The process of reconstituting files is called extracting or unzipping. As with compression, most laptops and desktop computers include extraction and unzipping soft ware; tablets and smarlphones may require a third-party app. Compressed files usually have. Compressed files may also end with. These files have to be extracted or unzipped before you can view the data they contain. The process is easy. To extract a file on a Mac, simply double-click the zipped folder.
Digital audio is stored in a variety of file formats. What are the default file format and sampling rate? There are several options for obtaining audio content,such as music, soundtracks, narrations, and sound effects.
TRY iTl Live recording is an option for obtaining digitai sound fiies from concerts or lectures. For casual recording. Voice Memos and similar apps work well. Professional recordings require more sophisticated software and hardware tools. A device called an audio interface accepts input from a standalone microphone and feeds it into a computer.
Ripping CD tracks is handy for someone who inherits a stack of old CDs and wants to convert the music into a format that plays on a smartphone or other mobile device. Ripping is a siang term that refers to the process of importing tracks from a CD or DVD to your computer's hard disk. The tech nical term for ripping music tracks is digital audio extraction. A down load copies a file from a private network or Internet server to a local device. The file is transferred as an unit and cannot be played until the entire file on your smartphone, but there is a pause before it begins.
This pause is associated with has arrived. Streaming offers yet another way of obtaining audio content. Unlike some digitai content, such as photos, that must be accessed as a whole piece, audio content plays back over a period of time.
Audio files can be acquired as a live stream or on-demand stream In addition to downloads Figure a. You can play back the file even server to your local device, where 4'V On-demand stream it is played, but not stored. An on-demand stream sends the This method is also known as media to your local device, where it is stored temporarily, or "buffered," Webcasting.
You have to be online while listen The file can be played with any ing. The content stream cannot be You can fast-forward to any point in the stream without waiting for the paused, stored, or rewound. To play a digital audio file, you must use some type of audio software. Whether you can use general-purpose audio software, a speciai-purpose player, or a browser plugin depends on the source and type of audio.
Audio piayers. Audio piayers might be inciuded with your computer's operating system, pack b. Audio piugins. An audio plugin is software that works in conjunction with your computer's browser to manage and play audio that you are illegally from the Internet c. Each audio plugin tends to work with only one audio format, so multiple piugins are necessary when you have audio files in several formats. Audio software. General-purpose audio software and apps provide toois for recording, playing, and modifying audio files.
X4I iM Work with more than one track for stereo and mixing fUl w« What's the difference between speech synthesis and speech recognition? Speech synthesis is the process by which machines pro duce sound that resembles spoken words. Speech recognition or voice recognition refers to the ability of a machine to understand spoken words. A basic sound unit, such as "reh' or "gay," is called a phoneme.
Most speech synthesizers string together phonemes to form words. For example, the phonemes "reh" and "gay" produce the word "reggae. Text-to-speech software analyzes the words in a section of text, finds corresponding phonemes, and combines them into sentences for output. Speech synthesis b. Speech recognition c. Entering a Google Voice command d. Voice dialing I How does speech recognition work? On a personal computer or smartphone, a speech recognition system collects words spoken into a microphone that's connected to sound processing circuitry.
This circuitry's analog-to-digital converter transforms the analog sound of your voice into digital data.
This data is then processed by speech recognition software. Speech recognition software analyzes the sounds of your voice and con verts each word into groups of phonemes. Next, the software compares the groups of phonemes to the words in a digital dictionary that lists pho neme combinations along with their corresponding English or French, Spanish, and so on words.
When a match is found, the software can dis play the word on the screen or use it to carry out a command. Most digital devices offer a way to use spoken commands Figure Open the Windows Speech Recognition application. After following the setup instructions, the Listening Mode con trol appears.
Saying "stop listen apps, navigate menus, and dictate text for email messages Ing" turns it off. Try it out. Vou can speak commands to launch and documents.
What makes modem technologies like Siri so much more versatile and lifelike? Figure provides an overview. Instead they recorded the words and sentences from a script. Although the script may appear nonsensical, the sen tences are rich in phonemes. When the recordings are complete, a team of linguists analyzes and tags various speech components and loads them into a database. The process Is called concatenative speech synthesis. Where is ttie nearest Starbucks?
Search algorithms look for an answer to the query, then 1. Apple's voice recognition server. Audio formats such as fvlPS, Ogg Vorbis, and 5. The audio components for Siri and similar ser AAC have good sound quality even though vices are obtained by recording real voices they use and then applying 1 compression.
