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Lecture 1

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BCS - Compute & Network Technology

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Lecture 1

  1. 1. Computer & Network Technology Chamila Fernando BSc(Eng) Hons,MBA,MIEEE
  2. 2. Lecture 1: Introduction       Overview History of Computers Application Areas Types of Computers Computer Configurations Computers as Information Processors Lecture 1: Introduction 2
  3. 3. Lecture 1: Introduction  Basic Machine Hardware Architecture     CPU Memory/Storage Main Memory Input/Output Devices  Basic Machine Software      Flowcharts Languages Operating Systems System Utilities Applications  What’s in Computer & Network Technology..? Lecture 1: Introduction 3
  4. 4. Overview of Part 1  Number system: how is information    represented in a computer. Boolean Algebra: the basis for logic design and manipulation of information. Logic gates: what are the gates used, and how circuits can be made from gates. Function simplification: to reduce the size of design, increase speed, etc. Lecture 1: Introduction 4
  5. 5. Overview of Part 1  Combinational circuits: simple circuit design without memory.     Sequential circuits: circuit design with memory. Disk: storage techniques. Bus: internal communication. I/O: devices, technology, etc. Lecture 1: Introduction 5
  6. 6. History of Computers  Abacus invented in Babylonia in 3000BC  Adding machine by Blaise Pascal (1642)  Difference engine and the analytical engine by Charles Babbage (1842)  IBM first electromechanical computer (using relays) designed by Howard Aiken (1937) was based on punched cards.  used to calculate tables of mathematical functions Lecture 1: Introduction 6
  7. 7. History of Computers  1st Generation Computers (1940s to early 1950s) – based on vacuum tubes technology.  1943 – ENIAC: first fully electronic computer, designed by John Mauchly  1944 – Mark I: Howard Aiken  1946 – EDVAC: first stored program computers, designed by John von Neumann  2nd Generation Computers (late 50s to early 60s) – based on transistors technology.  more reliable, less expensive, low heat dissipation  IBM 7000 series, DEC PDP-1 Lecture 1: Introduction 7
  8. 8. History of Computers  3rd Generation Computers (late 60s to early 80s) – integrated circuits (IC).  IBM 360 series, DEC PDP-8  IC – many transistors packed into single container  low prices, high packing density  4th Generation Computers (present day) LSI/VLSI  small size, low-cost, large memory, ultra-fast PCs to supercomputers  5th Generation Computers (future)  massively parallel, large knowledge bases, intelligent  Japan, Europe and US advanced research programs Lecture 1: Introduction 8
  9. 9. History of Computers  Web sites  History of Computers (http://www.comp.nus.edu.sg/~sf100/c1f7.htm)  ACM Timeline of Computing History (http://www.computer.org/computer/timeline)  The Virtual Museum of Computing (http://www.comlab.ox.ac.uk/archive/other/museums/computin g.html)  IEEE Annals of the History of Computing (http://www.computer.org/annals/)  and others (surf the web) Lecture 1: Introduction 9
  10. 10. Application Areas  Scientific: weather forecasting, simulation, spaceprogram.  one of the earliest application areas.  heavy computation but small amount of data.  Commercial: accounting, banking, inventory, sales.  changes nature of business – information is money.  high data throughput, simple calculations.  Manufacturing: numerical control, CAD/CAM, integration.  graphics, interfacing, device-drivers, networks. Lecture 1: Introduction 10
  11. 11. Application Areas  Real-time & Control System: air-traffic control, aircraft,nuclear power station.  real time, very fast, safety-critical.  Educational & Recreational  CAI software, multi-media, games, Internet, World Wide Web.  Telecommunication  Network, SCV, Singapore One. Lecture 1: Introduction 11
  12. 12. Types of Computers  Supercomputers:  very fast (Gflops) but expensive machine($10m), vector or parallel processors, used in scientific applications and simulations.  Mainframes:  fast (>10mips) but expensive ($1m), high-throughput, used in large commercial organisations, support many concurrent users interactively.  Mini-computers:  fast but affordable ($200k), used in medium-sized organisations (e.g. SoC), support multiple users. Lecture 1: Introduction 12
  13. 13. Types of Computers  Workstations:  affordable ($20k) and fast single-user systems (20 riscs mips), good graphics capabilities, engineering, network-based computing.  Micro/Personal/Home Computers:  cheap and affordable ($3k), transportable, home use, good for games and as educational tool, word processing, suitable for small enterprise. Lecture 1: Introduction 13
