Computer Science Vocabulary

PDF

Portable Document Format

This is a file format developed by Adobe Systems in 1992. PDF captures formatting information from a variety of desktop publishing applications, making it possible to send formatted documents and have them appear on the recipient’s monitor or printer as they were intended. This is because a PDF will maintain the original fonts, images, graphics as well as the exact layout of the file.


Innovation
A novel or improved idea, device, product, etc, or the developement thereof.
Computer


A computer is a programmable machine. A computer responds to a specific set of instructions in a well-defined manner and executes pre recorded  instructions.

Server

A computer. A computer that awaits and responds to requests for data.

Example: a DNS server awaits and responds to requests for urls to be translated to IP addresses

internet
A groups of computers and servers that are connected to each other.
ISP:Internet Service Provider

An ISP is your gateway to the Internet and everything else you can do online; a company that provides subscribers access to the Internet.

ISP.    Examples:Verizon, ATT, Comcast, Time Warner, Cox,

 

Client

A computer that requests data stored on a server.

Example: When you type an address into your browser, your computer is the client and it sends the request to the DNS server.

 

Web Server

  1. A program that uses HTTP (Hypertext Transfer Protocol) to serve the files that form Web pages to users, in response to their request, which are forwarded by their computers’ HTTP clients.

  2. Dedicated computer and appliances may be referred to as a Web servers as well.

  3. Web servers are computers on the internet that deliver(store) web pages. Every web server has an IP address and possibly a domain.

File Server

 

A computer and storage device dedicated in storing files. Any user on the network can store files on the server.

Proxy Server
A server that sits between a client application, such as a web browser, and a real server. It intercepts all requests to the real server to see if it can fulfill the requests itself. If not, it forwards the request ot the real server.
Cloud Computing
The practice of using a network of remote servers from data centers all over the world  hosted on the Internet to store, manage, and process data, rather than a local server or a personal computer.
Cloud Server
Cloud server hosting is when hosting services are made available to customers on demand via the internet. Rather than being provided by a single server or virtual server, cloud server hosting services are provided by multiple connected servers that comprise a cloud
Application Server
A program that handles all application operations between users and an organization’s backend business applications or databases.
Dedicated Server

 

A single computer in a network reserved for serving the needs of the network. For example, some networks require that one computer be set aside to manage communications between all the other computers.

Print Server
A computer that manages one or more printers, and a network server is a computer that manages network traffic.
Database Server
A computer system that processes database queries.
Binary

A way of representing information using only two options, usually 0’s and 1’s.

Yes/No

True/False

Packets
Small chunks of information that have been carefully formed from larger chunks of information.
Protocal
A set of rules and standards used to communicate between machines.
HTTP
HyperText Transfer Protocol – the protocol used for transmitting web pages over the internet.
HTML
HTML HyperText Markup Language) is the language in which the content and formatting of a web page are written.
ASCII

 

American Standard Code for Information Interchange. ASCII is the university recognized raw text format that any computer can understand.

Net Neutriality
The principle that all Internet traffic should be treated equally by Internet Service Providers.
Bit
A contraction of “Binary Digit.” A bit is the single unit of information in a computer typically represented as 0 or 1.
Code (verb)
To write code, or to write instructions telling the computer what to do.
ITEF
Internet Engineering Task Force – Develops and promotes voluntary Internet standards and protocols, in particular the standards that comprise the Internet protocol suite.
ISOC
the Internet Society strives to make the world a better place.
URL
Uniform Resource Locator: An easy-to-remember address for calling a web page (like www.code.org).
Internet Protocal Stack
DNS, TCP, IP, and Physical Internet
DNS
Domain Server Name or Domain Name Service: The service that translates URLs to IP addresses
TCP/IP
Transmission Control Protocol – Provides reliable, ordered, and error-checked delivery of stream of packets in the internet. TCP is tightly lightly linked with IP and usually seen as TCP/IP in writing.
IP Address
A number assigned to any item that is connected to the Internet.
Router
A device that forwards data packets along networks. A router is connected to at least two networks and are located at gateways.
Latency Time
Time it takes for a bit to travel from its sender to its receiver
Bitrate
The number of bits that are conveyed or processed per unit of time.
Bandwidth
Transmission capacity measure by bit rate.
Bit
A contraction of “Binary Digit.” A bit is the single unit of information in a computer, typically represented as a 0 or 1.
Byte
A byte is a sequence of 8 bits processed as a single unit of information.
Why is a Byte 8 Bits?

A byte is 8 bits since it was used to refer to groups of 8-bits that a

computer was processing.

Heuristic
A problem solving approach (algorithm) to find a satisfactory solution where finding and optimal or exact solution is impractical or impossible
Lossless Compression
A data compression algorithm that allows the original data to be perfectly reconstructed from the
Abstraction
Reducing information to a simpler form, to remove some details to focus on essential characteristics. It is typically possible to look at a system at many levels of abstraction, depending on how many detail is necessary to approach the challenge at hand. To simplify things pulling out specific differences to make one solution work  for multiple problems.
File Sizes Bytes, KB, GB ,MB , TB
A byte is a sequence of 8 bits (enough to represent one alphanumeric character) processed as a single unit of information. A single letter or character would use one byte of memory (8 bits), two characters would use two bytes (16 bits).
fILE SIZES 2
Put another way, a bit is either an ‘on’ or an ‘off’ which is processed by a computer processor, we represent ‘on’ as ‘1’ and ‘off’ as ‘0’. 8 bits are known as a byte, and it is bytes which are used to pass our information in its basic form – characters.
File Size 3

A byte is a sequence of 8 bits (enough to represent one alphanumeric character) processed as a single unit of information. A single letter or character would use one byte of memory (8 bits), two characters would use two bytes (16 bits).


byte – A series of 8 binarybits that digitally represent a single character to the

computer.  Example:  00000001 = 1  Learn more here.


kilobyte – Approximately 1,000 bytes.  Learn more here.


megabyte – Approximately 1,000,000 bytes.  Learn more here.


gigabyte – Approximately 1,000,000,000 bytes.  Learn more here.

