Process And Processor

Process

In computing, a process is an instance of a computer program that is being executed. It contains the program code and its current activity. Depending on the operating system (OS), a process may be made up of multiple threads of execution that execute instructions concurrently.
A computer program is a passive collection of instructions; a process is the actual execution of those instructions. Several processes may be associated with the same program; for example, opening up several instances of the same program often means more than one process is being executed.
Multitasking is a method to allow multiple processes to share processors (CPUs) and other system resources. Each CPU executes a single task at a time. However, multitasking allows each processor to switch between tasks that are being executed without having to wait for each task to finish. Depending on the operating system implementation, switches could be performed when tasks perform input/output operations, when a task indicates that it can be switched, or on hardware interrupts.
A common form of multitasking is time-sharing. Time-sharing is a method to allow fast response for interactive user applications. In time-sharing systems, context switches are performed rapidly. This makes it seem like multiple processes are being executed simultaneously on the same processor. The execution of multiple processes seemingly simultaneously is called concurrency.
For security and reliability reasons most modern operating systems prevent direct communication between independent processes, providing strictly mediated and controlled inter-process communication functionality.

Processor

A processor is the logic circuitry that responds to and processes the basic instructions that drive a computer.
The term processor has generally replaced the term central processing unit (CPU). The processor in a personal computer or embedded in small devices is often called a microprocessor.

Output Devices

Output device

An output device is any piece of computer hardware equipment used to communicate the results of data processing carried out by an information processing system (such as a computer) to the outside world.

In computing, input/output, or I/O, refers to the communication between an information processing system (such as a computer), and the outside world. Inputs are the signals or data sent to the system, and outputs are the signals or data sent by the system to the outside.

 

  Output Devices

Output devices are things we use to get information OUT of a computer.

Here are some examples of output devices.

Monitor - A monitor is the screen on which words, numbers, and graphics can be seem.  The monitor is the most common output device.
Compact Disk - Some compact disks can be used to put information on.  This is called burning information to a CD. NOTE:  A CD can also be an input device.
Printer - A printer prints whatever is on the monitor onto paper.  Printers can print words, numbers, or pictures.
Speaker - A speaker gives you sound output from your computer.  Some speakers are built into the computer and some are separate.
Floppy Disk - A floppy disk is used to record information on.  The information is stored on the floppy disk and can be used later or used on another computer.
Headphones - Headphones give sound output from the computer.  They are similar to speakers, except they are worn on the ears so only one person can hear the output at a time.

Input Devices

Input devices

In computing, an input device is any peripheral (piece of computer hardware equipment) used to provide data and control signals to an information processing system such as a computer or other information appliance. Input and output devices make up the hardware interface between a computer and a scanner or 6DOF controller.

 

Input Devices

Input devices are things we use to put information INTO a computer.

Here are some examples of input devices.

Note:  An APPLICATION is a type of computer program.
Some applications are word processing, spreadsheets, databases, and games.

Camera - most cameras like this are used during live conversations.  The camera transmits a picture from one computer to another, or can be used to record a short video.
Compact Disc (CD) - CDs store information.  The CD can then be put into another computer, and the information can be opened and added or used on the second computer. Note:  A CD-R or CD-RW can also be used as an OUTPUT device.
Keyboard - The keyboard is a way to input letters or numbers into different applications or programs.  A keyboard also has special keys that help operate the computer.
Mouse - The mouse is used to open and close files, navigate web sites, and click on a lot of commands (to tell the computer what to do) when using different applications.
Digital Camera - A digital camera can be used to take pictures.  It can be hooked up to a computer to transfer the pictures from the camera to the computer.  Some digital cameras hold a floppy disk, and the floppy disk can be taken out of the camera and put directly into the computer.
Drawing Tablet - A drawing tablet is similar to a white board, except you use a special pen to write on it and it's connected to the computer.  Then the word or image you draw can be saved on the computer.
Microphone - A microphone is used to record sound.  The sound is then saved as a sound file on the computer.
Scanner - A scanner is used to copy pictures or other things and save them as files on the computer.
Disk Drive - A disk drive can hold a CD or a floppy disk.  It reads the information on the disk so that the computer can use it.
Joystick - A joystick is used to move the cursor from place to place, and to click on various items in programs.  A joystick is used mostly for computer games.
Touch Screen - A touch screen is a computer screen or other screen that you can touch with your finger to enter information.  Examples of touch screens include a smart board, a microwave, a dishwasher, or an ATM at a bank.
Bar Code Scanner - A bar code scanner scans a little label that has a bar code on it.  The information is then saved on the computer.  Bar code scanners are used in libraries a lot.

Computer System

A computer system in contemporary usage refers to a desktop system, including the computer itself (aka "The CPU" or "The Box") and all the peripheral devices needed to operate it, usually including:


The computer, usually mounted in a tower (vertical) case, including components: the CPU or central processing unit; a mother board or mainboard, including a BIOS; A graphics card; a sound card (often build onboard, ie. into the mainboard), a variety of disk ports to serve hard drives, disk drives and optical drives, a variety of peripheral ports, including USB ports, legacy serial and parallel ports, legacy psx, and SCSI; and LAN ports, either ethernet or firewire. A hard drive (sometimes more) is included for long-term data storage. The case also contains a transformer power supply and a number of fans to keep the internal components cool while operating.

A monitor, typically either a CRT or an LCD flatscreen.
A set of speakers to hear sound.
A keyboard, typically a standard 104-key QWERTY keyboard.
A mouse, typically a three button mouse with scroll wheel.

Other peripherals can be added to the system to augment its functionality. Common ones include:



A wi-fi adapter to connect to wireless networks.
A bluetooth adapter to connect to wireless peripherals.
A modem for a direct connection to an internet service provider.
A printer to produce (paper) hardcopy
A scanner to input data from hardcopy

all these pieces, pulled together comprise a personal computer system.