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introduction to computers and component

  1. 1. Ms. Yagni Desai
  2. 2.  Computer architecture refers to those attributes of a system visible to a programmer. Those attributes that have a direct impact on the logical execution of a program. The attributes: ◦ Instruction set, ◦ The number of bits used to represent various data types (e.g., numbers, characters), ◦ I/O mechanisms, ◦ Techniques for addressing memory Eg. ◦ It is an architectural design issue whether a computer will have a multiply instruction. Ms. Yagni Desai
  3. 3.  Computer organization refers to the operational units and their interconnections that realize the architectural specifications. Those hardware details transparent to the programmer. The attributes: ◦ Control signals ◦ Interfaces between the computer and peripherals ◦ The memory technology used Eg. ◦ It is an organizational issue whether that instruction will be implemented by a special multiply unit or by a mechanism that makes repeated use of the add unit of the system. Ms. Yagni Desai
  4. 4.  Structure: The way in which the components are interrelated. Function: The operation of each individual component as part of the structure. Data Processing Data storage Data movement Control Ms. Yagni Desai
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  6. 6.  Data are received from or delivered to a device that is directly connected to the computer, the process is known as input– output (I/O), and the device is referred to as a peripheral. Data are moved over longer distances, to or from a remote device, the process is known as data communications. Ms. Yagni Desai
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  8. 8.  All of computers linkages to the external environment can be classified as peripheral devices or communication lines. Ms. Yagni Desai
  9. 9.  Central processing unit (CPU): Controls the operation of the computer and performs its data processing functions; often simply referred to as processor. Main memory: Stores data. I/O: Moves data between the computer and its external environment. System interconnection: Some mechanism that provides for communication among CPU, main memory, and I/O. ◦ Eg. system bus, consisting of a number of conducting wires to which all the other components attach. Ms. Yagni Desai
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  11. 11.  CPU’s major structural components are: Control unit: Controls the operation of the CPU and hence the computer. Arithmetic and logic unit (ALU): Performs the computer’s data processing functions. Registers: Provides storage internal to the CPU. CPU interconnection: Some mechanism that provides for communication among the control unit, ALU, and registers. Ms. Yagni Desai
  12. 12. Parallel Port USB Mouse&Keyboard Power Supply Plug inPCI Slot CPU SlotISA Slot CPU Chip RAM Slots CMOS Battery Floppy Controller IDE Controller AGP Slot Ms. Yagni Desai
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  17. 17.  Blaise Pascal invented the first mechanical adding machine in 1642 In 1671, Baron GottFried Wilhelm Von Leibniz of Germany invented the first calculator for multiplication. Keyboard machines originated in the United States around 1880 that we use today. Around 1880 Herman Hollerith came with the concepts of punched cards that were used as input medium in computers even in late 1970s Ms. Yagni Desai
  18. 18.  Business machines and calculators made their appearance in Europe and America towards the end of the nineteenth century. Charles Babbage, is considered the father of modern digital computers. In 1822 Babbage designed “Difference Engine” that could compute statistical tables. In 1842, Babbage came out with his new idea of a completely automatic Analytical Engine for performing basic arithmetic functions for any mathematical problem at an average speed of 60 additions per minute. Ms. Yagni Desai
  19. 19.  The Mark 1 Computer (1937-44): ◦ Known as Automatic Sequence Controlled Calculator. ◦ Full Automatic calculating machine designed by Howard A. Aiken in collaboration with IBM. ◦ Electro-mechanical device based on techniques used in punched card machines. ◦ Reliable, but complex in design and huge. ◦ It used over 3000 electrically activated switches to control its operations and was 50 feet long and 8 feet high. ◦ This machine was capable of performing 5 basic arithmetic operations:  Addition, subtraction, multiplication, division , table reference on numbers as big as 23 decimal digits. ◦ It took 0.3 second to add two numbers and 4.5 seconds for multiplication of 2 numbers. Ms. Yagni Desai
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  22. 22.  The Atanasoff-Berry Computer (ABC) (1939-42) : ◦ Dr. John Atanasoff developed with his assistant Clifford Berry to solve mathematical equations. ◦ It was called ABC after inventors & assistant name ◦ Used 45 vacuum tubes for internal logic and capacitors for storage. Ms. Yagni Desai
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  26. 26.  The ENIAC (1943-46): ◦ Electronic Numerical Integrator And Calculator (ENIAC) was the first Electronic Computer. ◦ Developed by Moore School of U.S.A by Professors J. Presper Eckert and John Mauchly. ◦ ENIAC was developed for military needs. ◦ It was huge, took 20X40 square feet room and used 18,000 vacuum tubes. ◦ It could add 2 numbers in 200 microseconds. ◦ Multiply 2 numbers in 2000 microseconds. Ms. Yagni Desai
