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Chapter 4. Hardware for Educators. The System Unit. System unit Boxlike case that houses the electronic components of the computer that are used to process data. Data Representation. Analog vs. Digital Digital Two states (1) on (0) off. Data Representation. Binary number system
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Chapter 4 Hardware for Educators
The System Unit • System unit • Boxlike case that houses the electronic components of the computer that are used to process data
Data Representation • Analog vs. Digital • Digital • Two states • (1) on • (0) off
Data Representation • Binary number system • Combination of ones and zeroes represent characters
Data Representation • ASCII • American Standard Code for Information Interchange • Converting a keyboard stroke into a byte
The Components of the System Unit • The Motherboard • Contains many of the electronic components • Chip • A small piece of semiconducting material on which one or more integrated circuits are etched
The Components of the System Unit • CPU and Microprocessor • Interprets and carries out the basic instructions that operate a computer • Microprocessor contains the CPU in a PC
The Components of the System Unit • The Control Unit • A component of the CPU that directs and coordinates most of the operations in the computer • Fetch - get the next instruction from memory • Decode - translate the instruction • Execute - carry out the command • Store the result - write the result to memory • Machine cycle
The Components of the System Unit • The Arithmetic/Logic Unit • Performs the execution part of the machine cycle • Arithmetic (addition, subtraction, multiplication, division) • Comparison (greater than, equal to, less than) • Logical (AND, OR, NOT)
The Components of the System Unit • The System Clock • Synchronizes all computer operations • Each tick is called a clock cycle • Faster clock means more instructions the CPU can execute each second • Speed measured in megahertz (MHz) and gigahertz (GHz)
The Components of the System Unit • Memory • Used to store data, instructions, and information • The operating system and other system software • Application programs • Data being processed by application programs • Bytes are stored at specific locations or addresses
Seats in a stadium are similar to addresses in memory: • A seat in memory holds one person at a time, and an address in memory holds a single byte • Both a seat and an address can be empty • A seat has a unique identifying number and so does an address
The Components of the System Unit • Memory • Size of memory is measured by the number of bytes available • Volatile memory – contents are lost when the computer is powered down • Nonvolatile memory – contents are not lost when the computer is powered down
The Components of the System Unit • Random Access Memory (RAM) • The memory chips in the system unit • When the computer starts, operating system files are loaded from a hard disk into RAM • Synchronous Dynamic RAM (SDRAM) • Dual Inline Memory Module (DIMM)
The Components of the System Unit • Random Access Memory (RAM) • RAM Chips • Smaller in size than processor chips • Packaged on circuit boards called single inline memory modules(SIMMs) or dual inline memory modules (DIMMs)
The Components of the System Unit • Random Access Memory (RAM) • Configuring RAM • The more RAM, the more programs and files a computer can work on at once • Software usually tells you how much RAM is required • Necessary RAM depends on what type of work the computer is used for
The Components of the System Unit • Read-Only Memory (ROM) • Cannot be modified • Contents not lost when the computer is turned off • Flash Memory • Type of nonvolatile memory that can be erased electronically and rewritten on
The Components of the System Unit • Expansion Slots and Expansion Cards • Expansion slot • An opening, or socket, where a circuit board can be inserted into the motherboard • Add new devices or capabilities to the computer • Expansion card • Circuit boards, such as a modem or graphics card, that add new capabilities to the computer
The Components of the System Unit • Expansion Slots and Expansion Cards • Three common types • Video card • Sound card • Internal modem • Plug and Play
The Components of the System Unit • PC Card • Thin credit card-sized device that adds capabilities to small computers • Flash Memory Card • Removable memory device that allows users to transfer data and information from a mobile device to a desktop computer
