Transcript Management Information Systems Introduction

Introduction to
Computers
Lecture 1
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Web Page and Book List
Main Course Web Page is at:
http://nnrose.weebly.com
 Recommended Text
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Shelly Cashman: Discovering Computer
2011
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Data vs. Information
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Data: Representation of a fact or idea
Information: Organized, meaningful data
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Data, Information
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Data vs. Information
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Data (PLURAL) - SINGULAR IS DATUM
A “given” or fact: a number, a statement, or a picture
 The raw facts in the production of information
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Information
Data that have meaning within a context
 Raw data or data that have been manipulated
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Computers Are Data
Processing Devices
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Computer’s four major functions:
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Gathers data (users input data)
Processes data into information
Outputs data or information
Stores data and information
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What Computers Do
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Basic Components of a Computer
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Input devices
 Keyboards and pointing devices
(mouse)
Output devices
 Display or video monitor
 Printer
 Speakers
Central Processing Unit (CPU)
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What Computers Do
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Basic Components of a Computer
Memory and storage devices
 Primary storage: RAM (Random Access Memory)
 Secondary storage: Storage devices that serve as
long-term repositories for data:
 Hard disk drives
 Recordable CD and DVD drives
 Tape drives
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Components of a Computer System
Memory
Central Processing Unit (CPU)
Input
Control
Unit
Arithmetic
Logic Unit
Output
Registers
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Bits and Bytes:
The Language of Computers
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Bit
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Byte
 Eight bits
Each letter, number, and character = a string of eight 0s and 1s
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 Binary
 0 or 1
digit
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A Bit About Bits
Bits, Bytes, and Buzzwords
Bit-related terminology
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Byte
Kilobyte (KB)
Megabytes (MB)
Gigabytes (GB)
Terabytes (TB)
= 8 bits
= 1 Thousand Bytes
= 1 Million Bytes
= 1 Billion Bytes
= 1 Trillion Bytes
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Chapter 2 Summary Questions
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What devices do you use to get data into the
computer?
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Chapter 2 Summary Questions
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What devices do you use to get information out of
the computer?
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Chapter 2 Summary Questions
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What’s on the front of your system unit?
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Chapter 2 Summary Questions
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What’s on the back of your system unit?
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History of Computers
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Mechanical and
electromechanical devices
preceded the electronic
computer.
Charles Babbage (1830’s):
the analytical engine, and
Augusta Ada Byron, the
first programmer.
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Charles Babbage’s Analytical Engine
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Electro-Mechanical Devices
 (1890’s): electrical tabulating machine, and
foundation of IBM (1924).
 Aiken’s Mark 1. (1944) based on Babbage’s
original design - built at IBM labs, electromechanical, weighed 5 tons.
 Admiral Grace Hopper worked as
programmer on this computer, and coined
in the term 'bug' for a computer fault.
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Electronic Computers
 To increase speed and reliability, the
mechanical components of these early
devices were replaced by electronic
equivalents.
 These fully electronic devices became
known as the of computers.
 Successive generations of electronic
computers have greater speed, smaller
size, larger memory.
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First Generation
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1st Generation: (1945-1956).
Vacuum Tubes used as switching and storage
components.
Atanasoff & Berry (1939) first electronic
digital computer.
Turing (1943) Colossus machine built to
decode encrypted messages. (*Turing Test)
ENIAC (1946) first general purpose
computer. (decimal not binary machine)
UNIVAC (1951) first commercial computer commissioned for 1950 US census.
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First Generation
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Problems with vacuum tube machines:
 severe overheating,
 manual setting of each instruction,
 use of machine language only.
Magnetic core used for memory, punched
cards and later magnetic tape for secondary
storage.
Computers used for scientific and government
purposes.
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First Generation
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In 1945 John von Neumann proposed the
‘stored program concept’, with memory to
store both data and instructions.
Loading a new program into memory then
allows a new function for the computer.
In Von Neumann’s basic design, the program
is executed in a sequential manner.
While still the model for most conventional
computers, parallel processing has recently
challenged this aspect of the traditional
computing device
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Second Generation
2nd Generation: (1956-1963). Transistors.
 Transistors replaced vacuum tubes.
smaller, faster, more reliable, and use less energy
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Development of symbolic languages
Simpler programming - eg ADD instead of 00000101,
high level languages Fortran and Cobol.
Provision of system software (OS).
Computers used by military, government and
big business.
Problems: 100s or 1000s of transistors required for
powerful machines, expensive and cumbersome
This problem was solved by the invention of
the integrated circuit
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Third Generation
3rd generation: (1964-1971).
Integrated Circuits.
 Complete electronic circuit on single silicon
chip, smaller than single transistor.
 1000’s of components on one chip.
(SSI to MSI)
 cheap, fast and reliable.
 used by small business
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Fourth Generation
4th generation: (1975-1984). Microprocessors
 Microprocessor contains ALL elements of CPU
on one chip (Intel’s 4004, 1971).
 Progressively greater integration
(from LSI to VLSI) - 100,000’s to millions of
components per chip.
 Increasing
 complexity of instruction sets,
 no of bits handled at once,
 amount of memory addressed.
 Advent of personal computers and other
microprocessor controlled devices.
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Fifth Generation
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5th Generation:Ultra Large Scale
Integrated Circuits (ULSI): over 1
million Transistors per Integrated
Circuit or Chip
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Performance Enhancements
Computer performance has been greatly
enhanced by the following :
 Faster clock speed
 Overlapping & Parallel instruction
processing
 Wider, faster data paths (Buses)
 Faster disk access
 Bigger and Faster memory, including
advanced cache technology
 Optimised software
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