The process of ripping tracks from an audio CD to a digital format such as MP3 is called digital audio synthesis. Photos Terminology plaster Pinterest boards like so many posters on a Paris kiosk. Facebook feeds offer a continu ous stream of vacation pics. Colorful icons dot the screens of every digital device. Infographlcs use images to convey information, and Web sites would be much less interesting if not for the col orful graphics they display.
Section C explains the technology that powers this polnt-and-shoot world to help you harness the power of digital graphics. I Describe how cameras and scanners produce I Explain how pixel color is represented in I Explain how 3D images are created. I Calculate the size of a bitmap file given its resolution. I Explain what a color histogram represents and how to use one. I Provide examples of image stitching. I Describe two types of stereoscopic imaging.
These graphics can produce still Images, such as photographs and diagrams, or motion graphics, Terminology The term 3D is used today to refer to a variety of commercial products that should be called stereoscopic.
For example, those so-called "30" glasses such as videos and animations. Computer graphics can produce two-dimensional flat images and stereo scopic images with visual depth that makes close-up objects appear near with blue and red lenses are enough to grasp. Despite their similarities, bitmap and vector images are quite different.
Bitmap graphics may be the most common, but they are less flexible than vector graphics and cannot be used to model three-dimensional objects. To find out why, let's take a look at the characteristics of bitmaps. As you continue in this module, pay attention to the difference between 3D and stereoscopic.
I What is a bitmap graphic? A bitmap graphic, also called a ras ter graphic or simply a bitmap, is composed of a grid of tiny rectangular cells.
Each cell is a picture element, commonly called a pixel. Each pixel is assigned a color, which is stored as a binary number. Figure illustrates these basic characteristics of a bitmap graphic. Bitmap graph ics are used to create realistic images, such as photographs. When you use a digital camera or camera-enabled ceil phone, your pho tos are stored as bitmaps. A scanner also produces bitmaps.
The photos you send or receive as email attachments are bitmaps, as are most Web page graphics. You can create a bitmap graphic from scratch using the tools provided by graphics software—specifically a category of graphics software referred to as paint software.
Other alternatives, such as AutoDesk Pixir, are available online and as downloads for smartphones and laptops. When you have a printed image, such as a photograph, a page from a magazine, or a picture from a book, you can use a scanner to convert the printed image into a bitmap graphic. Check the features of the photo app on your smartphone. Which of the following does it provide?
Retouch Crop Special effects Exposure adjustment A scanner essentially divides an image into a fine grid of cells and assigns a digital value for the color of each cell. As the scan progresses, these values are transferred to your digital device and stored as a bitmap graphics file. Scanners, such as the one pictured in Figure , are inexpensive and easy to use. Place the image face down on the scanner glass, then use the scanner software to initiate the scan.
The scanned image is saved in memory and can then be saved on your computer's hard disk or in another storage location. This technology is used in stand as bits. In a digital alone digital cameras and smartphone cameras.
A CCD contains a grid of liny light-sensitive diodes called photosites. The number of photosites depends on the size of the CCD. A one-half-inch square CCD can contain more than , photosites. Each photosite detects the brightness and color for its tiny piece of the image Figure A CCD's photosites correspond to pixels. The more pixels used to capture an image, the higher its resolution, and the better the resulting picture. Cameras with larger CCDs produce higher quality images.
Some cam eras contain multiple CCDs, which enhance the color quality of a camera's output. TTfi fviiNausv. Seiecting the best graphics file format to use depends on what you intend to do with the image.
Figure summarizes popuiar bitmap formats and their uses. The BMP format supports True Color and can be used for a wide variety of graphics applications, such as photographs, illustrations, and graphs.
BMP files are often too large for email attach ments. BMP graphics are not supported by most browsers, so they are not used on the Web. RAW Image formats contain the unprocessed pixel data Graphical elements, such as buttons and other controls for graphical user inter faces generated directly by a digital camera's sensor.
Up to Photographic images before they are stored 12 bits of data can be storedfor eachof the red, blue, in other formats and green values for a pixel, so RAW files are very large. Scanners and digital cameras commonly store bitmaps in TIFF format because ft supports True Color and can be easily converted Into other graphics file formats. The JPEG format Is popular for Web graphics, smartphone photos, and for photos Desktop publishing and any projects that require highresolution graphics; not supported by browsers General use, such as desktop publishing or Web pages, where flexibility In file size Is Important attached to email messages.
