Plotters

A plotter is a vector graphics printing device to print graphical plots, that connects to a computer. There are two types of main plotters. Those are pen plotters and electrostatic plotters.

Pen plotters print by moving a pen across the surface of a piece of paper. This means that plotters are restricted to line art, rather than raster graphics as with other printers. Pen plotters can draw complex line art, including text, but do so very slowly because of the mechanical movement of the pens. Pen Plotters are incapable of creating a solid region of color; but can hatch an area by drawing a number of close, regular lines. When computer memory was very expensive, and processor power was very slow, this was often the fastest way to produce color high-resolution vector-based artwork, or very large drawings efficiently.

Traditionally, printers are primarily for printing text. This makes it fairly easy to control, simply sending the text to the printer is usually enough to generate a page of output. This is not the case of the line art on a plotter, where a number of printer control languages were created to send the more detailed commands like "lift pen from paper", "place pen on paper", or "draw a line from here to here". The two common ASCII-based plotter control languages are Hewlett-Packard's HPGL2 or Houston Instruments DMPL with commands such as "PA 3000, 2000; PD".

Programmers in FORTRAN or BASIC generally did not program these directly, but used software packages such as the Calcomp library, or device independent graphics packages such as Hewlett-Packard's AGL libraries or BASIC extensions or high end packages such as DISSPLA. These would establish scaling factors from world coordinates to device coordinates, and translating to the low level device commands. For example to plot X*X in HP 9830 BASIC, the program would be

**************************************

10 SCALE -1,1,1,1
20 FOR X =-1 to 1 STEP 0.1
30 PLOT X, X*X
40 NEXT X
50 PEN
60 END
**************************************

Early plotters (e.g. the Calcomp 565 of 1959) worked by placing the paper over a roller which moved the paper back and forth for X motion, while the pen moved back and forth on a single arm for Y motion. Another approach (e.g. Computervision's Interact I) involved attaching ball-point pens to drafting pantographs and driving the machines with motors controlled by the computer. This had the disadvantage of being somewhat slow to move, as well as requiring floor space equal to the size of the paper, but could double as a digitizer. A later change was the addition of an electrically controlled clamp to hold the pens, which allowed them to be changed and thus create multi-colored output.

Hewlett Packard and Tektronix created desk-sized flatbed plotters in the late 1970s. In the 1980s, the small and lightweight HP 7470 used an innovative "grit wheel" mechanism which moved only the paper. Modern desktop scanners use a somewhat similar arrangement. These smaller "home-use" plotters became popular for desktop business graphics, but their low speed meant they were not useful for general printing purposes, and another conventional printer would be required for those jobs. One category introduced by Hewlett Packard's MultiPlot for the HP 2647 was the "word chart" which used the plotter to draw large letters on a transparency. This was the forerunner of the modern Powerpoint chart. With the widespread availability of high-resolution inkjet and laser printers, inexpensive memory and computers fast enough to rasterize color images, pen plotters have all but disappeared.

Plotters were also used in the Create-A-Card kiosks that were available for a while in the greeting card area of supermarkets that used the HP 7475 6 pen plotter.

Plotters are used primarily in technical drawing and CAD applications, where they have the advantage of working on very large paper sizes while maintaining high resolution. Another use has been found by replacing the pen with a cutter, and in this form plotters can be found in many garment and sign shops.

If a plotter was commanded to use different colors it had to replace the pen and select the wanted color and/or width.

A niche application of plotters is in creating tactile images for visually handicapped people on special thermal cell paper.

Pen plotters have essentially become obsolete, and have been replaced by large-format inkjet printers and LED toner based printers. Such printers are often still known as plotters, even though they are raster devices rather than pen based plotters by the definition of this article. The newer plotters still understand vector languages such as HPGL2. This is because the language is an efficient way to describe how to draw the file using just text commands. A technical drawing in HPGL2 can be quite a bit smaller file than the same drawing in a pure raster form.

A pen plotter's speed is primarily limited by the type of pen used. The typical plotter pen uses a cellulose fiber rod inserted through a circular foam tube saturated with ink, with the end of the rod sharpened into a conical tip. As the pen moves across the paper surface, capillary wicking draws the ink from the foam, down the rod, and onto the paper. As the ink supply in the foam is depleted, the migration of ink to the tip begins to slow down, resulting in faint lines. Slowing the plotting speed will allow the lines drawn by a worn-out pen to remain dark, but the fading will continue until the foam is completely depleted. Also as the fiber tip pen is used, the fiber tip slowly wears away from rubbing against the media, wearing down the thin conical tip into a thicker smudged line.

Ball-point plotter pens with refillable clear plastic ink reservoirs are available. They do not have the fading or wear effects of fiber pens, but are generally more expensive and uncommon.

Optical Mark Recognition

OPTICAL MARK RECOGNITION (OMR)

OMR Form

OMR Reader

'Optical mark recognition' is the process of capturing data by contrasting reflectivity at predetermined positions on a page. By shining a beam of light onto the paper the scanner is able to detect a marked area because it reflects less light than the blank areas of the paper. Some OMR devices use forms which are preprinted onto 'Transoptic' paper and measure the amount of light which passes through the paper, thus a mark on either side of the paper will reduce the amount of light passing through the paper.

It is generally distinguished from optical character recognition by the fact that a recognition engine is not required. That is, the marks are constructed in such a way that there is little chance of not reading the marks correctly. This does require the image to have high contrast and an easily-recognizable or irrelevant shape.

One of the most familiar applications of optical mark recognition is the use of #2 (HB in Europe) pencil bubble optical answer sheets in multiple choice question examinations. Students mark their answers, or other personal information, by darkening circles marked on a pre-printed sheet. Afterwards the sheet is automatically graded by a scanning machine. In most European countries, a horizontal or vertical 'tick' in a rectangular 'lozenge' is the most commonly used type of OMR form, the most familiar application being the UK National lottery form. Lozenge marks are a later technology and have the advantage of being easier to mark and easier to erase. The large 'bubble' marks are legacy technology from the very early OMR machines that were so insensitive a large mark was required for reliability. In most Asian countries, a special marker is used to fill in an optical answer sheet. Students, likewise mark answers or other information via darkening circles marked on a pre-printed sheet. Then the sheet is automatically graded by a scanning machine.

