Data In, Information Out

Outline

Learning Objectives

When you have finished reading this lesson, you will be able to

Identify the most common input devices

Explain why alternatives to keyed data are being developed

Discuss trends in pointing devices

Identify the most common output devices

Distinguish between hard copy and soft copy

When personal computers were first developed, a magazine received a letter from a reader. The reader asked the magazine to publish an article about using "those typewriter-television things." In those days, computer literacy was rare.

Even if you are just beginning to learn about computers, you know that a computer is more than an input/output device--more than a "typewriter-television thing." Still, much of what you do when you interact with a computer involves the use of input and output peripheral devices. You enter data (input) by means of input devices (such as keyboards), and you look at output on output devices (such as monitors or printers). So this chapter's examination of computer hardware includes the input and output devices of today--and tomorrow.

Input Devices

You can enter data into the computer in many ways. The most commonly used input devices are keyboards; pointing devices, such as mice and trackballs; and scanners. Many other special-purpose input devices are available, and computers often have more than one input device. For example, most personal computers have both a keyboard and a mouse.

Keyed Input

You enter most input data into the computer by using a keyboard. This input method is similar to typing on a typewriter.

Most typewriter and computer keyboards are QWERTY keyboards. The alphabetic keys are arranged so that the upper-left row of letters begins with the six letters Q W E R T Y. Designers of other keyboards claim that their boards are easier to learn than the QWERTY keyboard. The Dvorak keyboard is one example. It is not widely accepted, however, because most people have already learned the QWERTY keyboard.


This Chinese keyboard has many more characters than the QWERTY or Dvorak keyboard.	The Dvorak keyboard was designed to be more efficient than the QWERTY keyboard.

In other parts of the world, you will find different keyboards. The coding used on the QWERTY and Dvorak keyboards works with an 8-bit code, which accommodates 256 different characters. Asian languages have many more characters. The Kanji alphabet, for example, has 50,000 characters. Japanese keyboards have to work with a 16-bit code to accommodate all the characters.

Computer keyboards include keys that are designed to perform specific tasks. These special keys include function keys, directional keys, and special-purpose keys such as Alt, Ctrl, Del, Enter, Ins, and Esc. These keys enable the user to perform complex tasks easily when using the application. For example, many applications use a function key to access online help for the user.


This computer keyboard has typewriter keys, function keys, numeric keys, directional keys, and special-purpose keys.

Some new keyboards have 107 keys, with the three new keys designed to simplify working with Windows 95. Two of these keys, next to the Alt keys, bring up the Start menu. The third key, next to the right Ctrl key, brings up a menu of functions that are frequently accessed in whichever application is currently being used.


A Windows 95 ergonomic keyboard.

Prolonged keyboard use can cause wrist problems, sometimes so serious as to require surgery. To help prevent these problems, ergonomic keyboards are beginning to appear on the market. (See Lesson 8B for a more detailed discussion.)

One special type of keyboard construction is the membrane-switch keyboard, on which the keyboard is covered by a protective film. Membrane-switch keyboards are reliable, durable, and resistant to such hazards as liquids or grease. However, membrane keys require more pressure than keys on a standard computer keyboard. You have probably seen membrane-switch keyboards in fast-food restaurants. Membrane-switch keyboards are ideal in manufacturing situations that require little actual keying.

Many computer systems are designed for source-data automation. These systems place keyboards and display units at the most convenient spot for data entry. An example is the use of point-of-sale (POS) cash registers in retail stores. POS registers send data directly to a computer file for later processing. This technique gives an advantage because most so-called computer errors are actually keying errors. Capturing data at the source minimizes errors because the people who key the data are doing a variety of tasks and are therefore less likely to make errors due to boredom.


You may have heard of 'computer errors' causing strange mistakes. For example, a Michigan woman received a gas bill for more than one million dollars! Almost all these errors are due to errors in keyboard data input.

Pointing Devices

Many people use pointing devices instead of keyboards whenever possible. Pointing devices minimize the amount of typing (and the number of errors). The many pointing devices available include the mouse, trackball, light pen, digitizing tablet, touch screen, and pen-based system.

