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					You know, Toggle! Today at the
supermarket I saw magic. The           You didn't is a magic,
                                      Yes! Goggle. It see type of an
  A bar code reader? Is
cashier would hold a small machine    input device. Come,saw
                                       Goggle. What you         let's
                                      knowa more about that, and
                                       was bar code reader.
  that what it’s called?
over whatever we wanted to
                                      other devices.
purchase, and with a beep-like
sound the product price and details
were displayed on the computer!
Input Devices

   The devices with which data and instructions are entered into a
   computer are called input devices.




    The most common input devices are the keyboard, the joystick
    and the mouse. There are some more input devices which are
    more specialized in their use, such as light pens, scanners,
    digital cameras and bar code readers.
Light Pen


   A light pen is a light-sensitive input device shaped like a pen, used
   to draw on the computer screen or to make menu selections .It is a
   pointing device and is connected to the monitor.




   Light pens were popular in the 1980s and early 1990s but most have
   now been replaced with other input devices.
Scanner

   In some situations, information (picture or text) is available on paper
   and is needed on a computer disk. The simplest way is to take a
   photograph of the image directly from the source and convert it into a
   form that can be saved on to the disk and also printed, if needed. A
   scanner is an input device that can be used for such a purpose .
There are four types of scanners available:


Flatbed scanners Flatbed scanners are also called
desktop scanners. They are the most versatile and the
most commonly used. The flatbed scanner is very
similar to a photocopier.




                            Sheet-fed scanners They are similar to flatbed
                            scanners except that the document is moved
                            and the scanhead is immobile. A sheet-fed
                            scanner looks a lot like a small portable printer.
Handheld scanners Handheld scanners use the
same basic technology as a flatbed scanner, but
here the user has to move the document instead
of it being done by a motorized belt. The image
quality in this type of a scanner is typically not
very good, but it is quite useful for text.




                             Drum scanners Drum scanners are used by the
                             publishing industry.
Digital Camera
   Digital cameras provide near photographic quality, hence are
   being increasingly used. They can be combined with a
   computer monitor for applications like videoconferencing, or
   can be used simply to take photographs that can be displayed
   in any software.
Bar Code Reader

   A bar code reader is a device that can read special lines called bar
   codes. On different products, a unique bar code is represented by the
   difference in the widths of the bars and the distance between them.




    The code for each product is a unique combination of these vertical
    bars. These vertical bars include information about the manufacturer
    and the item’s price.
With the help of the bar code, the computer system identifies
the product, its brand name and other information and uses this
data to find the item’s price. It then prints out both the product
name and the price. The computer keeps track of each item sold
and thus helps the store manager to find out the current
inventory status.
Output Devices

    Output is the result of processing done by a computer. An
    output device receives information from the computer and
    translates it from machine language to a form that humans
    can read or hear, or so that another machine can understand
    the information. We have already learnt about the different
    types of printers available. Some other output devices are
    speakers and LCD projectors.
Speakers

    A speaker gives you sound output from your computer. Some
    speakers are built into the computer and some are separate. A sound
    card in the computer is necessary for your computer to play music or
    sound.
LCD Projectors

   An LCD projector is a device for giving presentations generated on a
   computer. They are the modern equivalent to the slide projector and
   overhead projector used in the past.
Memory
   You already know that a computer has a very large memory to store a
   vast amount of information. This stored information can also be
   recalled instantly and correctly whenever desired.




   You learnt that the primary memory stores the necessary programs of
   the system software, which are required to execute user or
   application programs. Primary memory is of two types—RAM
   (Random Access Memory) and ROM (Read Only Memory).
RAM      It is a read/write memory. This means that information can be
written into and read from RAM. It is also volatile, i.e., it retains the
stored information only as long as the power supply is on.




ROM      It is permanent memory, i.e., its contents will not be lost even
after the power supply has been switched off. But it is a memory unit
that can only be read from, and the user cannot write onto ROM. It
stores permanent programs and other instructions; information
which are needed by the computer to execute user or application
programs.
Representing Characters in Memory


      Information in a computer is stored in the form of strings of 0s
      and 1s. The symbols 0 and 1 are together called Binary digits or
      bits and form the binary number system. The memory of a
      computer can be thought of as a group of cells. Each of these
      cells contains one bit of information, i.e., each cell contains a 0
      or a 1.




