Copyright 2012 Pearson Education, Inc. Chapter 1 INTRODUCTION TO COMPUTING AND ENGINEERING PROBLEM SOLVING

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1 Chapter 1 INTRODUCTION TO COMPUTING AND ENGINEERING PROBLEM SOLVING

2 Outline Objectives 1. Historical Perspective 2. Recent Engineering Achievements 3. Computing Systems 4. Data Representation and Storage 5. An Engineering Problem-Solving Methodology

3 Objectives Introduce computing and engineering problem solving, including: A brief history Recent engineering achievements A discussion of Numbering Systems A discussion of hardware and software A five-step problem-solving methodology

4 Historical Perspective Augusta Ada Byron ( , below) wrote the first computer program. Charles Babbage, ( , above) designed the Analytical Engine (left) to process decimal numbers.

5 Charles Babbage, Esq English mathematician. Designed the Analytical Engine in the early 1800s. Published Of the Analytical Engine in 1864.

6 Analytical Engine Designed to process base ten numbers. Consisted of four parts: Storage unit Processing unit Input device Output device

7 Analytical Engine Luigi F. Menabrea, French engineer and mathematician, described Babbage s vision of a machine capable of solving any problem using: Inputs Outputs Programs written on punch cards

8 Augusta Ada Byron Wrote the English translation of Menabrea s Sketch of the Analytical Engine. Envisioned the multidisciplinary potential of the Analytical Engine. Wrote detailed instructions for performing numerical computations using the Analytical Engine.

9 Digital Computers ABC (Atanasoff Berry Computer) Developed at Iowa State University between 1939 and 1942 by John Atanasoff and Clifford Berry. Weighed 700 pounds. Executed one instruction every 15 seconds.

10 Digital Computers ENIAC(Electronic Numerical Integrator And Calculator) Developed by research team lead by John Mauchly and J. Presper Eckert during the early 1940s. Weighed 30 tons. Executed hundreds of instructions every second.

11 ENIAC vs. Intel Pentium 4 ENIAC executes hundreds of operations per second (30 tons) Today s processors execute trillions of operations per second and weigh ounces.

12 Recent Engineering Achievements Image credits: NASA/JPL/Malin Space Science Systems.

13 Recent Engineering Achievements Extraterrestrial Explorations First manned lunar landing (July 21, 1969) Mars Global Surveyor, Mars Reconnaissance Orbiter, and Mars Exploration Rovers Terrestrial Application Satellites Computer Axial Tomography (CAT) Scanners Computer simulations Advanced composite materials. Speech understanding Weather, climate, and global change prediction

14 Recent Engineering Achievements Digital computers facilitate multidisciplinary engineering achievements that: Improve our lives. Expanded the possibilities for our future. Changing engineering environment requires engineers with: Communication skills. Skills for working in interdisciplinary teams. An awareness of ethic issues and environmental concerns. A global perspective.

15 Computing Systems The von Neumann Computing Model

16 Computing Systems A computing system is a complete working system that includes: Hardware Software

17 Hardware Hardware refers to the physical parts off the computing system that have mass (i.e. they can actually be touched): Computer Display Mouse Printer

18 Hardware Jon von Neumann computing model Input device(s) Output device(s) Memory Unit CPU (Central Processing Unit) consisting of: Control Unit ALU (Arithmetic Logic Unit)

19 Software Interface to Computer Hardware

20 Software Computer 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

21 Building a Program Computers only understand machine language. High-level languages like C++ must be translated to machine language for execution.

22 Key Terms Source Program printable/readable Program file Object Program nonprintable machine readable file Executable Program nonprintable executable code

23 Errors in Programs Syntax/Parse Errors Mistakes with the language. Always reported by the compiler Linking Errors Missing pieces prevent the final assembly of an executable program. Run-time Errors Occur when program is executing. May or may not be reported.

24 Logic Errors Can be difficult to find. Debugging can be time consuming. Better tools for find bugs It is important to carefully check the output of your programs for errors. Even programs that appear to work correctly may have bugs!

25 Debugging Process of eliminating logic errors (i.e. bugs) from programs. User-friendly programming environments such as Microsoft Visual C++ integrate the compiler with text processors and code editors special tools to help find bugs in programs (debugger) testing tools and much more

26 Data Representation and Storage

27 Data Representation and Storage Digital computers store information as a sequence of bits (binary digits). The value or state of a bit at any given time can be 0 or 1 (off or on). Data is stored as a sequence of bytes. A byte is a sequence of 8 bits.

28 Memory Diagram Address Sixteen Bit Word Address Space = 8 Word Size = 16

29 Data Representation Right most bit is referred to as the least significant bit. Left most bit is referred to as the most significant bit. Value stored at address 000 is = But what does it represent?

30 Numbering Systems Base ten number system Ten decimal digits (0,1,2,3,4,5,6,7,8,9) Each digit multiplies a power of ten Example: = 2* * *10 0

31 Numbering Systems Base two (binary) number system Two binary digits (0,1) Each digit multiplies a power of two Example: = 1* * * * *2 0 = 1*16 + 0*8 + 1*4 + 1*2 + 0*1 = = 22 10

32 Numbering Systems Base eight number system Eight octal digits (0,1,2,3,4,5,6,7) Each digit multiplies a power of eight Example: = 2* * *8 0 = 2*64 + 4*8 + 5*1 = = 165 8

33 Numbering Systems Base sixteen number system Sixteen hex digits (0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F) Each digit multiplies a power of sixteen Example: 2FB 16 = 2* F* B*16 0 = 2*256 + F*16 + B*1 = =

34 Practice with Number Systems =? =? =? 10 3A1B 16 =? 2

35 Practice with Number Systems = = = A1B 16 =

36 Data Types Integer Data Type: Often represented in 4 bytes (System Dependent) Left most bit is reserved for the sign of the number Remaining 31 bits represent the magnitude of the number.

37 Data Types Representation of data affects the efficiency of arithmetic and logic operations. For efficiency, negative integers are often represented in their 2 s complement form. The 2 s complement of an integer is formed by negating all of the bits and adding one.

38 Two s Complement Form the 2 s complement representation for the value assuming a word size of 8 bits for simplicity = Negate bits: Add 1: s complement is

39 Two s Complement Add to = = 0 10

40 Data Types Floating Point Data Floating point types represent real numbers, such as 1.25, that include a decimal point. Digits to the right of the decimal point form the fractional part of the number. Digits to the left of the decimal point form the integral part of the number.

41 Practice with Decimals Convert to binary.

42 Practice with Decimals Convert to binary. First convert the integer part: = Then repeatedly multiply the fractional part by 2:.25*2=0.5C0.50*2=1.0C1 Therefore: =

43 Engineering Problem-Solving Methodology

44 Five Step Problem-Solving Methodology 1. State the problem clearly. 2. Describe the input and output. 3. Work a hand example. 4. Develop a solution. 5. Test your solution.