The compression process eliminates some image data, however, so highly compressed fries suffer some quality deterioration. GIF Graphics Interchange Format , pronounced "gif" or "jiff," was specifically designed to create Images that can be Web graphics and simple animations displayed on multiple platforms, such as PCs and Macs. GIF graphics are limited to colors, but the format supports simple animations.
PNG was developed as a public domain format without any restrictions on its use. Color and resolution are key elements in bitmap data representation. Today's color display devices represent color using the RGB color model. The color displayed for a pixel Is based on the Intensity of red, green, and blue signals received by the screen's color elements.
Each red. A pixel appears while if the red, green, and blue signals are set to maximum intensity. If red, green, and blue signals are equal but at a lower intensity, the pixel displays a shade of gray. A pixel appears violet if it receives high red and blue signals andjust a bit of green Figure It is a subtractive system, whereas RGB is an additive system. CMYK is typically used for projects that require color printing.
Color numbers are shown in decimal, hexadecimal, and binary. I How are colors specified? Color values can be specified in decimal base 10 , hexadecimal base 16 , or binary base 2. Even artists need to know their way around number systems! Whichever notation is used, however, color data is ultimately repre sented as binary digits when it is stored and transmitted. Figure , the decimal value for green is What are the In decimal, a pixel color is specified with values such as Red , Green equivalent hexadecimal and binary values for green?
In hexadecimal, each pair of digits refers to a color value. For example, the hexadecimal number for violet is EE82EE.
You can find lists of colors and their hexadecimal triplets on the Web. In binary, eight bits are used to represent the red value, another eight bits are used for the green value, and eight more bits are used for blue. With eight bits used to represent each color value, one pixel requires 24 bits. Because each R, G, and B can have values, the number of possible colors is The number of colors available in a graphic is referred to as color depth, images that use 24 bits for each pixel have a color depth of The resolution of a bitmap is usually expressed as the number of horizontal and vertical pixels it contains.
I How does resolution relate to image quality? High-resolution graphics contain more data than low-resolution graphics. With more data, it is possible to display and print high-quality images that are sharper and clearer than images produced using less data.
Bitmap graphics are resolution dependent because each element is a discrete pixel. Imagine that a bitmap image and its grid come on a surface that you can stretch or shrink.
As you stretch the surface, the grid maintains the same number of horizontal and vertical cells, but each cell becomes larger, the grid becomes more visible, and the image develops an undesirable jagged appearance referred to as pixelation. Simply stretching a bitmap to enlarge it doesn't produce highquality results Figure Graphics software offers options for changing the resolution of bitmap images.
Suppose you reduce the resolution from x to x The image grid becomes a quarter of its original size, but every fourth pixel was removed from the image, which typically reduces image quality. If you attempt to enlarge a bitmap by increasing its resolution, your com puter must somehow add pixels because no additional picture data exists. But what colors should these additional pixels become?
Most graphics soft ware uses a process called pixel interpolation to create new pixels by averaging the colors of nearby pixels. For some images, pixel interpolation produces an enlargement that appears very similar to the original.
Open an image with Photoshop or similar graphics software. I So how much resolution does a bitmap need to be printed Check its size and its ppi. At as a poster? Graphics software, such as Adobe Photoshop, can help you gauge how large an image can be printed before the quality begins to dete ppi, how large can the image be printed before its quality begins riorate.
The minimum resolution for printed output is 72 pixels per inch ppi. Suppose that a photo taken with a smartphone has a resolution of x At 72 ppi.
To print the same photo but with a better resolution of ppi, the poster would be Pixel Dimensions: To I Bicubic best for smc maintain quality, do not resample. An image with a resolution of x contains 5,, pixels. Each pixel requires 24 bits, so the RAW image file could be as large as ,, bits 12,, bytes or 12 megabytes. By any measure, that's a lot of data to store and move. Various image com pression techniques can be used to shrink bitmap files.
Image compression refers to any technique that recedes the data in an image file so that it contains fewer bits. RLE graphics format when it is saved. I Which formats apply lossless compression? Images stored in these for mats do not lose any quality when compressed.
Various techniques exist for lossless image compression. As a simple example, consider a type of lossless compression called run- length encoding. Run-length encoding RLE replaces a series of similarly colored pixels with a binary code that indicates the number of pixels and their colors.
