LANGUAGES OF COMPUTER

A language is defined as the medium of expression of thoughts . All the human beings in this world communicate with each other by a language. Similarly, computer also needs some expression medium to communicate with others

A computer follows the instructions given by the programmer to perform a specific job. To perform a particular task, programmer prepares a sequence of instructions, know as programmed. A program written for a computer is known as Software. The programmed is stored in RAM. The CPU takes one instruction of the programmed at a time from RAM and executes it. The instructions are executed one by one in sequence and finally produce the desired result.

The Journey of computer software machine language to high level languages to modern 4GL / 5GL languages is an interesting one. Let us talk about this in detail.

FIRST GENERATION LANGUAGES 1GLs (Machine language)

When the human being stared programming the computer the instruction were given to it in a language that it could easily understand. And that language was machine language. The binary language a language, a language of Is and Os is known as Machine language. Any instruction in this language is given in the form of string of 1s and 0s. Where the symbol I stand for the presence of electrical pulse and 0 stands for the absence of electric pulse. A set of 1s and 0s as 11101101 has a specific meaning to a computer even through it appears as binary number to us.

The writing of programmer in machine language is very cumbersome and complicated and this was accomplished by experts only. All the instructions and input data are fed to the computer in numeric form, specifically a binary form.

SECOND GENERATION LANGUAGES 2GLs (Assembly Language)

Lots of efforts are made during last 50 years to obviate the difficulties faced for using the machine language. The first language similar to English was developed in 1950 which was known as Assembly Language or Symbolic Programming Languages. After 1960, the High Level Languages were developed which bought the common man very to the computer. And this was the main reason for tremendous growth in computer industry. The high level languages are also known as Procedure Oriented Languages.

THIRD GENERATION LANGUAGES (3GLs ) (High Level Languages)

The assembly language was easier to use compared with machine la language as it relieved the programmer from a burden of remembering the operation � codes and addresses of memory location. Even though the assembly languages proved to be great help to the programmer, a search was continued for still better languages nearer to the conventional English language. The languages developed which were nearer to the English language, for the use of writing the programmer in 1960 were known as High Level languages.

The different high level languages which can be used by the common user are FORTRAN, COBOL, BASIC, PASCAL, PL-1 and many others. Each high level language was developed to fulfill some basic requirements for particular type of problems. But further developments are made in each language to widen its utility for different purposes.

FOURTH GENERATION LANGUAGES (4GLs)

The 3GLs are procedural in nature i.e., HOW of the problem get coded i.e., the procedures require the knowledge of how the problem will be solved . Contrary to them, 4GLs are non procedural. That is only WHAT of the problem is coded i.e., only �What is required� is to be specified and rest gets done on its own.

Thus a big program of a 3GLs may get replaced by a single statement of a 4GLs. The main aim of 4GLs is to be cut down on developed and maintenance time and making it easier for users.

GUI BASED LANGUAGES

With the invention and popularity of GUI based interfaces. GUI based languages include:

1. TCL/Tk
2. Visual basic
3. Visual C++
4. C# (Pronounced as C sharp)
5. Visual basic.NET
6. Visual basic 2005

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LANGUAGES OF COMPUTER

By Muhammad Meer → Friday, April 3, 2015

GENERATION OF COMPUTER

COMPUTER
Computer is an advanced electronic device that takes raw data as input from the user and processes it under the control of set of instructions (called program), gives the result (output), and saves it for the future use.
This Computer Fundamentals tutorial covers a foundational understanding of computer hardware, software, operating systems, peripherals etc. along with how to get the most value and impact from computer technology.

Generation of Computer

Generation in computer terminology is a change in technology a computer is/was being used. Initially, the generation term was used to distinguish between varying hardware technologies. But nowadays, generation includes both hardware and software, which together make up an entire computer system. There are totally five computer generations known till date. Each generation has been discussed in detail along with their time period and characteristics. Here approximate dates against each generations have been mentioned which are normally accepted.
Following are the main five generations of computers

First Generation (1940-1956) Vacuum Tubes:

The period of first generation was 1946-1959. The computers of first generation used vacuum tubes as the basic components for memory and circuitry for CPU (Central Processing Unit). These tubes, like electric bulbs, produced a lot of heat and were prone to frequent fusing of the installations, therefore, were very expensive and could be afforded only by very large organisations. In this generation mainly batch processing operating system were used. Punched cards, paper tape, and magnetic tape were used as input and output devices. The computers in this generation used machine code as programming language.