  14. 14. Computer Configurations  Stand-alone computer system  Modem connection Lecture 1: Introduction 14
  15. 15. Computer Configurations  Terminals-host connections Lecture 1: Introduction 15
  16. 16. Computer Configurations  Network of computers Lecture 1: Introduction 16
  17. 17. Computers as Information Processors Driver Example: An automobile augments our power of locomotion. A computer is a device capable of solving problems according to designed program. It simply augments our power of storage and speed of calculation. Lecture 1: Introduction Programmer 17
  18. 18. Computers as Information Processors  Unlike previous inventions, computers are special because they are general-purpose. general-purpose  Could be used to perform a variety of tasks.  Computer = Hardware + Software. Software  Hardware: physical components for computation/processing; should be simple, fast, reliable.  Software: set of instructions to perform tasks to specifications; should be flexible, user-friendly, sophisticated. Lecture 1: Introduction 18
  19. 19. Computer as Information Processors Computer are Information Processors Raw data Computer system Processed information Data Units: 1 bit (binary digit): one of two values (0 or 1) 1 byte: 8-bits 1 word: 1, 2, or 4 bytes, or more (depends on ALU) Lecture 1: Introduction 19
  20. 20. Basic Machine Hardware Architecture  Main Components:  CPU (Central Processing Unit: controls devices and processes data).  Memory: stores programs and intermediate data. Memory  Input Devices: accept data from outside world. Devices  Output Devices: presents data to the outside world. Devices  An analogy with Human Information Processors:  CPU – brain’s reasoning powers  Memory – brain’s memory  Input Devices – eyes, ears, sensory sub-system  Output Devices – mouth, hands, facial and body expressions Lecture 1: Introduction 20
  21. 21. Basic Machine Hardware Architecture Headphone (Output) Monitor (Output) Hardware box (contains processor, memory, buses etc.) Mouse and Keyboard (Input) Lecture 1: Introduction 21
  22. 22. Basic Machine Hardware Architecture Network card and CRT card Motherboard (Printed Circuit Board) Floppy disk drive and Hard disk drive Cage for mounting drives Slots for RAM chips Processor © above picture: Patterson and Hennessy Lecture 1: Introduction 22
  23. 23. Hardware – CPU  CPU = control unit + ALU + registers  Control Unit : monitors and directs sequences of instructions  Execution Cycle (repeated):  fetch (next instruction)  decode  execute Lecture 1: Introduction 23
  24. 24. Hardware – CPU  ALU: performs simple arithmetic and logical operations.  Examples: Add, subtract, and, or, invert, increment etc. A select B R = A op B ALU n-bits operations R Lecture 1: Introduction 24
  25. 25. Hardware – CPU  Registers: temporary results + status information  ACC (accumulator) – current data  PC (program counter) – points to next instruction  IR (instruction register) – current instruction  MA (memory address) – address to read/write  MB (memory buffer) – data to read/write Lecture 1: Introduction 25
  26. 26. Hardware – Memory/Storage  Purpose: to store program and data.  Desirable Traits: fast access, large capacity, economical, non-volatile.  However, most memory devices do not have all these traits. Lecture 1: Introduction 26
  27. 27. Hardware – Memory/Storage  Solution: hierarchical combination Fast, expensive (small numbers), volatile registers main memory disk storage magnetic tapes Lecture 1: Introduction Slow, cheap (large numbers), non-volatile 27
  28. 28. Hardware – Main Memory  Fast BUT volatile (need power to maintain data)  Logical structure – table of memory cells/units. addresses M A R M B R address 8 bits or more 0 1 2 3 memory cells data 2m-3 2m-2 2m-1 Lecture 1: Introduction 28
  29. 29. Hardware – Main Memory  Memory cells may be grouped into pages (say 512 consecutive words per page).  Units  1 KBytes = 1024 (or 210) bytes  1 MBytes = 1024 Kbytes (or 220 bytes)  1 GBytes = 1024 Mbytes (or 230 bytes) Lecture 1: Introduction 29
  30. 30. Hardware – Input/Output Devices  Input devices: read/accept data (into computer) devices  obsolete: card reader, paper tape reader  present: keyboard, mouse, light-pen, optical char reader  future: voice and vision recognition.  Output devices: write/display data (to users) devices  obsolete: card & paper punch, teletype  present: VDU (visual display unit), printers, plotters, graphics display, sound  future: voice synthesis. Lecture 1: Introduction 30
