Chapter 1

09/04/13

Change Your Password

The command is: passwd In the lab first do: ssh -Y onyx

You will have to see me to change it, if you forget it.

Change it to something you can remember

Computer Architecture and Language

Know Basic Computer Architecture Know Basic Software and Languages Identify Types of Programming Errors

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COMPUTER ARCHITECTURE

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CPU

Central Processing Unit

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CPU

"Brain" of the Computer• Executes program instructions• Controls Other Devices• Carries out arithmetic operations• Fetches data from memory and stores

it back

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Primary Memory

RAM Stores program while it is executed Also stores data the program needs Temporary

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Secondary Memory

Long term storageDevices

• Hard Drive• Flash Drive• Tapes

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Input and Output Devices

Input Devices• Let user enter data• Mouse, Keyboard, Camera

Output Devices• Let user access data in system• Display Screen, Printer, Speaker

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Anatomy of a Computer

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SOFTWARE

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SoftwareComputer software refers to programs

that reside and execute electronically on the hardware.• Compilers

• Translate source code

• Operating systems• Provide the HCI (Human Computer Interface)

• Application programs• Provide problem solutions

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Languages Machine Code

• Only code computer understands• Numeric(binary) Code

• 161 40000 45 100 127 11280• Extremely primitive

High Level Languages• More like English• Instructions more powerful• C++, Java, VB, Python• Must be translated with a Compiler

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LanguagesThe compiler translates C++ programs into machine code.

The linker combines machine code with library code into an executable program.

C++ for Everyone by Cay HorstmannCopyright © 2012 by John Wiley & Sons. All rights reserved

Engineering Problem Solving with C++ second edition, J. ingber

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Executing a C++ Program

Source File• printable/Readable Program file• Created with vi or other editor

Object File• nonprintable machine readable file• Created by compiler

Executable Program• nonprintable executable code• Linker links libraries with object code to create it.

Engineering Problem Solving with C++ second edition, J. ingber

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Errors

Syntax errors• Reported by the compiler• Error in language rules, such as leaving out a ";"

Execution/Run-time errors• Reported by the operating system• Cause program to stop abnormally• e.g. Zero divide

Logic errors• Not reported• Just cause bad program results• e.g. Program converts 24 inches to 7 feet.

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Questions

What is the purpose of the CPU? How does it know what to do?

Give an example of an input device.

Where is a program stored while it is executing?

What linux command is used to translate a C++ program into machine code?

A program to convert fahrenheit to celsius asks the user for a fahrenheit temperature then stops abnormally. What kind of error is this?

Another temperature conversion program gets a fahrenheit temperature of 32 then outputs 50 degrees celsius. What kind of error is this one?

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Quiz Next Wednesday

Linux and Vim

Chapter 1