Chapter 2: A Closer Look at Hardware and Software

Transcription

1 Understanding Computers in a Changing Society, 3 rd Edition Chapter 2: A Closer Look at Hardware and Software

2 Learning Objectives Understand how data is represented to a computer. Identify several types of input devices and explain their functions. Explain the functions of the primary hardware components found inside the system unit, namely the motherboard, the CPU, and the memory. List several output devices and explain their functions. Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 2

3 Learning Objectives Understand the difference between storage and memory, as well as between a storage device and a storage medium. Name several types of storage systems and explain the circumstances under which they are typically used. Describe the purpose of communications hardware. Understand basic software concepts and commands. Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 3

4 Overview A computer system consists of: Hardware Software This chapter covers: What data is and how it is represented to a computer A closer look at the hardware of a computer system Various types of products used for input, processing, output, storage and communications Brief look at some basic software concepts and operations Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 4

5 Digital Data Representation Most digital computers are binary computers Understand only two states, off and on Off and on are represented by the numbers 0 and 1 Digital data representation: Representing data in digital form so that it can be processed and stored by a binary computer The computer translates input and output between digital data representation and a form that can be understood by the user Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 5

6 Digital Data Representation Bits and bytes The separate 1s and 0s are called bits (derived from the term binary digits ) Bit: Smallest unit of data a binary computer can recognize Bits are generally grouped together to form larger pieces of data Byte: Eight bits Prefixes are used to represent larger amounts of data (KB, MB, etc.) Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 6

7 Digital Data Representation Numbering system: Way of representing numbers Decimal numbering system use ten symbols (0-9) to represent all possible numbers Binary numbering system uses only two symbols (0 and 1) to represent all possible numbers Base number = 2, so rightmost column is the 1s column; next column is the 2s column, next column is the 4s column, etc. 101 in binary = 5 (1x x x 2 0 or or 5) Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 7

8 Digital Data Representation Coding system: Used to represent text-based data ASCII (American Standard Code for Information Interchange) 8 digits allow for 256 characters Unicode: Universal standard used to represent text-based data written in any ancient or modern language Replacing ASCII Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 8

9 Input Hardware Input device: Any piece of hardware used to perform data input Keyboard: Used to type data into a computer Can be wired or wireless Can be peripheral device or attached to a device Nearly always used with desktop and notebook PCs Increasingly built into mobile phones and mobile devices (slide-out keyboards, thumb pads, etc.) Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 9

10 Typical Desktop Keyboard Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 10

11 Input Hardware Pointing device: Used to select objects, issue commands, etc. by pointing to and selecting objects Mouse: Nearly always used with desktop PCs; can be used with notebook PCs Can be wired or wireless Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 11

12 Input Hardware Electric pen and stylus: Used to select items and/or write electronically on the screen Can be used with PCs and a variety of other devices Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 12

13 Input Hardware Other pointing devices Touch screens Joysticks and other gaming devices Control buttons and wheels Touch pads Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 13

14 Scanners and readers: Used to capture data from a source document and input it into the computer Optical scanners Handheld scanners Barcode readers RFID readers Biometric readers and digital cameras Input Hardware Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 14

15 Input Hardware Digital cameras: Record images on digital storage media such as flash memory cards, hard drives, DVD discs, etc. Digital still cameras Digital video cameras Digital camcorders PC video cameras» Used for Web cams, videoconferencing, video phone calls, etc. Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 15

16 Other input devices Input Hardware Microphones and headsets: Used to input voice Commands, dictation, podcasts, etc. MIDI keyboards: Used to input original music Adaptive input devices: Designed for users with physical disabilities Ergonomic input devices: Designed to lessen the physical effects of using a computer Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 16

