An input device is any device that puts data into a computer. One example of an input device is a keyboard, because it is used to input commands for the computer to follow.

An output device is a device that is capable of taking information from a computer and representing it visually or audibly.
A computer monitor would qualify as an output device because it gives a visual display of the information in a computer. For example, a word document is nothing but data on the computer’s hard drive, but the monitor displays it in a way that allows humans to read it with ease.

Processing is the act of performing operations on data, such as making a calculation with a set of numbers.

Storage is the capacity of a device to hold and retain data. Devices with larger storage are able to hold more data, and devices with smaller storage are not able to hold as much. Over the years, the amount of storage that devices have has increased at a phenomenal rate. In just thirty years, devices have gone from being able to store 128 bytes to 500 gigabytes.

RAM stands for Random Access Memory. It is a space where data is written so that it can be accessed by the CPU. It is only temporary, however, so once the computer is turned off, any information that was stored in RAM will disappear. Word processing documents such as Microsoft Word often store unsaved information in RAM.
ROM stands for Read Only Memory. Unlike RAM, ROM is permanent and cannot be removed. A computer’s ROM sector will typically contain information that is vital to the computer, such as what to do when the computer turns on, or what operating system to use.

ASCII stands for American Standard Code for Information Interchange. It is a standard code that is used for creating and encoding text documents so that they are viewable by any program. An ASCII text file will not contain any special embedded control characters. In ASCII, every number, letter, and symbol is assigned a special code, called an ASCII code. A capital A, for example, has an ASCII code of 65.
Because operating systems often are programmed very differently, programs may have varying degrees of compatibility when run on different operating systems. For example, there was a time when Microsoft Office was compatible with Windows, but did not run on Mac computers. Also, programs may experience compatibility issues with different versions of the same operating system. A program designed to work on Windows XP may not work well with a computer running Windows 95.

OCR is an acronym for Optical Character Recognition. It is the ability of a computer to recognize text that is printed on an image instead of an actual text file. An example of this is having a book scanned into a computer, and then having the computer be able to recognize the image as text. From then on, it is possible to edit the text with a word processor. In order for OCR to work, some sort of optical scanner is required to feed the images into the computer.

OMR stands for Optical Mark Recognition. It is technology which involves reading data from marked fields. An example of OMR is in an application form or voting ballot. The answers for the form are written down on the paper in a marked field with a pencil, and an optical scanner then reads whatever is printed in the field and interprets it before feeding the data into the computer. Another example of OMR is the bubbles on SAT tests. These bubbles are read by an optical scanner and fed into the computer.

Bar code is a way of representing the UPC, or Universal Product Code, so that it can be easily read by machines. The UPC is a 12 digit number assigned to products. It’s purpose is to identify the product and the product’s vendor. Bar code represents this code in a series of black and white bars, with the widths of the bars signifying individual digits in the UPC.

Peripheral is a type of computer hardware that is added to a host computer in order to expand its abilities. The term also tends to be applied to devices that are hooked up externally, typically through some form of computer bus like USB. Typical examples include joysticks, printers and scanners. Devices such as monitors and disk drives are not considered peripherals when they are not truly optional, and video capture cards are typically not referred to as peripheral because they are internal devices.

A firewall is an information technology (IT) security device which is configured to permit, deny or proxy data connections set and configured by the organization’s security policy. Firewalls can either be hardware and/or software based.

Malware (Malicious Software) is software designed to infiltrate or damage a computer system without the owner’s informed consent Many normal computer users are however still unfamiliar with the term, and most never use it. Instead, “(computer) virus” is used in common parlance and often in the general media to describe all kinds of malware.

A computer worm is a self-replicating computer program. It uses a network to send copies of itself to other systems and it may do so without any user intervention. Unlike a virus, it does not need to attach itself to an existing program. Worms always harm the network (if only by consuming bandwidth), whereas viruses always infect or corrupt files on a targeted computer.