Introduction to Computer Science

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Introduction to Computer Science
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What is Computer Science?

• Science
• Subject to limitations
• experimental
• Mathematics
• At the lowest level, its just arithmetic using
  binary numbers
• Logic
• Determines which path will be followed

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• Engineering
• Transformation of abstract ideas into models
• Use an information structure as the building
  blocks, and an algorithmic method as the
  blueprints
• Communication
• Presenting solutions, either hardware or software
• Interdisciplinary Field
• Solving problems in a variety of disciplines
• Mathematics, physics, chemistry, biology,
  business, etc.

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Computer Ethics

• Undefined Vague
• Piracy - illegal use of software
• Viruses
• Theft - mostly hardware
• Artificial intelligence
• Neural networks

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What is a computer?

• According to Webster
• an electronic machine which by means of stored
  instructions and information, performs rapid,
  often complex calculations or compiles,
  correlates, and selects data
• Mainframes
• very large, very expensive, and very powerful
• intended for multiple users

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• Minicomputers / Workstations
• smaller scale of a mainframe with smaller storage
  capacity and smaller price tag
• also intended for multiple users, although often
  set up for a single user
• Microcomputers / PC
• limited storage capacity theoretically, but
  continuing to become more powerful and extensible
• intended for a single user
• Supercomputers
• most powerful most expensive

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Hardware Software

• Hardware
• the actual machine and its support devices
• Examples Monitor, disk drive, CD ROM, printer,
  CPU, keyboard, mouse
• Software
• programs that make the machine do something
• Examples OS, word processing, games
• Neither would be of much value without the other!

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Computer Hardware

• A main unit connected to peripheral devices
• The main unit
• Central processing unit (CPU)
• Arithmetic Logic Unit (ALU) - responsible for
  evaluating arithmetic logical expressions
• Control Unit - responsible for the execution of
  the program
• Main memory (RAM)
• A sequence of locations where information
  representing instructions and data can be stored

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More Hardware

• Peripherals
• Input devices - keyboards, mouse
• Output devices - monitor, printers
• Secondary memory devices - floppy disks, hard
  drives, CD-ROM
• Communication
• Organized around a group of wires called a bus
• Note Us software geeks know very little about
  hardware!

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Conceptual View of A Computer
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Computer Software

• System software
• The operating system
• A large program that allows the user to
  communicate with the hardware
• control computer access/security, allocate
  peripheral resources, schedule resources
• Without this your system is worthless!
• Applications software
• Programs designed for a specific use
• word processing, games, CAE tools
• The reason why people actually buy/use computers!

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Computer Languages

• Machine language
• a sequence of binary digits
• architecture dependent
• Assembly language
• uses opcodes and registers
• also architecture dependent
• High level languages
• These are the ones that youll be programming in
• C, C, Pascal, PL/1, Fortran, Cobol, Basic, Ada,
  Smalltalk
• Not as much architecture dependent
• Some have become standardized
• Compilers
• Translate instructions in a particular language
  into machine language