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  28. 28.  The EDVAC (1946-52): ◦ Abbreviated form of Electronic Discrete Variable Automatic Computer. ◦ Drawback of ENIAC was its program wired on boards that made difficult to change the program. ◦ Dr. John Von Newuman’s “Stored Program” concept solved above mentioned problem. ◦ Idea behind this concept is that sequence of instructions and data stored in memory of computer for automatically directing flow of operations. ◦ Multiple programs can be stored on same computer using this “Stored Program” concept. ◦ Due to this Modern Digital Computers also called Stored Program digital computers. Ms. Yagni Desai
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  30. 30. ◦ Von Neumann gave idea of storing instructions and data in binary form (0 and 1), instead of decimal numbers or human readable form. The EDSAC (1947-49): ◦ Abbreviated name of Electronic Delay Storage Automatic Calculator (EDSAC) ◦ It was developed by group of scientists headed by Professor Maurice Wilkes at the Cambridge University Mathematical Laboratory in May 1949 ◦ Addition operation took 1500 microseconds and Multiplication took 4000 microseconds. Ms. Yagni Desai
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  32. 32.  The UNIVAC I (1951): ◦ Abbreviated name of Universal Automatic Computer ◦ 1st UNIVAC machines was installed in Census Bureau in 1951 & was used for continuously 10 years. ◦ 1st business use of UNIVAC I was by General Electric Corporation in 1954. ◦ In 1952, the International Business Machines (IBM) corporation introduced the IBM-701 commercial computer. ◦ Then improved models of UNIVAC I and other 700- series machines were introduced. ◦ In 1953, IBM produced IBM-650 and sold over 1000 of these computers. Ms. Yagni Desai
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  34. 34.  There are 5 computer generations known till today. Generations with their characteristics are stated below. First Generation (1942-1955) ◦ Vacuum tube is a fragile(delicate ) glass device, It used filaments (fiber) as a source of electronics. ◦ It could control and amplify electronic signals. ◦ It was the only high-speed electronic switching device available those days. Ms. Yagni Desai
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  36. 36.  They were the fastest calculating devices of their time. They were Bulky in size required large rooms. These used thousands of vacuum tubes which emitted large amount of heat. So AC was required in room. Each VT consumed half a watt of power. Each computer used more than 1000 VT so power consumption was high. Ms. Yagni Desai
  37. 37.  Vacuum tubes used filaments so they had a limited life. And Computers used vacuum tubes so these computers had frequent h/w failures. Computers frequently failed so they required constant maintenance. Various individual components were assembled by hand into electronic circuits. Thus commercial production was difficult and costly. These computers were difficult to program and use so they had limited commercial use. Ms. Yagni Desai
  38. 38. ◦ VT computers could perform computations in milliseconds and were referred to as first- generation computers.◦ Memory of these computers used electromagnetic relays◦ All data and instructions were fed into the system from punched cards.◦ The instructions were written in machine and assembly languages because high-level programming languages were introduced much later. Ms. Yagni Desai
  39. 39.  John Bardeen, William Shockley and Walter Brattain invented transistors in 1947 Transistor was better than Vacuum tubes ◦ Transistors were rough and easier to handle because they were made of germanium semiconductor material rather than glass. ◦ They were more reliable as compared to tubes as they don’t have filament which could burnt ◦ They could switch much faster than tubes. Hence, switching circuits made of transistors could operate much faster than tubes ◦ Consumed One-Tenth the power consumed by a tube ◦ Smaller than a tube in size ◦ Less Expensive to produce ◦ Dissipated much less heat as compared to vacuum tubes. Ms. Yagni Desai
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  42. 42.  On software front, high-level programming languages (like Fortran, Cobol, Algol and Snobol) and Batch Operating System emerged during Second Generation. High level language is easier to use and thus makes programming easier Batch OS enabled multiple jobs batched together and submitted at time Batch OS causes automatic transition from One job to another as former jobs completes. Ms. Yagni Desai
  43. 43. CHARATERISTICS◦ 10 times faster than 1st Generation computers.◦ Smaller than 1st Gen. Computers◦ Consumed less power and dissipate less heat. But A.C still required◦ More reliable and less prone to H/W failures.◦ Faster & larger primary & secondary storage◦ Easier to program and use, hence had wider commercial use◦ Thousand of transistors assembled by hand in electronic circuits making commercial production of these computers difficult and costly. Ms. Yagni Desai
