and ends with closing brace }. Program body contains statements.

5) Statements:

A statement is an instruction to the computer to perform a certain task. In C++ programming each statement ends with semicolon ( ; ). Thus semicolon is called statement terminator.

<iostream.h>:

<iostream.h> stands for input output stream. It is a header file, it contains the definition of objects like cin>> and cout<<. cin>> is used for taking input while cout<< is used for displaying output.

<conio.h>:

<conio.h> stands for console input output. It is also a Header file that contains the definitions of many predefined functions like getch ( ), clrscr ( ).

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Computer Information

Breaking

Thursday, August 2, 2018

System Bus

Data Bus

Address Bus

Control Bus

Wednesday, August 1, 2018

Types of Register

General Purpose Register

Accumulator (AX)

Base Register (BX)

Counter Register (CX)

Data Register

Special Purpose Registers

Instruction Register (IR)

(adsbygoogle = window.adsbygoogle || []).push({}); Memory Address Register (MAR)

Memory Buffer Register (MBR)

Program Counter (PC)

Tuesday, July 31, 2018

Computer Casing

There are two types of computer Casing.

Desktop Casing

Tower Casing

Central Processing Unit (CPU) and system unit

System Unit

CPU (Central Processing Unit)

Monday, July 30, 2018

Basic Components of CPU

Arithmetic and Logic Unit(ALU)

Control Units (CU)

Registers

Cache Memory

Internal Buses

Saturday, July 21, 2018

System:

Testing Activities in SDLC:

Declaration & Initialization of variable in C++ Program:

Variable initialization in C++ Program:

Define Structure of C++ Program:

1. Pre-Processor Directives:

2) Header File:

3. Main function:

4. Program Body:

5) Statements:

<iostream.h>:

<conio.h>:

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