The main features of first generation are:

Vacuum tube technology
Unreliable
Supported machine language only
Very costly
Generated lot of heat
Slow input and output devices
Huge size
Need of A.C.
Non-portable
Consumed lot of electricity

Some computers of this generation were:

ENIAC
EDVAC
UNIVAC
IBM-701
IBM-650

Second Generation (1956-1963) Transistors:

Transistors replaced vacuum tubes and ushered in the second generation of computers. The transistor was invented in 1947 but did not see widespread use in computers until the late 1950s. The transistor was far superior to the vacuum tube, allowing computers to become smaller, faster, cheaper, more energy-efficient and more reliable than their first-generation predecessors. Though the transistor still generated a great deal of heat that subjected the computer to damage, it was a vast improvement over the vacuum tube. Second-generation computers still relied on punched cards for input and printouts for output.

Second-generation computers moved from cryptic binary machine language to symbolic, or assembly, languages, which allowed programmers to specify instructions in words. High-level programming languages were also being developed at this time, such as early versions of COBOL and FORTRAN. These were also the first computers that stored their instructions in their memory, which moved from a magnetic drum to magnetic core technology.
The first computers of this generation were developed for the atomic energy industry.

The main features of second generation are:

Use of transistors
Reliable in comparison to first generation computers
Smaller size as compared to first generation computers
Generated less heat as compared to first generation computers
Consumed less electricity as compared to first generation computers
Faster than first generation computers
Still very costly
A.C. needed
Supported machine and assembly languages

Some computers of this generation were:

IBM 1620
IBM 7094
CDC 1604
CDC 3600
UNI VAC 1108

Third Generation (1964-1971) Integrated Circuits:

The development of the integrated circuit was the hallmark of the third generation of computers. Transistors were miniaturized and placed on silicon chips, called semiconductors, which drastically increased the speed and efficiency of computers.

Instead of punched cards and printouts, users interacted with third generation computers through keyboards and monitors and interfaced with an operating system, which allowed the device to run many different applications at one time with a central program that monitored the memory. Computers for the first time became accessible to a mass audience because they were smaller and cheaper than their predecessors.

The main features of third generation are:

IC used
More reliable in comparison to previous two generations
Smaller size
Generated less heat
Faster
Lesser maintenance
Still costly
A.C needed
Consumed lesser electricity
Supported high-level language

Some computers of this generation were:

IBM-360 series
Honeywell-6000 series
PDP(Personal Data Processor)
IBM-370/168
TDC-316

Fourth Generation (1971-Present) Microprocessors:

The period of fourth generation was 1971-1980. The computers of fourth generation used Very Large Scale Integrated (VLSI) circuits. VLSI circuits having about 5000 transistors and other circuit elements and their associated circuits on a single chip made it possible to have microcomputers of fourth generation. Fourth generation computers became more powerful, compact, reliable, and affordable. As a result, it gave rise to personal computer (PC) revolution. In this generation time sharing, real time, networks, distributed operating system were used. All the high-level languages like C, C++, DBASE etc., were used in this generation.

The main features of fourth generation are:

VLSI technology used
Very cheap
Portable and reliable
Use of PC's
Very small size
Pipeline processing
No A.C. needed
Concept of internet was introduced
Great developments in the fields of networks
Computers became easily available

Some computers of this generation were:

DEC 10
STAR 1000
PDP 11
CRAY-1(Super Computer)
CRAY-X-MP(Super Computer)

Fifth Generation (Present and Beyond) Artificial Intelligence:

The period of fifth generation is 1980-till date. In the fifth generation, the VLSI technology became ULSI (Ultra Large Scale Integration) technology, resulting in the production of microprocessor chips having ten million electronic components. This generation is based on parallel processing hardware and AI (Artificial Intelligence) software. AI is an emerging branch in computer science, which interprets means and method of making computers think like human beings. All the high-level languages like C and C++, Java, .Net etc., are used in this generation.