The Mouse and the Trackball

The mouse is a palm-size device with a ball built into the bottom. The mouse is usually connected to the computer by a cable (computer wires are frequently called cables) and may have from one to four buttons (but usually two). The mouse may be mechanical or optical. Mice come in many shapes and sizes. When you move the mouse over a smooth surface, the ball rolls, and the pointer on the display screen moves in the same direction. The Apple Macintosh, with its graphical user interface, made the mouse popular. Now most microcomputer systems, regardless of the manufacturer, use a mouse. With the mouse, you can draw, select options from a menu, and modify or move text. You issue commands by pointing with the pointer and clicking a mouse button. In addition to minimizing typing errors, a mouse makes operating a microcomputer easier for beginning users.

A trackball is like an upside-down mouse. Used similarly to the mouse, the trackball is frequently attached to or built into the keyboard. The main advantage of a trackball is that it requires less desk space than a mouse. (Some individuals in the computer industry believe that the mouse will soon be replaced by devices that do not require as much space to use.)


A mouse usually has two or three buttons. Most mouse operations use the left button only.

The mouse is not practical for people using a laptop computer in a small space. Early alternatives, such as trackballs clipped to the side of the keyboard, have not proved satisfactory. The Apple PowerBook uses a central trackball. The IBM ThinkPad replaces the trackball with a red plastic button, called a trackpoint, located in the middle of the keyboard. You move the button with your thumbs. The newest Apple PowerBooks have a small square of plastic on the front of the keyboard that moves easily to control the pointer.



Pointing devices include the LogiTech Trackman, the IBM ThinkPad Trackpoint, and the RISC System/6000 Spaceball.

A device that was released in 1995 enables the user to move the cursor using an infrared pen. The pen is cordless and works when it is as far as fifteen feet from the screen. Although the mouse is still the most popular pointing device, these innovations may change that.


You can move the joystick in any direction to mark a location on the display screen.

Joysticks

A joystick is a pointing device often used for playing games. The joystick has a gearshift-like lever that is used to move the pointer on the screen. On most joysticks, a button on the top is used to select options. In industry and manufacturing, joysticks are used to control robots. Flight simulators and other training simulators also use joysticks.

Touch-Sensitive Screens

Perhaps the easiest way to enter data is with the touch of a finger. Touch screens enable the user to select an option by pressing a specific part of the screen. Touch screens are commonly used in grocery stores, fast-food restaurants, and information kiosks.


ALPS' TouchPad and GlidePoint Keyboard.

Pen-Based Systems

Have you received a package from United Parcel Service recently? If so, you probably signed for it on a special pad, using an electronic pen.


The Apple Newton.

Pen-based systems are especially useful for people who do not like to type or who are frequently on the move. Personal digital assistants (PDA), such as the Apple Newton, are designed for people on the go. The Newton can link entries with stored files. For example, if you write "Call Margaret and wish Happy Birthday," the Newton adds a line to your "To do" list and links Margaret's phone number from your telephone directory. If your friend Ken moves, you can simply change his address and phone number. The Newton serves equally well as a calendar, calculator, and notepad.

Pen-based systems are not perfect--they do not always register handwriting correctly. Pen-based computing is just beginning to gain widespread acceptance. For example, many stores no longer have you sign a carbon form to charge a purchase; instead you sign on a tablet that automatically records your signature.


This ThinkPad subnotebook computer features a monitor that interprets pen input.

A different type of pen called a light pen is used by many engineers and architects. The light pen uses a photoelectric (light-sensitive) cell to indicate screen position to the computer. You operate the pen by touching it to the screen. Light pens are frequently used for computer-aided design (CAD) applications.

Another tool used in CAD applications and other graphics applications is a digitizing tablet. A digitizing tablet consists of a grid on which designs and drawings can be entered. Most tablets are pressure-sensitive, and the user draws directly on the tablet using a special pen called a stylus, or a puck. Digitizing tablets are used to design cars, buildings, medical devices, and robots.


Digitizing tablets are used at Ford Motor Company to design new automobiles.

Data Scanning Devices

Optical recognition systems provide another means of minimizing keyed input by capturing data at the source. These systems enable the computer to "read" data by scanning printed text for recognizable patterns.