      A combination of bits is used to store instructions and data in the
      computer memory. They are called bytes, nibbles or words
      depending on the number of bits they have.
Byte    A combination of 8 bits forms one byte. Each byte represents one
character such as A, a, B, 1, 2, etc.



Nibble A nibble is a group of 4 bits. It can store one decimal digit in its
binary form.


Word A group of bits representing data or instruction that forms the
basic information unit of the computer is called a word. A word may be of
8, 16, 32 or 48 bits or more. The size of the word depends on the
architecture of the computer. A machine with 16-bit words will be slower
than a machine with 32-bit words.
Most microprocessor-based computers have 16-bit or 32-bit words.



Other units of memory are:


Kilobyte (KB) = 210 bytes or 1024 bytes


Megabyte (MB) = 210 KB or 1024 X 1024 bytes


Gigabyte (GB) = 210 MB or 1024 X 1024 X 1024 bytes


Terabyte (TB) = 210 GB or 1024 X1024 X1024 X 1024 bytes
Secondary Storage

    Since a computer’s memory is largely temporary in nature,
    secondary memory is used for bulk storage of programs and
    data. The two most common secondary storage devices—the
    floppy disk and the hard disk.




    CD-ROMs and DVDs are bigger capacity storage devices.
CD-ROM


  A Compact Disk Read Only Memory (CD-ROM) is a silver-colored
  disk that uses the same technology as audio CDs do for recording
  music. It is usually 4.75 inches in diameter and less than one-
  twentieth of an inch thick.




  A CD-ROM can record text, graphics, video and sound.
For a computer to read the contents of a CD-ROM, you need a
CD-ROM drive. CD-ROM drives are available in specifications
such as 32X, 48X, 52X, etc. The ‘X’ represents the data transfer
rate. For example, in a 1X CD-ROM the data transfer rate is 150
Kbps (Kilobytes per second) or 0.146 Mbps (Megabytes per
second).
CDs are very cheap and have a long life. A CD-ROM can hold up to 700 MB
of data, which is about 450 times than can be stored on a 3½" floppy disk.
Because of its speed, capacity and low cost, it is being used for the
distribution of softwares and for keeping backups.




CD-ROMs are available in two forms:

(i) CD-R It is also called a recordable CD. Data once written on it cannot be
erased but can be read again and again.



(ii) CD-RW CD-RW stands for Compact Disk-Rewritable. It is also called an
erasable CD. The user can erase previously recorded information and then
record new information onto the same physical location on the disk.
DVD (Digital Versatile Disk)
 Although CD-ROMs have a large storage capacity, they are not sufficient for
 many complex programs. Some softwares need more than one CD-ROM to
 be recorded in full. To meet these storage requirements, DVD-ROMs are
 used.


 Physically, a CD-ROM and a DVD-ROM are similar but a DVD can
 hold up to 25 times more data. It can store up to 4.7 GB. Another
 important feature of a DVD-ROM is its quality which is far superior to
 that of a CD-ROM.



 In order to read a DVD-ROM, you need a DVD-ROM drive or
 DVD player. These drives have speeds up to 40X and can even
 read CD-ROMs.
Zip Drive
   A zip drive is a small, portable disk used to take back-ups and for
   archiving personal computer files. Zip drives and disks come in two
   sizes. The 100 MB size actually holds 100,431,872 bytes of data or the
   equivalent of 70 floppy diskettes. There is also a 250 MB drive and
   disk. The zip drive comes with the software utility that lets you copy
   the entire contents of your hard drive to one or more zip disks.
Tricky Terms
       RAM           Random Access Memory
       ROM           Read Only Memory
       CD-ROM Compact Disk Read Only Memory
       DVD            Digital Versatile Disk
       Bit   Binary digit 0 or 1
       Byte           A combination of 8 bits
       Nibble         A group of 4 bits
       Word           A group of bits representing data
                  or instruction that forms the basic
                  information unit for a computer.
       Command Any instruction given to the
                 computer.
   3000 BCE, early
    form of beads on
    wires, used in
    China
   From semitic abaq,
    meaning dust.
100,000 -------------------------------------
 50,000 ---------------------------------------
 10,000 -------- --- -----------------------
  5,000 ---------------------------------------
  1,000 -------------------------------------
    500 -----------------------------------------
    100 ----------------------------------        50
  -------- -------------------------------
     10 ------------------------------------------
       5 ------------------------------------------
       1 ---------------------------------------
 Born: December 26, 1791
 son of Benjamin Babbage a London banker

