1. Chapter 17 Looking “Under the Hood”

2. Practical PC 5th Edition Chapter 17
Getting Started
In this Chapter, you will learn:
How does a computer work
What do RAM and processing circuitry look like
How does data get into chips
Does a computer use the same code for all types of data
Practical PC 5th Edition Chapter 17

3. Practical PC 5th Edition Chapter 17
Getting Started
In this Chapter, you will learn (continued):
How does software tie into chips, codes, and circuits
About Hardware: Microprocessors
Practical PC 5th Edition Chapter 17

4. How does a computer work?
A computer works by manipulating data
Data refers to the symbols that describe people, events, things, and ideas
A computer works with data in four ways
Accepting input data
Processing data
Producing output data
Storing data
Input is the data that goes into a computer
The computer puts data into RAM (Random Access Memory), a temporary holding area for data
Practical PC 5th Edition Chapter 17

5. How does a computer work?
RAM holds data and tells the computer what to do
A computer’s circuitry reads data and processes it
Processing data means manipulating it in some way, such as performing a calculation
An instruction indicates that data should be transferred from RAM to a printer, modem, or display screen as output
Data sent to the hard disk drive is done using a a process called “storing data”
Practical PC 5th Edition Chapter 17

6. How does a computer work?
Input data arrives in RAM and is processed
Practical PC 5th Edition Chapter 17

7. What do RAM and processing circuitry look like?
RAM and processing circuitry are contained in “chips” inside PC
Chip: nickname for an integrated circuit
Integrated circuit: thin slice of silicon etched with microscopic circuitry
Microprocessor chip: carries out most of the processing work on PC
RAM chips: temporarily hold data
ROM chips: hold the instructions for PC to boot up
Practical PC 5th Edition Chapter 17

8. What do RAM and processing circuitry look like?
Chip is housed in small, black, rectangular chip carrier
Circuit board contains electrical pathways that allow data to travel between chips
In a typical PC, a large circuit board houses the microprocessor chip, ROM chips, and support chips
Series of RAM chips are connected to a small circuit board called a memory module
Practical PC 5th Edition Chapter 17

9. What do RAM and processing circuitry look like?
PC System Board
Practical PC 5th Edition Chapter 17

10. How does data get into chips?
PC works with data converted into code and then into electronic signals that travel through circuits on chips and circuit boards
Computer codes are based ones and zeros
Each 1 or 0 is a bit (short for binary digit)
Eight bits form a byte
Data is coded to transmit electronically
As data is gathered, processed, stored, and transmitted, special controller chips constantly convert it from one type of signal to another
Practical PC 5th Edition Chapter 17

11. Does a computer use the same code for all types of data?
Computers use different codes for different types of data
Text data: ASCII, extended ASCII, ANSI, Unicode, or EBCDIC codes
Numbers for calculations: binary number system
Bitmap images: binary color code for each dot
Recorded sound: binary number represents height of wave sample
Codes share characteristics
Digital: converts data into a finite set of numbers
Binary: uses only 0s and 1s
Fixed length: use the same number of bits to represent each data item
Practical PC 5th Edition Chapter 17

12. Does a computer use the same code for all types of data?
ASCII code: Digital, Binary, and Fixed Length
Practical PC 5th Edition Chapter 17

13. How does software tie into chips, codes, and circuits?
Software is a collection of programs or program modules containing a list of instructions
Instructions are written in a computer programming language
Today’s programming languages use English-like words
English-like words must be converted into a machine language of 1s and 0s
Compiling is the process of converting English-like words into 1s and 0s
Compiling creates executable EXE files
Practical PC 5th Edition Chapter 17

14. Hardware: Microprocessors
Microprocessor is a single integrated circuit
Microcomputer is a type of computer that uses a microprocessor as its main processing unit, such as your PC
Most microcomputers contain x86 microprocessors
Able to work with the x86 instruction set
Intel is the original x86 chipmaker and is still the largest
Both Intel and AMD offer chips with speeds over 3 GHz
Clock speed is measured in megahertz (MHz) or gigahertz (GHz)
One MHz is 1 million cycles per second and one GHz is 1 billion cycles per second
Clock speed is analogous to how fast you pedal a bike. Faster cycles mean faster computer processing
Practical PC 5th Edition Chapter 17

15. Hardware: Microprocessors
Several factors can affect the speed at which a microprocessor processes instructions
Instructions per clock cycle: Processors that execute multiple instructions per clock cycle are referred to as superscalar
Cache memory is data-holding circuitry that can be accessed faster than RAM
Level 1 cache is on the microprocessor chip
Level 2 cache is on a separate chip
Accelerated front side bus; fast version will move data quickly and will allow the processor to work at full capacity
HyperTransport is a technique to accelerate the rate data travels on the front side bus
Practical PC 5th Edition Chapter 17

16. Hardware: Microprocessors
Several factors can affect the speed at which a microprocessor processes instructions (continued)
Extended instruction sets: some processors have this feature to speed up certain types of processing
Multi-core architecture: multi-core processor is a single microprocessor chip with circuitry that allows it to process more than one instruction at a time
Benchmark test is a set of standard processing tasks that measure the performance of computer hardware and software
Microprocessor benchmark tests measure processor speed
Practical PC 5th Edition Chapter 17

17. Hardware: Microprocessors
Benchmark tests measuring processor performance fall into categories:
Multimedia benchmarks measure performance when processing multimedia data
Integer benchmarks measure performance when processing words and numbers used in word processing, presentation, spreadsheet, and database applications
Floating-point benchmarks measure performance for numbers stored in a special “floating point” format used in 3-D graphics, computer-aided design, and many computer games
Real-world performance benchmarks measure how well a computer executes a predefined set of tasks while running word processing, spreadsheet, and other productivity software
Practical PC 5th Edition Chapter 17

18. Who invented the first electronic digital computer?
What do you think?
Do you think the judge made the right decision, despite the fact that Atanasoff never filed for a patent?
Do you think that Zuse, instead of Atanasoff, should be declared the inventor of the first electronic digital computer?
Do you think that the computer industry would be different today if Sperry Rand had won its patent case?
Practical PC 5th Edition Chapter 17

19. Practical PC 5th Edition Chapter 17
Chapter Summary
You should now:
Understand how a computer works
Know what RAM and processing circuitry look like
Understand how data gets into chips
Know if a computer uses the same code for all types of data
Practical PC 5th Edition Chapter 17

20. Practical PC 5th Edition Chapter 17
Chapter Summary
You should now be able to (continued):
Know how software ties into chips, codes, and circuits
Understand Microprocessors
Practical PC 5th Edition Chapter 17