1. Define input and differentiate among a program, command and 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.
- A computer program (also a software program, or just a program) is a sequence of instructionscomputer. A computer requires programs to function, typically executing the program's instructions in a central processor. The program has an executable form that the computer can use directly to execute the instructions. The same program in its human-readable source code form, from which executable programs are derived (e.g., compiled), enables a programmer to study and develop its algorithms. written to perform a specified task for a
- 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.
2. Identify the keys and buttons commonly found in the desktop computer keyboards, and describe keyboards for mobile computers and devices differ from desktop computer keyboard.
For desktop computers with separate keyboards, when you don’t like the layout or when you find some keys are in an uncomfortable place in the keyboard, it’s easy to change and buy another keyboard.
For laptops or notebooks however, you can’t do that. You’re stuck with how the keys are situated or laid out. So how do we fix that?
Fortunately for Windows users (Windows NT/2000/XP/Vista/ Win 7), you just need to install Key Tweak Jurassic. Key Tweak is technically a keyboard remapper which is absolutely free to download and use. You can interchange keys, change the assignment of several keys or change the layout of the whole keyboard if you want.
A mobile computer keyboard is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator. In contrast, the batch processing or time-sharing models allowed large expensive mainframe systems to be used by many people, usually at the same time. Large data processing systems require a full-time staff to operate efficiently.
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. Following the decline of punch cards and paper tape, interaction via teletype-style keyboards became the main input device for computers.Despite the development of alternative input devices, such as the mouse, touchscreen, pen devices, character recognition and voice recognition, the keyboard remains the most commonly used and most versatile device used for direct (human) input into computers. created by Travis
For desktop computers with separate keyboards, when you don’t like the layout or when you find some keys are in an uncomfortable place in the keyboard, it’s easy to change and buy another keyboard.
For laptops or notebooks however, you can’t do that. You’re stuck with how the keys are situated or laid out. So how do we fix that?
Fortunately for Windows users (Windows NT/2000/XP/Vista/ Win 7), you just need to install Key Tweak Jurassic. Key Tweak is technically a keyboard remapper which is absolutely free to download and use. You can interchange keys, change the assignment of several keys or change the layout of the whole keyboard if you want.
A mobile computer keyboard is any general-purpose computer whose size, capabilities, and original sales price make it useful for individuals, and which is intended to be operated directly by an end-user with no intervening computer operator. In contrast, the batch processing or time-sharing models allowed large expensive mainframe systems to be used by many people, usually at the same time. Large data processing systems require a full-time staff to operate efficiently.
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. Following the decline of punch cards and paper tape, interaction via teletype-style keyboards became the main input device for computers.Despite the development of alternative input devices, such as the mouse, touchscreen, pen devices, character recognition and voice recognition, the keyboard remains the most commonly used and most versatile device used for direct (human) input into computers. created by Travis
3. Describe different mouse types and explain how to use a mouse.
The first type of mouse which was released was the mechanical mouse, which is also called the ball mouse. It is called like that because has a small rubber ball underneath it and when you moved the ball, the information was transmitted to the computer and in return, the cursor moved as well.
The optical mouse is another type of computer mouse. This type replaced the rubber ball with an LED light and when the light moved across the mouse pad the cursor moved as well. This type of mouse, just like the mechanical one, requires certain mouse pads in order to work effectively. The optical mouse still needs certain maintenance but not as often as the mechanical one.
The laser mouse is another type of computer mouse. This one is very similar to the optical mouse the only difference being that instead of an LED it uses a laser. This one is the most sensitive mouse-style data up to this point and it is great for gaming and other activities. The benefit of this mouse is the fact that it uses less power than the other types.
The first type of mouse which was released was the mechanical mouse, which is also called the ball mouse. It is called like that because has a small rubber ball underneath it and when you moved the ball, the information was transmitted to the computer and in return, the cursor moved as well.
The optical mouse is another type of computer mouse. This type replaced the rubber ball with an LED light and when the light moved across the mouse pad the cursor moved as well. This type of mouse, just like the mechanical one, requires certain mouse pads in order to work effectively. The optical mouse still needs certain maintenance but not as often as the mechanical one.
The laser mouse is another type of computer mouse. This one is very similar to the optical mouse the only difference being that instead of an LED it uses a laser. This one is the most sensitive mouse-style data up to this point and it is great for gaming and other activities. The benefit of this mouse is the fact that it uses less power than the other types.
 This is the way I hold the mouse when I'm at the computer. I'm actually right handed, but I use my left hand for the mouse. |  If you hold the mouse with a right hand. |
I keep my finger on the left button. To single click I gently press down and then release the mouse button.To double click, I quickly press the button twice in a row. I keep my finger resting on the button, I do not take my finger off while double clicking. I've seen people raise their finger up to click or double click. For clicking that works, but for double clicking it is easier to leave your finger on the button and press down twice.To drag, I press the mouse button down, and keep it down. Then I move the mouse. In some programs you drag and drop items. You first click on the object you want to drag, hold the mouse button down, and then drag the object to some location. Now you release the mouse button and the object is in a new location.
4. Describe various types of touch screens and explain how a touch-sensitive pad works.
1. Resistive Touchscreen:
cheap and resistant to water and dust, but they get easily scratched and cannot be used with sharp objects. You can use any object to touch it, for instance finger, stylus, etc. You need to apply a bit of pressure in order to press the touchscreen. They have a good lifespan of about 35 million clicks.
The screen is basically of two layers and there’s a small plastic dots layer between the two layers. Electricity is supplied through each one of the layers and in the event of contact, a chain is formed. The amount of the electricity, passing between the layers is then measured, in order to determine the point of touch. The biggest con of these type of touchscreens is that it can’t recognize two touches at the same moment. In addition to this they are more prone to damages and the sensitivity reduces when it gets scratched. Moreover only 85% of the light emitted by the screen is let out.
Examples of Resistive touchscreens: HTC diamond, LG Viewty
2. Capacitive touchscreen:
Capacitive touchscreens are basically of two types- one that can recognize multiple touches simultaneously and the other which cannot. These type of touchscreens are costlier than the resistive types. They are scratch, moisture and dust-proof.
This type of touchscreen employs just one layer known as grid. It’s covered with an electroconductive material which provides continuous current with a certain frequency. When screen is touched with an object emitting a constant electric flow, for example a human finger (the human body generates electricity), a change in the current occurs and that’s how the contact point is determined.
It has an extremely long life of about 225 million clicks. In addition to this it lets through about 92% of the light emitted by the screen. There’s one serious disadvantage- it can’t be touched with just any object that you may like.
Examples of Capacitive touchscreens: Apple iPhone, LG Prada, Samsung F480
3. Infrared touchscreens:
Infrared touchscreens are the most expensive of the all the three mentioned here. It doesn’t require physical force, just a gentle touch is enough. In addition to this it is not influenced by dust, moisture or scratches. Moreover it’s the most durable compared to the other ones. They are basically of two types: optical and heat-sensitive.
This optical type uses infrared beams, which are not visible to the human eye. It works, using a number of sensors, arranged above and around the screen, forming a grid of invisible beams. If an object (finger or a stylus) touches the display, it interrupts the rays in a certain area and thus the touch point is determined. It has a lifespan of about 7 years. It suffers from a serious disadvantage- a strong ambient light can have a negative impact on its productivity.
The heat-sensitive type is the widely used one, but it is rarely used in screens. It is applied in other components of mobile devices like buttons. The best examples are Samsung SGH-E900 and Samsung U600, which can only be touched with warm objects. It suffers from one serious drawback- If your finger is frozen in winter and you touch this phone it won’t respond to your finger as its cold.
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