Another example of OMR is the recognition of scannable bar codes.

Recent improvements in OMR have led to various kinds of two dimensional bar codes called matrix codes. For example, United Parcel Service (UPS) now prints a two dimensional bar code on every package. The code is stored in a grid of black-and-white hexagons surrounding a bullseye-shaped finder pattern. These images include error-checking data, allowing for extremely accurate scanning even when the pattern is damaged.

Most of today's OMR applications work from mechanically generated images like bar codes. A smaller but still significant number of applications involve people filling in specialized forms. These forms are optimized for computer scanning, with careful registration in the printing, and careful design so that ambiguity is reduced to the minimum possible. Due to its extremely low error rate, low cost and ease-of-use, OMR is a popular method of tallying votes

Digital Cameras

A digital camera (or digicam for short) is a camera that takes video or still photographs, or both, digitally by recording images via an electronic image sensor. Many compact digital still cameras can record sound and moving video as well as still photograph. In the Western market, digital cameras outsell their 35 mm film counterparts.

Digital cameras can do things film cameras cannot, displaying images on a screen immediately after they are recorded, storing thousands of images on a single small memory device, recording video with sound, and deleting images to free storage space.

Digital cameras are incorporated into many devices ranging from PDAs and mobile phones (called camera phones) to vehicles. The Hubble Space Telescope and other astronomical devices are essentially specialised digital cameras.

Compact digital cameras

Compact cameras are designed to be small and portable; the smallest are described as subcompacts or "ultra-compacts". Compact cameras are usually designed to be easy to use, sacrificing advanced features and picture quality for compactness and simplicity; images can usually only be stored using Lossy compression (JPEG). Most have a built-in flash usually of low power, sufficient for nearby subjects. Live preview is almost always used to frame the photo. They may have limited motion picture capability. Compacts often have macro capability, but if they have zoom capability the range is usually less than for bridge and DSLR cameras. They have a greater depth of field, allowing objects within a large range of distances from the camera to be in sharp focus. They are particularly suitable for casual and "snapshot" use.

Bridge cameras

Bridge or SLR-like cameras are higher-end digital cameras that physically resemble DSLRs and share with them some advanced features, but share with compacts the framing of the photo using live preview and small sensor sizes.

Fujifilm FinePix S9000

Bridge cameras often have superzoom lenses which provide a very wide zoom range, typically between 10:1 and 18:1, which is attained at the cost of some distortions, including barrel and pincushion distortion, to a degree which varies with lens quality. These cameras are sometimes marketed as and confused with digital SLR cameras since the appearance is similar. Bridge cameras lack the mirror and reflex system of DSLRs, have so far been fitted with fixed (non-interchangeable) lenses (although in some cases accessory wide-angle or telephoto converters can be attached to the lens), can usually take movies with sound, and the scene is composed by viewing either the liquid crystal display or the electronic viewfinder (EVF). They are usually slower to operate than a true digital SLR, but they are capable of very good image quality (with sufficient light) while being more compact and lighter than DSLRs. The high-end models of this type have comparable resolutions to low and mid-range DSLRs. Many of these cameras can store images in lossless RAW format as an option to JPEG compression. The majority have a built-in flash, often a unit which flips up over the lens. The guide number tends to be between 11 and 15.

Digital single lens reflex cameras

Digital single-lens reflex cameras (DSLRs) are digital cameras based on film single-lens reflex cameras (SLRs), both types are characterized by the existence of a mirror and reflex system. See the main article on DSLRs for a detailed treatment of this category.

Digital rangefinders

A rangefinder is a user-operated optical mechanism to measure subject distance once widely used on film cameras. Most digital cameras measure subject distance automatically using acoustic or electronic techniques, but it is not customary to say that they have a rangefinder. The term rangefinder alone is sometimes used to mean a rangefinder camera, that is, a film camera equipped with a rangefinder, as distinct from an SLR or a simple camera with no way to measure distance.

Professional modular digital camera systems

This category includes very high end professional equipment that can be assembled from modular components (winders, grips, lenses, etc.) to suit particular purposes. Common brands include Hasselblad and Mamiya. They were developed for medium or large format film sizes, as these captured greater detail and could be enlarged more than 35 mm.

Typically these cameras are used in studios for commercial production; being bulky and awkward to carry they are rarely used in action or nature photography. They can often be converted into either film or digital use by changing out the back part of the unit, hence the use of terms such as a "digital back" or "film back". These cameras are very expensive (up to $40,000) and are typically not used by consumers.

Line-scan camera systems

A line-scan camera is a camera device containing a line-scan image sensor chip, and a focusing mechanism. These cameras are almost solely used in industrial settings to capture an image of a constant stream of moving material. Unlike video cameras, line-scan cameras use a single array of pixel sensors, instead of a matrix of them. Data coming from the line-scan camera has a frequency, where the camera scans a line, waits, and repeats. The data coming from the line-scan camera is commonly processed by a computer, to collect the one-dimensional line data and to create a two-dimensional image. The collected two-dimensional image data is then processed by image-processing methods for industrial purposes.

Line-scan technology is capable of capturing data extremely fast, and at very high image resolutions. Usually under these conditions, resulting collected image data can quickly exceed 100MB in a fraction of a second. Line-scan-camera–based integrated systems, therefore are usually designed to streamline the camera's output in order to meet the system's objective, using computer technology which is also affordable.

Line-scan cameras intended for the parcel handling industry can integrate adaptive focusing mechanisms to scan six sides of any rectangular parcel in focus, regardless of angle, and size. The resulting 2-D captured images could contain, but are not limited to 1D and 2D barcodes, address information, and any pattern that can be processed via image processing methods. Since the images are 2-D, they are also human-readable and can be viewable on a computer screen. Advanced integrated systems include video coding and optical character recognition (OCR).

Digital Camera has got many faces

Lightpen

A light pen is a computer input device in the form of a light-sensitive wand used in conjunction with a the computer's CRT TV set or monitor. It allows the user to point to displayed objects, or draw on the screen, in a similar way to a touch screen but with greater positional accuracy. A light pen can work with any CRT-based display, but not with LCD screens, projectors and other display devices.

