A Brief Overview of the History of Computer and Introduction

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Lecture 1

• A Brief Overview of the History of Computer and
  Introduction

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History of Computer Technology

• A complete history of computing would include a
  multitude of diverse devices such as the ancient
  Chinese abacus, the Jacquard loom (1805) and
  Charles Babbage's analytical engine (1834).
• Chinese abacus

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History of Computer Technology

• Jacquard loom

• analytical engine

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History of Computer Technology

• The evolution of digital computing is often
  divided into generations. Each generation is
  characterized by dramatic improvements over the
  previous generation in the technology used to
  build computers.

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History of Computer Technology

• The Mechanical Era (1623-1945)
• The idea of using machines to solve mathematical
  problems can be traced at least as far as the
  early 17th century.
• Mathematicians who designed and implemented
  calculators that were capable of addition,
  subtraction, multiplication, and division

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History of Computer Technology

• The first multi-purpose, (i.e. programmable)
  computing device was probably Charles Babbage's
  Difference Engine, which was begun in 1823 but
  never completed.
• Difference Engine

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History of Computer Technology

• First Generation Electronic Computers
  (1937-1953)
• Three machines have been promoted at various
  times as the first electronic computers.
• The first generation is characterized by the
  emergence of commercial computers.
• During this time, computers were used only by
  professionals.

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History of Computer Technology

• Computers were bulky and used vacuum tubes as
  electronic switch.

Vacuum
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History of Computer Technology

• Second Generation (1954-1962)
• Second generation computers used transistors
  instead of vacuum tubes.
• It reduced the size of computers as well as their
  cost and made them affordable to small and
  medium-size corporations.
• transistors

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History of Computer Technology

• Third Generation (1963-1972)
• The invention of the integrated circuit reduced
  the cost and size of computers even further.
• Minicomputers appeared on the market.
• Canned programs, popularly known as software
  packages, became available.

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History of Computer Technology

• Integrated circuit is a small electronic device
  made out of a semiconductor material.

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History of Computer Technology

• Fourth Generation (1972-1984)
• The fourth generation saw the appearance of
  microcomputers.
• It saw the use of large scale integration (LSI)
  and very large scale integration (VLSI) in the
  construction of computing elements.

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History of Computer Technology

• Large-Scale Integration (LSI) Refers to the
  placement of thousands of electronic components
  on a single integrated circuit.
• Very-Large-Scale Integration (VLSI) It is the
  process of creating integrated circuits by
  combining thousands of transistor-based circuits
  into a single chip.

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History of Computer Technology
LSI
VLSI
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History of Computer Technology

• Fifth Generation (1984-)
• It is characterized mainly by the acceptance of
  parallel processing.
• Until this time parallelism was limited to
  pipelining and vector processing, or at most to a
  few processors sharing jobs.

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History of Computer Technology

• Debugging
• It is a methodical process of finding and
  reducing the number of bugs, or defects, in a
  computer program or a piece of electronic.
• The story goes that when one of the early
  computers that Hopper was working with
  malfunctioned, it was discovered that a moth had
  gotten into a relay, causing it to fail.

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History of Computer Technology

• The first computer bug

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The Parts of a Computer System

• What is a Computer?
• A computer is an electronic device used to
  process data.
• A computer can convert data into information that
  is useful to people.

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The Parts of a Computer System

• A complete computer system includes four distinct
  parts
• Hardware
• Software
• Data
• User

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The Parts of a Computer System

• Hardware
• A computer's hardware consists of electronic
  devices the parts you can see and touch.
• The term "device" refers to any piece of hardware
  used by the computer, such as a keyboard,
  monitor, modem, mouse, etc.

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The Parts of a Computer System

• Software
• Also called programs consists of organized sets
  of instructions for controlling the computer.
• Some programs exist for the computer's use, to
  help it manage its own tasks and devices.
• Other programs exist for the user, and enable the
  computer to perform tasks for you, such as
  creating documents.

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The Parts of a Computer System

• Data
• Data consists of raw facts, which the computer
  can manipulate and process into information that
  is useful to people.
• Computerized data is digital, meaning that it has
  been reduced to digits, or numbers. The computer
  stores and reads all data as numbers.

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The Parts of a Computer System

• Although computers use data in digital form, they
  convert data into forms that people can
  understand, such as text, numerals, sounds, and
  images.

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The Parts of a Computer System

• Users
• People are the computer's operators, or users.
• Some types of computers can operate without much
  intervention from people, but personal computers
  are designed specifically for use by people.

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Looking Inside the Machine

• Types of Hardware
• A computer's hardware devices are categorized as
  follows
• Processor
• Memory
• Input and output (I/O) devices
• Storage devices

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Looking Inside the Machine

• The CPU
• The procedure that transforms raw data into
  useful information is called processing.
• This function is divided between the computer's
  processor and memory.
• The processor is also called the central
  processing unit (CPU). It manages all devices and
  performs the actual processing of data.

