Chapter 1 Computers and Digital Basics 1 B

Chapter 1 Computers and Digital Basics

1 B SECTION Digital Devices ïComputer Basics ïPersonal Computers, Servers, Mainframes, and Supercomputers ïPDAs, Portable Players, and Smart Phones ïMicrocontrollers Chapter 1: Computers and Digital Basics 2

1 Computer Basics ï 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 3

1 Computer Basics ï Computer input is whatever is typed, submitted, or transmitted to a computer system ï Output is the result produced by a computer ï Data refers to the symbols that represent facts, objects, and ideas ï Computers manipulate data in many ways, and this manipulation is called processing – Central Processing Unit (CPU) – Microprocessor Chapter 1: Computers and Digital Basics 4

1 Computer Basics ï Memory is an area of a computer that temporarily holds data waiting to be processed, stored, or output ï Storage is the area where data can be left on a permanent basis when it is not immediately needed for processing ï A file is a named collection of data that exists on a storage medium ï The series of instructions that tells a computer how to carry out processing tasks is referred to as a computer program – Software Chapter 1: Computers and Digital Basics 5

1 Computer Basics ïA stored program means that a series of instructions for a computing task can be loaded into a computer’s memory – Allows you to switch between tasks – Distinguishes a computer from other simpler devices Chapter 1: Computers and Digital Basics 6

1 Computer Basics ïApplication software is a set of computer programs that helps a person carry out a task ïThe primary purpose of system software is to help the computer system monitor itself in order to function efficiently – Operating system (OS) Chapter 1: Computers and Digital Basics 7

1 Personal Computers, Servers, Mainframes, and Supercomputers ïA personal computer is a microprocessorbased computing device designed to meet the computing needs of an individual Chapter 1: Computers and Digital Basics 8

1 Personal Computers, Servers, Mainframes, and Supercomputers ïThe term workstation has two meanings: – An ordinary personal computer that is connected to a network – A powerful desktop computer used for highperformance tasks Chapter 1: Computers and Digital Basics 9

1 Personal Computers, Servers, Mainframes, and Supercomputers ïA videogame console, such as Nintendo’s Wii, Sony’s Play. Station, or Microsoft’s Xbox, are not generally referred to as personal computers because of their history as dedicated game devices Chapter 1: Computers and Digital Basics 10

1 Personal Computers, Servers, Mainframes, and Supercomputers ï The purpose of a server is to serve computers on a network (such as the Internet or a home network) by supplying them with data ï A mainframe computer (or simply a mainframe) is a large and expensive computer capable of simultaneously processing data for hundreds or thousands of users ï A computer falls into the supercomputer category if it is, at the time of construction, one of the fastest computers in the world Chapter 1: Computers and Digital Basics 11

1 Personal Computers, Servers, Mainframes, and Supercomputers Chapter 1: Computers and Digital Basics 12

1 PDAs, Portable Players, and Smart Phones ï A PDA (personal digital assistant) is a pocket-sized digital appointment book with a small qwerty keyboard or a touchsensitive screen, designed to run on batteries and be used while holding it ï A handheld computer is essentially a PDA enhanced with features such as removable storage, e-mail, Web access, voice communications, built-in camera, and GPS ï A smart phone, which in addition to voice communication, includes features such as full qwerty keypad, text messaging, e -mail, Web access, removable storage, camera, FM radio, digital music player, and software options for games, financial management, personal organizer, GPS, and maps ï i. Pods and similar devices are classified as portable media players because their main strength is playing music, showing videos, and storing photos Chapter 1: Computers and Digital Basics 13

1 PDAs, Portable Players, and Smart Phones Chapter 1: Computers and Digital Basics 14

1 Microcontrollers ïA microcontroller is a special-purpose microprocessor that is built into the machine it controls ïMicrocontrollers can be embedded in all sorts of everyday devices Chapter 1: Computers and Digital Basics 15

1 C SECTION Digital Data Representation ïData Representation Basics ïRepresenting Numbers, Text, and Pictures ïQuantifying Bits and Bytes ïCircuits and Chips Chapter 1: Computers and Digital Basics 16

1 Data Representation ïData representation refers to the form in which data is stored, processed, and transmitted ïDigital devices work with distinct and separate data ïAnalog devices work with continuous data Chapter 1: Computers and Digital Basics 17

