Fundamentals of Computer.
C – COMMON
O - OPERATIVE
M- MACHINE
P - PARTICULARLY
U – USED FOR
T - TECHNICAL
E – EDUCATION / ENTERTAINMENT
R – RESEARCH
What is Computer?
Computer is an electronic device which can compute a large amount of data and can store or retrieve it with full accuracy at any time.
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2) Octal (0-7)8
3) Decimal (0-9)10
4) Hexadecimal(0-9,A,B,C,D,E,F)16
What is the uses of Computer?
(1) In engineering and scientific research (2) In data processing (3) In commercial and financial application (4) In office automation (5) In drawing and manufacturing field (6) In publishing work (7) In process control application. (8) In Graphics. (9) In teaching aids. (10) In information and communication system. (11) In robotics and remote sensing. (12) In weather forecasting.
What is Data?
Data are basic facts which are not organized but may be organized. This is like raw material.
What is Information?
Information are organized data in useful form for direct utilization of mankind. This is like a processed material.
What is Database?
Database is a collection of information organized in such a way that a computer program can quickly select the desired data.
What is Data Processing?
Data processing is the method to produce information from data. Data processing consists of three basic stages. Input > Processing > Output.
How many types of computer are available?
Computers may be classified in different ways as (1) Classification according to the Task performed (2) Classification according to logic (3) Classification according to the size.
How can you classify the computer according to the Task performed?
(1) General purpose computer (2) Special purpose computer.
How can you classify the computer according to Logic or signal system?
(1) Analog Computer (2) Digital Computer (3) Hybrid Computer.
How can you classify the computer according to Size?
(1) Super Computer (2) Mainframe Computer (3) Minicomputer (4) Small
Computers as Desktop, Laptop, Palmtop, Tablets, Notebooks, Net books etc.
What is workstation?
Workstations are expensive powerful machines used by engineers, scientists, and other professionals. It can process a lot of data to run complex programs and display both work in progress and results graphically. Workstations also use powerful networking links to other computers.
What is Servers?
A server is a system (software and suitable computer hardware) that responds to requests across a computer network to provide, or help to provide, a network service. Servers can be run on a dedicated computer, which is also often referred to as "the server", but many networked computers are capable of hosting servers. In many cases, a computer can provide several services and have several servers running.
What is Personal Computer?
A small, relatively inexpensive computer designed for an individual user. In price, personal computers range anywhere from a few hundred dollars to thousands of dollars. All are based on the microprocessor technology that enables manufacturers to put an entire CPU on one chip. Businesses use personal computers for word processing, accounting, desktop publishing, and for running spreadsheet and database management applications.
What is Portable Computer?
Now computers are becoming smaller but powerful. One type of PC that is rapidly growing in popularity is the portable computer, which can be easily carried around. There are three categories of computers are available : Laptops or notebooks, Sub notebooks and Personal Digital Assistance (PDA).
What is Central Processing Unit (CPU)?
CPU is the most important unit of microprocessor. It is the brain of the computer system. An 8-bit CPU is called a general purpose microprocessor. It can do all mathematical and logical operations. CPU receives instructions, generates control, signals and finally executes the instruction.
A) CPU is the nerve center of the computer system
B) It performs the central control functions
C) All mathematical operations are controlled by CPU.
D) All logical and decision making operations are controlled by CPU.
It consists of three basic parts as Arithmetic Logic Unit (ALU), Control Unit (CU) and Memory as Storage Unit for computer system.
It is the part of the computer which stores data temporarily or permanently for future use. Memory can be classified as Primary Memory, Secondary Memory, Cache Memory, Registers.
What is Primary memory?
Primary memory is a storage device which stores data and program temporarily. It generally holds data and program till the supply remains on. For example Random Access Memory (RAM), Read Only Memory (ROM).
What is Secondary memory?
It is the storage unit that stores data and program permanently. It holds the current data and program even if the supply is withdrawn. For example Hard Disk, Digital Versatile Disk (DVD), Compact Disk (CD), Floppy, Pen drives, Optical Drives.