Suppose that a section of a picture has consecutive white pixels, and each pixel is described by three bytes of data. RLE compresses this series of bytes into as few as four bytes, as shown in Figure The first byte is the binary representation of The next three bytes are the 5 26 code for white. JPEG files are com pressed using lossy compression, so some quality is lost when the file is saved.
When saving an image as a JPEG, you may be able to select a com pression level. Take care with lossy compression to ensure that your image is not further compressed every time you save it Figure Lossy compression techniques discard some data from an image to shrink its file size. JPEG is a lossy version of run-length encoding that can be applied to images, such as photographs, that don't have large areas of solid color.
A True Color photograph might not have any adjoining pixels of the same color. Applying RLE to such a photo would not result in any compression whatsoever. JPEG preprocesses an image by tweaking the colors in adjoin ing pixels so that they are the same color whenever possible. After this preprocessing is complete, run-length encoding can be applied with more success. For many images, lossy compression results in only a minor reduction in the sharpness of the image.
The reduction in quality can be unnoticeable in many circumstances. Figure illustrates a section of a noncompressed image and a section of that same image after JPEG compression has been Open a JPEij image, use the Save As command or Duplicate command to make a copy of the image with a name different from the original.
As you save the copy, apply as much compression as possible. Close both files and then reopen them. Is there a visible difference in quality? Can you see any difference? The same compression tools used to shrink text and numeric data can be used with bitmaps. Photoshop software and a host of iocal and online apps make it easy to modify digital images. I What characteristics of a bitmap can I modify?
It Is stored in a compressed format b. It cannot be modified until you unzip it color of pixels. In the early days of digital Imaging, primitive photoediting was limited to c. You can no longer edit changing the color of individual pixels, or roughly cropping out objects to individual pixels in the delete them or paste them elsewhere. Knowing how to use the available toolset can improve the images you pro duce.
Understanding the extent to which photos can be edited also builds awareness of the "tricks" that can be used to alter images in news stories and other information sources. Noise reduction. In an image,"noise" refers to artifacts such as spots, dust, and scratches that may be produced when old photos are scanned. Histograms can perform miracles!
Open a photo using Noise reduction tools can remove these noisy artifacts. A mediocre photo can benefit from image enhance ment techniques that correct brightness, improve color saturation, and sharpen the focus. Beyond one-click enhancement tools, image editors provide an image histogram that can be used to adjust the brightness val Apple Photos, or Photo Galiery. Locate the histogram control and experiment to see what you can reveal In the shadows.
Dark Mid-range Light By sliding the Levels bar, more pixels become mid-range and the details of the buildings begin to emerge. The mannequin at an online store displays a red dress, which is also available in other colors. How would it look In blue? The photographer did not have to take a photo of the dress In every color.
Photoediling software can outline the dress in the original photo and then apply the new color. Similar algorithms are used to colorize black-and-white photos. Correcting image distortion. The human eye compensates for per spective, but the camera does not. When a rectangular object in a photo appears distorted, reconstructing the straight edges is easy with photo edit ing software Figure Correcting image distortion straightens the sides.
Cloning employs algorithms that pull pixels from one area of an image and then apply them to another area. Cloning can be used to remove small blemishes as shown In Figure I r 1 inpainting. Reconstructing lost, unwanted, or deteriorated areas In a photo is called inpainting.
Using information from nearby pixels, and tak ing into account the overall structure of the image, Inpainting algorithms essentially scrub out designated areas and miraculously replace the miss ing pixels with a background or an object that fits with the rest of the image Figure The original photo Includes a man in the foreground.
Photoshop's Content-Aware Tiil algorithm creates a Removing the man leaves a blank area. Have you seen the photo of a great white shark attacking a U. Air Force helicopter? That image and many more bizarre photos are a product of digital compositing, which assembles several images into one.
Compositing is achieved using two tools: clipping paths and alpha blending. A clipping path essentially cuts an object out of an image and knocks out the background to make it transparent. This object can then be superim posed on a background. Alpha blending alters the pixel colors where the edges of the object and the background meet, so that the object appears to TRY IT! If you have access to Photoshop, open a few of your own photos and see what kind of crazy composite you can create.
They've gone beyond the box to become panoramic views, degree images, and immersive photo spheres. These image formats are made possible by a technology called image stitching. I What is image stitching? Image stitching or photo stitching cre ates a panoramic image by combining two or more separate photographs that have overlapping edges. The photos are captured from a fixed loca tion.
