Chapter 3

megabyte

(MB) is a unit for characterizing the amount of data. It is roughly 1 million bytes or, more precisely, 220 bytes, which is 1,048,576 bytes.

byte

8 bits

ASCII

American Standard Code for Information Interchange is a character encoding scheme in which each character is represented by a 7-bit (originally) or 8-bit binary sequence. For example, the ASCII sequence 01000001 represents the letter 'A'. is a code for representing English characters as numbers, with each letter assigned a number from 0 to 127.

Parity

In math, usually means the fact of being even or odd.

OCR

Optical character recognition is the process of reading text from paper and translating the images into a form that the computer can manipulate.

algorithm

a step-by-step procedures for solving a particular problem.

bitmap

a type of memory organization or image file format used to store digital images.

digital

any system based on discontinuous data or events. Computers are digital machines because at the basic level they can distinguish between just two values, 0 and 1.

bit

binary digit

spam

electronic junk mail or junk newsgroup postings.

parity bit

is a bit that acts as a check on a set of binary values, calculated in such a way that the number of 1s in the set plus it should always be even (even parity) or should always be odd (odd parity).

lossless compression

one in which no data are lost; the original data can be completely recovered.

lossy compression

one in which some data are lost; the original data cannot be completely restored.

megapixel

one million pixels, used in reference to the resolution of a graphics device.

analong

one that represents changing values as continuously variable physical quantities.

cloud computing

relies on sharing resources online on the Internet rather than having data and process located on a personal computer.

run length encoding

represents an image in terms of the lenght of runs of identical pixels

cryptography

secret writing. It is the science of protecting information by transforming it into an unreadable format.

pixel

short for 'picture element', is a single physical point in a raster image.

steganography

the art and science of hiding information by embedding messages within other, seemingly harmless messages.

even parity

the number of 1s in the sequence add up to an even number.

odd parity

the number of 1s in the sequence add up to an odd number.

render

the process of adding realism to a computer graphics by adding 3-D qualities, such as shadows and variations in color and shade.

modeling

the process of representing a real-world object of phenomenon as a set of mathematical equations.

raster

the rectangular area of a display screen actually being used to display images.

download

to copy data (usually an entire file) from an online source to a personal computer.

upload

to transmit data from a computer to an online repository or service such as a bulletin board service, or drop box, or network.