Introduction of computer:
Computer Full Form :-
C : Common or Commonly
O : Operating
M : Machine
P : Particular
U : Use for
T : Technical or Technology
E : Education and
R : Research
What is Computer :-
Computer is an electronic device, which can store data, manipulates them and gives output according to the instruction fed in it by the user. It is not only a calculating device, but it stores large amount of data, and takes logical decision.
What is the means by a computer system :-
Actually the word “computer” means the computer system, which is generally the combination of one or more input device, output device, and a processing unit.
INPUT DEVICE :-
The device, which is used to giving instruction/inputting data to the computer system is called input device. Keyboard, mouse, scanner, camera, light pen, joystick, touch sensitive monitor etc. are some examples of input device.
PROCESSING DEVICE :-
Processing device is the device, which is used to process the inputted data, prepares the result accordingly and produces the output. Hence, you can say that, the processing device control whole computer system. Processing device is also known as CPU.
OUTPUT DEVICE :-
The device, which is used to getting the output/result from the computer system is called output device. Monitor, printer, speaker etc. are some examples of output device.
Block diagram of computer :-
CONTROL UNIT (CU) :-
Control Unit is the part of the central processing unit. Control Unit reads every instruction given by you through input device (such as, keyboard), and then send the instruction to the appropriate part for processing, and after processing it get the result from them and again send the result to the output device (such as, monitor, printer etc.)
Arithmetical Logical Unit (ALU) :-
ALU stands for Arithmetic Logic Unit/ Arithmetical Logical Unit. It does all the calculations and makes decisions on the given data/instruction. Every type of arithmetical and logical tasks is performed by ALU. i.e., every type of addition, subtraction, multiplication, division etc. is done by ALU. It also takes logical decision like yes or no, true or false, on or off etc.
MEMORY :-
Memory is a Important Part in a computer system. Data and programs are stored in memory before any operation. Input device send data and instruction to CPU, which are first stored in memory and then processed by the control unit.
STRUCTURE OF MEMORY :-
INTERNAL MEMORY :-
The memory is inside the computer. Where data and programs are stored after processing is called internal memory. There are two types of internal memory: –
(1) Primary Memory (2)Secondary Memory
PRIMARY MEMORY :-
The data and instructions supplied by the user are first stored in primary memory and after execution it can be stored in the secondary memory for the reusing the result in future. The primary memory is the part of processing device because without it the computer is not able to boot/work. Primary memory is also known as main memory. There are two type of primary memory:
(1) Ram (2) Rom
RAM :-
RAM stands for Random Access Memory. The data and instructions stored in RAM can be read over and over again without destroying them. Its data are destroyed if the power fails, i.e., the contains of RAM are lost if power supply is cut off, RAM is also known as main memory. RAM can be altered.
ROM :-
ROM stands for Read Only Memory. ROM’s instruction is permanently built into circuitry by the manufacture of the program. A ROM can’t be altered. It is a permanently built in memory. When the power is lost the contains of ROM can’t be lost. Check the hardware parts connection using ROM.
Like :- Keyboard , Mouse, HardDisk, etc.
SECONDARY MEMORY :-
The secondary memory is basically used to store every data, which you want to reuse in future. It stores every data in the form of ‘File’. The primary memory is a random access memory. It rotates at very high speed, to read/write data. Hard disk is an example of secondary memory.
HARD DISK :-
It is the most essential storage device of a computer. All the programs, software’s etc, which you needs, are stored in a hard disk. It is fixed disk in the computer system. You can’t transfer the hard disk any where from the computer. It rotates at high speed varying from 1000 r/m to 6000 r/m. Its storage capacity varies from few Kilobyte (KB) to Terabyte (TB).
STRUCTURE OF MEMORY :-
EXTERNAL MEMORY :-
The memory, which is externally used to store data and programs are Called External memory. Floppy disk, CD ROM etc. are example of external memory. It is like secondary memory, but used externally.
EXAMPLE OF EXTERNAL MEMORY :-
FLOPPY DISK :-
Floppy disk is a external storage device. It is used to store data externally. You can carry it easily from one place to other place. Floppy disk is very popular device used for move/carry data from one place to other place or one computer system to other computer. It can store about 1.44 MB data at a time. It is made up of iron oxide, covered with a thick hard plastic jacket.
DVD Rom / Write :-
DVD Rom / Write stands for Digital versatile Disc. It is a storage device. Its capacity is much greater than floppy disk. It is a kind of read / write DVD and CD (Compact Disk). It’s storing capacity is about 4.8GB . It is made up of optical fiber.