A light pen is fairly simple to implement. The light pen works by sensing the sudden small change in brightness of a point on the screen when the electron gun refreshes that spot. By noting exactly where the scanning has reached at that moment, the X,Y position of the pen can be resolved. This is usually achieved by the light pen causing an interrupt, at which point the scan position can be read from a special register, or computed from a counter or timer. The pen position is updated on every refresh of the screen.

The light pen became moderately popular during the early 1980s. It was notable for its use in the Fairlight CMI, and the BBC Micro. Even some consumer products were given light pens, in particular Thomson's TO7 and TO7/70 computers. Due to the fact that the user was required to hold his or her arm in front of the screen for long periods of time, the light pen fell out of use as a general purpose input device.

The first light pen was used around 1957 on the Lincoln TX-0 computer at the MIT Lincoln Laboratory, and is mentioned as the "Lincoln Wand" in the first RFC, RFC 1.

Since the current version of the game show Jeopardy! began in 1984, contestants have used a light pen to write down their wagers and responses for the Final Jeopardy! round.

Since light pens operate by detecting light emitted by the screen phosphors, some nonzero intensity level must be present at the coordinate position to be selected.

Track Ball

A trackball is a pointing device consisting of a ball housed in a socket containing sensors to detect rotation of the ball about two axes—like an upside-down mouse with an exposed protruding ball. The user rolls the ball with the thumb, fingers, or the palm of the hand to move a cursor. Large tracker balls are common on CAD workstations for easy precision. Before the advent of the touchpad, small trackballs were common on portable computers, where there may be no desk space on which to run a mouse. Some small thumbballs clip onto the side of the keyboard and have integral buttons with the same function as mouse buttons. The trackball was invented by Tom Cranston and Fred Longstaff as part of the Royal Canadian Navy's DATAR system in 1952, eleven years before the mouse was invented. This first trackball used a Canadian five-pin bowling ball.

When mice still used a mechanical design (with slotted 'chopper' wheels interrupting a beam of light to measure rotation), trackballs had the advantage of being in contact with the user's hand, which is generally cleaner than the desk or mouse-pad and doesn't drag lint into the chopper wheels. The late 1990s advent of scroll wheels, and the replacement of mouse balls by direct optical tracking, put trackballs at a disadvantage and forced them to retreat into niches where their distinctive merits remained important. Most trackballs now have direct optical tracking which follows dots on the ball. Some mice, in place of a scroll wheel, acquired a small trackball between the buttons, useful in maps and other circumstances calling for scrolling in two dimensions.

Special Applications

Large tracker balls are sometimes seen on computerized special-purpose workstations, such as the radar consoles in an air-traffic control room or sonar equipment on a ship or submarine. Modern installations of such equipment may use mice instead, since most people now already know how to use one. However, military mobile anti-aircraft radars and submarine sonars tend to continue using trackballs, since they can be made more durable and more fit for fast emergency use. Large and well made ones allow easier high precision work, for which reason they are still used in these applications (where they are often called "tracker balls") and in computer-aided design.

Trackballs have appeared in computer and video games, particularly early arcade games (see a List of trackball arcade games) notably Atari's Centipede and Missile Command. "Football", by Atari, was the first arcade game to use a trackball, released in 1978 - though Atari spells it "trak-ball". Console trackballs, once common in the early 1980s, are now fairly uncommon: the Atari 2600 and 5200 consoles had one as an optional peripheral, with a joystick as standard. The Bandai Atmark, a Japanese console introduced in 1995 had a trackball as standard for its game-pad. Trackballs are also preferred by many so-called professional gamers, who value their consistency highly. A trackball requires no mouse-pad and enables the player to aim swiftly (in first person shooters). Trackballs remain in use in pub golf machines (such as Golden Tee) to simulate swinging the club.

Computer gamers have been able to successfully use trackballs in most modern computer games, including FPS, RPG, and RTS genres, with any slight loss of speed compensated for with an increase in precision. Many trackball gamers are competent at "throwing" their cursor rapidly across the screen, by spinning the trackball, enabling (with practice) much faster motion than can be achieved with a mouse and arm motion. However, many gamers are deterred by the time it takes to 'get used to' the different style of hand control that a trackball requires. Trackballs have also been regarded as excellent complements to analog joysticks, as pioneered by the Assassin 3D 1996 trackball with joystick pass-through capability. This combination provides for two-hand aiming and a high accuracy and consistency replacement for the traditional mouse and keyboard combo generally used on first-person shooter games. Many such games natively support joysticks and analog player movement, like Valve's Half-Life and id Software's Quake series.

Trackballs are provided as the pointing device in some public internet access terminals. Unlike a mouse, a trackball can easily be built into a console, and cannot be ripped away or easily vandalised. Two examples are the Internet browsing consoles provided in some UK McDonalds outlets, and the BT Broadband Internet public phone boxes.

Because trackballs for personal computers are stationary, they may require less space for operation than a mouse, and may simplify use in confined or cluttered areas such as a small desk.

The world's first trackball working on the invented by Tom Cranston, Fred Longstaff and Kenyon Taylor Royal Canadian Navy's DATAR project in 1952. It used a standard Canadian five-pin bowling ball.

Joystick

Joystick elements: 1. Stick 2. Base 3. trigger 4. Extra buttons 5. Autofire switch 6. Throttle 7. Hat Switch (POV Hat) 8. Suction Cup

A joystick is an input device consisting of a stick that pivots on a base and reports its angle or direction to the device it is controlling. Joysticks are often used to control video games, and usually have one or more push-buttons whose state can also be read by the computer. A popular variation of the joystick used on modern video game consoles is the analog stick.

The joystick has been the principal flight control in the cockpit of many aircraft, particularly military fast jets, where centre stick or side-stick location may be employed (see also Centre stick vs side-stick).

Joysticks are also used for controlling machines such as cranes, trucks, underwater unmanned vehicles and zero turning radius lawn mowers. Miniature finger-operated joysticks have been adopted as input devices for smaller electronic equipment such as mobile phones.

