1.Define Input and differentite 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. 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).
Input may refer to:

• Advice (opinion), an opinion or recommendation offered as a guide to action, conduct.
• Information, any data entered into a computer or data processing system, see input output
• The act of entering data into a computer or data processing system (see Input/output).
• Input device, any peripheral (piece of computer hardware equipment) used to provide data and control signals to an information processing system (such as a computer)
• Stimulus (physiology), a detectable change in the environment that influences an activity of an organism
• Power consumption, an amount of power used by a system.
• International Public Television Screening Conference, an international public television organization
• In economics, a factor of production, a resource employed to produce goods and services.

           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.^[1] A computer requires programs to function, typically executing the program's instructions in a central processor.^[2] 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.
Computer source code is often written by computer programmers. Source code is written in a programming language that usually follows one of two main paradigms: imperative or declarative programming. Source code may be converted into an executable file (sometimes called an executable program or a binary) by a compiler and later executed by a central processing unit. Alternatively, computer programs may be executed with the aid of an interpreter, or may be embedded directly into hardware.
Computer programs may be categorized along functional lines: system software and application software. Two or more computer programs may run simultaneously on one computer, a process known as multitasking.

•            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. Specifically, the term command is used in imperative computer languages. These languages are called this, because statements in these languages are usually written in a manner similar to the imperative mood used in many natural languages. If one views a statement in an imperative language as being like a sentence in a natural language, then a command is generally like a verb in such a language.

Many programs allow specially formatted arguments, known as flags, which modify the default behaviour of the command, while further arguments describe what the command acts on. Comparing to a natural language: the flags are adverbs, whilst the other arguments are objects.

             User Response may refer to:

• Response (liturgy), a line answering a versicle
• Response (music) or antiphon, a response to a psalm or other part of a religious service
• Output or response, the result of telecommunications input
• Response, a phase in emergency management
• The second half of the stimulus-response relationship in psychology

2.    Identify the keys and buttons commonly found on desktop computer keyboards,and describe  now     keyboards for mobile computers and devices differ from desktop computer keyboards?

 

  There is no differences in terms of key arrangement but the desktop keyboard is separated from the system unit while the mobile keyboard is built in.

 

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

1.   Mechanical mouse: Houses a hard rubber ball that rolls as the mouse is moved. Sensors inside the mouse body detect the movement and translate it into information that the computer interprets.

• Optical mouse: Uses an LED sensor to detect tabletop movement and then sends off that information to the computer for merry munching.

•   Infrared (IR) or radio frequency cordless mouse: With both these types, the mouse relays a signal to a base station wired to the computer's mouse port. The cordless mouse requires power, which comes in the form of batteries.

• A mouse with many buttons: The extra buttons can be programmed to do specific things, such as navigate the Web or turn pages when you’re reading a document. The typical button-ified mouse has about five buttons.

• Trackball mouse: Like an upside-down mouse. Rather than roll the mouse around, you use your thumb or index finger to roll a ball on top of the mouse. The whole contraption stays stationary, so it doesn’t need a lot of room, and its cord never gets tangled.

• Stylus mouse: Another mouse mutation enjoyed by the artistic type is the stylus mouse, which looks like a pen and draws on a special pad.

• Cordless 3-D mouse: This kind of mouse can be pointed at the computer screen like a TV remote.

4. Describe various types of touch screens and explain how a touch-sensitive   pad works?

Three Types of Touch Screen 

·             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.