What is Cache memory?
Cache Memory is a high speed storage unit. It is much more faster than real memory or main memory. Cache memory is extremely expensive compared to main memory.
What is Storage Registers?
In computer architecture, a processor register is a small amount of storage available as part of a CPU or other digital processor. Such registers are (typically) addressed by mechanisms other than main memory and can be accessed more quickly. Almost all computers, load-store architecture or not, load data from a larger memory into registers where it is used for arithmetic, manipulated, or tested, by some machine instruction. Manipulated data is then often stored back in main memory, either by the same instruction or a subsequent one. Modern processors use either static or dynamic RAM as main memory, the latter often being implicitly accessed via one or more cache levels. A common property of computer programs is locality of reference: the same values are often accessed repeatedly and frequently used values held in registers improves performance. This is what makes fast registers (and caches) meaningful.
What is RAM?
Random Access Memory (RAM) is that part of the primary memory which is used by the computer for performing all jobs supplied by the user. At power off condition, the RAM looses all its contents permanently. That is why it’s called as Volatile Memory. Basically RAM can be categorized as SRAM (Static Random Access Memory) and DRAM (Dynamic Random Access Memory).
What is ROM?
Read Only Memory is circuit based and all the instructions stored here uses logic gates rather than electric charges. This makes ROM nonvolatile and hence its contents are not erased due to power shutdown or due to human manipulation. The contents of ROM remains unchanged throughout its life. Basically ROM can be categorized as Programmable Read Only Memory (PROM), Erasable Programmable Read Only Memory (EPROM), Erasable Alterable Programmable Read Only Memory (EAPROM), Electronically Erasable Programmable Read Only Memory (EEPROM) and Ultra Violet Programmable Read Only Memory (UVPROM).
What is Softcopy ?
With the softcopy the Output is shown on monitor using dots of colors or lights. Each of these dots are individually called pixels or picture Elements. These dots, when concentrated on various parts of the screen, produce an output. If the density of dots is high then the output is clearer. This is called Resolution. Hence higher the resolution better is output. It can be viewed or read but cannot be touched. For Example digital books or documents in monitors.
What is Hardcopy?
With the hardcopy it can be produce on paper or on any surface. It can be touched and read also. For example the print out from printer.
What is Printer?
Printers are the output device which is generally used to produce text materials and other ordinary graphics as hardcopy output. Generally, the output generated by the printer can either be of single color or multicolor.
How many types of printers are available?
Usually printers can be divided in two types as (1) impact or non impact printer (2) Based on speed of printing.
What is Impact Printer?
In this type the printer’s head physically touches the paper surface to produce the output. The head always being in contact with the paper while printing, produces high friction thus making noise, for example Dot Matrix Printer, Daisy Chain Printers.
What is Non-Impact Printer?
In this type printer’s head does not physically touch the paper to produce the impression. Generally in this case a fine jet of ink is spread over the paper surface. Due to no contact between the printer head and paper, the friction generated is very low, making it virtually noiseless. More over multicolor output is possible, for example DeskJet or Inkjet printers, Laser Jet Printers.
What is Computer Terminals?
A computer terminal generally combines input and output functions. It consists of a keyboard as an input device and printer and TV screen as output device. Terminals are generally two types (1) Dumb Terminal (2) Intelligent Terminal (Built in Memory with Microprocessor).
What is OMR, OCR, MICR ?
OMR: Optical Mark Reader: It is popularly used for evaluating objective type answer script in examinations.
OCR: Optical Character Reader: It is special type of scanner which is popularly used for scanning alphabet, Numeric and alphanumeric symbols written using normal ink on plain paper.
MICR: Magnetic Ink Character Reader: It is popularly used in banks for verifying important documents like drafts, cheques etc. At the bottom side of such documents, a set of symbols are printed with magnetized ink. If the document is genuine, the magnetic field created by the symbols printed with magnetized ink on it interacts with the external magnetic to generate some force which is sensed by the MICR.