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Looking Inside the Machine

• The CPU consists of one or more chips attached to
  the computer's main circuit board (the
  motherboard).
• CPU

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Looking Inside the Machine

• Memory
• Memory also consists of chips attached to the
  motherboard.
• Memory holds data and program instructions as the
  CPU works with them. This memory is called Random
  Access Memory (RAM).

RAM
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Looking Inside the Machine

• The CPU can find any piece of data in RAM, when
  it needs it for processing.
• RAM is volatile, meaning it holds data only when
  the power is on. When the power is off, RAM's
  contents are lost.

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Looking Inside the Machine

• How Memory is Measured
• The smallest usable unit of measure for memory is
  the byte the amount of memory required to hold
  one character, like the letter A or the numeral
  2.
• Computers work with larger chunks of data,
  measured in multiple bytes.

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Looking Inside the Machine

• Input and Output Devices
• Input devices accept data and instructions from
  the user or from another computer system. For
  examples
• keyboard
• mouse

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Looking Inside the Machine

• Output devices return processed data back to the
  user or to another computer system. For examples
  
• printer
• Monitor
• Communications devices perform both input and
  output, allowing computers to share information.
  For examples
• modems
• network interface cards

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Looking Inside the Machine

• Storage Devices
• Storage devices hold data not currently being
  used by the CPU.
• Data is commonly stored on a magnetic or optical
  disk. Each type uses a special medium for storing
  data on its surface.

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Looking Inside the Machine

• A disk drive is a device that reads data from and
  writes data to a disk. Most new computers feature
  a floppy disk drive, a hard disk drive, and an
  optical disk drive.
• The most common optical storage devices are CDROM
  and DVD-ROM drives.

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Looking Inside the Machine

• Looking Inside the Machine - Storage Devices

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Bringing the Machine to Life

• What is Software?
• Software is a set of electronic instructions that
  tells the computer how to do certain tasks. A set
  of instructions is often called a program.
• When a computer is using a particular program, it
  is said to be running or executing the program.

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Bringing the Machine to Life

• The two most common types of programs are system
  software and application software.

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Bringing the Machine to Life

• System Software
• System software exists primarily for the computer
  itself, to help the computer perform specific
  functions.
• One major type of system software is the
  operating system (OS). All computers require an
  operating system.

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Bringing the Machine to Life

• The OS tells the computer how to interact with
  the user and its own devices.
• Common operating systems include Windows, the
  Macintosh OS, OS/2, and UNIX .
• Difference between Operating Systems
• Never turn off Solaris, FreeBSD, Linux, Windows
  NT, or Windows 2000 workstations because of
  rlogin and background jobs

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Bringing the Machine to Life

• Applications
• Application software tells the computer how to
  accomplish tasks the user requires, such as
  creating a document or editing a graphic image.

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Bringing the Machine to Life

• Some important kinds of application software are
• Word processing programs
• Spreadsheet software
• Database management
• Presentation programs
• Graphics programs
• Networking software
• etc.

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The Shapes of Computers Today

• Supercomputers
• The most powerful computers. They are used for
  problems requiring complex calculations.
• Because of their size and expense, supercomputers
  are relatively rare.
• Supercomputers are used by universities,
  government agencies, and large businesses.

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The Shapes of Computers Today
Super computer Cray T90
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The Shapes of Computers Today

• Mainframe Computers
• Mainframe computers can support hundreds or
  thousands of users, handling massive amounts of
  input, output, and storage.
• Mainframe computers are used in large
  organizations where many users need access to
  shared data and programs.

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The Shapes of Computers Today

• Mainframes are also used as e-commerce servers,
  handling transactions over the Internet.

Mainframe computers were big.
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The Shapes of Computers Today

• Minicomputers
• Minicomputers are smaller than mainframes but
  larger than microcomputers.
• Minicomputers usually have multiple terminals
• Minicomputers may be used as network servers and
  Internet servers.

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The Shapes of Computers Today

• Workstations
• Workstations are powerful single-user computers.
• Workstations are used for tasks that require a
  great deal of number-crunching power, such as
  product design and computer animation.

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The Shapes of Computers Today

• Workstations are often used as network and
  Internet servers.
• Sun workstation

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The Shapes of Computers Today

• Microcomputers, or Personal Computers
• Microcomputers are more commonly known as
  personal computers. The term "PC" is applied to
  IBM-PCs or compatible computers.
• Full-size desktop computers are the most common
  type of PC.

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The Shapes of Computers Today

• Notebook (laptop) computers are used by people
  who need the power of a desktop system, but also
  portability.
• Handheld PCs (such as PDAs) lack the power of a
  desktop or notebook PC, but offer features for
  users who need limited functions and small size.
• Handheld PCs