Computer Fundamental


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Computer Fundamental

  1. 1. Saturday, July 13, 2013 1Prof.(Dr.) Anand K. Tripathi
  2. 2. Computer Fundamentals Saturday, July 13, 2013 2Prof.(Dr.) Anand K. Tripathi
  3. 3. Q. What is a Computer? Ans. The term computer is derived from the word ‘to compute’ and therefore, can literally, be applied to any calculating device. However the term computer has come to mean as electronic computing device with certain characteristics e.g. high speed, memory, stored program etc. Saturday, July 13, 2013 3Prof.(Dr.) Anand K. Tripathi
  4. 4. • In simple terms, the computer can be defined as an electronic data processing machine. It receives data as input, processes the data, i.e. performs arithmetic and logical operation on the same time and produces output in the desired form on output device as per the instruction coded in the program. Saturday, July 13, 2013 4Prof.(Dr.) Anand K. Tripathi
  5. 5. • The processing function of the computer is directed by the stored program, a set of coded instructions stored in the memory unit, which guides the sequence of steps to be followed during processing. Saturday, July 13, 2013 5Prof.(Dr.) Anand K. Tripathi
  6. 6. Q. Define Computer? Ans. Computer system is made of two major components: Hardware and Software. Computer hardware is physical equipment .The software is the collection of programs (instructions) that allows the hardware to do its job. Figure depicts the computer system. Saturday, July 13, 2013 6Prof.(Dr.) Anand K. Tripathi
  7. 7. Q. What are the applications of Computers? Ans-The applicability of compute is in all the department of life .Some of them is as follows: 1. Weather forecasting 2. Management of organization 3. Entertainment Saturday, July 13, 2013 7Prof.(Dr.) Anand K. Tripathi
  8. 8. 4. CAD/CAM 5. E-mail 6. Scientific and education works 7. Advertisements 8. Medical 9. Database processing and word. 10. Sports activity Saturday, July 13, 2013 8Prof.(Dr.) Anand K. Tripathi
  9. 9. Q. WHAT ARE THE COMPONENTS OF A COMPUTER? Basically a computer consists of the following three units. Input Unit Central Processing Unit Output Unit The input and output units are usually abbreviated to I/O devices and the Central Processing Unit as C.P.U. Saturday, July 13, 2013 9Prof.(Dr.) Anand K. Tripathi
  10. 10. Q. State the functions performed by the above stated units. The above stated units namely Input unit, Output unit, and the Central processing unit perform the following functions. Saturday, July 13, 2013 10Prof.(Dr.) Anand K. Tripathi
  11. 11. 1) Input Unit. This unit serves as communication channel between user and the computer. All the instructions and data are fed to the computer through this unit. This unit consists of several devices called input devices. - Input device accepts instructions and data from the input unit Saturday, July 13, 2013 11Prof.(Dr.) Anand K. Tripathi
  12. 12. (2) Central Processing Unit (C.P.U.). This unit is called heart and nerve centre of a Computer. The C.P.U. performs the following functions. Controls and coordinates the working of all the parts of a computer. The input data is manipulated by the C.P.U. according to the instructions given by the user. This set of instructions is known as a program or a computer program or Receives instructions and data from the input unit. Saturday, July 13, 2013 12Prof.(Dr.) Anand K. Tripathi
  13. 13. Stores instructions and data in its primary memory. These instructions and data remain in its memory up to the time as required. Processes the data according to the instructions. The CPU consists of three units: A) C.U. (Control Unit) B) Primary Memory C) A L U (Arithmetical Logical Unit ) Saturday, July 13, 2013 13Prof.(Dr.) Anand K. Tripathi
  14. 14. A) C.U. (Control Unit): Control Unit is also known as the big boss of CPU or nerve centre of a computer system. -It controls and co-ordinates the functioning of all other units of a computer. -It is responsible for fetching or executing or running all the instructions and data from the main memory to the A.L.U. and it’s vice versa. Saturday, July 13, 2013 14Prof.(Dr.) Anand K. Tripathi
  15. 15. - Once the data is processed, this unit issues proper command (in the form of electrical signals or pulses) for the transfer back of this processed data along with feeded data (if required) to the main memory. -It also controls the input-output devices and the secondary storage devices too. Saturday, July 13, 2013 15Prof.(Dr.) Anand K. Tripathi
  16. 16. B) The Primary Memory Unit: The Memory Unit, as its name suggests stores all the instructions and data and is also called the Primary Storage Section/Memory or the Main Memory or the Immediate Access Memory (IAS). -Data and instructions entered into the main memory are held there until needed to be processed. -Similarly the results of action taken on data are held at primary memory until they required for out put. Saturday, July 13, 2013 16Prof.(Dr.) Anand K. Tripathi
