Technology in Action Chapter 6 Behind the Scenes: A Closer Look at System Hardware

Chapter Topics Computer switches Binary number system ASCII / Unicode Creating faster CPUs

Data Representation Process of transforming diverse data into a form computers can use for processing Digital devices work with distinct and separate data Analog devices work with continuous data 3

Digital vs. Analog Analog Signals Have an Infinite Number of Values Digital Signals Have a Discrete Number of Values In this case, the Analog Wave ranges from 0-1 Note that the Digital Wave is Either 0 or 1 (nothing between) 4

Representing Numbers We normally use the decimal numbering system, which uses 10 symbols (0, 1, 2, 3, 4, 5, 6, 7, 8, and 9). Computers use the binary numbering system, which represents all numbers using just two symbols (0 and 1). Everything a computer does is broken down into a series of 0s and 1s, stored with switches 5

Switches Representing Data The on/off state of a switch represents one bit of data Bit (binary digit) On = 1 Off = 0 OFF 0 ON 1 01 OR = 1 bit

The Binary Number System Describes a number as powers of 2 Also referred to as base 2 numbering system Used to represent every piece of data stored in a computer: all of the numbers, letters, and instructions

Chapter 2: Computer Hardware 8

The Binary Number System Number systems are organized ways to represent numbers Each number in one system has a corresponding number in another x x x x8 8 2x4 4 2x2 2 2x1 1 Binary Base = = 89 Binary Base 10

Representing Letters and Symbols American Standard Code for Information Interchange (ASCII) 8 bits = 1 byte = alphanumeric character or symbol 256 different combinations Unicode 16 bits = 2 bytes = one symbol 65,000 different combinations, used for all languages NOT a translator program! = a = A = # = m ASCII

ASCII Chart

ASCII Chapter 2: Computer Hardware 12

Microprocessor Performance Factors Serial Processing All Activities are Done on One CPU Pipelining Processes Independent Tasks Simultaneously Overall Job Finishes Earlier Example: If you have 4 sets of laundry to wash, dry, and fold… Do you completely finish one load then start another? 13

14 Serial Processing Pipelining

Microprocessor Performance Factors Parallel Processing The tasks are divided among multiple CPUs In previous example, would be like having multiple washer/dryer sets Modern Dual Core Processors actually contain all the circuitry for two separate microprocessors 15