The banking industry developed one of the earliest scanning systems in the 1950s for processing checks. The Magnetic Ink Character Recognition (MICR) system is still used throughout the banking industry. The bank, branch, account number, and check number are encoded on the check before it is sent to the customer. After the customer has used the check and it comes back to the bank, all that needs to be entered manually is the amount. MICR has not been adopted by other industries because the character set has only fourteen symbols.

Of all the scanning devices, you are probably most familiar with bar code readers. Many retail and grocery stores use some form of bar code reader to determine the item being sold and to retrieve the item price from a computer system. The code reader may be a handheld unit, or it may be embedded in a countertop. The bar code reader reads the Universal Product Code (UPC), a pattern of bars printed on merchandise. The UPC has gained wide acceptance since its introduction in the 1970s. Initially, workers resisted the use of the code because the system was used to check their accuracy and speed. Today, bar codes are used to update inventory and ensure correct pricing. Federal Express uses a unique bar code to identify and track each package. Federal Express employees can usually tell a customer within a matter of minutes the location of any package.


		As the bar codes are scanned, the computer updates the inventory quantities.

From taking exams, you are already familiar with Mark Sense Character Recognition systems. Every time you take a test with a "fill in the bubble" Scantron form and use a #2 lead pencil, you are creating input suitable for an optical mark reader (OMR). A #2 lead pencil works best because of the number of magnetic particles in that weight lead. The OMR senses the magnetized marks, enabling the reader to determine which responses are marked. OMR is very helpful to researchers who need to tabulate responses to large surveys. Almost any type of survey or questionnaire can be designed to be suitable for OMR devices. An OMR unit can be attached to a microcomputer, and the data transferred to a file directly.

Optical scanners can scan typed documents, pictures, graphics, or even handwriting into a computer. Photographs scanned into a microcomputer appear clearly on the screen and can be displayed whenever desired. The copy that the computer has stored will never yellow with age. Early scanners could recognize only text printed in a special optical character recognition (OCR) typeface. A scanner converts the image that it sees into numeric digits before storing the image in the computer. This conversion process is known as digitizing.


This LogiTech handheld scanner can scan small, odd-sized items or full pages of text.

Depending on the volume and type of material to be scanned, you can use drum scanners, flatbed scanners, sheet-fed scanners, and even small handheld scanners. The small, handheld scanners (priced at about $150) have been used most frequently with microcomputers; however, only 5 percent of all microcomputer systems are equipped with scanners. Manufacturers responded to user reluctance to use scanners by releasing in 1995 a number of new, small, paper scanners priced between $200 and $500. (In 1994, full-page scanners cost between $500 and $700.) Most of these new devices sit between the keyboard and the monitor and can interface with a fax machine, send e-mail, and store documents on disk for archive purposes.

Voice Recognition Devices

Voice input and control systems have the potential of revolutionizing the way we communicate with computers. Steady progress has been made in this area, although there are still some problems. The day may soon come when we can talk to our computers the way the actors do on Star Trek.

Computer scientists and linguists have been working on voice recognition systems for two decades. The major difficulty has been that people speak with different accents and intonations. For this reason, most successful voice recognition systems require a period of "training" while the system becomes accustomed to an individual's accent and intonation.

The first systems could recognize only a few dozen words. A system recently released by IBM, known as VoiceType, is capable of recognizing as many as 32,000 words and is speaker independent.



Voice recognition devices can recognize input from individuals and be used to enter commands. These devices can also provide a picture of the sound, which helps hearing-impaired people learn to speak.

Voice recognition has unlimited possibilities and will make computers much easier to use. Speech recognition systems are already being used in many types of settings. In factories, workers use speech recognition systems to control robotic arms when the worker's own hands are busy. Speech recognition systems enable physically disabled people to use computers. A microcomputer Voice User Interface (VUI), capable of recognizing input from a variety of individuals, will be considered standard soon.


The LogiTech Fotoman is a camera that converts the 'photograph' to a digital image the computer can read.

Video digitizers can capture input from virtually any type of video device, such as VCRs, televisions, and camcorders. Audio digitizers can digitize music or voice from a microphone. It is fairly easy to capture a portion of a television show, add some music that complements the picture, and play back the result on a microcomputer to create a multimedia presentation.