  17. 17. -The ideal memory is one which is large enough to store all the information and from which the information can be retrieved as fast as required. However the design limitations of main/primary memory is that it forces to store only a limited amount of information in the form of instructions and data that are needed immediately. Saturday, July 13, 2013 17Prof.(Dr.) Anand K. Tripathi
  18. 18. -The remaining bulk of information is stored in Secondary Storage Devices also called Auxiliary Memory. The other commonly used names for this auxiliary memory are External Memory or Backing Storage. -This external memory consists of magnetic tapes or floppy disks, the later being more common. Saturday, July 13, 2013 18Prof.(Dr.) Anand K. Tripathi
  19. 19. -Compared to main memory this memory is quite slow and does not form a part of C.P.U. -A memory is said to be faster if it takes lesser time to retrieve information from it. Inside a Computer a primary memory is divided into two parts: a) ROM (Read Only Memory) b) RAM (Random Access Memory) Saturday, July 13, 2013 19Prof.(Dr.) Anand K. Tripathi
  20. 20. a) ROM (Read Only Memory) -ROM stands for Read Only Memory. It is permanent in nature and stores of information in the form of built in programs which ultimately activates the computer to test whether all the parts or devices are available or attached or working properly. Saturday, July 13, 2013 20Prof.(Dr.) Anand K. Tripathi
  21. 21. - The information stored in this part of memory is of permanent in nature means information or data stored in this part can not be erased or lost even though the power supply is off, or switched off hence it is Non Volatile Memory -This part of memory is machine dependent. Saturday, July 13, 2013 21Prof.(Dr.) Anand K. Tripathi
  22. 22. b) RAM (Random Access Memory) -The other part of the Main Memory/Primary memory is known as RAM. - It stands for Random Access Memory. In this unit, the instructions and data are received through input device with respect to CU and are stored in this part of memory. - Saturday, July 13, 2013 22Prof.(Dr.) Anand K. Tripathi
  23. 23. RAM contains the information as long as power supply is on. All the information stored in this part of memory is lost or erased when power supply is switched off. Hence this Volatile Memory. -This part of memory is user dependent. Saturday, July 13, 2013 23Prof.(Dr.) Anand K. Tripathi
  24. 24. 3) Arithmetic Logic Unit (ALU): This unit itself consists of two units which are as follows: 1) Automatic Unit: Which performs the arithmetical operations on to feeded data? 2) Logical Unit: which performs the logical operations on to feeded data. -As the data comes to this unit relevant unit of these two automatically activates for doing operation. Saturday, July 13, 2013 24Prof.(Dr.) Anand K. Tripathi
  25. 25. - The basic operations of the type addition, subtraction, multiplication, and division are known as arithmetic operations. - A logical operation simply means the comparisons of two data numbers or two sets of alphabetic characters. Saturday, July 13, 2013 25Prof.(Dr.) Anand K. Tripathi
  26. 26. 3) Output Unit Communicates the results of data processing to the user. These results are communicated through the output devices or - Results along with along feeded data (if required) are sent from main memory to an output device which displays results in user readable form or Saturday, July 13, 2013 26Prof.(Dr.) Anand K. Tripathi
  27. 27. Once the data is processed, the output unit converts it into a form which can be understood by the user easily as sent by the memory with respect or order or instructions issued by the CU or - Output unit serves as a link between the computer and the user which displays the results along with feeded data. Saturday, July 13, 2013 27Prof.(Dr.) Anand K. Tripathi
  28. 28. • Some names of output devices. 1.Character Printer 9. OCR 2.Line Printer 10.OMR 3.Dot Matrix Printer 11. MICR etc 4.Visual Display Unit 5.Plotter 6.Optical Printer 7.Laser Printer 8. Audio Response Unit Saturday, July 13, 2013 28Prof.(Dr.) Anand K. Tripathi
  29. 29. - These three operations (of CU, Memory, and ALU) together are also known as Electronic Data Processing cycle popularly called as EDP cycle. The Fig. given below illustrates an EDP Cycle. Saturday, July 13, 2013 29Prof.(Dr.) Anand K. Tripathi
  30. 30. Working of Computer or CPU: 1) As we feed the data by the input device, it goes to primary memory storage section (e.g. RAM) first with respect to CU (Control Unit). 2) From Memory Storage Section data goes to ALU (Arithmetical Logical Unit), where it is executed and result comes back to memory again at the same memory location or address along with the feeded data. 3) Now from memory it goes to output device like screen or printer to display. This is known as working of CPU. Saturday, July 13, 2013 30Prof.(Dr.) Anand K. Tripathi
