Computers Are Your Future Chapter 5 Input / Output and Storage

Computers Are Your Future Chapter 5 What You Will Learn About The purpose of special keys and the most frequently used pointing devices Input devices used to get audio and digital data into the computer The characteristics of a monitor’s quality and the various types of monitors The two major types of printers The difference between memory and storage

Computers Are Your Future Chapter 5 What You Will Learn About The categories of storage devices The performance characteristics of hard drives How data is stored on both hard and floppy disks The various optical storage media available for personal computers

Computers Are Your Future Chapter 5 Input Input is any data entered into the computer’s memory. Types of input include:  Data – Unorganized information (words, numbers, images, or sounds) that the computer converts to meaningful information  Software – Programs transferred from storage devices to the computer’s memory  Commands – Instructions that tell the computer what to do  Responses – Prompts requiring user feedback

Computers Are Your Future Chapter 5 Input Devices: Giving Commands Keyboard Mouse Other Pointing Devices

Computers Are Your Future Chapter 5 Keyboard The keyboard allows the computer user to enter words, numbers, punctuation, symbols, and special function commands into the computer’s memory.

Computers Are Your Future Chapter 5 Enhanced / Extended Keyboard Ergonomic Keyboard Types of Keyboards Enhanced or Extended keyboard – Typically 101 keys laid out in the QWERTY fashion; connected to the computer by a cable Cordless keyboard – Uses infrared or radio wave signals Ergonomic keyboard – Designed to help prevent cumulative trauma disorder (CTD) or damage to nerve tissues in the wrist and hand due to repeated motion

Computers Are Your Future Chapter 5 The Mouse The mouse is the most widely used pointing device. A mouse is palm sized. As the mouse is moved, its movements are mirrored by the on- screen pointer.

Computers Are Your Future Chapter 5 Wheel Mouse Cordless Mouse Types of Mice Wheel mouse – Contains a rotating wheel used to scroll vertically within a text document; connects to PS/2 port or USB port Cordless mouse – Uses infrared signals to connect to the computer’s IrDA port; it must be within sight of the receiving port

Computers Are Your Future Chapter 5 Using the Mouse Mouse buttons enable the user to initiate actions.  Clicking (left-, right-, or double-clicking) allows the user to select an item on the screen or open a program or dialog box  Click and drag – Holding down the left mouse button and moving the mouse enables the user to move objects on the screen

Computers Are Your Future Chapter 5 Joystick Touch Pad Touch Screen Trackball Pointing Stick Pen Other Types of Pointing Devices

Computers Are Your Future Chapter 5 Audio Input Computers can accept input from a microphone. An expansion card called a sound card records and plays back sound files. Sound files contain digitized sound data. Popular sound file formats include:  Windows WAV  Moving Pictures Expert Group (MPEG)  MP2 and MP3  Musical Instrument Digital Interface (MIDI)

Computers Are Your Future Chapter 5 Audio Input: Speech Recognition Speech recognition is a type of input in which the computer recognizes words spoken into a microphone. Special software and a microphone are required. Latest technology uses continuous speech recognition where the user does not have to pause between words.

Computers Are Your Future Chapter 5 Digital Cameras Digital Video Digital Input: Digital Cameras and Digital Video

Computers Are Your Future Chapter 5 Scanners Flatbed Fax Machines Alternative Input Devices Barcode reader

Computers Are Your Future Chapter 5 Digital Cameras The image’s light falls on a charge-coupled device (CCD) which transforms the light’s patterns into pixels (individual dots). Images are stored in the camera using flash memory. The most popular types are CompactFlash and SmartMedia. Photo-editing programs enable the user to edit the images.

Computers Are Your Future Chapter 5 Digital Video A video capture board transforms analog video into digital video. Digital video cameras use digital technologies to record video images. A Web cam is a low resolution video camera. Web cam Digital video camera

Computers Are Your Future Chapter 5 Output Devices: Engaging our Senses Output devices are peripheral devices that enable us to view or hear the computer’s processed data.  Visual output – Text, graphics, and video  Audio output – Sounds, music, and synthesized speech

Computers Are Your Future Chapter 5 Monitors A monitor is a peripheral device which displays computer output on a screen. Screen output is referred to as soft copy. Types of monitors:  Cathode-ray tube (CRT) Cathode-ray tube (CRT)  Liquid Crystal Display (LCD or flat-panel) Liquid Crystal Display (LCD or flat-panel) CRT LCD

