1 / 45

Beginning Snapshots

Beginning Snapshots. Chapter 0. Objectives. Give an overview of computer science Show its breadth Provide context for computer science concepts Events from the past Describe basic components, organization of a computer. Algorithms and Data Structures Architecture

naoko
Download Presentation

Beginning Snapshots

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Beginning Snapshots Chapter 0

  2. Objectives • Give an overview of computer science • Show its breadth • Provide context for computer science concepts • Events from the past • Describe basic components, organization of a computer C++ An Introduction to Computing, 3rd ed.

  3. Algorithms and Data Structures Architecture Artificial Intelligence and Robotics Database and Information Retrieval Human-Computer Communication Numerical and Symbolic Computation Operating Systems Programming Languages Software Methodology and Engineering Social and Professional Context Areas of Computer Science C++ An Introduction to Computing, 3rd ed.

  4. Important Concepts in Computer History • The mechanism of arithmetic • The stored program • The graphical user interface • The computer network C++ An Introduction to Computing, 3rd ed.

  5. Machines to Do Arithmetic • Early calculators • Abacus 3000 B.C. • Stonehenge 1900 – 1600 B.C • Al-Khowarizm 12th Century • Napier's bones 1612 • Slide rule 1630 • Pascaline 1642 • Leibniz' calculator 1673 C++ An Introduction to Computing, 3rd ed.

  6. The Stored Program • Jacquard loom 1801 • Mechanical Computers • Babbage's Difference Engine 1822 • Babbage's Analytical Engine 1833 • Ada Augusta 1842 C++ An Introduction to Computing, 3rd ed.

  7. Electromechanical Computers • Hollerith's tabulating machine 1890 • Konrad Zuse 1935-1938 • Alan Turing 1937 • The Mark I 1944 • Atanasoff's ElectronicDigital Computer (ABC) 1936-1939 • Grace Hopper 1944 C++ An Introduction to Computing, 3rd ed.

  8. First-Generation Computers • Vacuum tube computers 1945-1956 • ENIAC 1943-1946 • John Von Neumann's"First Draft of a Report onthe EDVAC" 1945 • First bug in a computer 1945 • UNIVAC 1951 C++ An Introduction to Computing, 3rd ed.

  9. Second Generation Computers • Used transistors 1956-1963 • FORTRAN 1957 • IBM 7090 1958 LISP • COBOL 1960 ALGOL 60 C++ An Introduction to Computing, 3rd ed.

  10. Third-Generation Computers • Chips and Integrated Circuits 1964-1971 • The IBM System/360 1964 • The PDP-8 1965 • Douglas Englebart: the mouse, Two-D display, editing, hypermedia, 1968 Pascal • Ken Thompson: UNIX 1969 ARPANET – The beginning of the Internet C++ An Introduction to Computing, 3rd ed.

  11. Fourth-Generation Computers • Intel 4004 Chip 1971 • Dennis Richie: C 1973 • Ethernet • Court rules Atanasoff was legal inventor of first electronic digital computer • Altair, BASIC, Apple 1 1974 • Apple II, Cray 1, Apple Corp.Microsoft Corp. 1976 • IBM PC 1981 C++ An Introduction to Computing, 3rd ed.

  12. Fourth-Generation Computers • Bjarne Stroustrup: C++ 1983 Novell announces NetwareTCP/IP • Macintosh 1984 • Windows 1985 • Intel 386 Chip 1986 • Tim Berners—Lee: WWW 1991 • Linux 1992 C++ An Introduction to Computing, 3rd ed.

  13. Fourth-Generation Computers • Pentium chips, Power PC chip 1993 MOSAIC, Apple Newton • Netscape Navigator 1.0, Yahoo! 1994Palm computing • James Gosling: JAVA 1995Windows 95, Internet Explorer,Internet goes commercial • Windows 98, Apple's IMAC 1998Microsoft's court case C++ An Introduction to Computing, 3rd ed.

  14. Fourth-Generation Computers • Y2K Problem, Powermac G4 1999 • Windows 2000 20001 GHZ processors • Mac OS X 2001Windows XP • Quantum Computer 2002 C++ An Introduction to Computing, 3rd ed.

