Perhaps Computer is the most powerful and versatile tool created by human beings[span_0](end_span). [span_1](start_span)In today's scenario, computer plays a major role in almost every aspect of life and influences our lives in one way or the other[span_1](end_span). [span_2](start_span)A computer accepts the input through various input devices, performs different operations on the input, and finally generates the resultant output through various output devices[span_2](end_span). [span_3](start_span)Hence, a computer is a data processing device[span_3](end_span).
The origin of the computer is tied to the human effort to count large numbers[span_4](end_span). [span_5](start_span)This led to various systems of numeration, with the Indian system (0-9) being universally accepted and forming the basis of the modern decimal system[span_5](end_span).
Developed in China around 3000 B.C., the abacus may be considered the first computer[span_6](end_span). [span_7](start_span)[span_8](start_span)[span_9](start_span)It's a calculating board or counting frame used for arithmetic operations by manipulating beads on wires[span_7](end_span)[span_8](end_span)[span_9](end_span).
In 1617 A.D., mathematician John Napier built a mechanical device for multiplication known as Napier's bones[span_10](end_span). [span_11](start_span)It consisted of a set of eleven rods made of bone or ivory that could be used to find products and quotients of large numbers[span_11](end_span).
Developed by English mathematician E. Gunter, the slide rule could perform addition, subtraction, multiplication, and division[span_12](end_span). [span_13](start_span)It works by sliding two rulers marked with logarithmic scales against each other[span_13](end_span).
At the age of 19, French mathematician Blaise Pascal developed a machine capable of adding and subtracting numbers[span_14](end_span). [span_15](start_span)It was operated by dialing a series of wheels, gears, and cylinders[span_15](end_span).
English mathematics professor Charles Babbage started working on a 'Difference Engine' in the 1820s[span_16](end_span). [span_17](start_span)He realized that mathematical calculations could be broken into simple, repeated operations performed by an automatic machine[span_17](end_span). [span_18](start_span)He is often called the father of the computer[span_18](end_span).
Developed by Charles Babbage, the Analytical Engine marked a progression to general-purpose computation[span_19](end_span). [span_20](start_span)It had essential features of a modern computer, including a 'Store' (memory) and a 'Mill' (processor)[span_20](end_span). [span_21](start_span)It was capable of conditional branching, looping, and parallel processing[span_21](end_span).
The evolution of computers is divided into five distinct phases known as Generations of Computers, each distinguished by the type of switching circuits used[span_22](end_span)[span_23](end_span).
1) What is a computer? Why is it known as data processor ?
[span_41](start_span)A computer is an electronic device, which is used to accept, store, retrieve and process the data at faster speed and with greater accuracy[span_41](end_span). [span_42](start_span)It is also called as data processor because it is mainly used for processing the input data given to it and producing the desired result[span_42](end_span).
2) Into how many generations the evolution of computer is divided?
[span_43](start_span)Evolution of computer can be divided into five generations: First Generation (Vacuum tubes), Second Generation (Transistors), Third Generation (ICs), Fourth Generation (Microprocessor), Fifth Generation (Artificial intelligence)[span_43](end_span).
A digital computer is an electronic device that receives data, performs operations, and produces results according to a program[span_44](end_span). [span_45](start_span)The key components are the Central Processing Unit (CPU), Input, Output, and Memory[span_45](end_span).
The binary number system, with a base of 2, uses only two symbols (0 and 1) and is the fundamental language of digital computers[span_51](end_span)[span_52](end_span). [span_53](start_span)[span_54](start_span)A number system with base 'r' will have 'r' distinct symbols from 0 to r-1[span_53](end_span)[span_54](end_span). [span_55](start_span)Other number systems like octal (base 8) and hexadecimal (base 16) are also used in computer science[span_55](end_span).
ASCII (American Standard Code for Information Interchange) is a 7-bit code used to represent text, numbers, and symbols in computers[span_56](end_span). [span_57](start_span)It includes definitions for 128 characters[span_57](end_span).
[span_58](start_span)Unicode is a computing industry standard for encoding and handling text from most of the world's writing systems[span_58](end_span). [span_59](start_span)[span_60](start_span)It has a repertoire of over 107,000 characters and is essential for multilingual environments[span_59](end_span)[span_60](end_span). [span_61](start_span)UTF-8 is the most commonly used encoding on the World Wide Web[span_61](end_span).
An instruction tells the processor what task to perform[span_62](end_span). [span_63](start_span)The set of all instructions a processor can execute is its instruction set[span_63](end_span). [span_64](start_span)An instruction is comprised of two parts: an opcode (the operation to be performed) and operands (the data)[span_64](end_span). [span_65](start_span)The execution of an instruction involves multiple cycles: Fetch, Decode, Execute, and Write back[span_65](end_span).
3) Briefly state the reason why ASCII can not be less than 7 bit code?
[span_66](start_span)[span_67](start_span)ASCII code needs to represent 10 decimal digits, 26 uppercase letters, 26 lowercase letters, and other punctuation and special characters[span_66](end_span)[span_67](end_span). [span_68](start_span)A 6-bit code can represent only 64 characters ($2^6$), which is insufficient[span_68](end_span). [span_69](start_span)A 7-bit code, which can represent 128 characters ($2^7$), is required to accommodate all these symbols[span_69](end_span).
Memory is an essential computer component where data and information are stored as binary digits[span_70](end_span). [span_71](start_span)Storage devices are categorized by access time, storage capacity, and cost per bit[span_71](end_span).
Magnetic memory is an inexpensive, non-volatile medium for permanent storage[span_85](end_span).
Optical disks use a laser beam to read and write data[span_91](end_span).
To balance speed, size, and cost, modern computers use a memory hierarchy[span_96](end_span). [span_97](start_span)This hierarchy includes fast but small CPU registers at the top, followed by cache memory, main memory, and finally large but slow secondary storage[span_97](end_span). [span_98](start_span)The overall goal is to achieve the highest possible access speed while minimizing the total cost of the memory system[span_98](end_span).
4. What is the overall purpose of the memory hierarchy? Name the general class