Chapter 1 Computers and Digital Basics Computer Concepts
Chapter 1 Computers and Digital Basics Computer Concepts 2014
1 Chapter Contents Ø Ø Ø Section A: All Things Digital Section B: Digital Devices Section C: Digital Data Representation Section D: Digital Processing Section E: Password Security Chapter 1: Computers and Digital Basics 2
1 Section A: All Things Digital Ø Ø Ø The Digital Revolution Data Processing Personal Computing Network Computing Cloud Computing Digital Society Chapter 1: Computers and Digital Basics 3
1 The Digital Revolution Ø ongoing process of social, political, and economic change Ø brought about by digital technology; i. e. computers, Internet Driven by Ø technology based on digital electronics Ø idea that electrical signals can represent data, such as numbers, words, pictures, and music Chapter 1: Computers and Digital Basics 4
1 The Digital Revolution Ø Digitization is the process of converting text, numbers, sound, photos, and video into data that can be processed by digital devices Ø The digital revolution has evolved through four phases, beginning with big, expensive, standalone computers, and progressing to today’s digital world in which small, inexpensive digital devices are everywhere Chapter 1: Computers and Digital Basics 5
1 The Digital Revolution Chapter 1: Computers and Digital Basics 6
1 Data Processing Ø Some historians mark the 1980 s as the beginning of the digital revolution, but engineers built the first digital computers during World War II for breaking codes and calculating missile trajectories Ø Computers were operated by trained technicians Ø Back then, processing components for computers were housed in closet-sized cabinets that did not usually include a keyboard or display device Chapter 1: Computers and Digital Basics 7
1 Mainframe Computing 8
1 Data Processing Ø Data processing is based on an inputprocessing-output cycle Ø Data goes into a computer, it is processed, and then it is output Chapter 1: Computers and Digital Basics 9
1 Personal Computing Ø Second phase: personal computing Ø Characterized by: Ø small, Ø standalone computers Øpowered by local software Ø Local software refers to any software that is installed on a computer’s hard drive Chapter 1: Computers and Digital Basics 10
1 Personal Computing Chapter 1: Computers and Digital Basics 11
1 Network Computing Ø Third phase materialized as computers became networked and the Internet was opened to public use Ø A computer network is a group of computers linked together to share data and resources Ø The Internet is a global computer network Ø originally developed as a military project Ø then handed over to the National Science Foundation for research and academic use Chapter 1: Computers and Digital Basics 12
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1 Origin of the Internet Ø Internet is a network of networks connecting billions of computers globally Ø Developed while U. S. was in midst of Cold War with Soviet Union Ø Created to respond to two concerns: ØEstablishing a secure form of military communications ØCreating a means by which all computers could communicate 14
1 The Web vs. the Internet !! The WWW is NOT the INTERNET !! World Wide Web = Web Pages INTERNET = All services (includes: Web, Email, IM, etc…) 15
1 Network Computing Ø The Web (short for World Wide Web) is a collection of linked documents, graphics, and sounds that can be accessed over the Internet Ø From 1995– 2010, computing was characterized by: Ø the Web, e-mail, Ø multiplayer games – Doom, Wo. W, etc Ø music downloads, Ø and enormous software applications, such as Microsoft Office, Norton’s Internet Security Suite, and Corel Digital Studio Chapter 1: Computers and Digital Basics 16
1 Web Entertainment World of Warcraft (Wo. W) Ø MMORG Ø Released Nov 2004 Ø Peak: 12 million users Ø Current: 9. 1 million Ø Fee: $13 -15 per month Ø Interact with other human players 17
1 Cloud Computing Ø Local applications are being eclipsed by cloud computing, which characterizes the fourth phase of the digital revolution Ø Cloud computing: access information, applications, communications, and storage over the Internet Ø The expansion of cloud computing is due in part to convergence, a process by which several technologies with distinct functionalities evolve to form a single product Chapter 1: Computers and Digital Basics 18
1 Cloud Computing Chapter 1: Computers and Digital Basics 19
1 Cloud Computing Ø Convergence is important to the digital revolution because it created sophisticated mobile devices whose owners demand access to the same services available from full-size computers on their desks Ø Social media are cloud-based applications designed for social interaction and consumer-generated content Chapter 1: Computers and Digital Basics 20
1 Cloud Computing Chapter 1: Computers and Digital Basics 21
1 Digital Society Ø Digital technologies and communications networks make it easy to cross cultural and geographic boundaries Ø Anonymous Internet sites, such as Freenet, and anonymizer tools that cloak a person’s identity, even make it possible to exercise freedom of speech in situations where reprisals might repress it Ø Citizens of free societies have an expectation of privacy Ø Intellectual property refers to the ownership of certain types of information, ideas, or representations Chapter 1: Computers and Digital Basics 22
1 Digital Society Ø Expectation of privacy Ø Confidentiality? Ø Your personal information ØWhat did you buy? Or watch? ØWho did you call? ØWhere are you? Chapter 1: Computers and Digital Basics 23
