Tuesday, 16 July 2013

First ICT Task .. :-)



The Five Generations of Computers
The history of computer development is often referred to in reference to the different generations of computing devices. Each of the five generations of computers is characterized by a major technological development that fundamentally changed the way computers operate.
The history of computer development is often referred to in reference to the different generations of computing devices. Each of the five generations of computers is characterized by a major technological development that fundamentally changed the way computers operate, resulting in increasingly smaller, cheaper, more powerful and more efficient and reliable computing devices.
In this Webopedia reference article you'll learn about each of the five generations of computers and the technology developments that have led to the current devices that we use today. Our journey starts in 1940 with vacuum tube circuitry and goes to the present day -- and beyond --  with artificial intelligence.
First Generation (1940-1956) Vacuum Tubes
The first computers used vacuum tubes for circuitry and magnetic drums for memory, and were often enormous, taking up entire rooms. They 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.
First generation computers relied on machine language, the lowest-level programming language understood by computers, to perform operations, and they could only solve one problem at a time. Input was based on punched cards and paper tape, and output was displayed on printouts.
The UNIVAC and ENIAC computers are examples of first-generation computing devices. The UNIVAC was the first commercial computer delivered to a business client, the U.S. Census Bureau in 1951.

A UNIVAC computer at the Census Bureau.
Image Source: United States Census Bureau
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.
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.
Fourth Generation (1971-Present) Microprocessors
The microprocessor brought the fourth generation of computers, 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 Intel 4004 chip, developed in 1971, located all the components of the computer—from the central processing unit and memory to input/output controls—on a single chip.
In 1981 IBM introduced its first computer for the home user, and in 1984 Apple introduced the Macintosh. Microprocessors also moved out of the realm of desktop computers and into many areas of life as more and more everyday products began to use microprocessors.
As these small computers became more powerful, they could be linked together to form networks, which eventually led to the development of the Internet. Fourth generation computers also saw the development of GUIs, the mouse and handheld devices.
Fifth Generation (Present and Beyond) Artificial Intelligence
Fifth generation computing devices, based on artificial intelligence, are still in development, though there are some applications, such as voice recognition, that are being used today. The use of parallel processing and superconductors is helping to make artificial intelligence a reality. Quantum computation and molecular and nanotechnology will radically change the face of computers in years to come. The goal of fifth-generation computing is to develop devices that respond to natural language input and are capable of learning and self-organization.

Computer Components



 


A computer system consists of mainly four basic units; namely input unit, storage unit, central processing unit and output unit. Central Processing unit further includes Arithmetic logic unit and control unit, as shown in the figure:. A computer performs five major operations or functions irrespective of its size and make. These are
• it accepts data or instructions as input,
• it stores data and instruction
• it processes data as per the instructions,
• it controls all operations inside a computer, and
• it gives results in the form of output.

b. Storage Unit: The storage unit is used for storing data and instructions before and after processing.
c. Output Unit: The output unit is used for storing the result as output produced by the computer after processing.
d. Processing: The task of performing operations like arithmetic and logical operations is called processing. The Central Processing Unit (CPU) takes data and instructions from the storage unit and makes all sorts of calculations based on the instructions given and the type of data provided. It is then sent back to the storage unit. CPU includes Arithmetic logic unit (ALU) and control unit (CU)

• Arithmetic Logic Unit: All calculations and comparisons, based on the instructions provided, are carried out within the ALU. It performs arithmetic functions like addition, subtraction, multiplication, division and also logical operations like greater than, less than and equal to etc. 
 • Control Unit: Controlling of all operations like input, processing and output are performed by control unit. It takes care of step by step processing of all operations in side the computer. 
 Memory
Computer’s memory can be classified into two types; primary memory and secondary memory 

 RAM
a. Primary Memory can be further classified as RAM and ROM.
b. Secondary Memory
-CD ROM
 -Hard Disk
-Compact Disk
- Digital Video Disk
Input / Output Devices:
These devices are used to enter information and instructions into a computer for storage or processing and to deliver the processed data to a user. Input/Output devices are required for users to communicate with the computer. In simple terms, input devices bring information INTO the computer and output devices bring information OUT of a computer system. These input/output devices are also known as peripherals since they surround the CPU and memory of a computer system.
INPUT DEVICES
-Keyboard 
-Light 
-PenScanner

OUTPUT DEVICES
-Monitor:
- Plotter

]
 

 
Advantages of using computer
Advantages of using computer


One advantage is that message boards and online reflections, such as blogs, can give a voice to the voiceless in a classroom and increase collaboration. It can also let students share more of their work with the class at large. Normally not everyone participates in a class discussion and group work usually only exposes the students to the work of their groupmates. But in an online discussion forum, each student is required to add to the discussion. Each student is also able to see what their classmates wrote about in their responses. In a study done by Judith Mara Kish in her basic writing classroom, using a forum to share and comment on their classmates ideas for a paper assignment help to alleviate writers block for some students. With the forum, they were able to see how others generated topics and to offer suggestions on how to approach the different topics.
Another advantage comes when you make the students critically think about computers. An article by Particia J. McAlexader discusses how she makes the students begin to think critically about the grammar checker. She spends the first part of the semester going over common grammar errors with the students. Then she has the students test the grammar checker by having them input sentences with grammar errors to see what (or if) the grammar checker finds. They then must see if the advice the grammar checker gives is correct based on what they had learned previously and give her a report.
A meta-analysis of studies about how computers have affected student writing showed that the use of a computer increased the quantity of student writing and also the quality of student writing. This increase was also more dramatic in higher grades than in the lower grades (Goldberg 14–16). This meta-analysis also showed that in some studies there was an “improvement in students’ literacy skills, attitudes toward writing, and an increase in the number of students who demonstrated high-order thinking skills in their writing” (Goldberg 18).