17 Processing Hardware and Other Hardware Inside the System Unit System unit: Main case of the computer Usually a separate device for desktop PCs Usually combined with the screen to form a single piece of hardware for notebook and portable PCs System unit contains the processing hardware for a computer, plus interfaces, storage devices, power supply and cooling fan Motherboard: The main circuit board inside the system unit All devices used with a computer need to be connected in one way or another to the motherboard (directly, via port, etc.) Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 17

18 Inside the System Unit Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 18

19 Ports: Connectors exposed through the exterior of the system unit case Either built into the motherboard or created via expansion card Used to connect external devices to the PC (monitors, keyboards, mice, printers, etc.) ExpressCard slots used with notebook PCs The Motherboard Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 19

20 Central Processing Unit (CPU) Central processing unit (CPU) : Does the vast majority of processing for the computer Consists of a variety of circuitry and components that are packaged together and connected directly to the motherboard Also called microprocessor or processor CPU has two principle parts: Arithmetic/logic unit: Performs arithmetic involving integers and logical operations Control unit: Coordinates and controls the actions taking place within the CPU Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 20

21 Central Processing Unit (CPU) Most PCs today use CPUs manufactured by Intel or Advanced Micro Devices (AMD) and are multicore Dual-core CPU: Contains the processing components (cores) of two independent processors on a single CPU Quad-core CPU: Contains four cores Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 21

22 Central Processing Unit (CPU) Measurements of CPU processing speed CPU clock speed (measured in megahertz (MHz) or gigahertz (GHz)) Higher clock speed means more instructions can be processed per second than the same CPU with a lower clock speed Other factors can affect the overall processing speed of a computer Number of cores Amount of memory Speed of external storage devices Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 22

23 Memory Memory: Chip-based storage Typically refers to chip-based storage used by the computer usually the amount of the computer s main memory (random access memory or RAM) RAM: Temporary (volatile) storage used by the computer Used to store essential parts of the operating system while computer is running Stores the programs and data currently being used by the computer Content is lost when computer is shut down Data is also deleted from RAM when it is no longer needed Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 23

24 Memory Consists of circuits etched onto chips arranged onto circuit boards called memory modules Capacity is measured in bytes PCs must have enough RAM to run the necessary applications, as well as work efficiently More RAM allows more programs to run at one time Most PCs today come with at least 512 MB of RAM Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 24

25 Memory Four other types of computer memory Cache memory: Used to speed up the processing speed by storing the data that may be needed next by the CPU in handy locations Usually built into the CPU Level indicates the order the cache memory is accessed (L1 = fastest and check first, etc.) Registers: Used by the CPU to temporarily store data and intermediary results during processing Fastest type of memory Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 25

26 Memory ROM: Nonvolatile chips that permanently store data or programs accessed by the computer Attached to the motherboard like RAM Data and programs are retrieved by the computer when needed Cannot be written over and data is not erased when the computer is shut down Flash memory: Nonvolatile chips into which data can be stored and retrieved Flash memory chips have begun to replace ROM for storing system information, as it can be updated as needed Also used in flash memory storage systems Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 26

27 Output Hardware Output hardware: Devices used to produce the results of processing, typically on the computer screen, on paper, or as audio output Display device: Most common type of output device Displays output on some type of screen With a PC, this screen is called a monitor If the screen is built into the unit, the term display screen is often used Used with many consumer products as well Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 27

28 Display Devices CRT monitor: Traditional monitor for desktop PCs Uses cathode-ray tube technology Very large and bulky Becoming less common today Flat-panel displays: Form images by manipulating electronically charged chemicals or gasses sandwiched between panes of glass or other transparent surfaces Take up less space and consume less power than CRT monitors Becoming the norm for desktop PCs Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 28

29 Display Devices Pixel: A small area or dot that makes up an image Number of pixels used on a display screen determines the screen resolution With high resolution, more information can fit on the screen, but everything will be displayed smaller than with a lower resolution Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 29

30 Printers Printers: Produce hard copy permanent copy of the output on paper Personal printers are designed to be connected to a single computer Network printers are designed to be shared by multiple users via a network Impact printers: Strike paper to transfer ink to paper Non-impact printers: Form images without touching the paper Most common type of printer today Much quieter than impact printers Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 30