1 Digital Society Ø Digital technology is an important factor in global and national economies, in addition to affecting the economic status of individuals Ø Globalization can be defined as the worldwide economic interdependence of countries that occurs as cross-border commerce increases and as money flows more freely among countries Ø Some individuals are affected by the digital divide Ø the gap between people who have access to technology and those who do not Ø Digital technology permeates the very core of modern life Chapter 1: Computers and Digital Basics 24
1 Section B: Digital Devices Ø Computer Basics Ø Computer Types and Uses Ø Microcontrollers Chapter 1: Computers and Digital Basics 25
1 Computer Basics Ø A computer is a multipurpose device that accepts input, processes data, stores data, and produces output, all according to a series of stored instructions Chapter 1: Computers and Digital Basics 26
1 Computer Basics Ø Computer input is whatever is typed, submitted, or transmitted to a computer system Ø Output is the result produced by a computer Ø Data refers to the symbols that represent facts, objects, and ideas Ø Computers manipulate data in many ways, and this manipulation is called processing Ø Central Processing Unit (CPU) Ø Microprocessor Chapter 1: Computers and Digital Basics 27
1 Computer Basics Ø Memory (RAM) temporarily holds data waiting to be processed, stored, or output Ø Storage is the area where data can be left on a permanent basis when it is not immediately needed for processing Ø A file is a named collection of data that exists on a storage medium Ø The series of instructions that tells a computer how to carry out processing tasks is referred to as a computer program Ø Software Chapter 1: Computers and Digital Basics 28
1 Computer Basics Computer (1646~1940): a person who performs calculations Computer: a multipurpose device that: Ø Ø accepts input, processes data, stores data, and produces output. Ø A stored program: a series of instructions for a computing task can be loaded into a computer’s memory Ø Allows you to switch tasks Ø Distinguishes a computer from other simpler and less versatile digital devices Chapter 1: Computers and Digital Basics 29
1 Computer Basics Ø Application software is a set of computer programs that helps a person carry out a task Ø Software applications are sometimes referred to as apps, especially in the context of handheld devices Ø System software helps the computer system monitor itself in order to function efficiently Ø Operating system (OS) Ø E. g. Windows, Mac OS X, Android Chapter 1: Computers and Digital Basics 30
1 Computer Types and Uses Ø Personal computer Ø microprocessor-based computing device Ø designed for individual use Chapter 1: Computers and Digital Basics 31
1 Computer Types and Uses Ø Handheld digital devices Ø i. Phones, i. Pads, i. Pods, Garmin GPSs, Droids, and Kindles Ø incorporate many computer characteristics Ø Two broad categories: those that allow users to install software applications (apps) and those that do not Chapter 1: Computers and Digital Basics 32
1 Computer Types and Uses Ø Videogame console Ø Nintendo’s Wii, Sony’s Play. Station, or Microsoft’s Xbox Ø Generally not referred to as personal computer because of their history as dedicated game devices Chapter 1: Computers and Digital Basics 33
1 Computer Types and Uses Ø The term workstation has two meanings: Ø An ordinary personal computer that is connected to a network Ø A powerful desktop computer used for high-performance tasks Chapter 1: Computers and Digital Basics 34
1 Computer Types and Uses Ø A server serves computers on a network (such as the Internet or a home network) by supplying them with data Ø Client/server model – clients request data Ø A mainframe computer - a large, expensive computer capable of simultaneously processing data for hundreds or thousands of users Ø A supercomputer - at the time of construction, its one of the fastest computers in the world Ø A compute-intensive problem requires massive amounts of data to be processed using complex mathematical calculations; e. g. Large Hadron Collider Ø over 300 trillion proton collisions analyze Ø 25 petabytes per year = 25 000 000 000 Bytes Chapter 1: Computers and Digital Basics 35
1 Computer Types and Uses Chapter 1: Computers and Digital Basics 36
1 Microcontrollers Ø A microcontroller is a special-purpose microprocessor that is built into the machine it controls Ø Microcontrollers can be embedded in all sorts of everyday devices Chapter 1: Computers and Digital Basics 37
1 Embedded Systems Copyright 38 © 2013 Pearson Education,
1 Ø Ø Section C: Digital Data Representation Basics Representing Numbers, Text, Images, and Sound Quantifying Bits and Bytes Circuits and Chips Chapter 1: Computers and Digital Basics 39
1 Data Representation Basics Ø Data representation: the form data is stored in, processed, and transmitted. Ø Digital data is text, numbers, graphics, sound, and video that has been converted into discrete digits such as 0 s and 1 s Ø Analog data is represented using an infinite scale of values Chapter 1: Computers and Digital Basics 40
1 Representing Numbers, Text, Images, and Sound Ø Language of computers is Binary – base 2 number system Ø Only 0’s and 1’s. Chapter 1: Computers and Digital Basics 41
1 Representing Numbers, Text, Images, and Sound Ø Standards for representing characters: ASCII, Unicode Ø Represent a character by a binary sequence Ø ‘A’ is 100 0001 Ø ‘a’ is 110 0001 Ø ‘Pile of Poo’ is 11110000 10011111 10010010 10101001 Chapter 1: Computers and Digital Basics 42
