First Generation Computers

PICTURES OF FIRST GENERATION COMPUTERS

First Generation Computers

During the period of 1940 to 1956 first generation of computers were developed. The first generation computers used vacuum tubes for circuitry and magnetic drums for memory, and were often enormous, taking up entire rooms. The vacuum tube was developed by Lee De Forest. A vacuum tube is a device generally used to amplify a signal by controlling the movement of electrons in an evacuated space. First generation computers were very expensive to operate and in addition to using a great deal of electricity, generated a lot of heat, which was often the cause of malfunctions.

 CHARACTERISTICS OF FIRST GENERATION COMPUTERS
1) First generation computers were based on vacuum tubes.
2) The operating systems of the first generation computers were very slow.
3) They were very large in size.
4) Production of the heat was in large amount in first generation computers.
5) Machine language was used for programming.
6) First generation computers were unreliable.
7) They were difficult to program and use.

PICTURES OF FIRST GENERATION COMPUTERS

VACUUM TUBES

In electronics, a vacuum tube, an electron tube or just a tube (North America), or valve (Britain and some other regions) is a device that controls electric current between electrodes in an evacuated container. Vacuum tubes mostly rely on thermionic emission of electrons from a hot filament or a cathode heated by the filament. This type is called a thermionic tube or thermionic valve. A phototube, however, achieves electron emission through the photoelectric effect. Not all electronic circuit valves/electron tubes are vacuum tubes (evacuated); gas-filled tubes are similar devices containing a gas, typically at low pressure, which exploit phenomena related to electric discharge in gases, usually without a heater.

Computer Generations Languages

First Generation Languages (1GL)

The earliest computers were based on vacuum tube technology and hardware design was in its infancy. The only way to program these computers was to enter the machine language instructions directly into the hardware. Writing programs for these early computers had many limitations:

• Programming was tremendously time consuming,
• The programs were prone to errors
• Debugging often took longer than writing the original program
• Programmers needed a great deal of skill and specialized training and
• Machine languages were different for every type of computer.

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SECOND GENERATION COMPUTERS

SECOND GENERATION COMPUTERS

During the period of 1956 to 1963 second generation of computers were developed. The second generation computers emerged with development of Transistors. The transistor was invented in 1947 by three scientists J. Bardeen, H.W. Brattain and W. Shockley. A transistor is a small device made up of semiconductor material like germanium and silicon. Even though the Transistor were developed in 1947 but was not widely used until the end of 50s. The transistor made the second generation computers faster, smaller, cheaper, more energy-efficient and more reliable than their first-generation computers. Even though the transistor used in the computer generated enormous amount of heat which ultimately would lead to the damage of the computers but was far better than vacuum tubes.
Second generation computers used the low level language i.e. machine level language and assembly language which made the programmers easier to specify the instructions. Later on High level language programming were introduced such as COBOL and FORTRAN. Magnetic core was used as primary storage. Second generation computer has faster input /output devices which thus brought improvement in the computer.


CHARACTERISTICS

1) Transistors were used in place of vacuum tubes.
2) Second generation computers were smaller in comparison with the first generation computers.
3) They were faster in comparison with the first generation computers.
4) They generated less heat and were less prone to failure.
5) They took comparatively less computational time.
6) Assembly language was used for programming.
7) Second generation computers has faster input/output devices.



Second Generation Languages (2GL)
 Some improvements were made during the 1950s with the development of assembly languages. Early software pioneers, such as Grace Hopper, realized that they could write programs in a type of programming short-hand and then have the computer translate this short-hand notation into machine code. The advantages of Assembly Languages included:

• Operations are given a meaningful name
• Names are assigned to storage locations
• Programs are easier to read and therefore easier to debug
• The Assembler program does the tedious translation of the program into machine language.

Disadvantages include:

• Assemblers are machine dependent and programmers needed very specific skills
• It is still a complex language and writing programs is slow and tedious to debug.

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THIRD GENERATION COMPUTERS

THIRD GENERATION COMPUTERS

During the period of 1964 to 1971 Third generation computers were developed. The third generation computers emerged with the development of IC (Integrated Circuits). The invention of the IC was the greatest achievement done in the period of third generation of computers. IC was invented by Robert Noyce and Jack Kilby in 1958-59. IC is a single component containing a number of transistors. Transistors were miniaturized and placed on silicon chips, called semiconductors, which drastically increased the speed and efficiency of computers.
Keyboards and monitors developed during the period of third generation of computers. The third generation computers 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.

CHARACTERISTICS

1) IC was used instead of transistors in the third generation computers.
2) Third generation computers were smaller in size and cheaper as compare to the second generation computers.
3) They were fast and more reliable.
4) High level language was developed.
5) Magnetic core and solid states as main storage.
6) They were able to reduce computational time and had low maintenance cost.
7) Input/Output devices became more sophisticated.