Write the full form of CRT, LED, LCD, VDU, ALU, CU, EDPS, MIS, DSS, EP.
(1)CRT: Cathode Ray Tube. (2)LED: Light Emitting Diode. (3)LCD: Liquid Crystal Display. (4)VDU: Visual Display Unit. (5)ALU: Arithmetic Logic Unit. (6)CU: Control Unit. (7)EDPS: Electronic Data Processing System. (8)MIS: Management Information System. (9)DSS: Decision Support System. (10)EP: Expert System.
What is number system?
A number is a mathematical object used to count, label, and measure. In mathematics, the definition of number has been extended over the years to include such numbers as 0, negative numbers, rational numbers, irrational numbers, and complex numbers.
Number system is a procedure to calculate or compute different types of numbers in different theories.
What is decimal number system?
The decimal numeral system (also called base ten or occasionally denary) has ten as its base. It is the numerical base most widely used by modern civilizations.
What is binary number system?
In mathematics and computer science, the binary numeral system, or base-2 numeral system, represents numeric values using two symbols: typically 0 and 1. More specifically, the usual base-2 system is a positional notation with a radix of 2. Numbers represented in this system are commonly called binary numbers. Because of its straightforward implementation in digital electronic circuitry using logic gates, the binary system is used internally by almost all modern computers and computer-based devices such as mobile phones.
What is Hexadecimal number system?
In mathematics and computer science, hexadecimal (also base 16, or hex) is a positional numeral system with a radix, or base, of 16. It uses sixteen distinct symbols, most often the symbols 0–9 to represent values zero to nine, and A, B, C, D, E, F (or alternatively a–f) to represent values ten to fifteen. For example, the hexadecimal number 2AF3 is equal, in decimal, to (2 × 163) + (10 × 162) + (15 × 161) + (3 × 160), or 10995.
Each hexadecimal digit represents four binary digits (bits), and the primary use of hexadecimal notation is a human-friendly representation of binary-coded values in computing and digital electronics. One hexadecimal digit represents a nibble, which is half of an octet or byte (8 bits). For example, byte values can range from 0 to 255 (decimal), but may be more conveniently represented as two hexadecimal digits in the range 00 to FF. Hexadecimal is also commonly used to represent computer memory addresses.
What is Octal number system?
The octal numeral system, or oct for short, is the base-8 number system, and uses the digits 0 to 7. Octal numerals can be made from binary numerals by grouping consecutive binary digits into groups of three (starting from the right). For example, the binary representation for decimal 74 is 1001010, which can be grouped into (00)1 001 010 – so the octal representation is 112.
What is ASCII Code?
ASCII stands for American Standard Code for Information Interchange. Most computers and virtually all personal computers use ASCII code. This code is very popular and widely used for internal representation of data in digital computer. In ASCII code, individual character is encoded with its own 7-bit combination. The 7- bit can represent 27 = 128 unique string and it is sufficient to represent 94 characters is ASCII code including 26 upper case and 26 lower case English letters, 10 decimal digits and other 32 characters.
What is ISCII Code?
The Indian Standard Code for Information Interchange was standardize by Department of Electronics, Govt of India in 1986 to write Indian Scripts on Computer Screen. ISCII code is compatible to the ISO-8-bit code .
What is BCD Code?
BCD stands for Binary Coded Decimal. It is the binary code in which decimal digit is expressed by a group of four(4) bits. The right to left weightings of 4 – bits are 23,22,21 and 20 or 8,4,2,1. Each 4 digits are called as Nibble. It is used to represent decimal digits in digital calculator, voltmeter, ammeter etc.
What is EBCDIC Code?
EBCDIC stands for Extended Binary Coded Decimal Interchange Code. It is widely used in IBM mainframe computers. In EBCDIC, character is numerically encoded with its own unique 8-bit combination. The 8-bit can represent 28 i.e 256 unique string or character.
What is Boolean Algebra?