Computers Are Your Future Chapter 5 Cathode-ray tube (CRT) Resemble televisions Use picture tube technology Less expensive than a LCD monitor Take up more desk space and use more energy than LCD monitors

Computers Are Your Future Chapter 5 Liquid Crystal Display (LCD) Cells sandwiched between two transparent layers form images Used for notebook computers, PDAs, cellular phones, and personal computers More expensive than a CRT monitor Take up less desk space and use less energy than CRT monitors Types of LCD monitors:  Passive-matrix LCD  Active-matrix LCD  Gas plasma display  Field emission display

Computers Are Your Future Chapter 5 Monitor Specifications Screen size – The diagonal measurement of the screen surface in inches (15, 17, 19, 21) Resolution – The sharpness of the image determined by the number of horizontal and vertical dots (pixels) that the screen can display (800 x 600, 1024 x 768, 1600 x 1200) Refresh rate – The speed at which the screen is redrawn (refreshed) and measured in Hertz (Hz) (60Hz, 75Hz)

Computers Are Your Future Chapter 5 Printers A printer is a peripheral device that produces a physical copy or hard copy of the computer’s output.

Computers Are Your Future Chapter 5 Inkjet Laser Types of Printers Inkjet printer, also called a bubble-jet, makes characters by inserting dots of ink onto paper Letter-quality printouts Cost of printer is inexpensive but ink is costly Laser printer works like a copier Quality determined by dots per inch (dpi) produced Color printers available Expensive initial costs but cheaper to operate per page

Computers Are Your Future Chapter 5 Plotter A plotter is a printer that uses a pen that moves over a large revolving sheet of paper. It is used in engineering, drafting, map making, and seismology.

Computers Are Your Future Chapter 5 WMAMIDIMP3WAV Beethoven 1:15 min Rocky 2:56 min Hornsby 48 sec Cheers 15 sec Click an icon to play music. Click the icon again to stop playing. Try clicking on Cheers while playing music. Audio Output: Sound Cards and Speakers Audio output is the ability of the computer to output sound. Two components are needed:  Sound card – Plays contents of digitized recordings  Speakers – Attach to sound card

Computers Are Your Future Chapter 5 Hard Drive – storage RAM – memory Memory vs. Storage Storage, also known as mass media or auxiliary storage, refers to the various media on which a computer system can store data. Storage devices hold programs and data in units called files. Memory is a temporary workplace where the computer transfers the contents of a file while it is being used.

Computers Are Your Future Chapter 5 Why Is Storage Necessary? Storage devices:  Retain data when the computer is turned off  Are cheaper than memory  Play an important role during startup  Are needed for output

Computers Are Your Future Chapter 5 Storage Devices Storage devices are categorized by:  The type of operations they perform  The method they use to access the information  The technology they use  Their location in the storage hierarchy  Their capacity and speed

Computers Are Your Future Chapter 5 Sequential vs. Random Access Storage Sequential – Storage devices that read and write data in a serial (one after the other) fashion Random-Access – Storage devices that read and write data without going through a sequence of locations Tape Drive – sequential storage Hard Disk – random-access storage Floppy Disk Drive – random-access storage

Computers Are Your Future Chapter 5 Storage Technologies: Magnetic and Optical Magnetic – Storage devices use disks or tapes that are coated with magnetically sensitive material Magnetic Optical – Storage devices that use laser beams to read patterns etched into plastic disks Optical Magnetic Storage Optical Storage – CD/DVD drive

Computers Are Your Future Chapter 5 Track Sector Cluster Magnetic Disk Storage A disk is formatted; it is divided into tracks and sectors, and a file allocation table (FAT) is created.  Track – circular band  Sector – pie shaped section  Cluster – two or more adjacent sectors  FAT – keeps track of specific locations of files

Computers Are Your Future Chapter 5 Optical Disk Storage Microscopic indentations called pits scatter the laser beam’s light. A light-sensing device receives no light from the pits. A signal is sent to the computer corresponding to a 0 in the binary system. Flat, reflective areas, called lands, bounce the light back to the light sensing device, which sends a signal corresponding to a 1. Cross-section of a disk Disk surface magnified

Computers Are Your Future Chapter 5 The Storage Hierarchy The three levels of storage hierarchy are:  Online storage – Also called primary storage, it is made up of the storage devices that are actively available to the computer system. User action is not required.  Near-online storage – Also called secondary storage, it is not readily available to the computer system. The user performs an action, such as inserting a disk, to make it available.  Offline storage – Also called tertiary storage or archival storage, it is not readily available to the computer system. Devices such as tape backup units store data for archival purposes.