Third Generation Languages (3GL)

By the late 50s and early 60s, the computer industry was in full production. Many large and medium businesses as well as most universities and government departments were installing computers. Along with this boom came a crucial period often called the Software Crisis. While advances had been made in writing software such as assemblers, every computer system still required custom written software. There simply were not enough programmers and time to do it all. The solution: develop a faster way of writing and debugging software.

Leading thinkers such as Alick Glennie and Grace Hopper realize that they could extend the concept of the Assembler even further. The result was a series of computer programs (compilers) that translated high-level programming languages into machine code.

These high-level or 3GLs are characterized by their use of English-like commands in place of the obscure codes of Assembly languages. Each line of code in a 3GL often corresponds to many lines of machine code. These are often called procedural languages because the programmer must develop a clear logic to carry out each procedure within the program. Since 3GLs are portable or machine independent, international standards have often been developed. This has greatly simplified the training and preparation that software engineers need.

Some of the most significant 3GLs are:

• FORTRAN:  Developed in 1957 by a team headed by John Backus, Fortran was designed for scientists and engineers. It is geared to make programming mathematical formula quick and easy.




• COBOL: By 1959, the business community had their own programming language designed to handle business processes.




• PL/1: (Programming Language /1) was an attempt in the mid-60s to develop a language that could satisfy the needs of both the business and scientific communities. It combines the ease of writing formulas of Fortran with the string handling features of Cobol.




• BASIC: (Beginner's All-purpose Symbolic Instruction Code) Late in 1963, John Kemeney and Thomas Kurtz sat down and began to develop a new programming language written from the point of view of the user. It was designed to be easy to learn, more accessible to the user and accessible so that the average person might be able to write programs. By May 1st, 1964 with a lot of help from their students BASIC was born.




• Pascal: (named after the French mathematician, Blaise Pascal) from '68 to '72 Niklaus Wirth developed Pascal to provide his students (and others) with a relatively easy to learn language that maintained the principles of structured programming.

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FOURTH GENERATION COMPUTERS

FOURTH GENERATION COMPUTERS

After 1971 the fourth generation computers were built. The fourth generation computers were the extension of third generation technology. The fourth generation computers emerged with development of the VLSI (Very Large Scale Integration).With the help of VLSI technology microprocessor came into existence. The computers were designed by using microprocessor, as thousands of integrated circuits were built onto a single silicon chip. What in the first generation filled an entire room could now fit in the palm of the hand. The fourth generation computers became more powerful, compact, reliable and affordable. As a result, they give rise to personal computer (PC) revolution.
For the first time in 1981 IBM introduced its computer for the home user and in 1984 Apple introduced the Macintosh Microprocessor.

CHARACTERISTICS

1) The fourth generation computers have microprocessor-based systems.
2) They are the cheapest among all the computer generation.
3) The speed, accuracy and reliability of the computers were improved in fourth generation computers.
4) Many high-level languages were developed in the fourth generation such as COBOL, FORTRAN, BASIC, PASCAL and C language.
5) A Further refinement of input/output devices was developed.
6) Networking between the systems was developed.

 

Fourth Generation Languages (4GL)

The examples of 3GLs given above are all procedural languages because the programmer must list each instruction and indicate the order that these steps are to be executed through the use of logical control structures (Sequence-Selection-Iteration). Fourth Generation Languages are non-procedural languages. This means that the programmer does not specify a step-by-step method for executing a given problem. Instead, the inputs and required outputs are given and it is left up to the language to determine the step-by-step details.

The major disadvantage of 4GLS is that the resulting programs may not use the computer's processing power efficiently. Consequently more powerful computers are needed to run this type of program. The most significant advantage, however, is that 4GL programs are much easier to write. They contain a minimum of syntax rules and even people not trained as programmers can write applications.

One of the more common forms of 4GLs are query languages. These are frequently used to retrieve information from databases. An example of a query is "display all clients with date-of-birth before 1931". Other types of 4GL are report generators and application generators.

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FIFTH GENERATION COMPUTERS

FIFTH GENERATION COMPUTERS

Fifth generation computers are in developmental stage which is based on the artificial intelligence. The goal of the fifth generation is to develop the device which could respond to natural language input and are capable of learning and self-organization. Quantum computation and molecular and nanotechnology will be used in this technology. So we can say that the fifth generation computers will have the power of human intelligence.
CHARACTERISTICS
1) The fifth generation computers will use super large scale integrated chips.
2) They will have artificial intelligence.
3) They will be able to recognize image and graphs.
4) Fifth generation computer aims to be able to solve highly complex problem including decision making, logical reasoning.
5) They will be able to use more than one CPU for faster processing speed.
6) Fifth generation computers are intended to work with natural language.

Firth Generation Languages (5GL)

Not commonly listed in the generations of software are the Fifth Generation programming languages. Connected closely with Artificial Intelligence research and expert systems, there are few commercially available 5GLs.