Output Devices

Output devices are as varied and as innovative as input devices. From traditional printed output to audio output and robots, there are a multitude of forms of computer output.

Most output can be divided into two categories: soft copy and hard copy. Soft copy is ideal when you are writing a document, playing a game, watching a video clip, or reading the latest news. Soft copy is what you see on the monitor. Soft copy is temporary; after you have finished with it, there is nothing solid to hold. You can, however, transfer soft copy to a disk to transport it. Hard copy can be touched and carried. Hard copy is usually some form of paper output. It is especially helpful if you need to have a colleague look at your work or you need to give your work to a supervisor or teacher.

Monitors

When you think about viewing computer output, you probably visualize a monitor. Monitor output is soft copy; when you have finished viewing it, you cannot pick up the output and move it. Monitor displays are the most common form of soft copy.

Sometimes, when watching television, you may notice that the picture looks a little snowy. This condition occurs because the images are not solid but rather created by configurations of dots. These dots, or picture elements, combine to form the image you see. The more picture elements, also known as pixels, the better the resolution of the image. The better the resolution, the clearer the picture. Computer monitors are similar to television screens.


A PixelVision flat-panel monitor.

The large monitors that you see connected to desktop computers are cathode-ray tube (CRT) monitors. The smaller monitors that are used on laptops and notebook computers are known as flat-panel displays. Flat-panel displays weigh less and consume less electricity than CRTs. Common types of flat-panel displays include liquid crystal display (LCD), electroluminescent (EL) display, and gas plasma display. Flat-panel display monitors are still more expensive than CRTs but will eventually decrease in price. (PixelVision recently released a 16-inch flat-panel display that includes a two-million color palette and sells for $10,000.) Can you imagine hanging your monitor on the wall like a painting? It may be common in a few years.


Monitors are available in many sizes and shapes. Some monitors, such as the Radius dual-orientation monitor, can be rotated to provide a different view.

Most new monitors are SVGA (Super Video Graphics Adapter) with a pixel configuration of 800 by 600 at low-resolution mode and 1024 by 768 at high-resolution mode. (The first number designates the horizontal pixel count, and the second is the vertical pixel count.) The higher resolution with more pixels provides a clearer, more detailed image. Each pixel displays a single color at a time. Each color is represented by a numeric code (for example, bright red could be 12). If the monitor displays only 16 colors, the numeric code can be represented with only four bits. To display 256 colors (each with its own code) requires eight bits.

One monitor may look "sharper" than another even though they have the same pixel configuration. This is due to the dot pitch, which is the distance between pixels. (A .28 dot pitch gives a crisper image than a .30 dot pitch. The .28 dot pitch is fairly standard.) You should consider dot pitch when purchasing a monitor. The dot pitch is built in by the manufacturer and cannot be changed.

With users increasingly viewing video clips, animated objects, and complex graphics, monitors have taken on a new importance. Users now must decide how large a monitor they need. Fourteen-inch to seventeen-inch monitors are commonly used with desktop microcomputer systems. (Larger monitors are available but are expensive.)

Monitors are also categorized by whether they display in black and white (monochrome) or color. Monochrome monitors are rapidly becoming a thing of the past, as most applications today require color. In fact, a display of 256 colors is usually necessary for working with informational CD-ROMs and clip-art collections.

In order to connect a monitor to a microcomputer, you must have a graphics adapter board (also known as a video card). Each type of monitor requires a different type of board. The graphics board plugs into an expansion slot inside the computer, and the monitor plugs into the board. In order to run today's graphics-intensive programs properly and quickly, most graphics boards come with some memory capability, known as video memory. It is important to realize that video RAM (VRAM) must meet higher performance specifications than regular RAM. It is recommended that instead of using RAM on a video card, the user should place VRAM or dynamic RAM (DRAM), which is slightly slower than VRAM, on a video card.

The refresh rate on a monitor is also important and is affected by the video card. Even a steady image is constantly regenerated, or refreshed, from top to bottom. A slow refresh rate of 60 times per second (60Hz), can cause headaches; 70Hz is a reasonable minimum. Some monitors, known as interlaced monitors, refresh every other line; noninterlaced monitors are easier on the eyes. The Motion Picture Experts Group (MPEG), has developed standards for video compression that improve the quality of the video on the monitor. MPEG drivers are available as software or as hardware built in a video card.