The stitching process is based on sophisticated algorithms that match pixels near the edges of each image to determine how they fit together. Stitching con nects the photos and produces various kinds of images called projections Figure that can be viewed on flat screens or with VR headsets. Cloning b. Inpainting c. Compression d.
These images can be produced Images are captured from the using the panoramic feature of a front, back, and sides, and then digital camera. Spherical projections include images from the degree verti cal view as well as the degree horizontal panorama. A series of photos can be manually stitched together using software such as Autopano and AutoStitch, but many digital cameras take care of stitching automatically.
Most smartphones include a camera app with a panoramic function for capturing a rectilinear projection. Panoramic functions are also available on most standalone digital cameras. For producing degree cylindrical projections with a smartphone, a third-party app might be required.
Apps, such as Google Street View and Photo Sphere, guide photographers through the rotational process to cap ture a degree view, which is then stitched together into a continuous image. Special cameras are also available for capturing and stitching photos for cylindrical and spherical projections. These cameras typically use a fisheye lens to capture a half-sphere think of an upside-down cereal bowl of images.
Two of these fish-eye lenses can be linked to capture a full sphere of images. Computer graphics technology can produce images with the illusion of depth that make some objects seem close enough to touch.
These images are sometimes referred to as 3D, but technically they are stereoscopic. Stereoscopic imaging or stereoscopy is a graphical technique used to produce an illusion of spatial depth from flat, two-dimensional images.
The technique dates back to the s and the use of simple stereoscopes Figure Two Simply looking at two similar pho Because human eyes are spaced cameras, or a camera with two apart, they project two slightly different images onto the reti nas.
Those images are processed by the brain, which constructs front-facing lenses, can produce two photos called a stereo pair that mimic the dual Images captured by human eyes.
Two images from viewed with only one eye. A ste reoscopic viewer, or stereoscope, an Image of the world that cor responds to a three-dimensional environment with spatial depth. Each Image must be provides this differentiation using lenses. Old-fashioned stereoscopic viewers placed images " separate overlapping views. Modern stereoscopic imaging uses digital images and viewers. Apps for capturing a stereo pair with a single lens camera are available, but somewhat tricky to use.
Anaglyphs and stereograms A stereoscopic viewer, such as Google Cardboard, displays images gener ated by mobile devices. A smartphone simply slides into the device where b. Compositing and overlays an app displays a digital stereogram Figure Blue and red d. An anaglyph Is a graphic composed of two images, one that is tinted red and the other that is tinted blue.
The two images are printed on top of each other to produce a stereoscopic effect Figure Viewing anaglyph Images requires red-green or red-blue glasses.
Usually, the red lens on the left filters out blue and green, while the blue- or green-colored lens on the right filters out red. As a result each eye sees a slightly different image. The two images are processed in the brain to give the impression of three dimensions. A digital camera captures images on the pho- tosiles of a n I bits for each pixel. Hint: Use the acronym. The most popular True Color formats for Web that reducing the resolution also reduces the graphics include 1 Image quality.
This section begins with two-dimensional vector graphics. You'll find out how they differ from bitmaps and vector vector graphic SVG rasterization why you might want to use them. After covering the basics for two-dimensional graphics,the sec tion progresses to static 3D graphics and concludes 3D graphics wireframe rendering ray tracing vector animation frame keyframe pre-rendermg CGI real time rendering game engine with a look at vector motion graphics for virtual reality videogames and instructional modules.
Objectives I Identify vector graphics used on Web sites and social media. I Based on the characteristics of vector graphics, determine when they are more suitable for a project than bitmaps. I Convert a vector drawing into a bitmap. I Explain the process of rendering a 3D wireframe into an image. I Identify the key difference between rendering 3D graphics for computer games and creating special effects for movies.
I Describe the type of graphics commonly used for virtual reality. This type of graphic evolved in sophistication as the shapes became Tilled, then shaded, and then textured Figure A vector graphic consists of a set of instructions for creating a picture.
Instead of storing the color value for each pixel, a vector graphics file contains instructions that a computer uses to create the shape, size, position, and color for each object in an image.
Vector drawing instructions are similar to those a drafting teacher might give students: "Draw a line of width 3 beginning at coordinates 20, 20 and a. Flash extend the line to coordinates 20, Basic The command in "computerese" using an XML script would be: c. XML scripts Vector graphics include standard shapes such as circles and rectangles, so they don't have to be built from scratch. What is a computer? Most people can formulate a mental picture of a computer, but computers do so many things and come in such a vari ety of shapes and sizes that it might seem difficult to distill their common characteristics into an all-purpose definition.