LISP is one of the oldest programming languages still in use but it has been updated with 5GL programming methodology. The result is that most expert systems are coded in LISP. PROLOG is another 5GL that was developed in France in 1972. It has been expanded and improved over the last few decades and is used in Artificial Intelligence research.

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History of Operating Systems

History of Operating Systems

Historically operating systems have been tightly related to the computer architecture, it is good idea to study the history of operating  systems from the architecture of the computers on which they run.
Operating systems have evolved through a number of distinct phases or generations which corresponds roughly to the decades.

The 1940's - First Generations

The earliest electronic digital computers had no operating systems. Machines of the time were so primitive that programs were often entered one bit at time on rows of mechanical switches (plug boards). Programming languages were unknown (not even assembly languages). Operating systems were unheard of .

The 1950's - Second Generation

By the early 1950's, the routine had improved somewhat with the introduction of punch cards. The General Motors Research Laboratories implemented the first operating systems in early 1950's for their IBM 701. The system of the 50's generally ran one job at a time. These were called single-stream batch processing systems because programs and data were submitted in groups or batches.

The 1960's - Third Generation

The systems of the 1960's were also batch processing systems, but they were able to take better advantage of the computer's resources by running several jobs at once. So operating systems designers developed the concept of multiprogramming in which several jobs are in main memory at once; a processor is switched from job to job as needed to keep several jobs advancing while keeping the peripheral devices in use.
For example, on the system with no multiprogramming, when the current job paused to wait for other I/O operation to complete, the CPU simply sat idle until the I/O finished. The solution for this problem that evolved was to partition memory into several pieces, with a different job in each partition. While one job was waiting for I/O to complete, another job could be using the CPU.
Another major feature in third-generation operating system was the technique called spooling (simultaneous peripheral operations on line). In spooling, a high-speed device like a disk interposed between a running program and a low-speed device involved with the program in input/output. Instead of writing directly to a printer, for example, outputs are written to the disk. Programs can run to completion faster, and other programs can be initiated sooner when the printer becomes available, the outputs may be printed.
Note that spooling technique is much like thread being spun to a spool so that it may be later be unwound as needed.
Another feature present in this generation was time-sharing technique, a variant of multiprogramming technique, in which each user has an on-line (i.e., directly connected) terminal. Because the user is present and interacting with the computer, the computer system must respond quickly to user requests, otherwise user productivity could suffer. Timesharing systems were developed to multiprogram large number of simultaneous interactive users.

Fourth Generation

With the development of LSI (Large Scale Integration) circuits, chips, operating system entered in the system entered in the personal computer and the workstation age. Microprocessor technology evolved to the point that it become possible to build desktop computers as powerful as the mainframes of the 1970s. Two operating systems have dominated the personal computer scene: MS-DOS, written by Microsoft, Inc. for the IBM PC and other machines using the Intel 8088 CPU and its successors, and UNIX, which is dominant on the large personal computers using the Motorola 6899 CPU family.

Fifth Generation

The fifth generation computers are technologically advance and are still being developed to become more efficient, though there are some applications, such as voice recognition, advanced robotics that are being used today .The use of parallel processing and superconductors is helping to make artificial intelligence a reality.

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Computers Hardware Generations

Computers Hardware Generations

1. First Generation, 1946-59: Vacuum Tubes, Relays, Mercury  Delay Lines:

-ENIAC (Electronic Numerical Integrator And Computer): First electronic computer, 18000 vacuum tubes, 1500 relays, 5000 additions/sec.

-First stored program computer: EDSAC ( ELECTRONIC DELAY STORAGE AUTOMATIC CALCULATOR ).

2. Second Generation, 1959-64: Discrete Transistors.

3. Third Generation, 1964-75: Small And Medium Scale Integrated (MSI) Circuits.

4. Fourth Generation, 1975-present: The Microcomputers .

    VLSI- based Microprocessor.

5. Fifth Generation, Future: Based On Artificial Intelligence.

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People Behind The Inventions Of Computer Generations.

People Behind The Inventions Of Computer Generations.

1. First Generation Computers (vacuum tubes) - Vacuum tubes was invented by JOHN AMBROSE FLEMING.

2. Second Generation Computers (transistors) - Transistors was invented by WILLIAM SHOCKLEY, WALTER, HOUSER BRATTAIN, JOHN BARDEEN.

3.Third Generation Computers (integrated circuits) - Integrated circuits was invented by JACK KILBY, ROBERT NOYCE.

4.Fourth  Generation Computers (microprocessors) - Microprocessors was invented by MARCIAN HOFF, MASATOSHI SHIMA, STANLEY MAZOR.

 5. Fifth Generation Computers (artificial intelligence) - Artificial intelligence was invented by ALLEN NEWELL, J.C. SHAW, HERBERT A. SIMON.

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