For the centuries, mathematician felt that there was a connection between mathematician and logic but they had to wait till 1854 when George Boole Could find this missing link. He invented symbolic logic, particularly known as Boolean Algebra.
What are the Gates?
A logic gate is an idealized or physical device implementing a Boolean function, that is, it performs a logical operation on one or more logical inputs, and produces a single logical output. Logic circuits include such devices as multiplexers, registers, arithmetic logic units (ALUs), and computer memory, all the way up through complete microprocessors, which may contain more than 100 million gates. In practice, the gates are made from field-effect transistors (FETs), particularly MOSFETs (metal–oxide–semiconductor field-effect transistors). For example : AND-Gate, OR-Gate, NOT-Gate, NAND-Gate, XOR-Gate, XNOR-Gate.
What is Adder?
The heart of the arithmetic unit of computer is the adder circuit. It can add the bits by its logic circuits and produce larger value as output.
What is Half Adder?
Half adder is the simplest combinational circuit and it is used to add two least significant bits in a binary addition. The half adder performs addition between two bits and produces sum and carry.
What is Full Adder?
A full adder can three bits. So for a full adder, the inputs are two bits A and B to be added coming from two registers and a carry bit generated by previous addition and two outputs are Sum and Carry.
What is Subtractor?
In electronics, a subtractor can be designed using the same approach as that of an adder but for the binary subtraction process.
What is Half Subtractor?
A half Subtractor is used to subtract two bits at a time. The half Subtractor follows the rule of binary subtraction and produces the difference and borrow.
What is Full Subtractor?
A full Subtractor is used to subtract higher order bits. It has three inputs which are two for minuend (A) and subtrahend (B) the third input borrow (Wi) arising due to previous subtraction and two outputs which are difference (D) and output borrow (Wo).
What is Multiplexer?
The multiplexer is one set of the most widely used special combinational circuit in digital design. The multiplexer selects binary information from one out of several input lines and directs it to a single output line.
What is Decoder?
A decoder is combinational logic circuit which is used to select hardware by changing the input bit pattern. For an n input decoder, the maximum number of terminal is m where 2m=n.
What is Encoder?
An encoder is widely used combinational logic circuit. The operation of an encoder is exactly opposite to that of a decoder i.e the encoder expresses a distinct element into a group of bits. For an encoder with 2n input lines, it has n output lines.
What is Demultiplexer?
Demultiplexer is a combinational logic circuit which performs the reverse operation of a multiplexer. A demultiplexer contains one input line and 2n output line, where n is the number of selection lines.
What is Flip-Flop?
The digital computer operates only with the digits 0 and 1. Logic gates are used to execute logical program. During execution of program, it is often necessary to store digital information. The element used to storing data is known as memory. A flip flop is a 1 bit storage or memory element. There are different types of flip flops. The salient features of a flip flop are:
(1) A flip flop can store digital information either 0 or 1.
(2) A flip flop operates with one, two or three inputs.
(3) A flip flop consist of two outputs in which one output is the complement of other.
(4) The time for charging state of a clocked flip flop depends on external clock.
What is Counter?
A counter is a hardware element whose value changes by unity due to the change of input pulses i.e it can count the occurrence of successive pulse. Since these pulses occur at known and equally speed intervals of time, the counter may be used for measurement of time. However, the counter may count the pulses which may be random or at a prescribed time interval. Basically, the counters may be classified into synchronous counter and asynchronous counter.
What is registers?
A flip flop can store 1 – bit of digital information. Sometimes it is known as 1 – bit register. Generally an array of flip flop in a register is determined by the number of bits to be stored. Registers can be classified depending on the data entered or retrieved.
(1) Serial in, Serial Out (SISO)
(2) Serial in, Parallel Out(SIPO)
(3) Parallel in, Serial Out(PISO)
(4) Parallel in, Parallel Out(PIPO)
What is Flow Chart?