History

Joysticks were originally controls for an aircraft's ailerons and elevators.

The name "joystick" is thought to originate with early 20th century French pilot Robert Esnault-Pelterie.^[1] There are also competing claims on behalf of fellow pilots Robert Loraine, James Henry Joyce and Mr A.E. George. The latter was a pioneer aviator who with his colleague Mr. Jobling built and flew a biplane at Newcastle, England in 1910. He is alleged to have invented the "George Stick" which became more popularly known as the joystick. The George and Jobling aircraft control column is in the collection of the Discovery Museum in Newcastle Upon Tyne, England. The joystick itself was present in early planes, though the mechanical origins themselves are uncertain.^[2]

The first electrical 2-axis joystick was probably invented around 1944 in Germany. The device was developed for targeting the glide bomb Henschel Hs 293 against ship targets. Here, the joystick was used by an operator to steer the missile towards its target. This joystick had on-off switches rather than analogue sensors, i.e. a digital joystick. The signal was transmitted from the joystick to the missile by a thin wire.

This invention was picked up by someone in the team of scientists assembled at the Heeresversuchsanstalt in Peenemünde. Here a part of the team on the German rocket program was developing the Wasserfall missile, a variant of the V-2 rocket, the first ground-to-air missile. The Wasserfall steering equipment converted the electrical signal to radio signals and transmitted these to the missile.

Ralph H. Baer, inventor of television video games and the Magnavox Odyssey console, created the first video game joysticks in 1967. They were analog, using two potentiometers to measure position.^[3]

The Atari standard joystick, developed for the Atari 2600 was a digital joystick, with a single 'fire' button, and connected via a DE-9 connector, the electrical specifications for which was for many years the 'standard' digital joystick specification. Joysticks were commonly used as controllers in first and second generation game consoles, but then gave way to the familiar Game pad with the Nintendo Entertainment System and Sega Master System in 1985 and 86, though joysticks - especially arcade-style ones - were and are popular after-market add-ons for any console.

More recently, analog sticks (or thumbsticks, due to their being controlled by one's thumbs) have become standard on video game consoles and have the ability to indicate the stick's displacement from its neutral position. This means that the software does not have to keep track of the position or estimate the speed at which the controls are moved. These devices are usually using a magnetic flux detector to determine the position of the stick.

The joystick has found a new lease of life for flight control in the form of a 'sidestick' - a controller similar to a games joystick but which is used to control the electronics of the latest aircraft. Almost the entire family of Airbus aircraft (with the exception of the A300 and A310) up to the A380, the largest commercial aircraft in aviation, use the 'sidestick' which saves weight, improves movement and visibility in the cockpit and is said to be safer in the event of an accident than the traditional 'control yoke'.

A gaming joystick- with a computer

Computer Mouse

A device that controls the movement of the cursor or pointer on a display screen. A mouse is a small object you can roll along a hard, flat surface. Its name is derived from its shape, which looks a bit like a mouse, its connecting wire that one can imagine to be the mouse's tail, and the fact that one must make it scurry along a surface. As you move the mouse, the pointer on the display screen moves in the same direction. Mice contain at least one button and sometimes as many as three, which have different functions depending on what program is running. Some newer mouse also include a scroll wheel for scrolling through long documents.

Invented by Douglas Engelbart of Stanford Research Center in 1963, and pioneered by Xerox in the 1970s, the mouse is one of the great breakthroughs in computer ergonomics because it frees the user to a large extent from using the keyboard. In particular, the mouse is important for graphical user interfaces because you can simply point to options and objects and click a mouse button. Such applications are often called point-and-click programs. The mouse is also useful for graphics programs that allow you to draw pictures by using the mouse like a pen, pencil, or paintbrush.

There are three basic types of mice:

1. mechanical: Has a rubber or metal ball on its underside that can roll in all directions. Mechanical sensors within the mouse detect the direction the ball is rolling and move the screen pointer accordingly.
2. optomechanical: Same as a mechanical mouse, but uses optical sensors to detect motion of the ball.
3. optical: Uses a laser to detect the mouse's movement. You must move the mouse along a special mat with a grid so that the optical mechanism has a frame of reference. Optical mice have no mechanical moving parts. They respond more quickly and precisely than mechanical and optomechanical mice, but they are also more expensive.

Mice connect to PCs in one of several ways:

1. Serial mice connect directly to an RS-232C serial port or a PS/2 port. This is the simplest type of connection.
2. PS/2 mice connect to a PS/2 port.
3. USB mice.

4. Cordless mice aren't physically connected at all. Instead they rely on infrared or radio waves to communicate with the computer. Cordless mice are more expensive than both serial and bus mice, but they do eliminate the cord, which can sometimes get in the way.

Windows Keyboard Shortcuts

Windows system key combination

•	F1: Help
•	CTRL+ESC: Open Start menu
•	ALT+TAB: Switch between open programs
•	ALT+F4: Quit program
•	SHIFT+DELETE: Delete item permanently

Windows program key combination

•	CTRL+C: Copy
•	CTRL+X: Cut
•	CTRL+V: Paste
•	CTRL+Z: Undo
•	CTRL+B: Bold
•	CTRL+U: Underline
•	CTRL+I: Italic

Mouse click/keyboard modifier combination for shell objects

•	SHIFT+right click: Displays a shortcut menu containing alternative commands
•	SHIFT+double click: Runs the alternate default command (the second item on the menu)
•	ALT+double click: Displays properties
•	SHIFT+DELETE: Deletes an item immediately without placing it in the Recycle Bin