  44. 44.  Jack St. Clair Kilby and Robert Noyce invented first Integrated Circuits (Called ICs). ICs consist of several electronic components like transistors, resistors and capacitors grown on a single chip of silicon eliminating wired interconnection between components. Larger number of circuits were integrated in small surface (less than 5 mm square). SSI - Small scale Integration (10 to 20 Components Integrated) MSI - Medium Scale Integration (100 Components Integrated) Ms. Yagni Desai
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  47. 47. ◦ Larger Magnetic core based random access memory and Larger capacity magnetic disks and tapes constructed.◦ 3G computers had less than 5 Megabytes of main memory and magnetic disks stores few tens of megabytes of data per disk drive. Ms. Yagni Desai
  48. 48.  Standardization of high-level programming languages Time Sharing OS Creation of Independent Software Industry Fortran and Cobol were the most popular high-level programming languages Development & Intro of minicomputers In 1960 Mainframe Introduced were very costly and unaffordable. Digital Equipment Corporation introduced first commercially available minicomputer, the PDP-8 (Programmed Data Processor) in 1965 Ms. Yagni Desai
  49. 49.  More powerful than 2nd Generation. Performed 1 million instructions/sec Smaller than 2nd Gen Computers. Consumed less powers and dissipate less heat but A.C still required More reliable and less prone to H/W failures and so required less maintenance cost. Faster and Larger Primary and Secondary storage Ms. Yagni Desai
  50. 50.  Used for scientific and commercial applications. Did not require manual assembly of individual components into electronic circuits resulting in reduced human labor and cost. Commercial production was easier. Standardization of high-level programming languages, program written for 1 computer can be easily ported to and executed on another computer. Timesharing OS allowed interactive usage and simultaneous use of systems by multiple users Ms. Yagni Desai
  51. 51.  Timesharing OS improves productivity of programmers cutting down time and cost Timesharing OS made on-line systems feasible Unbundling of S/W from H/W gave users opportunity to invest only in s/w of their need and value. Minicomputers of third-generation made computers affordable even by smaller companies. Ms. Yagni Desai
  52. 52.  This was era of LSI(Large Scale Integration) when 30,000 electronic components integrated on a single chip. Followed by VLSI(Very Large Scale Integration) when 1 Million electronic components integrated on a single chip. Then came Microprocessor. A Microprocessor contains all circuits needed to perform arithmetic logic and control functions, the core activities of all computers, on a single chip. Ms. Yagni Desai
  53. 53.  Hence now a complete computer was built with a microprocessor, a few additional primary storage chips, and other support circuitry Semiconductor Memories replaced magnetic core memories resulting in large Random Access Memories (RAM) with very fast access time. Hard disks became cheaper, smaller and larger in capacity. Compared to Magnetic tapes Floppy disks became popular Ms. Yagni Desai
  54. 54.  Interconnection of multiple computers to share data. LAN for connecting PC’s within organization or campus WAN for connecting computers located at larger distances. Ms. Yagni Desai
  55. 55.  OS like MS-DOS, MS-Window, and Apple’s propriety OS developed GUI developed Ms. Yagni Desai
  56. 56.  PCs were smaller and cheaper than mainframes or minicomputers of third generation Fourth Generation mainframes required AC, PCs didn’t required AC Consumed less power than 3rd Gen PCs. More Reliable and less prone to H/W failures so low maintenance required Ms. Yagni Desai
  57. 57.  Faster & have larger primary and secondary storage General purpose machines Manual assembling not required hence less cost. Manufacturing LSI & VLSI costly High level Programming languages GUI Used in Office & Home N/W enabled sharing of data, disks Individuals could afford Ms. Yagni Desai
  58. 58.  Portable PCS (Notebook Computers) Desktop more powerful than in 4th Generation No A/C required Less Power Consumption More Reliable & Less prone to H/W, less maintenance cost Large scale systems have hot-plug feature that enables failed component to be replaced with a new one without shutdown Ms. Yagni Desai
  59. 59.  General purpose machine Manufacturing does not require manual assembly Standard high-level programming languages User- friendly Powerful applications using multimedia increased comp use Computer for any type of user available Internet bade tools and applications have made these systems influence the life of even common people Ms. Yagni Desai
  60. 60.  Computer architecture is based on three key concepts: ◦ Data and instructions are stored in a single read– write memory. ◦ The contents of this memory are addressable by location, without regard to the type of data contained there. ◦ Execution occurs in a sequential fashion (unless explicitly modified) from one instruction to the next. Ms. Yagni Desai
  61. 61.  A small set of basic logic components that can be combined in various ways to store binary data and to perform arithmetic and logical operations on that data. To perform a particular computation, a configuration of logic components designed specifically for that computation, this kind of program is referred to as hardwired program. The system accepts data and produces results. Ms. Yagni Desai