A flowchart is a type of diagram that represents an algorithm or process, showing the steps as boxes of various kinds, and their order by connecting them with arrows. This diagrammatic representation illustrates a solution to a given problem. Process operations are represented in these boxes, and arrows; rather, they are implied by the sequencing of operations. Flowcharts are used in analyzing, designing, documenting or managing a process or program in various fields.
What is Algorithm?
In mathematics and computer science, an algorithm is a step-by-step procedure for calculations. Algorithms are used for calculation, data processing, and automated reasoning.
An algorithm is an effective method expressed as a finite list of well-defined instructions for calculating a function. Starting from an initial state and initial input (perhaps empty), the instructions describe a computation that, when executed, proceeds through a finite number of well-defined successive states, eventually producing "output" and terminating at a final ending state. The transition from one state to the next is not necessarily deterministic; some algorithms, known as randomized algorithms, incorporate random input.
What is Neolithic Computation?
In the history of computer, the first computer was found at about 3500 years ago in England. It was in the form of a heap of huge stones arranged in a circular manner kept on a big ground. This was known as Neolithic Computer. Following the method of calculation known as stone henge calculation, it was used to make different astronomical calculations.
What is Soroban or Abacus?
Probably during 600 B.C abacus an improved system of computation was developed in which the numbers were represented by the number of beads placed on a rack and their position. Simple addition and subtraction could be done using this by properly positioning the beads on the rack. The name Abacus came from the Greek word ‘Abakos’. This is also known as ‘Soroban’ computer.
Q. Write short note on the historical development of Computer.
Ans: In the history of computer, the first computer was found at about 3500 years ago in England. It was in the form of a heap of huge stones arranged in a circular manner kept on a big ground. This was known as Neolithic Computer. Following the method of calculation known as stone henge calculation, it was used to make different astronomical calculations.
Probably during 600 B.C abacus an improved system of computation was developed in which the numbers were represented by the number of beads placed on a rack and their position. Simple addition and subtraction could be done using this by properly positioning the beads on the rack. The name Abacus came from the Greek word ‘Abakos’. This is also known as ‘Soroban’ computer.
A Scottish mathematician, John Napier developed a card board multiplication calculator during early Seventeenth Century. In the year 1642, a French mathematician Blasie Pascal developed an adding machine utilizing several wheels marked as unit’s wheel, ten’s wheel, hundred’s wheel. Etc. Utilizing the concept of this machine, Leibnitz, a German mathematician developed a machine ‘Stepped Reckover’ in the year 1673 which could add and multiply.
A major development in computer took place in the nineteenth century. Herman Hollarith, a German Scientist developed the punch card system. He utilized Hollarith code to enter instruction and data to the machine. The major break through came in the year 1830, when Charles Babbage, an Englishman developed the first form of a modern digital computer. He is the first man to give a definition of computer. He is known as the Father of Computer Science. Earlier in 1822, Babbage designed a “Difference Engine”, which could compute various reliable mathematical and statistical tables. In 1842, he developed a new idea of automatic analytic engine which could be capable of performing basic arithmetical process. Unfortunately he could not develop the model of his Analytical Engine due to the constraints of precision engineering methodology, but gave the fundamental idea of a digital computer. He also specified the definition of a computer. According to Babbage, a machine may be called a computer if it would satisfy the following criteria.
- The machine must be able to solve all types of arithmetic (add, subtract, multiply, quotient) and logical calculations.
- The machine must have some storage unit for storing data to be required during computation.
- The machine must have some input and output unit for bi directional (man to machine, machine to man) communication.
- The machine must have some decision making ability.
The first fully automatic calculating machine known as the Mark –I Computer was designed by Howard A. Aiken in collaboration with International Business Machines (IBM) Corporation (1937 -44). It was an automatic sequence controlled Calculator and its design was based on the technique of punch card machinery. It was very big machine (50 feet in length and 8 feet in height) accommodating about 3000 electrically operated switches. It was a basically electro mechanical device. It could perform all fundamental and mathematical calculations together with reference. Maximum permissible data size, the machine could handle was 23 decimal digits. Its operating speed was 0.3 seconds and 4. Seconds for adding and subtracting two numbers respectively.