1 Representing Numbers, Text, Images, and Sound Ø Standards for representing characters: ASCII, Unicode Ø Represent a character by a binary sequence Ø ‘A’ is 100 0001 Ø ‘a’ is 110 0001 Ø ‘Pile of Poo’ is 11110000 10011111 10010010 10101001 Chapter 1: Computers and Digital Basics 43
1 Representing Numbers, Text, Images, and Sound Ø Standards for representing characters: ASCII, Unicode Ø Represent a character by a binary sequence Ø ‘A’ is 100 0001 Ø ‘a’ is 110 0001 Ø ‘Pile of Poo’ is 11110000 10011111 10010010 10101001 Chapter 1: Computers and Digital Basics 44
1 Analog to Digital Ø Sample analog signal - approximate it Ø CD sample rate: 44, 000 times per second 45
1 Speech is very complex 46
1 Digitize Images - approximate Chapter 1: Computers and Digital Basics 47
1 Quantifying Bits and Bytes Chapter 1: Computers and Digital Basics 48
1 Circuits and Chips Ø An integrated circuit (IC) is a super-thin slice of semiconducting material packed with microscopic circuit elements Chapter 1: Computers and Digital Basics 49
1 Circuits and Chips Ø The electronic components are mounted on a circuit board called a system board, motherboard, or main board Chapter 1: Computers and Digital Basics 50
1 Section D: Digital Processing Ø Programs and Instruction Sets Ø Processor Logic Chapter 1: Computers and Digital Basics 51
1 Programs and Instruction Sets Ø Computers and dedicated handheld devices all work with digital data under the control of a computer program Ø Computer programmers create programs that control digital devices. These programs are usually written in a high-level programming language; e. g. C/C++, Java, Python Ø The human-readable version of a program created in a highlevel language by a programmer is called source code Chapter 1: Computers and Digital Basics 52
1 Programs and Instruction Sets Chapter 1: Computers and Digital Basics 53
1 Programs and Instruction Sets Ø A microprocessor has a language that it understands. Ø called an Instruction Set Ø Includes math operators: + - / *; comparisons: < > = Ø Ø Each instruction is a sequence of 0 s and 1 s Instruction in binary is called a machine code Machine code has 2 parts: An op code (operation code) which specifies the instruction such as add, compare, or jump Ø An operand the data for the operation Chapter 1: Computers and Digital Basics 54
1 Programs and Instruction Sets Chapter 1: Computers and Digital Basics 55
1 Processor Logic Microprocessor or Central Processing Unit (CPU) has 2 parts • ALU (arithmetic logic unit) Ø part of the CPU that performs arithmetic operations Ø uses registers to hold data that is being processed Ø Control Unit Ø fetches each instruction of your program Ø instruction cycle refers to the process in which a computer executes a single instruction Chapter 1: Computers and Digital Basics 56
1 Processor Logic Chapter 1: Computers and Digital Basics 57
1 Processor Logic Chapter 1: Computers and Digital Basics 58
1 Section E: Password Security Ø Authentication Protocols Ø Password Hacks Ø Secure Passwords Chapter 1: Computers and Digital Basics 59
1 Authentication Protocols Ø Authentication protocol: any method that confirms a person’s identity using something the person knows, something the person possesses, or something the person is Ø A person can be identified by biometrics: fingerprint, facial features (photo), or retinal pattern Ø A user ID is a series of letters/numbers/special symbols that becomes a person’s unique identifier Ø A password is a series of characters that verifies a user ID and guarantees that you are the person you claim to be Chapter 1: Computers and Digital Basics 60
1 Authentication Protocols Chapter 1: Computers and Digital Basics 61
1 Password Hacks When someone gains unauthorized access to your personal data and uses it illegally, it is called identity theft. Ø Hackers employ a whole range of ways to steal passwords Ø A dictionary attack: guess your password by stepping through a dictionary containing thousands of the most commonly used passwords Ø The brute force attack uses password-cracking software, tries every combination of letters/numbers/symbols Chapter 1: Computers and Digital Basics 62
1 Nasty Tools - Cain and Able
1 Password Hacks Ø If hackers can’t guess a password, they can use another technique called sniffing, which intercepts information sent out over computer networks Ø An even more sophisticated approach to password theft is phishing Ø A keylogger is software that secretly records a user’s keystrokes and sends the information to a hacker Chapter 1: Computers and Digital Basics 64
1 Secure Passwords Chapter 1: Computers and Digital Basics 65
1 Passwords – From OLD Textbook Ø Strong passwords are difficult to guess ØAt least 14 characters, including numbers, symbols, and upper- and lowercase letters ØNot a single word or a word from a dictionary ØNot easily associated with you (birth date, name of pet, nickname) ØUse different passwords for different Web sites ØNever tell anyone or write down password ØChange password regularly (every month) 66
1 Secure Passwords Ø Strive to select a unique user ID that you can use for more than one site Ø Maintain two or three tiers of passwords Chapter 1: Computers and Digital Basics 67
1 Secure Passwords Ø A password manager (sometimes called a keychain) stores user IDs with their corresponding passwords and automatically fills in login forms Chapter 1: Computers and Digital Basics 68
Chapter 1 Complete Computer Concepts 2014
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