Audio Output

Have you ever listened to a concert or watched a television show on a computer? Audio output is a second type of soft copy. New computer systems have such good audio systems that it is possible to listen to music while you work, have the computer tell you when the printer needs paper, play games that include sound, or compose music on the computer. In order to have high-quality audio output, a good quality sound card and speakers are needed.

New sound cards even include the capability to have the computer read a text file to you while you continue working on a different application. Voice input and output have proved helpful to individuals with speech and vision impairments. Someone with a speech impairment can key a message into a computer and have the computer say it. Of course, computer-generated voices are not human; they are synthesized. Speech synthesis, having the computer speak, is a much simpler process than speech recognition.

Printers

The second most common form of computer output is printed documents. Although a computer can operate perfectly without a printer, it is certainly helpful to the user to have one. Because you can hold printed output, it is considered a form of hard copy.

Printers can be categorized by whether anything mechanical actually touches the paper; whether they do or do not produce a solid character; and whether they produce a page, a line, or a character at a time.

When a part of the printer presses the paper to form the character, the printer is considered an impact printer. Impact printers can produce carbon copies and are fairly loud, although covers are available to muffle the noise. In contrast, nonimpact printers are quiet. However, because nothing presses on the page, a nonimpact printer cannot produce carbon copies. This fact is usually not a problem because it is easy to produce multiple originals, but sometimes carbons are required for legal purposes.

Impact Printers

Impact printers can produce a page, a line, or a character at a time. Large computers use line printers. The main drawback to line printers is that they can produce only text--no graphics.

Many small computers use character printers. Although only one character can be produced at a time, many types of character printers can produce graphics as well as text. The most common character printers create images by using a dot pattern. These printers are known as dot-matrix printers. If you use a magnifying glass to look at a report created with a dot-matrix printer, you can see the small dots forming each character.

Nonimpact Printers

Nonimpact printers are increasing in popularity largely because of improvements in print quality coupled with decreasing cost. Nonimpact printers can produce both text and graphics. Because nothing actually strikes the paper, nonimpact printers are fairly quiet. Some of the most popular nonimpact printers are laser printers and inkjet printers.

Laser printers work in the same manner as copy machines; a laser beam creates electrical charges that attract toner to form an image and transfer it to paper. Laser printers come in a variety of sizes; generally the larger and faster the printer, the more expensive it is. Large laser printers are used on mainframes and minicomputers where high-quality graphic output is required. Small, "personal" laser printers are suitable for home use. Hewlett-Packard recently began production of a wireless printer. The HP5P (IBM) and HP5PM (Mac) enable the user to beam a document from a laptop to an infrared receiver in the front of the printer. The laptop needs to have a built-in infrared transmitter installed, but no cables or wires are required.


The side-by-side black and color cartridges of the Hewlett-Packard DeckJet 660C printer enable you to print in true black and color on the same page without having to swap cartridges.	The Hewlett-Packard Color LaserJet 5 printer is useful for workgroups.

The Hewlett-Packard LaserJet 5L produces high-quality reports very quickly, and its design requires little space.	The faster speed of the Hewlett-Packard LaserJet 5Si MX accommodates more users and higher print volumes.

Inkjet printers are also popular for microcomputers. Although the resolution is lower on inkjet printers than on laser printers, the resolution is higher than that of dot-matrix printers. Inkjet printers are significantly less expensive than laser printers. Electronically charged ink is sprayed through a jet nozzle and passed through an electronic field, which deflects the ink to form a dot-matrix character. Color inkjet printers, which use multiple nozzles, are available at very reasonable prices. Canon recently released a color inkjet printer that weighs three pounds and stands two inches high--perfect for traveling!

A well-equipped office, at home or at work, includes an inkjet printer, a fax machine (with its own telephone), a copier, and a full-sheet scanner. A recent addition to the market is one device that does all four functions. The technology to print a document that has been faxed to you and the technology to copy a document are similar to the technology to print a document from a PC. All three technologies use similar digital patterns, and the mechanical aspects are nearly identical.