AI includes:

Robotics
Neural Networks
Game Playing
Development of expert systems to make decisions in real life situations.
Natural language understanding and generation.
Fifth Generation

The main features of fifth generation are:

ULSI technology
Development of true artificial intelligence
Development of Natural language processing
Advancement in Parallel Processing
Advancement in Superconductor technology
More user friendly interfaces with multimedia features
Availability of very powerful and compact computers at cheaper rates

Some computer types of this generation are:

Desktop
Laptop
NoteBook
UltraBook
ChromeBook

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GENERATION OF COMPUTER

By Muhammad Meer →

PN-JUNCTION DIODE OR SEMICONDUCTOR DIODE

INTRODUCTION:

A pn - junction diode is an electronic device formed from a p-type and an n-type substance semiconductor. A semiconductor diode has the property of one way conduction i.e. it allows electric current to flow in only one direction.

FABRICATION OF pn-JUNCTION:

A pn-junction is fabricated by placing a small amount of indium on a plate or wafer of n -type germanium. Indium on heating at 550^oC melts and diffuses through a small part of the n-type germanium. Indium being a p-type impurity, converts the part of the n-type germanium to p-type material. Thus a junction is formed between p-type section and an n-type section of germanium.

A brass-base is used to fix the pn-junction to which leads are attached as shown:

The whole apparatus is sealed in a glass tube or a metallic tube.

WORKING OF pn-JUNCTION DIODE:

As we know that a p-type substance has excess of mobile positive charge or holes and n-type substance has an excess of negative charge or electrons, the electrons from n-type and holes from p-type sections flow across the junction and combine. In this way a layer of positive charges is formed on the n-type and a layer of negative charges on p-type material. Due to induction of these layers a potential barrier is now developed across the junction and further flow of charges is prevented from one side to the other.

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PN-JUNCTION DIODE OR SEMICONDUCTOR DIODE

By Muhammad Meer →

MOVING COIL GALVANOMETER

GALVANOMETER:

Galvanometer is an electromagnetically instrument which is used for the detection of electric currents through a circuit. Being a sensitive instrument, Galvanometer cannot be used for the measurement of heavy currents.

WORKING PRINCIPLE:

Galvanometer works on the principle of conversion of electrical energy into mechanical energy. When a current flows in a magnetic field it experiences a magnetic torque. If it is free to rotate under a controlling torque, it rotates through an angle proportional to the current flowing through it.

ESSENTIAL PARTS OF GALVANOMETER:

There are five essential parts of a Galvanometer.

    1. A U-shaped permanent magnet with concave poles.

    2. Flat rectangular coil of thin enameled insulated wire C?.

    3. A soft iron cylinder 'B'.

    4. A pointer or needle.

    5. A scale.

CONSTRUCTION:

The flat rectangular coil of thin enameled insulated wire of suitable number of turns wound on a light nonmetallic or aluminum frame is suspended between the cylindrical concave poles of magnet by a thin phosphor bronze strip. One end of the wire of the coil is soldered to strip. The other end of the strip fixed to the frame of the galvanometer and connected to an external terminal. It serves as one leas current lead through which the current enters or leaves the coil. The other end of the wire of the coil is soldered to a loose and soft spiral of wire connected to another external terminal. The soft spiral of a wire serves as the other current lead. A soft-iron cylinder, coaxial with the pole pieces, is placed within the frame of the coil and is fixed to the body of the galvanometer. In the space between it and the pole  pieces, where the coil moves freely, the soft iron cylinder makes the magnetic field stronger and radial such that into whatever position the coil rotates, the magnetic field is always parallel to its plane.

WORKING:

When a current passes through the galvanometer coil, it experiences a magnetic deflecting torque, which tends to rotate it from its rest position. As the coil rotates it produces a twist in the suspension strip. The twist in the strip produces an electric restoring torque. The coil rotates until the elastic restoring torque due to the strip does not equal and cancels the deflecting magnetic torque, then it attains equilibrium and stops rotating any furthers.

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MOVING COIL GALVANOMETER

By Muhammad Meer →