General keyboard-only commands

•	F1: Starts Windows Help
•	F10: Activates menu bar options
•	SHIFT+F10 Opens a shortcut menu for the selected item (this is the same as right-clicking an object
•	CTRL+ESC: Opens the Start menu (use the ARROW keys to select an item)
•	CTRL+ESC or ESC: Selects the Start button (press TAB to select the taskbar, or press SHIFT+F10 for a context menu)
•	ALT+DOWN ARROW: Opens a drop-down list box
•	ALT+TAB: Switch to another running program (hold down the ALT key and then press the TAB key to view the task-switching window)
•	SHIFT: Press and hold down the SHIFT key while you insert a CD-ROM to bypass the automatic-run feature
•	ALT+SPACE: Displays the main window's System menu (from the System menu, you can restore, move, resize, minimize, maximize, or close the window)
•	ALT+- (ALT+hyphen): Displays the Multiple Document Interface (MDI) child window's System menu (from the MDI child window's System menu, you can restore, move, resize, minimize, maximize, or close the child window)
•	CTRL+TAB: Switch to the next child window of a Multiple Document Interface (MDI) program
•	ALT+underlined letter in menu: Opens the menu
•	ALT+F4: Closes the current window
•	CTRL+F4: Closes the current Multiple Document Interface (MDI) window
•	ALT+F6: Switch between multiple windows in the same program (for example, when the Notepad Find dialog box is displayed, ALT+F6 switches between the Find dialog box and the main Notepad window)

Shell objects and general folder/Windows Explorer shortcuts

For a selected object:

•	F2: Rename object
•	F3: Find all files
•	CTRL+X: Cut
•	CTRL+C: Copy
•	CTRL+V: Paste
•	SHIFT+DELETE: Delete selection immediately, without moving the item to the Recycle Bin
•	ALT+ENTER: Open the properties for the selected object

To copy a file

Press and hold down the CTRL key while you drag the file to another folder.

To create a shortcut

Press and hold down CTRL+SHIFT while you drag a file to the desktop or a folder.

General folder/shortcut control

•	F4: Selects the Go To A Different Folder box and moves down the entries in the box (if the toolbar is active in Windows Explorer)
•	F5: Refreshes the current window.
•	F6: Moves among panes in Windows Explorer
•	CTRL+G: Opens the Go To Folder tool (in Windows 95 Windows Explorer only)
•	CTRL+Z: Undo the last command
•	CTRL+A: Select all the items in the current window
•	BACKSPACE: Switch to the parent folder
•	SHIFT+click+Close button: For folders, close the current folder plus all parent folders

Windows Explorer tree control

•	Numeric Keypad *: Expands everything under the current selection
•	Numeric Keypad +: Expands the current selection
•	Numeric Keypad -: Collapses the current selection.
•	RIGHT ARROW: Expands the current selection if it is not expanded, otherwise goes to the first child
•	LEFT ARROW: Collapses the current selection if it is expanded, otherwise goes to the parent

Properties control

•	CTRL+TAB/CTRL+SHIFT+TAB: Move through the property tabs

Accessibility shortcuts

•	Press SHIFT five times: Toggles StickyKeys on and off
•	Press down and hold the right SHIFT key for eight seconds: Toggles FilterKeys on and off
•	Press down and hold the NUM LOCK key for five seconds: Toggles ToggleKeys on and off
•	Left ALT+left SHIFT+NUM LOCK: Toggles MouseKeys on and off
•	Left ALT+left SHIFT+PRINT SCREEN: Toggles high contrast on and off

Microsoft Natural Keyboard keys

•	Windows Logo: Start menu
•	Windows Logo+R: Run dialog box
•	Windows Logo+M: Minimize all
•	SHIFT+Windows Logo+M: Undo minimize all
•	Windows Logo+F1: Help
•	Windows Logo+E: Windows Explorer
•	Windows Logo+F: Find files or folders
•	Windows Logo+D: Minimizes all open windows and displays the desktop
•	CTRL+Windows Logo+F: Find computer
•	CTRL+Windows Logo+TAB: Moves focus from Start, to the Quick Launch toolbar, to the system tray (use RIGHT ARROW or LEFT ARROW to move focus to items on the Quick Launch toolbar and the system tray)
•	Windows Logo+TAB: Cycle through taskbar buttons
•	Windows Logo+Break: System Properties dialog box
•	Application key: Displays a shortcut menu for the selected item

Microsoft Natural Keyboard with Intel i Type software installed

•	Windows Logo+L: Log off Windows
•	Windows Logo+P: Starts Print Manager
•	Windows Logo+C: Opens Control Panel
•	Windows Logo+V: Starts Clipboard
•	Windows Logo+K: Opens Keyboard Properties dialog box
•	Windows Logo+I: Opens Mouse Properties dialog box
•	Windows Logo+A: Starts Accessibility Options (if installed)
•	Windows Logo+SPACEBAR: Displays the list of Microsoft IntelliType shortcut keys
•	Windows Logo+S: Toggles CAPS LOCK on and off

Dialog box keyboard commands

•	TAB: Move to the next control in the dialog box
•	SHIFT+TAB: Move to the previous control in the dialog box
•	SPACEBAR: If the current control is a button, this clicks the button. If the current control is a check box, this toggles the check box. If the current control is an option, this selects the option.
•	ENTER: Equivalent to clicking the selected button (the button with the outline)
•	ESC: Equivalent to clicking the Cancel button
•	ALT+underlined letter in dialog box item: Move to the corresponding item

Key boards- Type

In computing, a keyboard is an input device partially modeled after the typewriter keyboard which uses an arrangement of buttons, or keys which act as electronic switches. A keyboard typically has characters engraved or printed on the keys, and each press of a key typically corresponds to a single written symbol. However, to produce some symbols requires pressing and holding several keys simultaneously or in sequence. While most keyboard keys produce letters, numbers or signs (characters), other keys or simultaneous key presses can produce actions or computer commands.
In normal usage, the keyboard is used to type text or numbers into a word processor, text editor, or other program. In a modern computer the interpretation of key presses is generally left to the software. A computer keyboard distinguishes each physical key from every other and reports all key presses to the controlling software. Keyboards are also used for computer gaming, either with regular keyboards or by using special gaming keyboards which can expedite frequently used keystroke combination. A keyboard is also used give commands to the operating system of a computer, such as the Control-Alt-Delete combination, which brings up a task window or shuts down the machine.


The Dvorak Simplified Keyboard layout arranges keys so that frequently used keys are easiest to press, which reduces muscle fatigue when typing common English.

