a problem solving approach (algorithm) to find a satisfactory solution where finding an optimal or exact solution is impractical or impossible

a data compression algorithm that allows the original data to be perfectly reconstructed from the compressed data.

A type of data used for graphics or pictures

is data that describes other data. For example, a digital image my include metadata that describe the size of the image, number of colors, or resolution.

short for "picture element" it is the fundamental unit of a digital image, typically a tiny square or dot which contains a single point of color of a larger image

the RGB color model uses varying intensities of (R)ed, (G)reen, and (B)lue light are added together in to reproduce a broad array of colors.

a data compression method that uses inexact approximations, discarding some data to represent the content. Most commonly seen in image formats like .jpg.

Pulling out specific differences to make one solution work for multiple problems

a computation in which rows from a data set are grouped together and used to compute a single value of more significant meaning or measurement. Common aggregations include: Average, Count, Sum, Max, Median, etc.

in most spreadsheet software it is the name of the tool used to create summary tables.

a table that shows the results of aggregations performed on data from a larger data set, hence a "summary" of larger data. Spreadsheet software typically calls them "pivot tables"

A novel or improved idea, device, product, etc, or the development thereof.

A way of representing information using only two options.

A contraction of "Binary Digit". A bit is the single unit of information in a computer, typically represented as a 0 or 1.

Transmission capacity measure by bit rate

the number of bits that are conveyed or processed per unit of time. e.g. 8 bits/sec

Time it takes for a bit to travel from its sender to its receiver.

A set of rules governing the exchange or transmission of data between devices.

the universally recognized raw text format that any computer can understand

to write instructions for a computer.

develops and promotes voluntary Internet standards and protocols, in particular the standards that comprise the Internet protocol suite (TCP/IP).

A group of computers and servers that are connected to each other.

the principle that all Internet traffic should be treated equally by Internet Service Providers.

A number assigned to any item that is connected to the Internet.

Small chunks of information that have been carefully formed from larger chunks of information.

provides reliable, ordered, and error-checked delivery of a stream of packets on the internet. TCP is tightly linked with IP and usually seen as TCP/IP in writing.

The service that translates URLs to IP addresses.

the protocol used for transmitting web pages over the Internet

An easy-to-remember address for calling a web page (like www.code.org).

A precise sequence of instructions for processes that can be executed by a computer

A piece of code that you can easily call over and over again

a collection of commands made available to a programmer

a description of the behavior of a command, function, library, API, etc.

a collection of commands / functions, typically with a shared purpose

An extra piece of information that you pass to the function to customize it for a specific need.

A particular kind of looping construct provided in many languages. Typically, a for loop defines a counting variable that is checked and incremented on each iteration in order to loop a specific number of times.

The action of doing something over and over again.

a predication made by Gordon Moore in 1965 that computing power will double every 1.5-2 years, it has remained more or less true ever since.

a technique for encryption that shifts the alphabet by some number of characters

the generic term for a technique (or algorithm) that performs encryption

When you attempt to decode a secret message without knowing all the specifics of the cipher, you are trying to "crack" the encryption.

a process that reverses encryption, taking a secret message and reproducing the original plain text

a process of encoding messages to keep them secret, so only "authorized" parties can read it.

an encryption technique that maps each letter of the alphabet to a randomly chosen other letters of the alphabet.

a "hard' problem for a computer is one in which it cannot arrive at a solution in a reasonable amount of time.

used in public key encryption, it is scheme in which the key to encrypt data is different from the key to decrypt.

a mathematical operation that returns the remainder after integer division. Example: 7 MOD 4 = 3

In an asymmetric encryption scheme the decryption key is kept private and never shared, so only the intended recipient has the ability to decrypt a message that has been encrypted with a public key.

Used prevalently on the web, it allows for secure messages to be sent between parties without having to agree on, or share, a secret key. It uses an asymmetric encryption scheme in which the encryption key is made public, but the decryption key is kept private.