31 Printers Can be color or black-and-white Printer quality is measured in dots per inch (dpi) Printer speed is measured in pages per minute (ppm) Most common types: Laser printers and ink-jet printers Laser printers Standard for business documents Come in personal and network versions Can be color or black-and-white Faster and of better quality than ink-jet printers Use technology similar to photocopy machines (toner powder, lasers, heat, etc.) Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 31

32 Laser Printers Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 32

33 Printers Ink-jet printers Spray tiny drops of ink onto the page, one printed line at a time Some print using different-sized ink droplets, multiple nozzles, and varying electrical charges for precision Fairly inexpensive, although replacement ink cartridges can add up Good quality and usually can print in color Printer of choice for home use With special paper, ink-jet printers can print photos Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 33

34 Ink-Jet Printers Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 34

35 Other Output Devices Special-purpose printers Photo printers: Designed to print photographs Barcode printers: Print barcodes Portable printers: Designed to be carried with you to print while on the go Plotters and wide-format ink-jet printers: Print large documents, such as blueprints and signs 3D printers: form a 3D replica of an object, typically using plastic powder Other types of output devices: Speakers: Used for audio output Headphones, headsets, earbuds: Used for personal audio output Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 35

36 Storage Hardware Storage systems: Used to save documents for future use Non-volatile Consist of a storage device and a storage system Storage medium: The hardware where the data is actually stored CD, flash memory card, etc. Storage device: The device that reads data from or writes data to the storage medium CD drive, flash memory card reader, etc. In some systems, such as a hard drive, the parts are sealed together to form one piece of hardware called fixed-media storage Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 36

37 Storage Hardware Storage systems can be: Internal storage: Located inside the system unit External storage: Plugged into an external port on the system unit Remote storage: Located on another computer, such as a network server Letters and/or names are assigned to each storage device so that it can be found easily when needed Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 37

38 Storage Hardware Data is usually stored: Magnetically: 1s and 0s are represented using different magnetic alignments Optically (CDs, DVDs): Data is stored using laser beams On some optical media, the laser burns permanent marks into the surface of the medium With rewritable optical media, the laser changes the reflectivity of the medium but does not permanently alter the disc surface, allowing for reuse Some systems combine optical and magnetic technology, and some use different technology altogether Flash memory represents data using electrons Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 38

39 Magnetic Disk Systems Magnetic disk systems: One of the primary systems used with today s computers Data is written using read/write heads that magnetize particles on the surface of the medium to represent 1s and 0s Include floppy disks and hard disks Floppy disk: Written to and read by floppy disk drives Fairly slow Small capacity compared to other more modern storage media Considered a legacy drive, though can often be added as an option Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 39

40 Floppy Disks and Drives Floppy disks are organized into: Tracks: Circular rings Sectors: Pie-shaped groups Cluster: One or more sectors (the smallest storage area on a disk) Tracks, sectors, and clusters are numbered by the computer so files can be located after they are stored on the disk Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 40

41 Floppy Disks and Drives To access data, the drive spins the disk and uses read/write heads to access data stored on the tracks on the disk Floppy disks are: 3.5 inches in diameter Store 1.44 MB of data (about 500 pages of double-spaced text or 1 or 2 digital photos Inserted into floppy drive to be used Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 41

42 Hard Disk Drives (HDDs) Virtually all PCs come with a hard disk drive (hard drive) Used to store programs and data Store data magnetically like floppy disks Disks are organized into tracks, sectors, clusters like floppy disks Disks are made of metal and permanently sealed, along with read/write heads and an access mechanism, inside the hard drive to Avoid contamination Allow disks to spin faster Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 42