At its core, a computer is a multipurpose device that accepts input, processes data, stores data, and produces output, ail according to a series of stored instructions. Prior to , machines designed to perform calculations were usually referred to as calculators and Input is whatever is typed, submitted, or transmitted to a computer.
Output is the result produced by a computer. Input and output can be handled by components contained within the computer or by add-on, such as keyboards and printers, that are attached to the computer with cables or use of the term computer emerged in the s, when connected wireiessly.
Processing is handled by the computer's central processing unit CPU. The CPU of most modern computers is a microprocessor, which is an electronic component that can be programmed to process data. The modern definition and Computers store data and the software that processes data.
Most computers have temporary holding areas called memory in addition to long-term storage housed on hard disks or flash drives. Figure illus trates the IPOS input, process, output, store activities characteristic of computers. Input movies b. Process schedules c. The instruclions Lhat tell a digital device how to carry out processing tasks are referred to as a computer program, or simply a program.
These programs form the software that sets up a computer to do a specific task. When a computer "runs" software, it performs the instruc tions to carry out the task. Changing tasks meant rewiring the a. The term stored program means that a series of instructions for a computing task can be loaded into a computer's memory.
These instruc tions can be replaced easily by a different set of instructions when it is time b. This ability to switch programs c. It is the single most Important characteristic that dis tinguishes computers from other simpler and less versatile digital devices, such as digital clocks, Word processing Music software software I What kinds of software do comput ers run? Computers run three main types of software: application software, system soft ware, and development tools Figure A calculators, and cameras.
Application software is a set of computer programs that helps a per son carry out a task. Application software is sometimes referred to as an app. Whereas application software is designed to help a person carry out a task, the primary purpose of system software is to help the computer system monitor itself in order to function efficiently. An example of system soft ware is a computer operating system OS , which is essentially the master controller for all the activities that take place within a computer.
Development tools are used for cre ating software applications. Web sites, operating systems, and utilities. As digital electronics evolved, components became smaller and smaller.
Open up a digital device. You won't see clumps of wires and gears. Instead, you'll see small circuit boards and integrated circuits. Digital electronics represent data bits as electrical signals that travel over circuits in much the same way that electricity flows over a wire when you turn on a light switch. To represent data, such as , high-voltage signals are used for 1 bits, and lowvoltage signals are used for 0 bits.
All the calculations performed by digital devices take place in a maze of electronic circuitry Figure The electronics for digital devices require millions of similar circuits.
Today, this circuitry is condensed into integrated cir cuits. An integrated circuit IC Is a set of microscopic electronic components etched onto a thin slice of semi conducting material. The terms computer chip, microchip, and chip are commonly used to refer to integrated circuits.
Some integrated circuits are devoted to collecting input, while others might be devoted to processing tasks, output, or storage. The first computer chips contained fewer than miniaturized components, such as resistors and transistors. The chips for today's digital devices contain billions of transistors. To fabricate a chip, the conductive properties of selective parts of the semiconductor can be enhanced to essentially create min iature electronic pathways and components, such as transistors, as shown in Figure They are made from purified silicon sand.
They are basically insulators made from wood. Integrated circuits are packaged in protec tive carriers that vary In shape and size. Figure iiiuslrates some chip carriers, including small rectangular DIPs dual in-iine packages with caterpiiiar-iike legs protruding from a black, rectangular body, and pincushion-iike LGAs land-grid arrays.
DIPs have two rows of pins that connect the chip to a circuit board. An LGA is a square chip package, typicaily used for microprocessors, with The chips on a circuit board have identifying numbers that pins arranged in concentric squares.
The electronic components of most digital devices are mounted on a circuit board called a system board, motherboard, or main board. The system board houses all essential chips and provides connecting circuitry between them. Figure illustrates the main chips on the front and back sides of a laptop system board. Can you find out what it does? The devices we use today have a fairly predictable collection of features, depending on the device's form factor.
I What is a form factor? The term system unit is tech speak for the part of a digital device that holds the system board, it can apply to the body of a smartphone or laptop, as well as to the tower unit of a desktop computer. Digital devices are available in ail sorts of form factors; some of the most popular include component, ciamsheii, and slate. One on the system unit ponent device is composed of various standalone parts, such as a display unit, system unit, and keyboard.
Components can be connected using cables or wireless signals. Most of the first personal computers were component systems. Today, this form factor is much less popular because of the effort required to assemble the components.
