Иностранные языки, филология и лингвистика
A mouse is a device for controlling the cursor and selecting items on the screen. Typically, a mouse is a palm-sized device, slightly smaller than a pack of cards. On top of the mouse there are one or more buttons for communicating with the computer.
Input devices are the pieces of hardware
which allow us to enter information into the computer. The most common are the keyboard and the mouse.
The keyboard allows the user to key in programs and data and to control the computer system. There are keyboards with different number of keys nowadays.
A mouse is a device for controlling the cursor and selecting items on the screen. Typically, a mouse is a palm-sized device, slightly smaller than a pack of cards. On top of the mouse there are one or more buttons for communicating with the computer. A tail or wire extends from the mouse to a connection on the back of the computer.
Besides the mouse there are other cursor control devices. They are a trackball and a joystick.
A trackball is similar to a mouse but it has the ball on top. To move the cursor on the screen, the user rotates the ball using his fingers.
To operate a joystick, the user grips and moves a vertical lever. The movement of the lever causes the cursor to move around the screen. Pressing a button on the joystick puts the required process into operation. Cursor movements can be made very quickly using this device therefore it is often used for playing fast action games.
We can also interact with the computer by using many other specialized input devices: a scanner, a lightpen, a graphics tablet, or a voice recognition device.
A scanner converts text or pictures into electronic codes that can be manipulated by the computer.
Lightpens and graphics tablets are referred to drawing devices used for CAD (Computer-Aided Design).
A lightpen is similar in shape to an ordinary pen. It is held against the screen and works by sending signals to the computer when it senses the light given off by the screen. This enables the computer to calculate its position. As the light pen is moved, lines appear on the screen. The special programs used with the light pen allows the lines to be increased or decreased in size or moved to different positions.
A graphics tablet has a flat board (or tablet) across which a pen is moved. By using the reflection of light, ultrasound or other methods the graphics tablet can measure the distance of the pen from the sides of the tablet and therefore calculate its position. As the pen is moved across the tablet lines are displayed on the screen.
A voice recognition device allows the user to input data by speaking into a microphone. The computer compares the input with the sound patterns of words stored in the memory. To reduce the amount of memory required, the vocabulary used with this device is limited to a few words. However, the large amount of memory needed to analyse the input makes it difficult to use this device with microcomputer.
Do you know any other input devices?
Can you describe them according to the same plan?
Any keyboard has the following groups of keys:
Most keys of the keyboard are auto-repeating, that means that , if they are held down, they repeat their function again and again until they are released.
The mouse is designed to slide around on your desktop. As it moves, it moves an image on the screen called a pointer or mouse cursor. The pointer usually looks like an arrow or I-bar, and it mimics the movements of the mouse on your desktop.
What makes the mouse especially useful is that it is a very quick way to move around on a screen. The mouse also issues instructions to the computer very quickly. Point to an available option with the cursor, click on the mouse, and the option has been chosen.
Mice are so widely used in graphic applications because they can do things that are difficult, if not impossible, to do with keyboard keys. For example, the way you move an image with a mouse is to put the pointer on the object you want to move, press the button and drag the image from one place on the screen to another. When you have the image where you want it, you release the button and the image stays there. Similarly, the mouse is used to grab one corner of the image (say a square) and to stretch it into another shape (say a rectangle).
The buttons on the mouse are used to select items at which the mouse points. You position the pointer on an object on the screen, for example, on a menu or a tool in a paint program, and then you press the mouse button to select it. Mice are also used to load documents into a program: you put the pointer on the file name and double-click on the name that is, you press a mouse button twice in rapid succession.
In a flatbed scanner, the paper with the image is placed face down on a glass screen similar to a photocopier. Beneath the glass are the lighting and measurement devices. Once the scanner is activated, it reads the images as a series of dots and then generates a digitized image that is sent to the computer and stored as a file. The manufacturer usually includes software which offers different ways of treating the scanned image.
A colour scanner operates by using three rotating lamps, each of which has a different coloured filter: red, green and blue. The resulting three separate images are combined into one by appropriate software.
расположение; набор чего-л.; переключаться с …на …; редактировать текст; давать распоряжение; автоповтор; удерживать; имитировать; указатель; щелкать; тащить; отпускать; подобно; захватывать что-л.; в быстрой манере; лицом вниз; под чем-л.; серия чего-л.; вращающаяся лампа.
On Macintoshes, the equivalent key is called the Option key.
Working in pairs make up dialogues
discussing the following problems.
