computer organisation

 

Computer Organisation

Computer is an electronic device.

Computer works are IPO cycle (input àProcessàOutput).

Computer process a certain input and provides a specific output.

CPU (ALU,Resisters,CU ) memory ,input unit ,output unit,,storage unit etc.

 

Ø Input Units

Input devices connected to a computer system makes its input unit.

It is responsible to take Input and convert into computer understable format.

Exp=keyboard ,mouse ,OMR ,OBCR,MICR,JOY STICK,camera ,bio metric ,scanner ,touch screen.

 

Ø Output Unit:

Output devices connected to a computer system makes its  output .

It is the respondibility of an output unit to produce after processing.

Different output devices are used for different types of Output,example:Monitor ,Projector ,speaker ,plotter.

 

v CPU (Central Processing Unit)

CPU is the main controlling and processing unit of computer where all calculations takes place.

CPU is also known as brain  of the computer system because it directs ,guides and controls working of computer system.

Components are :

1.Arithmetic Logic Unit-performs logical and mathematical operations.

2.Control Unit:It control and directs every task.

3.Registers:It is the place to store data temporarily for the purpose of correct  calculation.

 

* Memory

 

Memory is often  known as Primary Memory .

It is not like a human memory because data stored in this memory automatically flushes out with power out off which can not recover later.It is the workplace of a computer  system where data is to kept an temporarily basis for the purpose of processing.

Smallest unit of memory is a bit .

8 bit=1 byte

1 bits =1 Nibble

1024 byte==1 Kilobytes(1Kb)

Random Access Memory (RAM)

ROM_Read Only memory.

The total time taken to access data from memory is known as memory access time.

 

1.RAM-

In RAM  any memory cell can be accessed from any desiring memory Location.It is not possible to imagine processing without RAM.

RAM supports both read and write operations.

There  RAM is divided into two parts .

Types OF RAM:

1.DRAM (dramitcal RAM)-It is basically consists of transistors and capacitors  which stores electric charge .

As per switching of transistor ,capacitor does contain 1 bit or does not contain a charge 0 bit.

Storage density of DRAM is from 10 to 100 Giga Bits.

 

2.SRAM (Static RAM)-It is made up of internal flip flops wire.

Note:1 Flip Flop is capable of storing 1 bit.

It occupies more space as compared to DRAM.

It is fast as compared to Dynamic Random Access Memory.

 

Now we will move forward to learn about ROM (Read only memory ) -It is also known as permanent stored data memory.

 

AS its name input implies ,this memory is only for Read operations.It is programmed at the time of hardware setting and whatever store in this ,memory can not change later.

 

It is also divided into sub parts

i.Programmable Read Only Memory (PROM)

ii.Erasable Programmable Read only memory

iii.Electrically Erasable Programmable Read only memory

 

Storage Unit-It is required to store data in computer for the  purpose of processing in future.

Secondary Storage is used to store large amount of data.

Example:

Hard Disk(internal,external),Pen drive,CD,DVD,Blue ray disks,Memory card ,<agnetic Tapes.

 

 

v     Softwares

Software is set of programmes which is designed for a special purpose .Hardware can not work without software.

It behaves like an interface between hardware abd user.Software gives directions to control various operations .

Machine language was the first system in 1 generation .

Software is divided into two parts i.e System software and Application software.

 

1.System Software-

Software that controls inner operations of a computer system is called system software.

It follows the instructions related to system and facilities smooth working system.It is not possible to work  without system software.

And it is dived into two parts operating system ,language processor .

i.Operating System-It is an interface between hardware and user .It is like a manager of whole computer system .It contols all resources of hardwares.

 

Types OF OS:

Single  user OS

Multi user OS

Time sharing OS

Real Time OS

Multiprocessing OS

Distributed OS

ii.Language Processor

It is a special software which translates source code to object code or machine code.

Source Code is group of instructions written by programmer using some computer programming language.

 

It is divided into three parts are Assembler ,Interpreter,And compiler.

 

 

Compiler-A Compiler convert High level language programme is machine language .If there are errors  in the programme ,it gives error list along with the line number.

An iinterperter convert high level language into machine language line by lien and executes converted line.It must always be present in the memory along the program for its executer .If Error occur in line ,the line es display and interpreter does not proceed unless the error is rectified.



2.Application software

These are the softwares designed for some specific tasks.

These are to be installed after installation of OS only.

OS provides environment to run an application software.

 

These are divides into 4 categories.

Packages (MS office)

Utilities (Text editor, paint brush disk defragme)

Customized software (Tally business software)

Developer Tools (Software libraries).

 

 

v Mobile System Organization

Modern mobile phone is like a small computer in hand.

They gave less processing power as compared to computer system.

Function of mobile phone -

Calling

Photo taking with camera

To works in various apps

Touch screen facility

 

Mobile phone recieves poer from battery.

 

 

 

Mobile Processor

 

It is the brain of smart phone

It immediately responds in recieving a command.

It has two main syb processors:

1) Communication processing unit

2)Application processing unit.

I) Camera sub system

·       It is bases on image signal processing

·       It performs following tasks.

·       Instant image

·       High resolution support

·       Other image enhancement.

 

Mobile system memory

It is of two types

RAM it is available in 2GB, 4GB, 6GB, 8GB

 

ROM it is available in 16 to 128 GB.

 

Mobile storage it is an external storage and also known as expandable.

 

 

 

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