Figure illustrates the hardware features of a typical component system. One for each standalone device c. Clamshell devices have a keyboard as the base and a screen on the hinged cover. One System unit b. Two c. Three d. Devices config ured in the slate form factor feature a touchscreen that covers most of the device's surface. The screen can display a virtual keyboard for text and numeric input.
An additional control, such as a Home button or a circular control pad, is featured on some slate devices. The system unit also includes controls for commonly used features, such as volume and airplane mode Figure Can you find all of the components listed in the figures? You can extend their life with a bit of regu lar maintenance. There are four components of digital devices that require maintenance: the system unit, keyboard, screen, and battery, i How do I start?
Before you undertake any maintenance, turn the device off—that's off, not just asleep—and disconnect any power cables. Doing so will prevent random screen swipes or key presses from altering your device settings. The products you can use depend on the component you are cleaning. What might work well to scrub out stubborn stains on the system unit case could permanently cloud or scratch your touchscreen.
Always follow the manufacturer's advice for cleaning procedures and products Figure Do not allow cleaning agents to drip on key boards or touchpads. Do not spray cleaning agents directly on the device; spray them onto a cleaning cloth.
Basic system unit maintenance is simple. You want to keep the unit clean, prevent it from overheating, shield it from damage, and protect it from electrical surges Figure Touchscreens collect fingerprints and are a breeding ground for bacte ria, so it is a good idea to clean them periodically.
Many touchscreens are made from Gorilla Glass, which Is designed to resist scratching and cracking. Wipe It with a soft clothb. Remove the screen protector. These films can be cleaned using water and a soft cloth, or a c. When the screen protector gets grubby, simply peel it d. Vacuum the fan vents. Turn the device off. Many touchscreens have an oteophobic coating designed to repel the oils deposited by fingertips. When alcohol is used to clean these screens, each application degrades the coating.
Non-alcohol wipes are available, or use eyeglass cleaner. Keyboards quickly build up grime, gather dust, and collect crumbs. To start the cleaning process, turn the keyboard upside down and shake it gently to dislodge debris. Most manu facturers suggest using an antibacterial wipe to clean key surfaces. Take a moment to test the cleaning product on a small unnoticeable spot just to make sure it will not discolor the keys or leave a residue.
Use cotton swabs to clean between the keys. I What is the best way to clean up spills? Liquids and elec tronics don't mix. If you spill liquid on a device, turn it off immediately. With luck, that step will prevent electrical shorts that would permanently damage circuit boards.
Once the device is off, you can assess the dam age. If the spill is water, dry off the device, shake out the moisture, and set it in a warm, dry place where there is good air circulation. A fan or hair dryer set on low can help drive out moisture. Allow the device to dry for at least 72 hours. Sticky spills are another matter. If the goo has penetrated the interior of the device, it is best to leave the cleanup to a professional. If you think the spill only affected the surface, you can wipe the device with clean water and allow it to dry for 24 hours Figure Shut off the device immediately.
Back up all your data before turning off the device. Rinse the device with clear water. You know how it goes.
It happens to everyone. The battery on your device dies just when you really need it. Battery life is the time your device operates before it must be recharged. Battery lifespan is the amount of time a bat tery lasts until it must be replaced. Good maintenance extends the life of your battery and Its lifetime, so your digital devices are ready when you need them. Most of today's battery-powered digital devices contain a lithium ion Li-ion battery.
Unlike batteries of the past, Li-ion batteries contain no toxic compounds and operate efficiently, but they are sensitive to heat. Most devices today contain circuitry to prevent heat-trig gered damage, but smart consumers don't operate devices that are hot to the touch. Batteries have a discharge rate at which they lose charge even when not in use. The discharge rate for Li-ion batteries is quite low—about 1.
Device manufacturers often advertise battery watts per hour Wh. A 60 Wh battery will last 60 hours if it expends 1 watt per hour. Some applications require more battery power than others. Locationbased apps that keep track of your whereabouts are constantly using extra power to check cell towers or Wi-Fi networks. Push applications, such as autoretrieving email, make your device continually check for new messages. To extend battery life, disable these kinds of apps when you are not using them.
Figure summarizes good practices for charging and using Li-ion batteries. Suppose your smartphone has a battery rated at 5. When Avoid totally discharging the battery. Remove the device from the charger when it's fully charged. How long can you travel before your phone runs out of juice? One hour If your device becomes hot while in use, turn it off. Four hours Disable unused apps that constantly connect to the Internet. Eight hours d. Ten hours Switch to airplane mode when in an area with no cell coverage.
