Quiz 1

1. Define input and differentiate among a program, command, and user response.

Ans:   Input is the term denoting either an entrance or changes which are inserted into a system and which activate/modify a process.

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. A computer requires programs to function, typically executing the program's instructions in a central processor.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.

Response or output is the term denoting either an exit or changes which exit a system and which activate/modify a process. It is an abstract concept, used in the modeling, system(s) design and system(s) exploitation

2. 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.

In computing, a keyboard is a typewriter-style keyboard, which uses an arrangement of buttons or keys, to act as mechanical levers or electronic switches

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.

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.

 A telephone keypad is a keypad that appears on a "Touch Tone" telephone. It was standardised when the dual-tone multi-frequency system in the new push-button telephone was introduced in the 1960s, and replaced the rotary dial

3. Describe different mouse types and explain how to use a mouse?

Ans:

In computing, a mouse is a pointing device that functions by detecting two-dimensional motion relative to its supporting surface. Physically, a mouse consists of an object held under one of the user's hands, with one or more buttons. It sometimes features other elements, such as "wheels", which allow the user to perform various system-dependent operations, or extra buttons or features that can add more control or dimensional input. The mouse's motion typically translates into the motion of a cursor on a display, which allows for fine control of a graphical user interface.

Types:

Early mice

The trackball was invented by Tom Cranston, Fred Longstaff and Kenyon Taylor working on the Royal Canadian Navy's DATAR project in 1952. It used a standard Canadian five-pin bowling ball. It was not patented, as it was a secret military project

Mechanical mice

Operating an opto-mechanical mouse. moving the mouse turns the ball. X and Y rollers grip the ball and transfer movement Optical encoding disks include light holes. Infrared LEDs shine through the disks. Sensors gather light pulses to convert to X and Y vectors.

Bill English, builder of Engelbart's original mouse, invented the ball mouse in 1972 while working for Xerox PARC

Optical and Laser mice

A wireless optical mouse on a mouse pad

Main article: Optical mouse

Optical mice make use of one or more light-emitting diodes (LEDs) and an imaging array of photodiodes to detect movement relative to the underlying surface, rather than internal moving parts as does a mechanical mouse. A Laser mouse is an optical mouse that uses coherent (Laser) light.

Inertial and gyroscopic mice

Often called "air mice" since they do not require a surface to operate, inertial mice use a tuning fork or other accelerometer (US Patent 4787051) to detect rotary movement for every axis supported. The most common models (manufactured by Logitech and Gyration) work using 2 degrees of rotational freedom and are insensitive to spatial translation. The user requires only small wrist rotations to move the cursor, reducing user fatigue or "gorilla arm".

3D mice

Also known as bats, flying mice, or wands, these devices generally function through ultrasound and provide at least three degrees of freedom. Probably the best known example would be 3DConnexion/Logitech's SpaceMouse from the early 1990s.Tactile mice

In 2000, Logitech introduced the "tactile mouse", which contained a small actuator that made the mouse vibrate. Such a mouse can augment user-interfaces with haptic feedback, such as giving feedback when crossing a window boundary. To surf by touch requires the user to be able to feel depth or hardness; this ability was realized with the first electrorheological tactile mice but never marketed.

Connectivity and communication protocols

A Microsoft wireless Arc mouse

To transmit their input, typical cabled mice use a thin electrical cord terminating in a standard connector, such as RS-232C, PS/2, ADB or USB. Cordless mice instead transmit data via infrared radiation (see IrDA) or radio (including Bluetooth), although many such cordless interfaces are themselves connected through the aforementioned wired serial buses.

 Operation

A mouse typically controls the motion of a cursor in two dimensions in a graphical user interface (GUI). Clicking or hovering (stopping movement while the cursor is within the bounds of an area) can select files, programs or actions from a list of names, or (in graphical interfaces) through small images called "icons" and other elements. For example, a text file might be represented by a picture of a paper notebook, and clicking while the cursor hovers this icon might cause a text editing program to open the file in a window. (See also point-and-click)

Users can also employ mice gesturally; meaning that a stylized motion of the mouse cursor itself, called a "gesture", can issue a command or map to a specific action. For example, in a drawing program, moving the mouse in a rapid "x" motion over a shape might delete the shape.