Types

Standard keyboards

Standard keyboards such as the 104-key Windows keyboards include alphabetic characters, punctuation symbols, numbers, and a variety of function keys. The internationally-common 102/105 key keyboards have a smaller 'left shift' key and an additional key with some more symbols between that and the letter to its right (usually Z or Y).

Keyboards with extra keys such as multimedia keyboards have special keys for accessing music, web, and other oft-used programs, a mute button, volume buttons or knob, and standby (sleep) button. Gaming keyboards have extra function keys which can be programmed with keystroke macros. For example, ctrl+shift+y could be a keystroke that is frequently used in a certain computer game. Shortcuts marked on color-coded keys are used for some software applications and for specialized for uses including word processing, video editing, graphic design, and audio editing.

Multimedia keyboards have special keys for accessing music, websites, and computer programs.

Smaller keyboards have been introduced for laptops, PDAs, cellphones, or users who have a limited workspace. The size of a standard keyboard is dictated by the practical consideration that the keys must be large enough to be easily pressed by fingers. To reduce the size of the keyboard, the numeric keyboard to the right of the alphabetic keyboard can be removed, or the size of the keys can be reduced, which makes it harder to enter text. Another way to reduce the size of the keyboard is to reduce the number of keys and use chording keyer, i.e. pressing several keys simultaneously. For example, the GKOS keyboard has been designed for small wireless devices. Other two-handed alternatives more akin to a game controller, such as the AlphaGrip, are also used as a way to input data and text. Another way to reduce the size of a keyboard is to use smaller buttons and pack them closer together. Such keyboards, often called a "thumbboard" (thumbing) are used in some personal digital assistants such as the Treo and BlackBerry and some Ultra-Mobile PCs such as the OQO.

Keyboards on laptops such as this Sony VAIO usually have a shorter travel distance for the keystroke and a reduced set of keys.

Numeric keyboards contain only numbers, mathematical symbols for addition, subtraction, multiplication, and division, a decimal point, and several function keys (e.g. End, Delete, etc.). They are often used to facilitate data entry with smaller keyboard-equipped laptops or with smaller keyboards that do not have a numeric keypad.

Non-standard or special-use types

A keyset or chorded keyboard (also called a chord keyboard or chording keyboard) is a computer input device that allows the user to enter characters or commands formed by pressing several keys together, like playing a "chord" on a piano. The large number of combinations available from a small number of keys allows text or commands to be entered with one hand, leaving the other hand free to do something else. A secondary advantage is that it can be built into a device (such as a pocket-sized computer) that is too small to contain a normal sized keyboard. A chorded keyboard designed to be used while held in the hand is called a keyer.

The Microwriter MW4 (circa 1980) uses a chording keyboard in which several key presses are needed for each letter.

Virtual keyboards, such as the I-Tech Virtual Laser Keyboard, project an image of a full-size keyboard onto a surface. Sensors in the projection unit identify which key is being "pressed" and relay the signals to a computer or personal digital assistant. There is also a virtual keyboard, the On-Screen Keyboard, for use on Windows.

Touchscreens such as with the iPhone and the OLPC laptop can be used as a keyboard. (The OLPC initiative's second computer will be effectively two tablet touchscreens hinged together like a book. It can be used as a convertible tablet PC where the keyboard is one half-screen (one side of the book) which turns into a touchscreen virtual keyboard.)

Foldable keyboards are made of soft plastic which can be rolled or folded over for travel. When in use, the keyboard can conform to uneven surfaces, and it is more resistant to liquids than a standard keyboard

.Foldable Keyboard

Paper tape

From the early days of computing up till well into the 70's, paper tape was heavily used in the computer industry as a cheap and reliable means of data storage. Besides, it was used in telecommunications (telex), and in the printing industry as the input medium for hot-metal typesetting machines. Up till the turn of the century it has been in use for numerical control of milling and drilling machines. For heavy duty applications, paper was often replaced by synthetic materials like mylar.
In computer applications, tapes were usually 1 inch wide with 8 information hole positions and one sprocket feed hole in each row, see the top illustration [1]. Occasionally, the narrower 7, 6 or 5 'channel' varieties were used. The dimensions were well standardized; hence all varieties could be read on an single tape reader with a minimum of adjustment. One meter of 8-channel tape can contain about 400 bytes of data.
Paper tape punches have been built with operating speeds from 10 - 300 rows per second. Tape readers worked either mechanically (with sense pins) or electro-optically. Using the latter technique, very expensive readers could handle up to 2000 [3] rows per second while being able to stop on one row. For such fast readers, special equipment (servo-controlled reels) was needed for feeding the tape to and from the reader. A simple solution used with medium-speed readers (300 rows/s) was to use fan-fold tape, which re-folds automatically if it is catched from the reader in an appropriately dimensioned receptacle.
Special equipment existed for comparing tapes: for critical applications, data entry was done by two typists at the same time. By comparing the resulting tapes typing errors could be detected. Paper tapes could be corrected, edited or repaired easily by manually adding missing holes, or by cut-and-paste operations, using some very simple mechanical tools.

Computer paper tapes mostly used parity check for detecting punch or read errors; the tape fragment shown here uses odd-parity coding. The diagram [2] shows the ASCII 8-channel paper tape code used by the popular Teletype ASR33 electro-mechanical computer terminal. Similar machines like the Friden Flexowriter used an entirely different code.

Punched Cards - For Computers

With the advent of computers, complex pre-formatted cards continued to be used for to hold data, but in addition, cards were printed with formats specific to the needs of programmers. Some of these were equal in complexity to the standard data processing cards.

The "IBM CALCULATOR INSTRUCTION CARD" shown here was printed in the early 1950's probably for use by programmers of the IBM 701, IBM's first general purpose computer. The card includes fields for both symbolic and numeric addresses, so it is probable that it was used with a rudimentary assembler that directly punched the assembled object code onto the cards holding the source code.

As programming languages grew more sophisticated, they shifted from fixed format to free format, and the preprinted material on cards began to shift to other functions. The card shown above is an assembly language card printed for Bell Labs, for the GE 600 computer they purchased in the mid 1960's as part of their work in the Multics project. This card contains a few fixed fields, but the artwork centers on a corporate logo, and to help programmers, much of the space on the card is devoted to documentation of the punch positions used for each character in the GE 600 character set.