Plotters

A plotter, like a printer, produces hard-copy output. Plotters, which produce high-quality color graphics, are usually categorized by whether they use pens or electrostatic charges to create images. A continuous-curve plotter is used to draw maps from stored data. Computer-generated maps can be retrieved and plotted or used to show changes over time. Plotters are generally more expensive than printers, ranging from about $1,000 to $75,000 (or even more).


Plotters are ideal for engineering, drafting, and many other applications that require intricate graphics.

Microfilm, Microfiche, and CD-ROM

Storing printed reports requires a great deal of space. What can be done to save paper and storage space? Computer Output Microfilm/Microfiche (COM) provides one answer. Microfilm stores images of reports on a roll of film; microfiche uses four-by-six-inch sheets of film to store images. Besides saving storage space, COM is less expensive than regular printed output. Producing output on microfilm or microfiche is also faster than producing printed output. COM devices can output in excess of 30,000 lines per minute. The major disadvantage of COM is that because of the small size, special readers are required to read the film or fiche.

For companies that store volumes of computer information, an alternative to COM is CD-ROM. Data Optics International offers a CD-ROM microfiche replacement service in which the computer information is recorded, indexed, and transferred to CD-ROM technology. The information can then be made available in report format through a PC or LAN network. Each CD-ROM can store one million pages, or 680M, of computer data. The advantages of this storage method are faster, simpler data retrieval and lower overall costs. Just as CDs have replaced lp records in the music industry, CD-ROM technology may eventually replace the traditional tape and microfiche methods of data storage.

Robots

Probably the most intriguing output device is the robot. Most robots are not the way you may imagine; they have little resemblance to R2D2 of Star Wars or Data of Star Trek: The Next Generation. Most robotic devices consist of a single arm that can perform a preprogrammed task. Robotic devices are frequently used in manufacturing for such tasks as spray painting or assembling parts.

Advanced robotic devices are used in scientific research. For example, Jason, a talking robot that can be seen at Epcot Center, was created for undersea exploration.


Robots can be used for many tasks, including the assembly of other computers.

Lesson Summary

Input and output devices are sometimes called peripheral devices.

The most common source of computer input is the keyboard. Keying mistakes cause most computer errors.

Source-data automation is the capture of data at the point where the transaction occurs and is accomplished with a minimum of keying.

POS (point-of-sale) terminals are a type of source-data automation device that can be found in most department stores.

A trackball or a mouse is used to point and select options that are shown on the screen.

Pen-based systems are used for computer-aided design and for encoding customer signatures.

Optical recognition systems enable the computer to read patterns. MICR, used by the banking industry, and Mark Sense Character Recognition Systems are types of optical recognition systems.

Computers can digitize the human voice and recognize verbal instructions. Speech and voice recognition systems are especially useful in factories and in assisting the physically disabled.

Hard copy is output that can be touched and carried. In contrast, soft copy output is displayed on a monitor.

The display on a monitor is composed of thousands of dots, or picture elements, known as pixels.

Printers are usually categorized as impact or nonimpact. With impact printers, something physically touches the paper. With nonimpact printers, nothing touches the paper but the ink.

A plotter is used to produce high-quality color graphics.

Robots are a type of output device.

Lesson Review

Further Discovery

PC Secrets. Caroline M. Halliday (Foster City, CA: IDG, 1996).

Peter Norton's Inside the PC, Sixth Edition. Peter Norton, Lewis C. Eggebrecht, and Scott N. A. Clark (Indianapolis, IN: Sams, 1995).

Winn L. Rosch Printer Bible. Winn Rosch (New York: Henry Holt, 1996).

Magazines such as Byte, PC World, and PC Magazine feature articles on new input/output developments.

Online Discovery

You can access the Internet resources for the following questions by going to the Que Education and Training Web site at URL http://www.mcp.com/queet/ciyf/onlinelinks.html. From this page, click the link for Lesson 2C and then click the link to the resource you want to access.

The Yahoo! directory page for Input Devices (http://www.yahoo.com /Business_and_Economy/Companies /Computers/Peripherals /Input_Devices) points to the Web pages of many different companies that manufacture input devices. Browse several of these Web pages. What types of input devices do you see? How are they different from each other? What are the most prevalent types of input devices? Do you see any that are intended for people with disabilities?