Computers Are Your Future Chapter 5 Floppy DiskHard DriveCD ROM / DVD Capacity – 720 KB to 1.44 MB Access Time – 100ms Capacity – Up to 6 TB Access Time – 6 to 12ms Capacity – CD-ROM 700 MB; DVD 8.5 GB Access Time – 80 to 800ms Storage Capacity and Speed A storage device’s performance is measured by:  Capacity – The number of bytes of data that a device can hold  Access Time – The amount of time, in milliseconds (ms), it takes the device to begin reading data

Computers Are Your Future Chapter 5

Platter Read/Write head Hard Disks Hard disks are high-speed, high-capacity storage devices. They contain metal disks called platters. They contain two or more stacked platters with read/write heads for each side. Hard disks can be divided into partitions to enable computers to work with more than one operating system.

Computers Are Your Future Chapter 5 Factors Affecting a Hard Disk’s Performance Seek time or positioning performance – How quickly the read/write head positions itself and begins transferring information. It is measured in milliseconds (ms). Spindle speed or transfer performance – How quickly the drive transfers data. It is measured in rotations per minute (RPM).

Computers Are Your Future Chapter 5 Floppy and Zip Disks and Drives A disk or diskette is a portable storage medium. High-density floppy disks that are commonly used today store 1.44 MB of data. Disks work with a disk drive. Zip disks store up to 750 MB of data and are not downwardly compatible with floppy disks. Zip Drive Floppy Drive Floppy Disk

Computers Are Your Future Chapter 5 CD-ROM Discs and Drives CD-ROM stands for Compact Disc- Read Only Memory. CD-ROM drives can not write data to discs. They are capable of storing 700 MB of data. They are used for storing operating systems, large application programs, and multimedia programs.

Computers Are Your Future Chapter 5 CD-R and CD-RW Discs and Recorders CD-R Discs can be read and written to Discs can only be written to “once” CD-R drives are capable of reading data CD-RW Discs can be read and written to Discs are erasable Discs can be written to many times CD-RW drives are capable of reading, writing, and erasing data

Computers Are Your Future Chapter 5 DVD-ROM Discs and Drives DVD stands for Digital Video Disc. DVD technology is similar to CD- ROM technology. DVDs are capable of storing up to 8.5GB of data. The data transfer rate of DVD drives is comparable to that of hard disk drives. DVD-R and DVD-RW drives have the ability to read/write data.

Computers Are Your Future Chapter 5 Solid State Storage Devices Solid state storage devices use nonvolatile memory chips to retain data. They do not have moving parts. They are small, lightweight, reliable, and portable.

Computers Are Your Future Chapter 5 Compact Flash Memory Flash Memory Smart Card Micro Drive Memory Stick PC Card Solid State Storage Devices

Computers Are Your Future Chapter 5 Summary Input is the software, data, and information that is entered into the computer’s memory. Input devices such as the keyboard, mouse, and trackball enable the user to enter data. A pointing device enables the user to control movements of an on-screen pointer. Speech recognition software enables the user to enter data into a computer by speaking into a microphone. Video and images can be entered into a computer by way of digital cameras, scanners, and fax modems. Monitors enable the user to view the computer’s processed data. The output is known as soft copy.

Computers Are Your Future Chapter 5 Summary (continued) The two types of monitors are the CRT and the LCD. A monitor’s quality is measured by screen size, resolution, and refresh rate. Printers produce permanent versions (hard copies) of the computer’s output. The two basic types of printers are the inkjet and laser. Memory makes software and data available for the CPU’s use. Storage devices are categorized by: Data access (sequential or random-access) Technology (magnetic, optical, or solid state) Hierarchy (online, near-online, or offline) Operations (read-only or read/write)

Computers Are Your Future Chapter 5 Summary (continued) A hard disk’s performance is measured by its positioning performance and transfer rate. Optical storage devices include: CD-ROM– Read-only CD-R– Record once CD-RW– Erasable, write repeatedly DVD-ROM– Read-only DVD-R– Read/write Solid state storage devices include: PC cards Flash memory cards Smart cards