  15. Graphical User Interface • Command line interface required precise and cryptic commands • Xerox PARK had developed GUI prototype in 1972 • Steve Jobs saw it several years later and used new hardware capabilities to implement • GUI makes computer easy to use C++ An Introduction to Computing, 3rd ed.

  16. Network • Defn: Two or more computers connect to exchange resources • Processing power • Storage • Access to a printer • Software resources • Messages C++ An Introduction to Computing, 3rd ed.

  17. Network • Time sharing in early 1960s • Users communicate with host computer • ARPANET connected research center computers in 1969 • Eventually developed into Internet • Local Area Network hardware and operating systems developed late 1970s • ISPs now affordable, widely available for even home computers C++ An Introduction to Computing, 3rd ed.

  18. Computing Systems Computers have two kinds of components: • Hardware – physical devices such as • CPU • memory • storage devices • Software – programs such as • Operating system • applications • utilities C++ An Introduction to Computing, 3rd ed.

  19. Hardware: CPU • Central Processing Unit (CPU): • the “brain” of the machine • Circuitry that performs arithmetic and logical ML statements • CPU measurement • Speed (roughly) in megahertz (millions of clock-ticks per second) • Examples • Intel Pentium, AMD K6, Motorola PowerPC, Sun SPARC, C++ An Introduction to Computing, 3rd ed.

  20. Storage • Random Access Memory (RAM) • “Main” memory, which is fast, but volatile... • Analogous to a person’s short-term memory. • Many tiny “on-off” switches • “on” is represented by 1, “off” by 0. • Each switch is called a binary digit, or bit. • 8 bits is called a byte. • 210 bytes =1024 bytes is called a kilobyte (1K) • 220 bytes is called a megabyte (1M). C++ An Introduction to Computing, 3rd ed.

  21. Storage • Secondary Memory (Disk): • Stable storage using magnetic or optical media. • Analogous to a person’s long-term memory. • Slower to access than RAM. • Examples: • floppy disk (measured in kilobytes) • hard disk (measured in gigabytes (230 bytes)) • CD-ROM (measured in megabytes), ... C++ An Introduction to Computing, 3rd ed.

  22. Input and Output • Input devices • Instructions and data must be encoded in binary form and transmitted to the CPU • Examples: • keyboard • mouse, trackball, joystick • scanner • audio, video capture boards C++ An Introduction to Computing, 3rd ed.

  23. Input and Output • Output devices • Convert data from binary to another form • Examples • monitors, printers • sound, video • robotics control • Communication between CPU and peripheral devices is through ports • Ports communicate via the system bus C++ An Introduction to Computing, 3rd ed.

  24. Hardware: the Bus • The Bus: • Connects CPU to other hardware devices. • Analogous to a person’s spinal cord. • Speed measured in megahertz • Like the CPU • Typically much slower than the CPU... • The bottleneck in most of today’s PCs. C++ An Introduction to Computing, 3rd ed.

  25. Hardware: Cache • Access speed of RAM • Faster than accessing secondary memory • Still quite slow, relative to the rate at which the CPU runs. • Solution: • Add a fast cache memory to the CPU • Store recently used instructions and data • Assumption: • These instructions/data were needed recently • They will be needed again in the near future. C++ An Introduction to Computing, 3rd ed.

  26. Hardware: Summary Putting the pieces together: CPU Main Memory Secondary Memory cache Bus • Program storage • Long-term in secondary memory • Loaded into main memory to run • From which the CPU retrieves and executes their statements. C++ An Introduction to Computing, 3rd ed.

  27. Disk CPU RAM Cache OS Bus Software: OS • Operating system (OS) • Loaded from secondary memory into main memory when the computer is turned on, • Remains in memory until the computer is turned off. C++ An Introduction to Computing, 3rd ed.

  28. Software: OS • OS acts as the “manager” of the system, • Making sure that each hardware device interacts smoothly with the others. • Provides an interface • Enables user to interact with the computer, • Awaits user input if no application is running. • Examples: MacOS, Windows-95, Windows-NT, UNIX, Linux, Solaris, ... C++ An Introduction to Computing, 3rd ed.

