- Define input and differentiate among a program, command, and a user response.
Input is the term denoting either an entrance or changes which are inserted into a system and which activate/modify a process. It is an abstract concept, used in the modeling, system(s) design and system(s) exploitation. It is usually connected with other terms, e.g., input field, input variable, input parameter, input value, input signal, input port, input device and input file (file format).
A computer program (also a software program, or just a program) is a sequence of instructions written to perform a specified task for a computer.
In computing, a command is a directive to a computer program acting as an interpreter of some kind, in order to perform a specific task. Most commonly a command is a directive to some kind of command line interface, such as a shell.
User response is a plan of action aimed at accomplishing a clear business objective, with what work is to be done, by whom, when and what means or resources will be used.
- Identify the keys and buttons commonly found on desktop computer keyboards and describe how keyboards for mobile computers and devices differ from desktop computer keyboards.
Basic PC shortcut keys
The below basic shortcut keys are a listing of shortcut keys that will work with almost all IBM compatible computers and software programs. It is highly recommended that all users keep a good reference of the below shortcut keys or try to memorize the below keys. Doing so will dramatically increase your productivity.
Shortcut Keys | Description |
Alt + F | File menu options in current program. |
Alt + E | Edit options in current program |
F1 | Universal Help in almost every Windows program. |
Ctrl + A | Select all text. |
Ctrl + X | Cut selected item. |
Shift + | Cut selected item. |
Ctrl + C | Copy selected item. |
Ctrl + Ins | Copy selected item |
Ctrl + V | |
Shift + Ins | Paste |
Home | Goes to beginning of current line. |
Ctrl + Home | Goes to beginning of document. |
End | Goes to end of current line. |
Ctrl + End | Goes to end of document. |
Shift + Home | Highlights from current position to beginning of line. |
Shift + End | Highlights from current position to end of line. |
Ctrl + Left arrow | Moves one word to the left at a time. |
Ctrl + Right arrow | Moves one word to the right at a time. |
Keyboard types
One factor determining the size of a keyboard is the presence of duplicate keys, such as a separate numeric keyboard, for convenience.
Further the keyboard size depends on the extent to which a system is used where a single action is produced by a combination of subsequent or simultaneous keystrokes (with modifier keys, see below), or multiple pressing of a single key. A keyboard with few keys is called a keypad. See also text entry interface.
Another factor determining the size of a keyboard is the size and spacing of the keys. Reduction is limited by the practical consideration that the keys must be large enough to be easily pressed by fingers. Alternatively a tool is used for pressing small keys.
Standard
Standard "full-travel" alphanumeric keyboards have keys that are on three-quarter inch centers (0.750 inches, 19.05 mm), and have a key travel of at least 0.150 inches (3.81 mm). Desktop computer keyboards, such as the 101-key US
Laptop-size
Keyboards on laptops and notebook computers usually have a shorter travel distance for the keystroke and a reduced set of keys. They may not have a numerical keypad, and the function keys may be placed in locations that differ from their placement on a standard, full-sized keyboard.
The keyboards on laptops have a shorter travel distance and (usually) a reduced set of keys.
Thumb-sized
Smaller keyboards have been introduced for laptops (mainly nettops), PDAs, smartphones, or users who have a limited workspace.
A chorded keyboard allows 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.
A thumb keyboard (thumbboard) is used in some personal digital assistants such as the Palm Treo and BlackBerry and some Ultra-Mobile PCs such as the OQO.
Numeric keyboards contain only numbers, mathematical symbols for addition, subtraction, multiplication, and division, a decimal point, and several function keys. They are often used to facilitate data entry with smaller keyboards that do not have a numeric keypad, commonly those of laptop computers. These keys are collectively known as a numeric pad, numeric keys, or a numeric keypad, and it can consist of the following types of keys:
- arithmetic operators such as +, -, *, /
- numeric digits 0–9
- cursor arrow keys
- navigation keys such as Home, End, PgUp, PgDown, etc.