  31. 31. Q. What is a secondary storage device? Ans. The ideal memory of a computer system is one which is large enough to store all the information and this information could be retrieved from it in as short time as possible. The design limitations of memory unit limit the size of the computer memory. So the bulk of information which cannot be stored in the main storage or primary storage is stored on external storage devices like magnetic tapes, floppy disks and magnetic drums, CD etc. These external devices are also known as Auxiliary memory, backing storage or External memory or secondary storage device. Saturday, July 13, 2013 31Prof.(Dr.) Anand K. Tripathi
  32. 32. • Q. What is the difference between Data and Information? • Generally in our day to day usage the words data and information are commonly used to mean one and the same thing. But in scientific and business applications the word data stands for facts relating to business and scientific investigations. For computational purposes, data is regarded as a fact on which a program or set of instructions acts to make it more meaningful, this data in the more meaningful form is known as information or we can say that data when organized into more useful form by manipulations is called information. Payroll is an example of data and information. Every organization has to pay salary to its employees for which records about employees are to be maintained. Saturday, July 13, 2013 32Prof.(Dr.) Anand K. Tripathi
  33. 33. The record of each employee consists of his name, address, identity number, basic pay, details of allowances. This record along with the data like leave taken if any, overtime hours, income tax deduction etc. is fed to the computer system. After processing of this data by the computer, the output that is obtained is the salary slip of the employee. Now the salary slip in computer language will be known as information and facts or data on which this salary calculation is based is called data. Figure-4 depicts the data and information Saturday, July 13, 2013 33Prof.(Dr.) Anand K. Tripathi
  34. 34. Q. What is analog computer and what are its uses. Ans. The analog computer operates by measuring the physical items rather than by counting. Analog computers measure the physical quantities. -These computers produces us appropriate results. -Ex. 1. Thermometer 2. Speedometer 3. Pressure meter etc. Saturday, July 13, 2013 34Prof.(Dr.) Anand K. Tripathi
  35. 35. -Uses: Analog computers are used mainly for scientific and engineering purposes because they deal with quantities that vary constantly .They give only approximate results. Saturday, July 13, 2013 35Prof.(Dr.) Anand K. Tripathi
  36. 36. Q. What is Digital Computer and what are its uses? - Digital Computer is used for mathematical and logical operation. - These computers provide us 99.9% accurate results .Mostly it give 100 % accurate results. Exp. 1. Calculator 2. Personnel Computer 3. Digital Watch etc. Saturday, July 13, 2013 36Prof.(Dr.) Anand K. Tripathi
  37. 37. Uses: Scientific purpose digital computer can be fixed permanently in the machine i.e. processors are installed in auto mobile to control fuel, breaking system etc . Saturday, July 13, 2013 37Prof.(Dr.) Anand K. Tripathi
  38. 38. Q. What is the most important characteristic of a digital computer? Ans. The most important characteristic of a digital computer is that it is a general purpose device capable of being used in a number of different applications. By changing the stored program, the same machine can be used to implement totally for different takes.Saturday, July 13, 2013 38Prof.(Dr.) Anand K. Tripathi
  39. 39. Q. How will you differentiate between an analog computer and a digital computer? Ans. The analog computer processes work electronically by analog. It uses an analog for each variable and produced analog as output. It, thus, measures continuously. It does not produce number but produces its results in the form of graph. It is more efficient in continuous calculations. Digital computer performs calculations by counting and thus counts discretely. It is most versatile machine. Saturday, July 13, 2013 39Prof.(Dr.) Anand K. Tripathi
  40. 40. • The analog computer accepts variable electrical signals (analog values) as inputs, and its output is also in the form of analog electrical signals. • Digital computer operators on inputs which are on-off type (being digits 0 or 1) and its output is also in form of on-off signal. Analog computer operates by measuring analog signals whereas digital computers are based on counting operation. • Most of the computers available today are digital computers and therefore term computer usually stands for digital computers Saturday, July 13, 2013 40Prof.(Dr.) Anand K. Tripathi
  41. 41. Q. What is Hybrid Computer? Ans. The combination of analog and digital computer is known as hybrid computer. Ex. Analog devices measure a patient vital sign like temperature, heart function etc. -Any fluctuations can thus be noticed immediately. Saturday, July 13, 2013 41Prof.(Dr.) Anand K. Tripathi
