Basics of Cs

1.Classification of computer.

• Types of Computers

Since innovation of first computer different types of sizes of computers are offering different services.

The computers are divided into three categories. 

1. Analog Computer:- These computers recognise data as a continuous measuring of physical properties their output is usually in the form of regarding on deals or graphs ,voltage, pressure, speed and temperature are some physical properties that can be measured in this way . Ex:-ECG( electrocardiography). 
    I】 a service station gasoline line pump contain and analog processor that contain fuel flow  measurements into quantity and price value.
   II】Antomobile speedometer etc..,.  .
2. Digital computer:- the digital computer works on the discontinuous data the convert the data into digits binary digits (0 and 1 ) and all operations are carried out on there this digits at extremely fast rates. A digital computer basically known how to count the the digits and add the digits . digital computer are must faster than the analog computer and for more accurate.
3. Super computer:- a supercomputer contains in number of CPU's which operates in parallel to make the faster they are used for a massive data processing and solving very sophisticated problems are used for weather forecasting ,weapon manufacturing  ,development ,rocketing arrodynamics, atomic ,nucleus ,etc..,
4. Mainframe computer:- Mainframe computers are very powerful, large general purpose computer if we used to where large amount of data are to be processed are very complex calculations are being made this task are beyond the computing capacity of mini computers. They are used in research organisations, large Industries ,large businesses and the government organisations, banks ,airline reservation where large database is required .
5. Micro computer:- micro computer is a low-cost, small ,digital computer it contains the microprocessor and its CPU, memory unit ,input device and output device micro computers have a wide range of applications like a general-purpose calculator ,industrial control ,home appliances, micro computers are also called personal computers
6. Mini computer:- mini computers are faster and more powerful than the microcomputers . Minicomputers are general purpose computer , smaller than Mainframe give the computing power without adding the probabilive expenses associated with the large system . They are used in accounting ,word pressing ,database Management ,statistical packages for social science ,CAD , and numerical analysis etc..,

2. Anatomy of Computer(Block diagram of computer).

Basic components of computer System:-

All computer system performs the following five basic operations for converting raw input data into Useful information and present it to a  user

• Input:-Process of entering data and instructions into a computer system.
• Storing:- saving data and instructions to make them readily available for initial or addition processing as and when required.
• Processing:- Performing arthmedi operation (addition, subtraction, multiplication division ,etc, )or logical operation (greater than ,less than ,equal to ,etc) on data to convert them into Useful information.
• Outputting:- process of producing Useful information result for a user such as printed report or visual display.

I】Input Unit:-

An input unit performs following functions:-

i) It accept or read instructions and data from outside  world.

ii) It convert their instructions and data in computer access table form.

iii) It supplies the converted instructions and data to computer system from further processing.

II】Output Unit:-

An out put unit performs following functions.

i) It accept the result produced by a computer which are in coded from and hence we cannot easily and understand them.

ii)It convert there code result to human acceptable (readable) form.

iii) It supplies the converted result to outside World.

III】Storage Unit:-

A storage unit holds:-

a) Data and instructions required for processing.

b) Intermediate results of processing.

c) Result for outputs , before they are released to an output device.

Storage unit of all computers is comprised of following two types of storage.

A) Primary storage:-

Primary storage of a computer , also known as like main memory , it is used to store data and Program instructions and data , intermediate result of processing , and recent produced results of those job on which computer is currently working.

B)Secondary storage:-

Secondary storage of a computer also known as its them and auxiliary storage ,is used to take ke care of the limitations of primary storage . That is, its supplements the The Limited storage capacity and the volatile characters of primary storage this is because secondary storage is much cheaper than primary storage and it can return information even when a computer system switch off or resets.

IV】Airthmetic Logic Unit:-

The ALU perform arithmetic and logical operation on data such as addition ,subtraction ,multiplication, division comparison ,AND ,OR , NOT into ALU receive data as a bytes (asmallest units of the data) and executes the process using operation understand the directions of the program  instructorctions. Most of the activities are within a computer is carried out by ALU

V】Control Unit:-

The control unit manages and coordinates the entire a computer system. It generates the control and training signals necessary for them execution of the instructions. This unit directs the specific instructions and data that are to be processed and determines the correct order and sequence.  The control unit obtain instructions from them program stored in a main memory, interpret the instructions and issues the signature that causes other unit of the system to execute them.

VI】Central Processing Unit(CPU):-

The primary function of the CPU is to execute the program stored in the main memory.

 CPU execute the program by performing the following operations.

1. Fetch instructions :-The CPU reads instructions from memory.
2. Interpret Instructions :-The fetched instruction is decoded into determine which action is needed .
3. Fetch data:-CPU fetches the data either from the memory or from input devices.
4. Process data:-Performs arithmetic or logical operations on data.
5. Write results:-The results of an execution are sent either to a memory location or to an output device.

3.Input Devices

An input device is an electr omechanical device that accept data from outside world and transform them into a form a computer can interpret. Several input devices are available today they can be broadly classified into the following categories.

1.Keyboard devices

2.Point-and-draw devices(Pointing devices)

3.Data scanningdevices

4.Digitizer

5.Eletronic cards based devices

6.Speech recognition devices