- Num Lock button, used to enable or disable the numeric pad
- enter key.
http://en.wikipedia.org/wiki/Computer_keyboard#Keyboard_types
- Describe different mouse types and explain how to use a mouse.
Different Mouse Types
The mechanical mouse requires a ball to move the cursor on the screen. To get more efficacies with this type of mice, a flat surface named mouse pads is necessary.
The optomechanical or optical-mechanical mouse is a combination of the optical and the mechanical technologies. It uses a ball but detects the mouse movement optically. It is now the most commonly used with PC.
The optical mouse uses a laser; precisely an optical sensor to help detecting the mouse’s moving. More expensive than the two other types, the optical mouses offer more precision and speed and even can be used on any surface.
The cordless mouse uses the wireless communication technology (via infrared, radio or Bluetooth) to transmit data to the computer. And like the wireless, it doesn’t use any cord.
How To Use a Mouse
The computer’s mouse controls a graphical mouse pointer or mouse cursor on the screen. When you move the mouse around by rolling it on your desk, the pointer on the screen moves in a similar manner. Roll the mouse left, and the pointer moves left; roll it in circles, and the pointer mimics that action.
Here are some of the more basic mouse operations:
· Point: When you’re told to “point the mouse,” you move the mouse on the desktop, which moves the mouse pointer on the screen to point at something interesting (or not).
· Click: A click is a press of the mouse button — one press and release of the main button, the one on the left. This action makes a clicking sound, which is where this maneuver gets its name.
Clicking is often done to select something or to identify a specific location on the screen.
· Right-click: This action is the same as a click, although the right mouse button is used.
· Double-click: This one works just like the single click, although you click twice in the same spot — usually, rather rapidly.
This is most commonly done in Windows to open something, such as an icon. Both clicks must be on (or near) the same spot for the double-click to work.
· Drag: The drag operation is done to graphically pick up something on the screen and move it. To do that, you point the mouse at the thing you want to drag, press and hold the mouse’s button (which “picks up” the object), and then move the mouse to another location. When you move the mouse (and keep the button down), the object moves. To release, or drop, the object, release the mouse button.
· Right-drag: This action is the same as a drag, but the mouse’s right button is used.
Many of these basic mouse operations can be combined with keys on the keyboard. For example, Shift-click means holding down the Shift key on the keyboard while clicking the mouse.
http://www.dummies.com/how-to/content/how-to-use-your-computer-mouse.html
- Describe various types of touch screens and explain how a touch-sensitive pad works.
Three Types of Technology
· Touch-screen technology falls into three categories: resistive, capacitive and surface wave. Each technology has strengths suited for specific applications.
Resistive
· Resistive-type screens lack the clarity of other touch screens but they tend to be very durable and can be used in a variety of environments. Resistive-type screens are the most common in use today.
Capacitive
· Capacitive screens are resistant to outside elements, making them very durable, and they still maintain a high clarity. Unlike resistive and surface wave screens, which can be used with stylus, capacitive panels must be touched with a finger.
Surface Wave
· Surface wave touch panels are the more advanced of the three types, offering the highest clarity. But they are more easily damaged by outside elements.
How the Touch Pad Works
The touch pad contains several layers of material. The top layer is the pad that you touch. Beneath it are layers (separated by very thin insulation) containing horizontal and vertical rows of electrodes that form a grid. Beneath these layers is a circuit board to which the electrode layers are connected. The layers with electrodes are charged with a constant alternating current (AC). As the finger approaches the electrode grid, the current is interrupted and the interruption is detected by the circuit board. The initial location where the finger touches the pad is registered so that subsequent finger movement will be related to that initial point. Some touch pads contain two special places where applied pressure corresponds to clicking a left or right mouse button. Other touch pads sense single or double taps of the finger at any point on the touch pad.
http://searchmobilecomputing.techtarget.com/definition/touch-pad
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