  42. 42. • -As a hybrid computer is combination of both analog and digital computers i.e. a part of processing is done on analog computer and a part on digital computer. A hybrid computer combines the best characteristic of both analog and digital computers. It provides greater precision than can be attained with analog computers, greater control and speed than is possible with digital computers. It can accept input data in both analog and digital form. • Uses: It is used for simulation applications, MAT LAB purpose etc. Saturday, July 13, 2013 42Prof.(Dr.) Anand K. Tripathi
  43. 43. Q What is the input to a computer? The input to the computer consists of two kinds of information, the program and the data. The program is the set of instruction which the computer is to carry out, and the data is the information on which these instructions are to operate. Saturday, July 13, 2013 43Prof.(Dr.) Anand K. Tripathi
  44. 44. Q. What are the four basic operations performed by a computer? Ans. The four basic operations performed by a computer are: 1. To exchange information with the out side word via I/O devices. 2. To transfer data internally within the CPU. 3. To perform the basic arithmetical operations. 4. To perform the Boolean operations. Saturday, July 13, 2013 44Prof.(Dr.) Anand K. Tripathi
  45. 45. Q. Distinguish between mainframe computers, mini computers and micro computers. Ans. MAIN FRAME COMPUTERS: The advancement of technology has made it quite difficult to draw a line of demarcation between large mini- computers and small main frame computers. The design of mainframe computers is similar to that of the mini computers; however the following characteristics of main frame computers are worth noting. Saturday, July 13, 2013 45Prof.(Dr.) Anand K. Tripathi
  46. 46. i)These are big general purpose computers. These are capable of handling all kinds of problems whether scientific or commercial. Saturday, July 13, 2013 46Prof.(Dr.) Anand K. Tripathi
  47. 47. (ii) These have large storage capacities of millions of words. For example, IBM 370 can store up to 10 Mega words (1 mega-word = 1 million words) in its main memory Saturday, July 13, 2013 47Prof.(Dr.) Anand K. Tripathi
  48. 48. (iii) The main frame computers have a large number of backing storage devices attached to them. (iv) These computer can accept and transfer data from I/O devices at the rate of millions of bytes (One byte = 8 bits) per second. Saturday, July 13, 2013 48Prof.(Dr.) Anand K. Tripathi
  49. 49. (v)The main frame computers can accept all types of high level languages. (vi)The word length in these computers is quite large usually 32 to 64 bits. Saturday, July 13, 2013 49Prof.(Dr.) Anand K. Tripathi
  50. 50. (vii) The cost of these computers depending upon the facilities required varies from 1 crore to 10 crores of rupees. (viii) These computers can support a large number of terminals say up to 100 or more. • The examples of mainframe computers are IBM 360/370, ICL 1900/2900, and DEC 10. Saturday, July 13, 2013 50Prof.(Dr.) Anand K. Tripathi
  51. 51. • 2. MINI COMPUTERS. The mini computers have following characteristics. (i) These computers are also general purpose computers but have a smaller size central processing unit. (ii)These have lower storage capacity. For example, a mini computer PDP- 11 can store up to 2 Mega words. Saturday, July 13, 2013 51Prof.(Dr.) Anand K. Tripathi
  52. 52. iii) Mini Computers in general have hard disks for backing stores. Some mini- computers may use magnetic tapes for this purpose. (iv) These computers can accept and transfer data from I/O devices at the maximum speed of 4 million bytes per second. Saturday, July 13, 2013 52Prof.(Dr.) Anand K. Tripathi
  53. 53. (v)These mini computers accept all types of high level languages. (vi)The word length in these computer is comparatively smaller, usually 12 to 32 bits. (vii)The cost of these computers varies from 6 lakhs to 25 lakhs of rupees. (viii)These computers can support up to a maximum of 20 terminals. The examples of mini computers are PDP-11, Vase Range and Micro Galaxy etc. Saturday, July 13, 2013 53Prof.(Dr.) Anand K. Tripathi
  54. 54. 3. MICRO COMPUTERS. The micro computers have the following characteristics. (i) These computers have C.P.U. on a single chip. (ii)These have low storage capacity up to a maximum of 10 kilo words (1 kilo word = 1000 words). Saturday, July 13, 2013 54Prof.(Dr.) Anand K. Tripathi
  55. 55. (iii)These computers can accept and transfer data from I/O devices at the maximum speed of 5 lakhs bytes/sec. (iv)These computers have a display unit as a cathode ray tube attached to them. (v)These computers accept high level languages BASIC, PASCAL, FORTRAN and PL/1 and PL/M. The commonly used language on these computers is BASIC.Saturday, July 13, 2013 55Prof.(Dr.) Anand K. Tripathi
  56. 56. (vi) The maximum word length in these computers is 16: bits. However most of these computers use-bits words. (vii) These computers are quite inexpensive. The cost usually varies from 2 lakhs to 6 lakhs rupees. Personal Computers in these categories have very low costs up to a few thousands rupees. This factor has made the micro- computers a household item. The examples of micro computers have been discussed in previous sections. Saturday, July 13, 2013 56Prof.(Dr.) Anand K. Tripathi