1. Chapter 17 Looking “Under the Hood”

2. Practical PC 6th Edition Chapter 17
Getting Started
FAQs:
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?
How does software tie into chips, codes, and circuits?
Practical PC 6th Edition Chapter 17

3. 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 6th Edition Chapter 17

4. 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 process called “storing data”
Practical PC 6th Edition Chapter 17

5. How does a computer work?
Practical PC 6th Edition Chapter 17

6. What do RAM and processing circuitry look like?
RAM and processing circuitry are contained in “chips” inside the 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 6th Edition Chapter 17

7. 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 6th Edition Chapter 17

8. What do RAM and processing circuitry look like?
Practical PC 6th Edition Chapter 17

9. 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 6th Edition Chapter 17

10. Does a computer use the same code for all types of data?
Computers use different codes for different types of data
Text data: ASCII and Unicode
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 6th Edition Chapter 17

11. Does a computer use the same code for all types of data?
Practical PC 6th Edition Chapter 17

12. 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 using 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 6th Edition Chapter 17

13. How does software tie into chips, codes, and circuits?
Practical PC 6th Edition Chapter 17

14. Hardware: Microprocessors
Microprocessor is a single integrated circuit
Most computers 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 x86 microprocessors
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 6th 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
Most of today’s microprocessors have multi-level caches
L1, L2, or L3 caches
Accelerated front side bus; fast version will move data quickly and will allow the processor to work at full capacity
HyperTransport and QuickPath
Practical PC 6th 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
Word size: refers to the number of bits that a microprocessor can manipulate at one 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 6th 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 processing efficiency for integer data
Floating-point benchmarks measure performance for numbers stored in a “floating point” format used in 3-D graphics, computer-aided design, and many computer games
Practical PC 6th 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 6th Edition Chapter 17