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| Architecture of Computer System |
Architecture of a Computer System-
A complete computer installation including the central processing unit, the peripherals such as Monitor, Mouse, Keyboard, Hard Disk,Floppy disk drives, Printer and operating system which are designed to work and interact with each other and with the user is called a computer system.
Main Components of computer system are three-
Input/Output Unit
Central Processing Unit
Memory Unit
Input/ Output Unit-
The computer is a machine that processes the input data according to given set of instructions and gives output. The unit used for getting the data and instruction into the computer and displaying of printing output is known as I/O unit. Keyboard, mouse,light Pen, Trackball, Joystick, graphic tablet and digital camera barcode reader magnetic ink character reader optical character reader screen and microphone etc are input devices.Printer ,Visual Display Unit ,Plotter, Speaker etc are the output unit.
CPU consists of following distinct part-
Arithmetic Logic Unit - ALU is responsible for all the arithmetic operation like addition , subtraction multiplication and division as well as logical operations such as less than equal to, greater than.
Control unit- CU is Central Nervous System of computer responsible for the controlling the transfer of data instructions among other units of computer.It also perform the physical data Transfer between memory and the peripheral device.
Registers- are the small high speed circuits( memory location) which are used to store data, instruction and memory address, when ALU perform arithmetic and logical operation. Registers can store one word of data(1word=2bytes and 1 byte=8bit) .
Six type of Register- General Purpose Register,Pointer Register,Segment Register,Index Registers,Flag Register and Instruction.
Buses- Data is stored as a unit of 8 bits in a Register.Each bit is transferred from one Register to another by means of a separate wire. This group of 8 wires,which is used as a command way to transfer data between Register is called Bus.
Bus is a connection between two components to transmit signal between them.
Types of Bus-
1.Data Bus is used to move data
2.Address Bus is used to move address or memory location3.Control Bus is used to send control signals between various component of a computer.
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Clock- is used to measures and allocate a fixed time slot for processing each and every micro- operation.CPU executes the instructions in synchronization with the clock pulse. The clock speed of CPU is measured in terms of Mega Hertz (MHz) or Millions of Cycles per second.
Memory Unit
Memory unit is that component of a computer which is used to store the data instructions and information Before, during and after the processing by ALU . it is actually work area within the computer where CPU store the data and instruction it also known as main/ primary/ internal memory.Three Types
1.Read Only Memory
2.Random Access Memory
3.Complementary Metal Oxide Semiconductor Memory
Read Only memory
RAM is an essential component of the memory unit as we know that computer is a machine itself has no intelligence or memory and required the instruction which are given by man when computer is switched on It searches for the required instruction. The memory which has these essential instructions, is known as Read Only Memory. This is permanent and is not reached when system is switched off as a pair with its name it is a type of memory that is can be read only and not be written by user or programmer the memory capacity of form very from 64 kb to 256 KB depend on the model of computer.ROM contains a number of programs( set of instructions). The most important program of ROM is the Basic Input Output System(BIOS) which activated the hardware such as keyboard,monitor, floppy disk etc. In communicating with the system and Application software.
Types of ROM-
Mask ROM – is the Basic ROM chip, the information is stored at the time of its manufacturing. So it cannot be altered or erased .
PROM- Programmable Read Only Memory
The information is stored by programmer after its manufacturing. It also cannot be changed or erased.EPROM- Erasable Programmable Read Only Memory
Its information can be erased later on by ultra violet light and it can be reprogrammed.
EEPROM- Electronically Erasable Programmable Read Only Memory
It’s information can be erased by using a high voltage current.
EAPROM – Electronically Alterable Read Only Memory
It’s information can be altered later.
Random Access Memory-
RAM is used to store the data and Instruction during the execution of program. RAM is temporary and is erased when Computer is switched off. RAM is a read/ write type of memory by user.
Type of RAMStatic RAM – SRAM The information stored in SRAM need not be refreshed, but it remains stable as long as power supply is provided. SRAM is costlier but higher speed than DRAM.
Dynamic RAM(DRAM) The information stored in DRAM had to be refreshed after every few milliseconds and erased. It’s storage capacity high and cheaper than SRAM.
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Complementary Metal Oxide Semiconductor Memory-
CMOS memory is used to store the system configuration,date, time and other important data. When computer is switched on,BIOS matches, the information of CMOS with the peripheral devices and display as error in case of mismatching.
Secondary Memory -Secondary memory comprises peripheral devices that are slower but much cheaper than internal memory .These Devices do not lose the stored information even after the power is switch off . Hard disk, floppy disk, compact disk, magnetic tape,video disk,magneto optical drive, DVD etc are use as secondary Memory.
Read more about Secondary memory by clicking below -
Secondary Storage Devices Of Computer
Also Read
Knowledge- Output Devices Of Computer
Computer Knowledge-Input Devices Of Computer for all Competitive exam
Computer And Types of Computer
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