AP Computer Science Principles Final Exam Review

Overflow

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

Round-off

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

Lossy

Compressing data in a way that throws some data away and makes it almost impossible to recover the original, great compression, like JPEG images

Lossless

Compressing data in a way that preserves all data away and allows full recovery of the original, good compression -- usually not as good as lossy, like PNG images

Metadata

data about data, like a camera storing the location, aperture, shutter speed, etc. for a digital photo

Sequencing

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

Selection

a boolean condition to determine which of two algorithmic paths are taken, aka if-then

Iteration

using a looping control structure, like while, for, foreach, repeat, repeat-until, etc.

Reasonable time

polynomial in the number of steps an algorithm takes in the worst case based on the input size

Not reasonable time

Usually exponential in the number of steps, like doubling every time your input grows by one

Heuristic

using a "rule" to guide an algorithm, like always walking toward the north star if you were stuck in a forest

Undecidable

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

Linear vs binary search

Going one by one vs starting in the middle and going left/right like looking for a word in the dictionary -- binary search requires the list to be sorted in order

APIs

Application Programming Interface, how you define libraries and call them

Public key encryption

is any cryptographic system that uses pairs of keys: public keys which may be disseminated widely, and private keys which are known only to the owner.

Domain names

an identification string that defines a realm of administrative autonomy, authority or control within the Internet.

IP addresses

is an identifier assigned to each computer and other device (e.g., printer, router, mobile device, etc.) connected to a TCP/IP network[1] that is used to locate and identify the node in communications with other nodes on the network

TCP/IP network

the conceptual model and set of communications protocols used on the Internet and similar computer networks. It is commonly known as TCP/IP because the original protocols in the suite are the Transmission Control Protocol (TCP) and the Internet Protocol (IP).

Data compression

involves encoding information using fewer bits than the original representation

Cloud services

is a type of Internet-based computing that provides shared computer processing resources and data to computers and other devices on demand

Intellectual property

Intellectual property (IP) refers to creations of the mind, such as inventions; literary and artistic works; designs; and symbols, names and images used in commerce.

Malware attacks

short for malicious software, is any software used to disrupt computer or mobile operations, gather sensitive information, gain access to private computer systems, or display unwanted advertising

Phishing

is the attempt to obtain sensitive information such as usernames, passwords, and credit card details (and, indirectly, money), often for malicious reasons, by disguising as a trustworthy entity in an electronic communication.

DDos Attack

denial-of-service attack (DoS attack) is a cyber-attack where the perpetrator seeks to make a machine or network resource unavailable to its intended users by temporarily or indefinitely disrupting services of a host connected to the Internet.

DNS Server

is a hierarchical decentralized naming system for computers, services, or other resources connected to the Internet or a private network.

Citizen Science

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

Cloud Computing

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

Crowdsourcing

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

Creative Commons

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

Open Access

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

Moore's Law

The # of transistors on a chip doubles every two years

Peer-to-peer networks

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

Digital divide

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