  29. Software: Applications • Applications are non-OS programs • Perform some useful task • Including word processors, spreadsheets, databases, web browsers, C++ compilers • Example C++ compilers/environments: • CodeWarrior (MacOS, Win95, WinNT, Solaris) • GNU C++ (UNIX, Linux) • Turbo/Borland C++ (Win95, WinNT) • Visual C++ (Win95, WinNT) C++ An Introduction to Computing, 3rd ed.

  30. Software: User Programs • Programs that are neither OS programs nor applications are called user programs. • User programs are what you’ll be writing in this course. C++ An Introduction to Computing, 3rd ed.

  31. What is Programming? • Computer Program • A sequence of statements that instruct a computer in how to solve a problem. • Programming • The act of designing, writing and maintaining a program • Programmers • People who write programs C++ An Introduction to Computing, 3rd ed.

  32. What kinds of statementsdo computers understand? • A computer only understands machine language statements. • Characteristics of machine language • A sequence of ones and zeros • Cause the computer to perform a particular action, such as add, subtract, multiply, ... C++ An Introduction to Computing, 3rd ed.

  33. Machine Language (ML) • ML statements • Stored in a computer’s memory • Computer memory is a sequence of switches. • an “on” switch is represented by 1, • an “off” switch is represented by 0. • ML thus appears to be binary (base-2): 0010111010110101 C++ An Introduction to Computing, 3rd ed.

  34. Early Computers ... required a programmer to write in ML... • Problem • Easy to make mistakes! • Such mistakes are hard to find! • Not portable -- only runs on one kind of machine! • Programming was very difficult! C++ An Introduction to Computing, 3rd ed.

  35. Assembly languagestatements (mnemonics) Machine language statements A Bright Idea • Devise a set of abbreviations (mnemonics) corresponding to the ML statements • Create a program (the assembler) to translate them into ML. 100111001110010110100110110111 ADD 34, R1MOVE R1,1200CMPR R1, R2 Assembler C++ An Introduction to Computing, 3rd ed.

  36. More natural than binary. Much easier to read programs Much easier to find and fix mistakes Still not portable to different machines Each machine had its own set of mnemonics Each had its own assembler Advantages and Disadvantages C++ An Introduction to Computing, 3rd ed.

  37. High Level Languages • Improvement on assembly language • Devise a set of statements that are close to human language (if, while, do, ...) • Create a program to translate them into ML. • The set of statements is called a high level language (HLL) • The translation program is called a compiler. C++ An Introduction to Computing, 3rd ed.

  38. Assembler translates one mnemonic into one ML statement Compiler translates one HL statement into several ML statements Contrast Assembler and HLL Compiler 1010110011110101 0000000000010000 0010111010110101 0000000000010010 0010111011111101 0000000000010100 Compiler z = x + y; C++ An Introduction to Computing, 3rd ed.

  39. Advantage of HLLs • Programs are easier to read • Errors are easier to find • Programs are portable from one computer to another • Assumes the language is standard • Just create a new compiler which does the translation into the correct ML C++ An Introduction to Computing, 3rd ed.

  40. Correctly Efficiently Readably In user-friendly fashion It actually solves the problem Without wasting time or space Understandable by another person In a way that is easy for its user to use Objectives in ProgrammingA program should solve a problem: C++ An Introduction to Computing, 3rd ed.

  41. Low levelML in binary language Medium Level Assembly language High Levelas in C++ Hard to read, not portable Mnemonics, easier to read, still not portable Reads like English and algebra, portable Summary of "Levels" of Computer Languages C++ An Introduction to Computing, 3rd ed.

  42. App Disk CPU RAM Cache OS Bus Putting It All Together Programs and applications that are not running are stored on disk. C++ An Introduction to Computing, 3rd ed.

  43. App Disk CPU RAM Cache OS Bus Putting It All Together • When you launch a program • OS controls the CPU • Loads the program from disk to RAM. App C++ An Introduction to Computing, 3rd ed.

  44. App App Disk CPU RAM Cache OS Bus Putting it all together • The OS then relinquishes the CPU to the program, • Application program begins to run. App C++ An Introduction to Computing, 3rd ed.

  45. App Disk CPU RAM Cache OS Bus The Fetch-Execute Cycle • OS repeatedly fetches the next instruction (from memory / cache), • Executes it • Stores any results back to memory. App App • That’s all a computer does: fetch-execute-store, millions of times each second! C++ An Introduction to Computing, 3rd ed.

More Related