Computer Science Key Concepts: Algorithms, Programming, and Networks

abstraction

a technique or process that manages complexity in a program or computer system. Abstraction "hides" details or removes duplication, allowing the programmer to focus on high-level considerations and functions rather than the rules of a programming language.

algorithm

a set of steps to accomplish a specific task. An algorithm can be expressed in many kinds of notation, such as programming or natural language, pseudocode, and flowcharts. Algorithms are essential to the way computers process data because they contain the specific instructions for what a computer or program does.

algorithmic thinking

the process of solving problems by identifying the tasks required to solve a problem and using algorithms to clearly describe each task

application

a program run by the operating system to meet particular needs of a user

block of code

program statements that are grouped together, denoted by indentation

bug

part of a program that causes an error or undesired output

code segment

a collection of program statements that is part of a program

code statement

a part of a program code that expresses an action to be carried out

collaboration

the action of two or more people working together through idea sharing to accomplish a common goal

comment

a note in a program that describes what the code is doing. Adding comments is good programming practice because it helps others understand the code, especially when working on code with other people.

event

associated with an action and supplies input data to a program. Can be generated when a key is pressed, a mouse is clicked, a program is started, or by any other defined action that affects the flow of execution.

input

data that are sent to a computer for processing by a program. Can come in a variety of forms, such as tactile interaction, audio, visuals, or text.

output

any data that are sent from a program to a device. Can come in a variety of forms, such as tactile interaction, audio, visuals, or text.

program

a collection of program statements. Programs run (or "execute") one command at a time.

analog

a continuous method of representing information

bandwidth

the maximum amount of data that can be sent in a fixed amount of time, usually measured in bits per second

binary

a base-2 numeral system that represents all numbers, using only the two digits 0 and 1

bit

a single unit of binary consisting of only one place whose value can be 0 or 1

byte

eight bits, able to represent 256 distinct values (abbreviated "b")

computer network

a group of interconnected computing devices capable of sending or receiving data

computer system

a group of computing devices and programs working together for a common purpose

computing device

a physical artifact that can run a program. Some examples include computers, tablets, servers, routers, and smart sensors.

Domain Name System (DNS)

the system responsible for translating domain names like example.com into IP addresses.

fault tolerant

can continue to function even in the event of individual component failures. This is important because elements of complex systems like a computer network fail at unexpected times, often in groups.

Internet Protocol (IP)

a protocol for sending data across the Internet that assigns unique numbers (IP addresses) to each connected device.

IP address

the unique number assigned to each device on the Internet.

packet

a chunk of data sent over a network. Larger messages are divided into packets that may arrive at the destination in order, out-of-order, or not at all.

protocol

an agreed-upon set of rules that specify the behavior of some system.

redundancy

the inclusion of extra components so that a system can continue to work even if individual components fail, for example by having more than one path between any two connected devices in a network.

router

a type of computer that forwards data across a network.

Transmission Control Protocol (TCP)

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.