Long existing standards dictate the location of most
of the keys, such as the numbers, letters, symbol keys and the standard function keys, such as shift, new line and backspace. These keys are in the "touch" area and account for most of the keystrokes the user makes without breaking rhythm and losing speed. Special function keys, such as CLEAR are in nontouch locations and can be struck only if the user moves the hand away from the home position. They are in the nontouch area because they are infrequently used and should be viewed for verification before being struck.
The QWERTY layout is currently the most popular keyboard configuration. It is named after the first six keys of the upper left hand row. It was developed in 1872 and laid out to slow typists down somewhat and so prevent "jamming" of mechanical typewriters. The DVORAK layout was proposed in 1932 as a faster and more efficient layout (Dvorak, 1943). This layout places the most frequently used keys on the home row. While it can be shown to be an improvement over the QWERTY layout, the magnitude of the advantages have not been shown sufficient to justify retrofitting keyboards and retraining typists. Thus, it currently has limited acceptance.
Efficient keying requires that keys function with minimum adequate force and with sufficient displacement to provide muscular feedback to the user. Key forces for current high production keyboards are in the range of 0.40 to 1.25 newtons with key displacements of 3 to 5 mm. Key spacing, key travel, force and key feedback are keyboard characteristics generally agreed on by most manufacturers and are specified by ANSI as follows:
"Center line distances between adjacent keys shall be between 18 and 19 mm (0.71 and 0.75 inch) horizontally, and between 18 and 21 mm (0.71 and 0.82 inch) vertically (Clare, 1970).
"The keys...shall have a maximum vertical displacement between 1.5 and 6.0 mm (0.06 and 0.24 inch).
"The preferred displacement is between 2.0 and 4.0 mm (0.08 and 0.16 inch).
"The maximum force to depress the keys, expressed in Newtons (N)...shall range between 0.25 N and 1.5 N. The preferred key force is between 0.5 N and 0.6 N."
The more proficient the user, the lighter the touch can be. If too little force is required, however, extra keys may be struck accidentally, and if too much force or displacement is required, some keys may fail to be actuated because the user did not press hard enough. Also, excessive force induces finger fatigue. There is evidence (Kinkead and Gonzales, 1969; Alden, Daniels and Kanarick, 1972) that optimum force/displacement characteristics of a key require a steadily increasing force as the key is depressed until contact is made. Immediately beyond that point, the force is sharply changed so that users can easily "feel" when the key has been pressed sufficiently. A typical force displacement curve for a key with tactile feedback is shown in.
1. A. The keyboard and the mouse are the only available input devices.
C. Lightpens and joysticks are referred to drawing devices used for CAD (Computer-Aided Design).
D. A voice recognition device needs a lot of memory.
E. A graphics tablet like a lightpen is useful for making drawings with the help of the computer.
2. A. All keyboards have the same amount of keys.
3. A. To show that the mouse is more functional than the keyboard.
B. To show what the mouse can do as an input device.
4. A. To describe the difference between a flatbed and colour scanner.
B. To describe the operating mechanism of a flatbed and colour scanner.
C. To stress the difference between a flatbed and colour scanner.
Как утверждают некоторые производители программного обеспечения, чем меньше требуется нажатий клавиш, тем быстрее и эффективнее программа.
5. A. The faster the key pressings, claim some software producers, the fewer and more efficient the program.
This key has different meanings depending on which program is running.
6. A. Эта клавиша имеет различные значения вне зависимости от выполняемой программы.
В. Эта клавиша обладает одним и тем же значением при выполнении различных программ.
С. Эта клавиша обладает различными значениями в зависимости от выполняемой программы.
7. extend А. снижать
8. reduce В. сжать
9. rotate С. увеличивать
10. grip D. вводить с клавиатуры
11. refer E. вращать
12. The most popular keyboard layout is …….
13. The mouse is connected to the computer with the help of the
14. The input device, which is helpful for disabled people as they can input data by speaking into a microphone, is known as ………
15. Input devices that are especially useful for engineers are …….
16. Input device which is very good for copying text and graphic data is called ……...
17. A key that moves the cursor to the beginning of the next line is ……….
18. DVORAK was proposed in 1932 as a faster and more efficient ………….
19. Keys that instruct the computer and are found on most keyboard on their tops are known as ………….
20. If you want to put a file into operation you should ……..the mouse button.
C. Double-click D. Grab
21. Joystick looks like a ……. with a button on its top.
A. Lever B. Pen
C. Tablet D. Box
22. Graphics tablet includes a pen and a board that should be …….
A. Vertical B. Stable
C. Movable D. Flat
23. ……..is an example to copy.
24. ………are used for changing text material.
A. Functional keys B. Editing keys
C. Alphabetic keys D. Numeric keys
25. Touchpad has ………. instead of characters
A. Icons B. Pictures
C. Blank spaces D. Symbols
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