Gestural interfaces occur more rarely than plain pointing-and-clicking; and people often find them more difficult to use, because they require finer motor-control from the user. However, a few gestural conventions have become widespread, including the drag-and-drop gesture, in which:

1. The user presses the mouse button while the mouse cursor hovers over an interface object
2. The user moves the cursor to a different location while holding the button down
3. The user releases the mouse button

For example, a user might drag-and-drop a picture representing a file onto a picture of a trash can, thus instructing the system to delete the file.

Other uses of the mouse's input occur commonly in special application-domains. In interactive three-dimensional graphics, the mouse's motion often translates directly into changes in the virtual camera's orientation. For example, in the first-person shooter genre of games (see below), players usually employ the mouse to control the direction in which the virtual player's "head" faces: moving the mouse up will cause the player to look up, revealing the view above the player's head. A related function makes an image of an object rotate, so that all sides can be examined.

When mice have more than one button, software may assign different functions to each button. Often, the primary (leftmost in a right-handed configuration) button on the mouse will select items, and the secondary (rightmost in a right-handed) button will bring up a menu of alternative actions applicable to that item. For example, on platforms with more than one button, the Mozilla web browser will follow a link in response to a primary button click, will bring up a contextual menu of alternative actions for that link in response to a secondary-button click, and will often open the link in a new tab or window in response to a click with the tertiary (middle) mouse button.

Different ways of operating the mouse cause specific things to happen in the GUI:

• Click: pressing and releasing a button.
• (left) Single-click: clicking the main button.
• (left) Double-click: clicking the button two times in quick succession counts as a different gesture than two separate single clicks.
• (left) Triple-click: clicking the button three times in quick succession.
• Right-click: clicking the secondary button.
• Middle-click: clicking the ternary button.
• Drag: pressing and holding a button, then moving the mouse without releasing. (Use the command "drag with the right mouse button" instead of just "drag" when you instruct a user to drag an object while holding the right mouse button down instead of the more commonly used left mouse button.)
• Button chording (a.k.a. Rocker navigation).
• Combination of right-click then left-click.
• Combination of left-click then right-click or keyboard letter.
• Combination of left or right-click and the mouse wheel.
• Clicking while holding down a modifier key.

Standard semantic gestures include:

• Rollover
• Selection
• Menu traversal
• Drag and drop
• Pointing
• Goal crossing

4. Describe varios types of touch screens and explain how a touch-sesitive pad works.

A touchscreen is an electronic visual display that can detect the presence and location of a touch within the display area. The term generally refers to touching the display of the device with a finger or hand. Touchscreens can also sense other passive objects, such as a stylus. Touchscreens are common in devices such as all-in-one computers, tablet computers, and smartphones.

Types of Screens

When you go for buying a new television or monitor for a computer, you come across different types of screens. Some are wide; some are compact, some other with flat screen or of green colour. The difference is because of the advancement in technology. Today, we have a lot of variety and we can go for the one which we like. A certain amount of knowledge is necessary for the selection of right screen. If you have some knowledge about these developments in screen technology, you can have better idea about different types of screens. There are different specifications attributed to each type of screen.

The major specification through which you can better judge the quality of screen is its black level. The higher level production of black color in screen shows that screen is of good quality. The screen with higher black level guarantees the sharp image.

Touch Screen Types

Touch screens appliances are selling like a hot cake now –a - days because of its easy use and availability in various sizes. Any display device with touch screen feature sell as it comes in the market. Although people appreciate and enjoy this amazing new feature yet most of them don’t know about different types of touch screen. Different types of technologies are used in the formation of touch screen. As technology experiments are going on to derive the best devices ever so is the case with touch screen.

Different types of touch screens have different feature, characteristics and differences. These differences are resulted in different qualities of touch screen; some are long life others are sensitive while some others are economic.
 

Resistive Touch screen

This type of touch screen is made up of three sheets;

• conductive
• resistive
• protective layer

The mechanism used in the resistive touch screen is pressure detector. It senses the pressure on a specific place and carried on the intended action. Resistive touch screen is made up of three layers. First layer is made up of conductive layer and second is sensitive layer. These layers are placed upon one another with a space on the glass and further coated with the indium tin oxide a resistant chemical to protect the screen from scratches. When pressure is applied on the screen or the system comes into operational condition current passes through it. In response to the pressure both layers strike with each other and current passes through the space, detects the pressure point by the operating system which resultantly carries out the command.