In order to solve a problem on a computer, we should first evolve a detailed and a precise step by step method of solving it such a method is called as “ALGORITHM”.
An algorithm is expressed by using a precise notation is called “PROGRAM”. The precise notation itself is called “PROGRAMING LANGUAGE”. Thus a program is needed to solve a problem on a computer.
A COMPUTER (Commonly Operated Machine Particularly Used for Trade Education Research) is a machine that can perform computations. A computation involves the following 3 components shown in the figure, this architecture is commonly called as “NEUMANN ARCHITECTURE”.
Example : Keyboard, Mouse etc..
2. OUTPUT DEVICE:
These are the devices that are used to output a computation according to our input.
Example: Display, Printers etc..
3.PROCESSING UNIT:
The CPU (Central Processing Unit) is the brain of the computing device and performs the basic processing steps a CPU typically consists of –
1.Contol Unit
2.ALU(Arthematic Logic Unit)
3.GPR(General Purpose Registrations)
4.Storage unit
5.Bus
1.CONTROL UNIT:
The control unit (CU) controls all the activities or operations which are performed inside the computer system. This unit is responsible for controlling flow of data and instructions.
2.ARTHEMATIC LOGIC UNIT (ALU) :
The arithmetic and logical unit is the combinational digital electronic circuit that can perform arithmetic operations on integer binary numbers. The outputs of ALU will change asynchronously in response to the input. The basic arithmetic and bitwise logic functions are supported by ALU.
3.GENERAL PURPOSE REGISTRATIONS (GPR) :
A CPU usually consists of finite numbers of memory cells for storing intermediate results and values.
4.STORAGE UNIT:
A storage unit is classified into two categories
1.Main or Primary memory
2.Secondary memory
1.MAIN OR PRIMARY MEMORY:
This is of a high-speed memory that stays close to the CPU programs are first loaded in the main memory and then executed usually, main memories are volatile.
Volatile: Loss of power leads to loss of data
2.SECONDARY MEMORY:
This is a low-speed memory, normally meant for offline storage of programs and data usually, Secondary memories are non-volatile.
Non-Volatile: Loss of power never leads to loss of data
5. BUS:
A BUS is a set of wires that connect the set of above components, buses are responsible for the movement of data from the input device to the output device
HISTORY OF COMPUTERS:
Essentially these are three types of calculating devices
1.Manual
2.Mechanical
3.Automatic
1.MANUAL:
The manual device was ABACUS. The abacus was invented around 600BC and In this device, the numbers are represented by the position of beads on a rack. By positioning the beads appropriately simple addition and subtraction is carried out rapidly and efficiently.
2.MECHANICAL:
The first mechanical adding machine was first invented by B. PASCAL in the year 1642. This machine has limited the computation of addition, subtraction, multiplication, and division were done on series of addition and subtraction respectively but the result was inaccurate and late.
3.AUTOMATIC:
In Automatic the following machines are used, they are
1.The MARK-1 computer was the first fully automatic calculating machine designed by Howard Aiken of Harvard University in collaboration with IBM it was very complex, huge, and very slow.
2.ENIAC machine (Electronic Numerical Integrator and Calculator)was designed by a team led by Prof J.P.Eckest & John Mauchly of the USA in 1943 . It is a Huge machine of 30 tonnes require around 18,000 Vaccum tubes performed about 5,000 additions per second and consumes 150-kilo watts of power and also requires big room for its placement.
3.EDVAC machine (Electronic Discrete Variable Automatic Computer) was designed on stored programs concept by John von Neumann. This machine was developed in 1946.
4.EDSAC machine (Electronic Delay Storage Automatic Calculator) was designed by Prof.M.Wikes at Cambridge University in 1947.
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