 (part of the emerging middle class: property, education,
  wealth, and status)
 Trinity College, Cambridge [MA, 1817]

 with John Herschel and George Peacock, produced a
  translation of LaCroix’s calculus text.
My friend Herschel, calling upon me,
  brought with him the calculations
  of the computers, and we
  commenced the tedious process of
  verification. After a time many
  discrepancies occurred, and at one
  point these discordances were so
  numerous that I exclaimed, “I wish
  to God these calculations had been
  executed by steam.” 1821
   December 1830, a
    dispute with his chief
    engineer, Joseph
    Clement, over control
    of the project, ends
    work on the difference
    engine
   Clement is allowed to
    keep all tools and
    drawings by English
    law
   1. First attempt to devise a computing machine that
    was automatic in action and well adapted, by its
    printing mechanism, to a mathematical task of
    considerable importance.
   2. An example of government subsidization of
    innovation and technology development
   3. Spin offs to the machine-tool “industry”
   Difference Engine Number 2 (1847 to 1849)
    constructed according to Babbage’s original
    drawings (minor modifications)
   1991 Bicentenary Celebration
   4,000 parts
   7 feet high, 11 feet long, 18 inches deep
   500,000 pounds
   born on 10 December 1815.
   named after Byron's half sister,
    Augusta, who had been his
    mistress.
   After Byron had left for the
    Continent with a parting shot --
    'When shall we three meet again?'
    -- Ada was brought up by her
    mother.
   Translated Menebrea’s paper into English
   Taylor’s: “The editorial notes are by the translator, the
    Countess of Lovelace.”
   Footnotes enhance the text and provide examples of
    how the Analytical Engine could be used, i.e., how it
    would be programmed to solve problems!
   Myth: “world’s first programmer”
   Born: February 29, 1860
       Civil War: 1861-1865
   Columbia School of Mines (New York)
   1879 hired at Census Office
   1882 MIT faculty (T is for technology!)
   1883 St. Louis (inventor)
   1884 Patent Office (Wash, DC)
   1885 “Expert and Solicitor of Patents”
   Article I, Section 2: Representatives and direct
    Taxes shall be apportioned among the several
    states...according to their respective
    numbers...(and) every ...term of ten years
   1790: 1st US census
   Population: 3,929,214
   Census Office
 1790     4 million
 1840     17 million
 1870     40 million
 1880     50 million
 fear of not being able to enumerate the census in
  the 10 intervening years
 1890     63 million
   1911: Charles Flint
       Computing Scale Company
        (Dayton, OH)
       Tabulating Machine
        Company, and
       International Time Recording
        Company (Binghamton, NY)
  Thomas J. Watson
(1874-1956)
hired as first president

   In1924, Watson renames
    CTR as International
    Business Machines
   1st large scale electronic digital computer
   designed and constructed at the Moore School of
    Electrical Engineering of the University of
    Pennsylvania
       since 1920s, faculty had worked with Aberdeen
        Proving Ground’s Ballistics Research Laboratory
        (BRL)
   1943 Mauchly and Eckert prepare a proposal for
    the US Army to build an Electronic Numerical
    Integrator
       calculate a trajectory in 1 second
   May 31, 1943 Construction of ENIAC starts
   1944 early thoughts on stored program
    computers by members of the ENIAC team
   July 1944 two accumulators working
   January 1944 Moore School team thinks of better
    ways to do things; leverages delay line memories
    from War research
   September 1944 John von Neumann visits
       Goldstine’s meeting at Aberdeen Train Station
   October 1944 Army extends the ENIAC contract
    to include research on the EDVAC and the stored-
    program concept
   Spring 1945 ENIAC working well
   June 1945 First Draft of a Report on the EDVAC:
    Electronic Discrete Variable Automatic Computer
   John von Neumann prepares (?) a report on the
    EDVAC which identifies how the machine could be
    programmed (unfinished very rough draft)
     academic: publish for the good of science
     engineers: patents, patents, patents