A computer is a multipurpose device that accepts input, processes 4. I , stores data, and produces output, all according to the Three form factors for digital devices are component, 5. Touchscreens on many digital devices have a n instructions of a stored program.
An operating system is an example of software. A n circuit is a set of microscopic electronic components etched onto a thin slice of semiconducting material. Section B helps you sort out the devices that are on the market by function and price.
It addresses the tricky issue of Terminology supercomputer mainframe SCrver personal computer desktop computer compatibility and other factors important to con portabio computer laptop computer sumers. Chromebook tablet computer slate tabiut 2-in-1 smartphones PDA wearable computers microcontrollers compatible Objectives List three types of computers that are commonly used in businesses,serve multiple simultaneous users, and offer very fast processing speeds.
Draw a hierarchy chart showing the classifications of personal computers. List two applications that would tend to require a desktop computer. List the devices that typically support cellular voice and texting. List devices that can support cellular data plans. Specify three operating systems that are common in each of the following categories: desktops,laptops, tablets, and smartphones. Mainframes were housed in large, closet-sized metal frames. Microcomputers were clearly differentiated from computers in other categories because they were dedicated to a single user and their CPUs consisted of a single micro processor chip.
Today, microprocessors are no longer a distinction between computer categories because just about every computer uses one or more micropro cessors as its CPU. Today's most power ful computers include supercomputers, mainframes, and servers.
These devices are generally used in businesses and government agencies. They have the ability to service many simultaneous users and process data at very fast speeds Figure Supercomputer Supercomputers. A computer falls into the supercomputer category if it is, at the time of construction, one of the fastest computers in the world.
Because of their speed, supercomputers can tackle complex tasks that just would not be practical for other computers. Typical uses for supercomput ers include breaking codes, modeling worldwide weather systems, and simulating nuclear explosions. One petaflop is an astounding 1,,,,, quadrillion calculations per sec ond. That's about 20, times faster than your laptop computer. A mainframe computer or simply a mainframe is a large and expensive computer capable of simultaneously processing data for hundreds or thousands of users.
Its main processing circuitry is housed in a closet-sized cabinet like the one shown at left; but after large components are added for storage and output, a mainframe installation can fill a goodsized room.
Mainfreme Mainframes are generally used by businesses and government agencies to provide centralized storage, processing, and management for large amounts of data. For example, banks depend on mainframes as their com puter of choice to ensure reliability, data security, and centralized control. The purpose of a server is to "serve" data to computers con nected to a network. When you search Google or access a Web site, the information you obtain is provided by servers.
At ecommerce sites, the store's merchandise information is housed in database servers. Email, chat, Skype, and online multiplayer games are all operated by servers. Technically, just about any computer can be configured to perform the work of a server. However, computer manufacturers such as IBM and Dell offer devices classified as servers that are especially suited for storing and distributing data on networks.
These devices are about the size of a desk Servers drawer and are often mounted in racks of multiple servers. These computers were originally referred to as microcomputers. Personal computers provide access to a wide variety of computing appiications, such as word processing, photo editing, email, and Internet access. The term personal computer is sometimes abbreviated as PC.
It is not used as an abbreviation for personal computer. Desktop Personal computers can be classified as desktop, portable, or mobile devices. The lines that delineate these categories are sometimes a bit blurry, but the general characteristics of each category are described below and common configurations are shown in Figure A desktop computer fits on a desk and runs on power from an electrical wall outlet.
The keyboard is typically a separate component connected to the main unit by a cable. A desktop computer can be housed in a vertical case or in a horizontal case.
In some modern desktops, called all-in-one units, the system board is incorporated into the display device. Desktop computers are popular for offices and schools where portability is not important. The price of an entrylevel desktop computer starts at S or a bit less. Important Notice: Media content referenced within the product description or the product text may not be available in the ebook version.
As a college student, you need to know how to evaluate devices, choose apps, maintain a compelling online reputation, and lock down digital security. Numerous illustrations and interactive features in this complete book make mastering technical topics a breeze with a learning path that is structured with you, today's busy student, in mind.
This edition offers an insightful overview of what every college student should know about using technology to complete your education, launch a successful career, and engage in issues that shape today's world. Designed to get you up-to-speed on essential computer literacy skills, this market leading text goes deeper, providing technical and practical information relevant to everyday life.
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