43 Hard Disk Drives (HDDs) Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 43

44 Hard Disk Drives (HDDs) Internal hard drives: Permanently located inside the system unit Not designed to be removed, except for replacement or service External hard drives: Used to transport large amounts of data from one PC to another (by moving the entire drive) or for additional storage space or for backup Typically connect via USB port Portable hard drives: Designed to be easily transported from one PC to another Typically connect to PC via USB port Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 44

45 Optical Disc Systems Optical discs: Data is stored and read optically, using laser beams DVDs, CDs, Blu-ray Discs (BDs) Discs are divided into tracks and sectors, but use a single grooved spiral track beginning at the center of the disc Lasers create and read marks created on the disc surface (pits and lands) With read-only discs, the pits are permanent With recordable or rewritable discs, the pits are represented by changing the disc s reflectivity A transition between a pit and a land = 1; no transition for a certain period of time = 0 Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 45

46 Optical Disc Systems Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 46

47 Optical Disc Systems Conventional CDs: Use infrared lasers Conventional DVDs: Use red lasers High definition discs: Use blue-violet lasers More information can be stored (HD movies, etc.) Data is recorded more compactly Discs come in various sizes Capacity depends on format, as well as the number of sides and layers, used Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 47

48 Optical Disc Systems Optical discs are read by optical drives (CD drive, DVD drive, etc.) Hybrid drive: Drive that can read all or most types of optical discs, such as CDs, DVDs, and BDs Read-only discs (CD-ROM, DVD-ROM, BD-ROM) Come prerecorded with commercial products Data cannot be erased, changed, or added to Discs must be read by the correct drive, though DVD drives can typically read CD discs Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 48

49 Optical Disc Systems Recordable discs (CD-R, DVD-R, DVD+R, BD-R) Can be written to, but the discs cannot be erased and reused Commonly used for: Backing up files Sending large files to others Creating custom music CDs (CD-R) Storing home movies, digital photos, multimedia files, etc. (DVD-R/+R) Storing high-definition multimedia files (BD-R) Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 49

50 Optical Disc Systems Rewritable discs (CD-RW, DVD-RW, DVD+RW, BD- RE) Can be written to, erased, and overwritten like magnetic disks The correct drive must be used to write each type of disk Have not reached a single standard Be sure to purchase the optical media that is compatible with your drive Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 50

51 Flash Memory Systems Flash memory storage systems: Store data as electrical charges on flash memory media Have no moving parts Are not as subject to mechanical failure as optical and magnetic media Are more resistant to shock and vibration Consume less power Very small and quiet Rewritable Longer expected life that magnetic media More expensive per MB, but very convenient and widely used with PCs, digital cameras, etc. Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 51

52 Flash Memory Systems Flash memory is most often found in the form of: Embedded flash memory chips Flash memory cards USB flash drives Solid-state drives and hybrid hard drives Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 52

53 Flash Memory Cards Flash memory card: Small card containing one or more flash memory chips, a controller chip, other electrical components, and metal contacts to connect the card to the device or reader Read by flash memory card readers Commonly used with: Desktop PCs Handheld PCs Digital cameras Portable digital media players Mobile phones and other mobile devices Come in a variety of formats (SD cards, CompactFlash cards, MemoryStick, etc.) Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 53

54 USB Flash Drives USB flash drive: Flash memory media in selfcontained unit that uses a USB interface Also called USB flash memory drives, thumb drives, and jump drives Are powered via the USB port Very portable Can be carried in a pocket or on a keychain Wide range of colors, sizes, appearances Capacity ranges from 512 MB to 16 GB Widely used to transfer files from one location to another Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 54

55 Solid State Drives (SSDs) and Hybrid Hard Drives (HHDs) Solid state drive (SSD): Hard drive that uses flash memory instead of spinning platters and magnetic technology Appropriate for portable computers Smaller and faster than conventional hard drives Use less power Less susceptible to physical damage Hybrid hard drive (HHD): A magnetic hard drive that contains flash memory in addition to magnetic disks Increases performance while reducing the amount of energy required and the amount of heat generated Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 55