With the widespread standardization of high level languages such as FORTRAN and COBOL, generic punched cards for those language were widely sold. These were almost entirely free-form languages, with only a few constraints on format, but the tradition of cards with clearly labeled fields lived on for a long time. The FORTRAN card shown here was printed by IBM's New Zealand office, but it is otherwise indistinguishable from millions of similar cards printed around the world.

As fewer and fewer users asked for cards with field markings specific to their applications, it became more and more likely that users would use cards purchased for one purpose for some other purpose. In open shops, such as university computer centers, this became a particular problem. Anyone could walk in off the streets and "borrow" an handful of cards. The solution was to order cards with custom printing to identify the institution! The card here is from one of the oldest computer laboratories in the world, the University of Illinois Digital Computer Labratory, home of the ILLIAC computers and builder of ORDVAC. This card has two sets of column indicators across the top, one for printing keypunches, which printed directly above the column being punched, and one for IBM's standard line of interpreters, which printed the first 64 columns on one line and the remaining columns on the line immediately below.

Of course, merely putting the name of the institution on the card is not very exciting, so many institutions, large and small, added corporate logos. Princeton University did this very nicely, as illustrated above. Princeton is noteworthy as the home of the Institute for Advanced Study, where, in 1946, John Von Neumann convened the Princeton Summer School and launched the computer age.

The graphic design work that goes into making special printing plates for a punched card can cost money, so sometimes, institutions opted for a less expensive route, overprinting a standard form with their logo instead of designing the form around the logo, as Princeton did. The MIT card shown above is a remarkably crude example of this, from an institution from which better would have been expected. In fact, this card was a stopgap measure while MIT was in the process developing a modernized logo.

A high resolution scan is available.

In the 1960's, IBM introduced a 128 column card, containing 4 rows of 32 character positions each, where each character position was punched using a 6-bit code. These cards, at 2 5/8 inches high by 3 1/4 inches wide, were significantly smaller than the original Hollerith cards, and they could boast 38 more characters of data per card than the old UNIVAC standard. These cards were introduced along with IBM's System 3 line of "small business" computers, and they were intended to displace 80 column cards from the market. Despite their obvious advantages, they never caught on outside of certain specialized applications, notably retail sales price tags and inventory management. The 128 column cards were also used with only 96 columns of punched data, leaving room for 4 rows of print along the top edge instead of the usual 3 rows.

Most users considered these to be 96 column cards because punching the 4th row, the top row, punched through the textual version of the data, making it difficult for people to read what was printed there; furthermore, by the early 1970's, there was a strong demand for support for mixed upper and lower case text; this required the switch from a 6-bit to an 8-bit code. In order to maintain compatability, the high 2 bits of the 8-bit code were punched separately from the low 6 bits, subdividing the top row of the card (formerly reserved for columns 97-128) to hold 3 tracks of 2-bit data instead of one track of 6-bit data. Clever code design ensured that old cards, punched using the 6-bit code, were correctly read using 8-bit software so long as the card did not contain more than 96 columns of data.

By the mid 1970's, most large scale data processing operations were at least investigating moving their punched card operations to timesharing environments, with their data stored on disk or magnetic tape, and by the mid 1990's, with timesharing mainframes and personal computers, the shift was almost complete, with very few businesses still using cards for anything other than scratch paper.

Curiously, while cards are becoming rare, you can still occasionally find price quotes for them. For example, the University of California at Davis Central Stores Online Catalog listed cards as recently as 1996:

   Catalog Item Number: 71510-109
    IBM CARD, BLANK TOP, LEFT CUT, 2000/BOX
      Also known as data processing or keypunch cards.
    Price: $42.085 per Box
    Prices are current as of: Mar 2 06:00 (1996)

One of the last important uses of punched cards has proven to be be voting. Use of pre-scored punched card ballots was introduced in the 1960's, and despite problems in the 1968 general election in Detroit, where a sudden rainstorm drenched at least one load of ballots in transit from a polling place to the counting center, this format quickly grew to become the most widely used computer-based election technology. By the time of the contested presidential elections of the year 2000, it was estimated that 1/3 of the polling places in the United States still used punched card ballots.

The problems with punched card ballots in the 2000 presidential election should not have come as a surprise. By the 1984 general election, the state of Iowa had effectively banned the use of punched card ballots, and in 1988, the Computer Professionals for Social Responsibility published a call for a general ban on the use of pre-scored punched card ballots (see http://www.cpsr.org/publications/newsletters/old/1980s/Fall1988.txt ). By the early 1990's mark-sense ballots and direct-recording electronic voting machines had both been developed to the point where they were viable replacements for punched card ballots, and in fact, by the year 2000, the major vendors of card based voting systems had all shifted their marketing emphasis to these newer technologies.

Punched Cards - before computers

The standard punched card, originally invented by Herman Hollerith, was first used for vital statistics tabulation by the New York City Board of Health and several states. After this trial use, punched cards were adopted for use in the 1890 census. A brief description of the use of punched cards in the 1900 census is found in the January 1900 issue of National Geographic, pages 34-36, in an article by Dr F. H. Wines.

Hollerith wasn't working in a vacuum! His idea for using punched cards for data processing came after he'd seen the punched cards used to control Jacquard looms. Jacquard, working in France around 1810, originated the idea of using holes punched in card stock to control the pattern a loom weaves. Many Jacquard looms remain in use to this day, and you can occasionally find strings of Jaquard cards for sale.

A high resolution image is available.

The string of Jacquard cards illustrated here came from a small rug-making loom in a woolen mill in Amana, Iowa. Each card in this string is 9 inches long by 1.25 inches wide by 1/16 inch thick, but other Jaquard looms used different size cards. Like all Jaquard loom cards, these are strung together on cords. The heavy card stock is required because the "card reader" mechanism of a Jacquard loom is entirely mechanical. Modern high-volume Jacquard looms use metal cards!