ABC
In the period from 1939 to 1942, John Atanasoff, a professor at Iowa State University,and Clifford Berry, a graduate student at the same school, created what is now considered the first modern computer. Their machine, which they called the Atanasoff-Berry Computer, or ABC, weighed about 700 pounds and had to be housed in the basement of the physics department. By current standards, it was a terribly slow machine, reportedly capable of only a single calculation every fifteen seconds. In contrast, a computer today can perform billions of calculations a second.
ENIAC
Like William Hollerith’s punched cards, the ENIAC story is driven by governmental need. When World War II began, the United States was woefully underprepared for military operations. The army needed to develop and test a large number of weapons in a short period of time. In particular, it had to perform a number of ballistics tests to create artillery tables—in essence, a book showing how far an artillery shell would fly from a specific gun, given wind conditions, the angle of the gun barrel, and so on. Like the mathematical tables of Babbage’s time, these artillery tables had been created by hand, but by now the army already had some devices for assisting in calculation. Called differential analyzers, they operated on mechanical principles (much like Babbage’s machines), not on electronics. But something better was needed, in aid of which the army hired John Mauchly and J. Presper Eckert, computer scientists at the University of Pennsylvania. In 1946, the machine they proposed was called ENIAC, which stands for Electronic Numerical Integrator and Computer. Like the ABC, it was truly a modern computer.
The term “modern” might seem too strong if you actually saw this machine. Computers of that era relied on the vacuum tube, a device that resembled a lightbulb through which one electrical current can control another. This controlling aspect was used to build logical circuits, because by itself one vacuum tube doesn’t do much. Indeed, ENIAC required about 19,000 vacuum tubes to do its work, filled an entire room, weighed thirty tons, and drew about 200 kilowatts (that is, 200,000 watts) of power. In comparison, a desktop computer purchased today would draw about 400 watts of power, which means ENIAC drew about 500 times more current, even though its actual ability to compute is dwarfed by the most inexpensive desktop computers of today. What makes ENIAC so important is its reliance on electronics to solve a real-world problem. There were as few mechanical parts as possible, although some mechanics were inevitable. For example, ENIAC still used punch cards for input and output, and the parts that read and produced these cards were mechanical. The vacuum tubes were built into minicircuits that performed elementary logical functions and were built into larger circuits. Those circuits were built into even larger circuits, a design idea that is still used today.
UNIVAC
The UNIVAC-1 computer, the first digital computer in true form was developed in 1951. This Universal Automatic Computer was installed in Census Bureau. Later, General Electric Corporation used UNIVAC-1 commercially. Shortly IBM corporation developed different improved versions of commercial computers like IBM-650 and the era of commercial computer have been started. But now a days, it has been extended to include both hardware and software.
Five generations of computers are known till date.
FIRST GENERATION
Computers like ENIAC, EDVAC, EDSAC etc. belong to the first generation (1951 – 1959) of computers. The computers developed with vacuum tubes or valves as the basic elements fall under this generation.
SECOND GENERATION
In the year of 1947, a revolution took place in the field of semiconductor technology with the invent of transistors. The Second Generation (1959 -1965) of computers emerged when vacuum tubes had been replaced by transistors.
THIRD GENERATION
The period of third generation was 1965-1971.
The third generation of computer is marked by the use of Integrated Circuits (IC's) in place of transistors. A single I.C has many transistors, resistors and capacitors along with the associated circuitry. The I.C was invented by Jack Kilby. This development made computers smaller in size, reliable and efficient.In this generation Remote processing, Time-sharing, Real-time, Multi-programming Operating System were used.
FOURTH GENERATION
The period of Fourth Generation was 1971-1980.
The fourth generation of computers is marked by the use of 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 Higher level languages like C and C++, DBASE etc. were used in this generation.
FIFTH GENERATION
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 Higher level languages like C and C++, Java, .Net etc. are used in this generation.
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