   von Neumann never repudiates the myth that he
    wrote it; most members of the ENIAC team
    ontribute ideas
   Freddy Williams and Tom Kilburn
   Developed an electrostatic memory
   Prototype operational June 21, 1948 and machine to
    execute a stored program
   Memory: 32 words of 32 bits each
   Storage: single Williams tube (CRT)
   Fully operational: October 1949
   Ferranti Mark I delivered in February 1951
   Maurice Wilkes, University Mathematical Laboratory,
    Cambridge University
   Moore School Lectures
   Electronic Delay Storage Automatic Calculator,
    EDSAC operational May, 1949
   J. Lyons Company and the LEO, Lyons Electronic
    Office, operational fall 1951
   Alan Turing
   Automatic Computing Engine (ACE)
   Basic design by spring, 1946
   Harry Huskey joins project
   Pilot ACE working, May 10, 1950
   English Electric: DEUCE, 1954
   Full version of ACE at NPL, 1959
   On Computable
    Numbers with an
    application to the
    Entscheidungs-problem
   Code breaker
   43 UNIVACs were delivered to government
    and industry
   Memory: mercury delay lines: 1000 words of 12
    alphanumeric characters
   Secondary storage: metal oxide tape
   Access time: 222 microseconds (average)
   Instruction set: 45 operation codes
   Accumulators: 4
   Clock: 2.25 Mhz
   Addition time: 60 microseconds
   Multiplication: 456 microseconds
   Memory: 2048 (36 bit) words using Williams
    tubes
   Secondary memory:
       Magnetic drum: 8192 words
       Magnetic tape: plastic
   Delivered: December 1952: IBM World
    Headquarters (total of 19 installed)
   1958 Philco introduces TRANSAC S-2000
       first transistorized commercial machine
   IBM 7070, 7074 (1960), 7072(1961)
   1959 IBM 7090, 7040 (1961), 7094 (1962)
   1959 IBM 1401, 1410 (1960), 1440 (1962)
   FORTRAN, ALGOL, and COBOL are first
    standardized programming languages
   April 1964 IBM announces the System/360
       solid logic technology (integrated circuits)
       family of “compatible” computers
   1964 Control Data delivers the CDC 6600
   nanoseconds
   telecommunications
   BASIC, Beginners All-purpose Symbolic Instruction
    Code
   Large scale integrated circuits (MSI, LSI)
   Nanoseconds and picoseconds
   Databases (large)
   Structured languages (Pascal)
   Structured techniques
   Business packages
   Noyce, Moore, and Andrew Grove leave Fairchild
    and found Intel in 1968
       focus on random access memory (RAM) chips
   Question: if you can put transistors, capacitors, etc.
    on a chip, why couldn’t you put a central processor
    on a chip?
   Ted Hoff designs the Intel 4004, the first
    microprocessor in 1969
       based on Digital’s PDP-8
   Ed Roberts founds Micro Instrumentation Telemetry
    Systems (MITS) in 1968
   Popular Electronics puts the MITS Altair on the cover
    in January 1975 [Intel 8080]
   Les Solomon’s 12 year old daughter, Lauren, was a
    lover of Star Trek. He asked her what the name of the
    computer on the Enterprise was. She said “
    ‘computer’ but why don’t you call it Altair because
    that is where they are going tonight!”
   CPU    Year   Data   Memory    MIPS
   4004   1971   4      1K
   8008   1972   8      16K
   8080   1974   8      64K
   8088   1980   8      1M        .33
   80286 1982    16     1M        3
   80386 1985    32     4G        11
   80486 1989    32     4G        41
   Pentium1993   64     4G     111
   screen
   box, tower, etc.
     motherboard
     hard drive
     floppy drive
     cdrom
   keyboard and mouse
   peripherals
   program used to control computer, link
    between user and internal working of
    computer and programs
   Windows vs. Mac vs. Linux
   Windows 95, 98, 2000, ME, NT, XP?
   Desktop and icons
   Task bar
   Start button
   Programs
            Delete
Backspace   Key
Key
   Enter
   Page up, Page down
   F1-F12
   Esc
   Shift key
   CTL, ALT
   Arrows
   Backspace, Delete
   Any key
   pointing device that moves pointer or cursor
   point and click (tip of the arrow is the point)
   left and right buttons
   start programs - 1 click vs 2 clicks
   highlight text (click and drag)
   practice makes perfect
   Anchor by holding with thumb on left side and
    last two or three fingers on right side
   Click lightly with index finger
   Keep mouse upright with cord away from you
    and move side to side and up and down
   Keep mouse on mousepad
   Mouse
       Click on up and down arrows
       Click on top of and below that darker box without
        touching the box
       Click and drag the darker box
   Keyboard (make sure cursor is on page)
       Use arrow keys
       Use page up, page down, home and end

				
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