Computer Devices and Operating Systems

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COMPUTER DEVICES AND OPERATING SYSTEMS
INTRODUCTION:
The word 'computer' comes from the word compute which means 'to calculate'. Computers were developed from calculators as the need arose for more complex and scientific calculations. Charles Babbage is known as the father of computers because of his immense contribution to the world of programming. His idea was soon developed into a programmable computer that could calculate and print logarithmic tables with huge precision. But there were many practical problems and the progress was slow. MEANING AND DEFINITION:

An electronic device which is capable of receiving information (data) in particular form and of performing a sequence of operations in accordance with predetermined but variable set of procedural instructions (program) to produce a result in the form of information or signals. a person who makes calculations, especially with a calculating machine. The physical components from which a computer is constructed (electronic circuits and input/output devices) are known as "hardware”. Most computers have four types of hardware component: CPU, input, output and memory. The CPU (central processing unit) executes programs ("software") which tell the computer what to do. Input and output (I/O) devices allow the computer to communicate with the user and the outside world. There are several kinds of memory - fast, expensive, short term memory (e.g. ram) to hold intermediate results, and slower, cheaper, long-term memory (e.g. magnetic disk and magnetic tape) to hold programs and data between jobs. GENERATION OF COMPUTERS:

Each generation of computers is characterized by major technological development that fundamentally changed the way computers operate, resulting in increasingly smaller, cheaper, more powerful and more efficient and reliable devices. Read about each generation and the developments that led to the current devices that we use today. 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. A magnetic drum, also known as drum, is a metal cylinder coated with magnetic iron-oxide material on which data and programs can be stored. Magnetic drums were once used as a primary storage device but have since been implemented as auxiliary storage devices. 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 to perform operations, and they could only solve one problem at a time. Machine languages are the only languages understood by computers. While easily understood by computers, machine languages are almost impossible for humans to use because they consist entirely of numbers. Computer Programmers, therefore, use either high level programming languages or an assembly language programming. An assembly language contains the same instructions as a machine language, but the instructions and variables have names instead of being just numbers. 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. Second Generation - 1956-1963: Transistors

Transistors replaced vacuum tubes and ushered in the second generation computer. Transistor is a device composed of semiconductor material that amplifies a signal or opens or closes a circuit. Invented in 1947 at Bell Labs, transistors have become the key ingredient of all digital circuits, including computers. Today's latest microprocessor contains tens of millions of microscopic transistors. The transistor was invented in 1947 but did not see widespread use in computers until the late 50s. The transistor was far...
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