1 Representing Numbers, Text, and Pictures ïNumeric data – Binary number system ïCharacter data – ASCII, Extended ASCII, EBCDIC, and Unicode ïDigitizing is the process of converting analog data into digital format Chapter 1: Computers and Digital Basics 18

1 Data Representation Chapter 1: Computers and Digital Basics 19

1 Quantifying Bits and Bytes Chapter 1: Computers and Digital Basics 20

1 Circuits and Chips ïAn integrated circuit (computer chip) is a super-thin slice of semiconducting material packed with microscopic circuit elements Chapter 1: Computers and Digital Basics 21

1 Circuits and Chips ï The electronic components of most digital devices are mounted on a circuit board called a system board Chapter 1: Computers and Digital Basics 22

1 D SECTION Digital Processing ïPrograms and Instruction Sets ïProcessor Logic Chapter 1: Computers and Digital Basics 23

1 Programs and Instruction Sets ï Computers, portable media players, handheld computers, and smart phones all work with digital data ï Computer programmers create programs that control digital devices. These programs are usually written in a high-level programming language ï The human-readable version of a program, like the one above, created in a high-level language by a programmer is called source code Chapter 1: Computers and Digital Basics 24

1 Programs and Instruction Sets Chapter 1: Computers and Digital Basics 25

1 Programs and Instruction Sets ïAn instruction set is a collection of preprogrammed activities a microprocessor is hardwired to perform ïEach instruction has a corresponding sequence of 0 s and 1 s ïThe end product is called machine code – 1 s and 0 s Chapter 1: Computers and Digital Basics 26

1 Programs and Instruction Sets ïAn op code (short for operation code) is a command word for an operation such as add, compare, or jump ïThe operand for an instruction specifies the data (or the address of the data) for the operation ïIn the following instruction, the op code means add and the operand is 1, so the instruction means Add 1 Chapter 1: Computers and Digital Basics 27

1 Programs and Instruction Sets Chapter 1: Computers and Digital Basics 28

1 Processor Logic ï The ALU (arithmetic logic unit) is the part of the microprocessor that performs arithmetic operations ï The ALU uses registers to hold data that is being processed ï The microprocessor’s control unit fetches each instruction, just as you get each ingredient out of a cupboard or the refrigerator ï The term instruction cycle refers to the process in which a computer executes a single instruction Chapter 1: Computers and Digital Basics 29

1 Processor Logic Chapter 1: Computers and Digital Basics 30

1 Processor Logic Chapter 1: Computers and Digital Basics 31

1 E SECTION Password Security ïAuthentication Protocols ïPassword Hacks ïPassword Security Chapter 1: Computers and Digital Basics 32

1 Authentication Protocols ï Security experts use the term authentication protocol to refer to any method that confirms a person’s identity using something the person knows, something the person possesses, or something the person is – A person can also be identified by biometrics, such as a fingerprint, facial features (photo), or retinal pattern – A user ID is a series of characters—letters and possibly numbers or special symbols—that becomes a person’s unique identifier – 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 33

1 Authentication Protocols Chapter 1: Computers and Digital Basics 34

1 Password Hacks ï When someone gains unauthorized access to your personal data and uses it illegally, it is called identity theft ï Hackers can employ a whole range of ways to steal passwords ï A dictionary attack helps hackers guess your password by stepping through a dictionary containing thousands of the most commonly used passwords ï The brute force attack also uses password-cracking software, but its range is much more extensive than the dictionary attack Chapter 1: Computers and Digital Basics 35

1 Password Hacks ïIf hackers can’t guess a password, they can use another technique called sniffing, which intercepts information sent out over computer networks ïAn even more sophisticated approach to password theft is phishing ïA keylogger is software that secretly records a user’s keystrokes and sends the information to a hacker Chapter 1: Computers and Digital Basics 36

1 Password Security Chapter 1: Computers and Digital Basics 37

1 Password Security ïStrive to select a unique user ID that you can use for more than one site ïMaintain two or three tiers of passwords Chapter 1: Computers and Digital Basics 38

1 Password Security ïA password manager is utility software that generates secure passwords and stores them along with user IDs and their corresponding sites Chapter 1: Computers and Digital Basics 39

Chapter 1 Complete Computers and Digital Basics