56 Solid State Drives (SSDs) and Hybrid Hard Drives (HHDs) Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 56

57 Other Types of Storage Systems Remote storage systems: Use a storage device that is not connected directly to the user s PC Accessed through a local network or the Internet Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 57

58 Other Types of Storage Systems Smart cards: Credit card-sized piece of plastic that contains computer circuitry and components Hold small amounts of data (64 KB or less) Read by smart card reader Often used for payment or identification purposes Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 58

59 Evaluating Your Storage Alternatives Characteristics to consider: Speed Compatibility Storage capacity Convenience Portability Price Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 59

60 Communications Hardware Communications hardware: Enables the user to communicate with others over a network or the Internet The type of communications device used depends on: The device being used (desktop PC, notebook, mobile phone, etc.) The communication standard being used (such as Ethernet for wired networks, Wi-Fi for wireless networks, Bluetooth for short-range wireless connections, or a cellular standard for mobile phones) Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 60

61 Communications Hardware Network adapter (network interface card (NIC)): Used to connect a PC to a network The type of adapter used depends on the type of network and communications medium being used Modem: Used to connect a computer to another computer or to a network (typically the Internet) over phone lines Each type of modem matches a particular type of Internet connection (conventional dial-up, cable, fixed wireless, DSL, etc.) Both network adapters and modems are available in internal and external versions and in a variety of formats (USB, ExpressCard, etc.) Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 61

62 Communications Hardware Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 62

63 Communications Hardware Other networking hardware: Hub, switch, or router: Central device used to connect devices in a network together Wireless access point or wireless router: Central device for wireless networks Repeaters, range extenders, antennas: Used to increase the range of a network Cabling: Connects wired devices Twisted-pair, coaxial cable, fiber-optic cable Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 63

64 Software Basics Software ownership rights: Specify the allowable use of a program Software license specifies: Who can use the program Whether it can be shared How many computers it may be installed on Basic categories of software: Commercial: Developed and sold for profit Shareware: Distributed on the honor system Freeware: Given away free of charge Public domain: Not copyrighted Open source software: Programs whose source code is available to the general public Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 64

65 Software Basics Software can be: Installed software: Installed on and run from the end user s PC Web-based software: Accessed by the end user over the Internet Software as a Service (SaaS) Allows your programs and documents to be accessed from any PC with an Internet connection May be slower than applications stored on the hard drive Documents cannot be accessed if the server is down, or when you do not have Internet access Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 65

66 Common Software Commands Application programs have many concepts, commands in common Most commands are issued through: Menus: Text-based lists that provide access to commands that can be selected Keyboard shortcuts: Commands issued from the keyboard that correspond to command buttons Usually combinations using the Ctrl or Alt keys, the function keys, and/or alphanumeric keys Buttons located on a toolbar or Ribbon (Microsoft Office 2007) Ribbon consists of tabs, which contain groups of related commands for the program being used Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 66

67 Common Software Commands Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 67

68 Common Software Commands Editing a document: Changing the content of a document, such as adding or deleting text Insertion point marks the current location Typing text adds it at that location Delete and Backspace key are used to delete text at that location Formatting a document: Changing the appearance of a document Changing the font face, size, color, style Changing line spacing Changing the page margins Adding page numbering Adding borders or shading Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 68

69 Working with Files and Folders File: Anything stored on a storage medium (program, letter, digital photo, song, etc.) When the item is stored, the user gives the file a filename Folders: Used to store related files to keep files organized File management programs: Allow you to perform file management tasks easily and efficiently (copying files, deleting files, etc. Windows Explorer Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 69

70 Summary Digital Data Representation Input Hardware Processing Hardware and Other Hardware Inside the System Unit Output Hardware Storage Hardware Communications Hardware Software Basics Chapter 2 Understanding Computers in a Changing Society, 3 rd Edition 70