Lecture 1 Hardware, Software and Control Structures

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Lecture 1Hardware, Softwareand Control
Structures

• ENGR17 Engineering Programming
• Section 1
• Fall 2001

8/30/01
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Outline

• History of PC
• Components of PC
• History of Programming Languages
• Object-oriented languages
• Control Structures

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Microcomputer Systems

• First appeared in marketplace in the mid 70s
  (Altair)
• Also called personal computers
• Composed of hardware and software
• Hardware
• Physical components of the system
• Software
• Programs (step-by-step instructions) that tell
  the hardware how to perform a task
• Apple had first broadly successful personal
  computer
• Based on proprietary hardware and software
• IBM followed with the AT in early 80s
• Operation System Microsoft DOS
• Microprocessor Intel 8088

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Microcomputer Systems
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Hardware and Software

• Hardware
• System unit
• Internal memory (RAM and ROM)
• Central processing unit (CPU)
• Input devices
• Output devices
• Peripheral devices
• Software
• Operating system software
• Application software

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System Unit
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System Unit Internal Memory
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RAM and ROM

• Random-Access Memory (RAM) chips
• User can read and write to memory
• Volatile
• Read-Only Memory (ROM) chips
• User can only read from memory
• Nonvolatile

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Main Memory (RAM)
SIMM (Single In-line Memory Modules) most PCs
DIMM (Dual In-line Memory Modules) higher end
Laptop Memory usually proprietary
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CPU/Microprocessor

• Brain of the computer
• CPU resides on a microprocessor chip
• CPU contains two components
• Control unit
• Makes sure the computer correctly processes
  program instructions and data stored in internal
  memory
• Arithmetic/Logic Unit (ALU)
• Performs arithmetic calculations and logic
  operations
• Microprocessors
• Intel 32-bit 2GHz Pentium 4 (desktop) Xeon
  (servers)
• Intel 64-bit Itanium Family (servers)
• Sun Microsystems SPARC
• Hewlett Packard PA-RISC
• IBM PowerPC
• DEC Alpha

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Intel Pentium 4
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Operating System Software

• Manages computer and its peripheral devices
• Allows communication between user and computer
• Examples
• Windows 98, NT, ME, 2000, CE, XP (hits shelves in
  October)
• UNIX
• Linux
• DOS (obsolete)
• OS/2 (obsolete)
• For personal computers
• Windows 98, 2000, or XP
• For workstations, servers, and other big-iron
• Windows NT or 2000
• UNIX (HPUX, Berkeley, etc.)
• Linux (Red Hat, etc.)

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Application Software

• Word processors
• Spreadsheets
• Databases
• Graphics programs
• Programming languages

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History of Programming Languages

• Machine languages
• Assembly languages
• High-level procedure-oriented languages
• Object-oriented languages

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Machine Languages

• Are based on the binary number system
• Use combination of 0s and 1s to communicate
  directly with the computer
• Are tedious and error-prone require highly
  trained programmers
• Machine Language Example

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Machine Languages
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Assembly Languages

• Allow programmers to use mnemonics in place of 0s
  and 1s in the program
• Require an assembler (a program to convert
  assembly instructions into machine code)
• Are easier to write than machine language, but
  still tedious and require highly trained
  programmers
• Assembly Language Example

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Assembly Languages
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High-Level Procedure Languages

• Allow programmers to use instructions that more
  closely resemble English
• View a problem solution as a set of ordered steps
  (correct sequence is critical)
• Use top-down design approach
• Require a compiler to translate the program into
  machine language
• Do not require a great amount of technical
  expertise to write simple programs
• Examples COBOL, BASIC, Pascal, C
• Procedure language example

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High-Level Procedure Languages
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Object-Oriented Languages

• View a problem solution as a set of interacting
  objects
• Use object-oriented design methodology
• Require a compiler to translate high-level
  instructions into machine code
• Examples
• C
• Visual Basic
• Object-Oriented Language Example

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Object-Oriented Languages
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Advantages of OO Languages

• Allow programmer to use familiar objects to solve
  problems
• Because each object is viewed as an independent
  unit, an object can be used in more than one
  application, with little or no modification

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OOP Terminology

• OOP
• OOD
• Object
• Attributes (data) and behaviors
• Class
• Instance

• Encapsulation
• Abstraction
• Hidden/exposed
• Inheritance (derived class and base class)

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Illustration of OOP Terms
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Control Structures

• Control the flow of a programs logic
• Also called logic structures
• Three basic structures
• Sequence
• Selection
• Repetition

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Sequence Structure

• Directs the computer to process the instructions,
  one after another, in the order listed in the
  program
• Are found in every program
• Algorithm
• Step-by-step instructions to solve a problem
• Sequence Example

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Sequence Structure
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Repetition Structure

• Directs the computer to repeat one or more
  instructions until some condition is met
• Repetition Example

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Repetition Structure
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Repetition Structure
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Selection Structure

• Directs the computer to make a decision, and then
  select an appropriate action based on that
  decision
• Also called the decision structure
• Selection Example

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Selection Structure
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Selection Structure
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Summary

• Components of a microcomputer system
• Relationship between hardware and software
• History of programming languages
• Object-oriented languages
• Control structures
• Sequence structure
• Repetition structure
• Selection (decision) structure

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Questions

• Microcomputer System is composed of what two
  components?
• Hardware and Software
• System Unit is composed of what two components?
• Memory and CPU
• Two types of Memory?
• Random Access Memory Read Only Memory
• CPU is composed of what two components?
• Control Unit Arithmetic/Logic Unit
• Which microprocessor did your instructor help
  design?
• Itanium
• Three examples of an operating system?
• Windows, UNIX, Linux

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Questions

• 4 types of programming languages?
• Machine, Assembly, High-Level Procedural,
  Object-Oriented
• Advantages of High Level languages?
• Closer to English
• Ordered steps
• Top-down design
• Advantages of object-oriented?
• Code reuse
• Easier to solve some problems
• Three control structures?
• Sequence, Repetition, Selection
• Whats your favorite control structure and why?
• Selection

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Questions

• Write an algorithm using all three control
  structures to instruct someone to
• Walk to the light switch
• Turn the all the switches on if any are off
  otherwise turn the 1st switch off
• Return to their chair