  31. 31. Basic Machine Software  Software is the key to making computers general purpose.  Software are often built hierarchically, with layers of software providing successive higher-level of abstractions.  This structure is reflected by the following onion layer view of software. Lecture 1: Introduction 31
  32. 32. Basic Machine Software Hardware Operating system System utilities Applications/User programs Lecture 1: Introduction 32
  33. 33. Software – Flowcharts  The sequence of instructions of a software/program can be graphically specified using flowcharts. flowcharts  The flowchart technique maybe a little outdated but could still be used in a clear manner for simple problems.  As an example, the procedure to find the roots of a quadratic equation, ax2 + bx + c = 0, can be written using the following equation: roots = (−b ± b 2 − 4ac ) / 2a Lecture 1: Introduction 33
  34. 34. Software – Flowcharts  This procedure can be coded in the following flowchart: Read a,b,c roots = (−b ± b 2 − 4ac ) / 2a a=0? yes Write not quadratic no d:=b2 - 4ac = Write real root Lecture 1: Introduction d>0 d=0 d<0 > Write real roots < Write complex roots 34
  35. 35. Software – Languages  All programs will have to be coded in some programming language – usually text-based.  The native language of machine is called machine language. language  This consists of a set of primitive instructions, coded in numbers.  An example is "0310 0412 0512". But can you understand what it does? Lecture 1: Introduction 35
  36. 36. Software – Languages  Possible to use more human-readable mnemonic instructions.  These are know as assembly language instructions. Mnem onic Descript ion ADD 10 AC:= AC+ C(10) SUB 12 AC:= AC-C(12) STO 12 C(12)= AC  Normally, assembly language has a 1-to-1 correspondence with machine language. Lecture 1: Introduction 36
  37. 37. Software – Languages  Assembly language is still very primitive.  Higher-level Languages, like Pascal, C, Fortran, which are a Languages little closer to English language have been developed. Lecture 1: Introduction 37
  38. 38. Software – Languages  An example Pascal program to find roots of quadratic equation: read(a,b,c); if a=0 then writeln ("not a quadratic equation") else begin d := sqr(b)-4*a*c; if d>0 then writeln ("complex roots") else if d=0 then writeln("single root =",-b/(2*a)) else writeln ("root1=",-b+sqrt(d)/(2*a), "root2=", -b-sqrt(d)/(2*a)); end; Lecture 1: Introduction 38
  39. 39. Software – Operating Systems  Operating System (OS) is situated directly above hardware. It controls and manages the available hardware resources.  Often, OS has special access privileges to certain categories of instructions and certain hardware  User programs have to go through OS for these privileges. Lecture 1: Introduction 39
  40. 40. Software – Operating Systems  Associated Functions/Tasks:  boots up machine  loads user program  allocates main memory/storage space  schedules concurrent user programs  drivers to service various devices (terminals, printers, etc.) Lecture 1: Introduction 40
  41. 41. Software – System Utilities  Above the OS, there is a set of frequently executed programs,called System Utilities. These utilities are often Utilities packaged with OS.  Used by programmers/analyst to help develop applications.  Some examples  Editor: compose/edit user programs or data files  Assembler: translates assembly to machine code  Compiler: translates high-level language to assembler/machine code  Spooler: temporary stores print files for queuing Lecture 1: Introduction 41
  42. 42. Software – System Utilities  Some examples (continued)  Mailer: forwards/receives mails between users  DBMS (Data-Base Management System): centralised management of data at a more abstract level than files  Window Management System: multiple windows can appear on single screen. These together with various graphical entities (e.g. menus,panels, buttons) can be managed by WMS. Lecture 1: Introduction 42
  43. 43. Software – Applications  Word-Processors: compose/edit reports/articles Word-Processors  Accounting Package: keeps track of accounting Package transactions, produces daily/weekly/monthly (profit/loss) reports  Inventory System: keeps track of stock levels System  Personnel/Payroll System: staff records, monthly salary System CS1104-1 Lecture 1: Introduction 43
  44. 44. What’s in Computer & Network Technology..? Application (Netscape) Software Compiler Assembler Operating System (Windows XP) Processor Memory I/O system Datapath & Control Hardware CS1104-1 Instruction Set Architecture Computer Architecture Digital Design transistors Lecture 1: Introduction Digital Logic Design 44
  45. 45. Thank you Lecture 1: Introduction 45

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