An action that causes something to happen.

a program designed to run blocks of code or functions in response to specified events (e.g. a mouse click)

an overarching term for the coding tasks involved in making a program respond to events by triggering functions.

a command that can be set up to trigger a function when a particular type of event occurs on a particular UI element.

The visual elements of an program through which a user controls or communications the application. Often abbreviated UI.

on-screen objects, like buttons, images, text boxes, pull down menus, screens and so on.

Finding and fixing problems in your algorithm or program.

All values in a programming language have a "type" - such as a Number, Boolean, or String - that dictates how the computer will interpret it. For example 7+5 is interpreted differently from "7"+"5"

Any valid unit of code that resolves to a value.

A placeholder for a piece of information that can change.

A variable whose scope is "global" to the program, it can be used and updated by any part of the code. Its global scope is typically derived from the variable being declared (created) outside of any function, object, or method.

The common programming structure that implements "conditional statements".

A variable with local scope is one that can only be seen, used and updated by code within the same scope. Typically this means the variable was declared (created) inside a function -- includes function parameter variables.

dictates what portions of the code can "see" or use a variable, typically derived from where the variable was first created. (See Global v. Local)

to link together or join. Typically used when joining together text Strings in programming (e.g. "Hello, "+name)

Any sequence of characters between quotation marks (ex: "hello", "42", "this is a string!").

Statements that only run under certain conditions

A generic term for a type of programming statement (usually an if-statement) that uses a Boolean condition to determine, or select, whether or not to run a certain block of statements.

A single value of either TRUE or FALSE

in programming, an expression that evaluates to True or False.

To repeat in order to achieve, or get closer to, a desired goal.

a programming construct used to repeat a set of commands (loop) as long as (while) a boolean condition is true

a program which replicates or mimics key features of a real world event in order to investigate its behavior without the cost, time, or danger of running an experiment in real life.

A data structure in JavaScript or Java used to represent a list.

A generic term for a programming data structure that holds multiple items

A typical looping construct designed to make it easy to repeat a section of code using a counter variable. The for loop combines the creation of a variable, a boolean looping condition, and an update to the variable in one statement.

A value sent back by a function to the place in the code where the function was called form - typically asking for value (e.g. getText(id)) or the result of a calculation or computation of some kind. Most programming languages have many built-in functions that return values, but you can also write your own.

A computer that awaits and responds to requests for data

See image

A computer that requests data stored on a server

See image

a piece of code that is capable of copying itself and typically has a detrimental effect, such as corrupting the system or destroying data.

the fraudulent practice of sending emails purporting to be from reputable companies in order to induce individuals to reveal personal information, such as passwords and credit card numbers.

attack where multiple compromised systems, which are often infected with a Trojan, are used to target a single system causing a Denial of Service attack.

1000 bytes

1000 KB or 1,000,000 bytes

1000 MB or a billion bytes

1000 GB or a trillion bytes

1000 TB or a quadrillion bytes

1000 PB a quintillion bytes (10^18)

commonly used method of lossy compression for digital images

a raster graphics file format that supports lossless data compression

bitmap image format using lossless data compressin

8 bits

error that results when the number of bits is not enough to hold the number, like a car's odometer "rolling over"

error that results when the number of bits is not enough to represent the actual number, like 3 digits to represent π as 3.14

code flows line by line, one after another, like a recipe

A problem that is so difficult, we can't ever create an algorithm that would be able to answer yes or no for all inputs, like determining if a user's program run on some input would always stop and not run forever

Lots of people to help with a scientific project, like asking everyone around the world to count the butterflies they see one day

Using distributed calculations and/or storage for big data or a web application

Asking lots of users online to help with something, like funding a project, or running SETI@Home to help look for extraterrestrial signals

An alternative to copyright that allows people to declare how they want their artistic creations to be shared, remixed, used in noncommercial contexts, and how the policy should propagate with remixed versions

A policy that allows people to have read access to things, e.g., libraries or online data

A system where one user's computer connects through the Internet to another user's computer without going through an intermediary "centralized" computer to manage the connection

The idea that some communities / populations have less access to computing than others