What is Input? • Any data or instructions you enter into the memory of a computer • Data - unorganized facts • Programs - series of instructions that tells the computer how to perform a task • Commands - an instruction given to a computer program • User responses - responses to questions or messages from the software
What are Input Devices? • Any hardware component that allows you to enter data, programs, commands, and user responses into a computer
What are Input Devices? • The Keyboard • Typing area • Numeric keypad • Toggle keys • Status lights • Arrow keys - arrow control keys • Function keys • Specialized buttons
What are Input Devices? • Pointing Devices • An input device that allows you to control a pointer on the screen • Block arrow • I-beam • Pointing hand
What are Input Devices? • Pointing Devices • Mouse • One or two button mouse • Moving the mouse pointer • Clicking • Dragging • Double-clicking • Optical mouse • Cordless mouse
What are Input Devices? • Touchpad and Pointing Stick • Touchpad – small, flat, rectangular pointing device that is sensitive to pressure and motion • Pointing Stick – pressure-sensitive pointing device shaped like a pencil eraser
What are Input Devices? • Pointing Devices • Trackball • Like a mouse, but the ball is on top • Often used on portable computers
What are Input Devices? • Pointing Devices • Joystick • Uses the movement of a vertical lever • Often used with games • Wheel • Steering-wheel type input device • Used to simulate driving a car
What are Input Devices? • Pointing Devices • Touch screen • Monitor has a touch sensitive panel • Used to issue simple commands or choose from a list of options • Kiosks
What are Input Devices? • Optical Scanners • Captures an entire page of text or images such as photographs or artwork electronically • Converts the text or image on the original document into digital data that can be stored on a disk and processed by the computer
What are Input Devices? • Pen Input • Users write, draw, and tap on a flat surface to enter input • Stylus – small metal or plastic device that looks like a tiny ink pen but uses pressure instead of ink • Digital pen – slightly larger than a stylus
What are Input Devices? • Digital Cameras • Allows you to take pictures and store the photographed images digitally • Download, or transfer, pictures to your computer
What are Input Devices? • Audio and Video Input • Audio input • Entering music, speech, or sound effects • Sound card • Speech Recognition • Computer’s capability of distinguishing spoken words
What are Input Devices? • Audio and Video Input • Video input • Entering a full-motion recording into a computer and storing the video on a hard disk or some other medium • Video capture card
What are Input Devices? • Input Devices for PDAs, Smart Phones, and Tablet PCs • Stylus • Voice Input • Portable keyboard • Scanner • On-screen keyboard • Digital camera
What is Output? • Text • Graphics • Audio • Video
What are Output Devices? • Any computer component capable of conveying information to the user • Commonly used output devices • Monitors • Printers • Data Projectors • Facsimile machines • Multifunction devices • Speakers • Headsets
What are Output Devices? • Monitors and Display Devices • Screen housed in a plastic or metal case • Variety of sizes • Cathode ray tube (CRT) • Pixels • LCD (liquid crystal display) monitors
What are Output Devices? • Large Display Monitors • Allow an audience or a group of students in a classroom to easily view images and multimedia displayed on a computer • Available from 27 to 36 inches
What are Output Devices? • Large Display Monitors • High-definition television (HDTV) • Gas plasma monitor
What are Output Devices? • Flat Panel Monitors and Displays • Uses liquid crystal instead of a CRT • Consume less than 1/3 the power of a CRT • Thinner and lighter than a CRT
What are Output Devices? • Monitor Quality • Resolution (sharpness and clarity) • Expressed as number of columns and rows • 800 x 600 • 1800 x 1440 • Dot pitch • Refresh rate • ENERGY STAR
What are Output Devices? • Printers • An output device that produces text and graphics on a physical medium such as paper or transparency film • Hard copy (printout) • Portrait vs. landscape • Printing requirements vary
What are Output Devices? • Nonimpact Printers • Do not strike paper • Much quieter • Ink-jet printers • Spray tiny drops of ink onto the paper • Both black-and-white and color
What are Output Devices? • Nonimpact Printers • Laser printers • High-speed, high-quality nonimpact printer • Very high quality resolution