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Chapter 17 Looking “Under the Hood”. 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?.
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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
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
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
How does a computer work? Practical PC 6th Edition Chapter 17
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
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
What do RAM and processing circuitry look like? Practical PC 6th Edition Chapter 17
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
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
Does a computer use the same code for all types of data? Practical PC 6th Edition Chapter 17
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
How does software tie into chips, codes, and circuits? Practical PC 6th Edition Chapter 17
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
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
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
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
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