  62. 62.  As alternative, ◦ Construct a general-purpose configuration of arithmetic and logic functions. ◦ This set of hardware will perform various functions on data depending on control signals applied to the hardware. ◦ The system accepts data and control signals and produces results. Ms. Yagni Desai
  63. 63.  Define a unique code for each possible set of control signals, and add to the general- purpose hardware a segment that can accept a code and generate control signals. Instead of rewiring the hardware for each new program, provide a new sequence of codes, each code is, in effect, an instruction, and part of the hardware interprets each instruction and generates control signals, this method of programming, a sequence of codes or instructions is called software. Ms. Yagni Desai
  64. 64.  Two major components of the system(both constitute as CPU): ◦ an instruction interpreter ◦ a module of general-purpose arithmetic and logic functions I/O components Memory - consists of a set of locations, defined by sequentially numbered addresses. Each location contains a binary number that can be interpreted as either an instruction or data. CPU use internal registers for storage: ◦ Memory address register (MAR) - specifies the address in memory for the next read or write ◦ Memory buffer register (MBR) - contains the data to be written into memory or receives the data read from memory ◦ I/O address register (I/OAR) - specifies a particular I/O device ◦ I/O buffer register (I/OBR) - used for the exchange of data between an I/O module and the CPU. Ms. Yagni Desai
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  66. 66.  The basic function performed by a computer is execution of a program. Instruction processing consists of two steps: ◦ The processor reads (fetches) instructions from memory (one at a time) ◦ Executes each instruction. The processing required for a single instruction is called an instruction cycle. ◦ It consist of fetch cycle and execute cycle. Ms. Yagni Desai
  67. 67.  Program counter (PC) register holds the address of the instruction to be fetched next. The fetched instruction is loaded into a register in the processor known as the instruction register (IR). Accumulator (AC) is of temporary storage (like intermediate results). Ms. Yagni Desai
  68. 68.  The processor interprets the instruction and performs the required action. These actions fall into four categories: ◦ Processor-memory: Data may be transferred from processor to memory or from memory to processor. ◦ Processor-I/O: Data may be transferred to or from a peripheral device by transferring between the processor and an I/O module. ◦ Data processing: The processor may perform some arithmetic or logic operation on data. ◦ Control: An instruction may specify that the sequence of execution be altered.  For example, the processor may fetch an instruction from location 149, which specifies that the next instruction be from location 182. The processor will remember this fact by setting the program counter to 182.Thus, on the next fetch cycle, the instruction will be fetched from location 182 rather than 150. Ms. Yagni Desai
  69. 69.  Both instructions and data are 16 bits long. ◦ First 4 bits for the opcode ◦ 4-15 bits for address Opcode - is the portion of a machine language instruction, that specifies the operation to be performed Ms. Yagni Desai
  70. 70. EXAMPLE Ms. Yagni Desai
  71. 71. State Diagram of Instruction cycle Ms. Yagni Desai
  72. 72.  The states can be described as follows: ◦ Instruction address calculation (iac): Determine the address of the next instruction to be executed. (Usually, this involves adding a fixed number to the address of the previous instruction.) ◦ Instruction fetch (if): Read instruction from its memory location into the processor. ◦ Instruction operation decoding (iod): Analyze instruction to determine type of operation to be performed and operand(s) to be used. ◦ Operand address calculation (oac): If the operation involves reference to an operand in memory or available via I/O, then determine the address of the operand. Ms. Yagni Desai
  73. 73. ◦ Operand fetch (of): Fetch the operand from memory or read it in from I/O.◦ Data operation (do): Perform the operation indicated in the instruction.◦ Operand store (os): Write the result into memory or out to I/O. Ms. Yagni Desai
  74. 74.  A signal informing a programs that an event has been occur. When a program receives an interrupt signal, it takes a specified action. Interrupt signal cause a program to suspend itself to service an interrupt. Interrupts are provided primarily as a way to improve processing efficiency. Ms. Yagni Desai
  75. 75. No Interrupts Ms. Yagni Desai
  76. 76. Interrupt:short I/O wait Ms. Yagni Desai
  77. 77.  Interrupt handler – ◦ A section of a computer program or of the operating system that takes control when an interrupt is received and performs the operations required to service the interrupt. ◦ When the CPU gets an interrupt, it must execute a program to handle the interrupt. These special programs are called interrupt handlers or interrupt handler program. ◦ It handle all interrupts occurred. Ms. Yagni Desai
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