The use of punched cards in the Jacquard loom also influenced Charles Babbage, who decided to use punched cards to control the sequence of computations in his proposed analytical engine. Unlike Hollerith's cards of 50 years later, which were handled in decks like playing cards, Babbage's punched cards were to be strung together like Jaquard's. Despite this and the fact that he never actually built an analytical engine, Babbage's proposed use of cards played a crucial role in later years, providing a precident that prevented Hollerith's company from claiming patent rights on the very idea of storing data on punched cards.

Like many modern entrepreneurs, after Hollerith had perfected his first series of electromechanical punched-card machines, including a punch, a tabulating machine to accumulate statistics from the information punched on cards, and a sorting machine, he founded a company, originally the Tabulating Machine Corporation. As with many high-tech startups of today, it had a somewhat rocky start until an experienced manager entered the scene. Thomas Watson, previously working for NCR, took over. One of Watson's moves was to rename the company International Business Machines, and within a few decades, his company had expanded to the point that the Federal government sued it for anti-trust violations.

The overall dimensions of punched cards used for data processing have remained the same since Herman Hollerith invented the medium: 7 3/8 inches wide by 3 1/4 inches high by .007 inches thick. Prior to 1929, this was a standard size for many US banknotes, and Hollerith apparently chose it so that he could store cards in boxes made for the Treasury Department. Today, these dimensions are set by the EIA standard RS-292 media 1 punched card. This standard is augmented by ANSI X3.21-1967 governing the holes in the card and ANSI X3.26-1980 governing the use of the Hollerith code to encode alphanumeric data on cards.

The original code used for punched card data recording in the 1890 census had 22 columns with 8 punch positions each (although there was room on the card for a total of 11 punch positions per column). The coding used on those cards did not encode data in columnar fields, but rather, each punch position was assigned a specific meaning. The need to store more data on each card led to higher density formats, first 24 colums of 10 positions each in the 1900 census (inferred from the 1900 National Geographic article), and then 27 columns of 12 positions each in the 1910 census. By the end of the 1920's, the standard format used 45 columns of round holes per card and 12 punch positions in each column.

In 1928, Hollerith's company, now renamed IBM, introduced the rectangular hole 80 column format, almost doubling the amount of data that could be recorded on a card, and by the mid 1930's, IBM was predicting that round-hole cards would soon be things of the past.

A high resolution scan is available.

In fact, the round-hole format remained in use into the early 1990s, but in a very limited set of applications! The last use I am aware of is toll tickets on some eastern turnpikes. There are two reasons that the round hole format survived: First, IBM had a patent on their new rectangular format, so competitors were forced to limit themselves to the old format. Second, Remington Rand, one of IBM's major competitors in the pre-computer era, moved from Hollerith's code to a 6-bit code that allowed 90 columns of text to be stored on the old 45 column cards. When Remington Rand bought UNIVAC, they naturally integrated their 90 column card format with UNIVAC computers. In many ways, the UNIVAC card code was superior to IBM's "improved" rectangular hole version!

Oliver J. Jones wrote me that, in addition to surviving on some eastern turnpikes, UNIVAC's 90 column cards also remained in use through the 1960's at Macy's Department store and Lerner Stores, in the retail sector, the US Navy Medical Supply office and the Polaris missle control system, in the military sector, the New York City Tax Department, Long Island Lighting, and more. He sent along an image of the cover from a Remington Rand brochure and a promotional poster.

Mike Albaugh wrote me that he helped dismantle a UNIVAC SS90 system in 1974 or 1975 that had been in use up until the week before. He also saw a similar UNIVAC system in use at the Concord Naval Weapons Station around the same time. These apparently used 90 column cards.

If you look at the punched card equipment sold by IBM after 1931, you will find complete hardware support for IBM's alphanumeric Hollerith code, but you will also find that the majority of the machines sold were limited to numeric applicatons. At a time when, for example, the University of Iowa was punching student names on cards using the Hollerith code, other universities were developing 4-digit numeric encodings of common names so that they could avoid the need for the more expensive alphanumeric equipment.

The book Practical Applicatons of the Punched Card Method in Colleges and Universities, edited by G. W. Baehne an published by Collumbia University Press in 1935, contains an excellent summary of the state of the art in punched card data processing in 1935, including an appendix that appears to be a reprint of IBM's catalog for that year and many illustrated descriptions of typical applicatons.

When cards were used to store fixed-format information for data processing applications, they were almost always printed with format information, so that a casual reader could easily determine what punches on the card held what information. This printing could be quite specialized to one application, or it could merely set off fields in a standard way, with no indication on the card of what the purpose was.

The card shown here is typical of those used with IBM's line of card processing equipment from the 1930's onward. This particular example was printed for a range of retail applications where it must have been expected that the customer would handle the cards, as indicated by the warning: Do not fold or mutilate. This warning would be unnecessary if the card were only to be handled by data processing workers. While most fields of this card have no clear purpose, it contains an interesting and very specialized feature, a tab the cashier was supposed to tear off along a perforated line when the card was processed. A card with this tab removed would be seen by card processing equipment as having a punch in column 1, row 12.

It is important to note that the typical card processing applications from the 1890's to the 1950's did not require the use of computers! A deck of cards from a retail application, for example, could be sorted by the category field on a card sorter, and then each category could be run through a tabulating machine to sum the price fields of all cards in that category or similar accounting functions.

Usually, fixed format cards documented the format on the top edge of the card, since keypunches almost always printed their textual information along this edge. Sometimes, as illustrated above, the interpretation was elsewhere. Such departures from the norm were most common on cards that were intended to be machine punched, as in this Gardner Denver wire-wrap machine card. This card was used to control a semi-automatic wire-wrap machine, the machine used to wire the backplanes of many of the mainframes and minicomputers of the 1960's. The wire-list for a backplane was typically produced with the aid of computer-aided-design tools, so this card would typically only be read by people during debugging.

In the 1950's, IBM also supported a truncated version of the 80 column card, with only 51 columns. These were frequently used in retail sales and other applications requiring limited storage capacity per card; they saved both bulk and paper, but added complexity to IBM's card processing equipment to allow support of both formats. In many cases, they began life as 80 column cards from which a stub could be torn, for example, as a receipt, leaving a 51 column remainder for tabulation.