 

Internet Protocal Layers

DNS: Translates a URL into an IP address. Note that a DNS request still is conducted over TCP/IP


TCP: Breaks larger messages into multiple packets and ensures all packets are received and ordered correctly


IP: Assigns IP addresses to computers and routes packets of data to the correct address

The Physical Internet: copper wire, fiber, optic cable, radio waves, etc


Server
A computer that awaits and responds to requests for data. Example: a DNS server awaits and responds to requests for urls to be translated to IP addresses.
Client
A computer that requests data stored on a server. Example: When you type an address into your browser, your computer is the client and it sends the requests to the DNS server.
Lossy Compression
To save space, some information is thrown away
Resolution

The dimensions by which you can measure how many pixels are on a screen.

640 x 480

Metadata
Data the describs data. For example, a digital image may include metadata that describes the size of the image, number of colors, or resolution.
Pixel
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.
Hexadecimal Number System
A number system consisting of 16 distinct symbols – 0-9 and A-F – which can occur in each place value.
Favicon
Short for Favorite Icon
RGB
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.
Aggregation
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, Sum, Max, Min, Count. A Summary Table, Calculation Area.
Lossy Compression
(or irreversible compression) a data compression method that uses inexact approximations, discarding some data to represent the content. Most commonly seen in image formats like .jpg
Pivot Table
In spreadsheet software, it is the name of the tool used to create summary tables.
Summary Table
A table that shows the results of aggregations performed data from a larger data set
Boolean
A single value of either TRUE or FALSE
Boolean Expression
In programming, an expression that evaluates to TRUE or FALSE
Computationally Hard
A “hard” problem for a computer is one in which it cannot arrive at a solution in a reasonable amount of time.
Javascript

A programming language designed by Sun Microsystems that can be integrated into standard HTML pages to add some dynamic features.  

    Learn more here.

Event Handling
An  overarching term for the coding tasks involved in making a program respond to events by triggering functions.
UI Elements

On-screen objects, like buttons, images, text boxes, pull down menus, radio buttons, check boxes,  screens and so on.Input Controls: checkboxes, radio buttons, dropdown lists, list boxes, buttons, toggles, text fields, date field.

 

Expression
Any valid unit of code that resolves to a value.
Debugging
Finding and fixing problems in your algorithm or program.


==

The equality operator (sometimes read: “equal equal”) is used to compare two values, and returns to Boolean (true/false). Avoid confusion with the assignment operator “=”.
If- statement
The common programming structure that implements “conditional statements”.
Variable Scope
Dictates what portions of code can “see” or use a variable, typically derived from where the variable was first created. (See Global v. Local)
Conditionals
Statements that only run under certain conditions
Selection
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.
While Loop
A programming construct used to repeat a set of commands (loop) as long as (while) a boolean condition is true.
String
Any sequence of characters between quotation marks (ex: “hello”, “42”, “this is a string!”).
Event
Any sequence of characters between quotation marks (ex: “hello”, “42”, “this is a string!”).
Key Event
In JavaScript, an event triggered by pressing or releasing a key on the keyboard. For example: “keyup” and “keydown” are event types you can specify. Use event.key – from the “event” parameter of the onEvent callback function – to figure out which key was pressed.

Parameter

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

An extra piece of information that you pass to the function to customize it for a specific need.
Malmeter
Software that is intended to damage or disable computers, computer systems, and other software programs
For loop
A typical looping construct designed to make it easy to repeat a section of code using a counter variable. The loop combines the creation of a variable, a boolean looping condition, and an update to the variable in one statement.
Modulo
A mathematical operation that returns the remainder after integer division. Example: 7 MOD 4 = 3
Documentation
A description of the behavior of a command, function, library, API, etc
Canvas
A user interface element to use in HTML/JavaScript which acts as a digital canvas, allowing the programmatic drawing and manipulation of pixels, basic shapes, figures and images.
Moore’s law
A prediction made by Gordon Moore in 1965 that computing power will double every 1.2-2 years, it has remained more or less true ever since
Encryption
A process of encoding messages to keep them secret, so only :authorized” parties can read it.
Cracking Encryption
When you attempt to decode a secret message without knowing all the specifics of the cipher, you are trying to “crack” the encryption.
Public Key Encryption

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.


Assmmetric
Used in public key encryption, it is scheme in which the key to encrypt data is different from the key to decrypt.
loop
The action of doing something over and over again.
Cipher
The generic term for a technique (or algorithm) that performs encryption. In cryptography, a cipher (or cypher) is an algorithm for performing encryption or decryption—a series of well-defined steps that can be followed as a procedure. An alternative, less common term is encipherment. … When using a cipher the original information is known as plaintext, and the encrypted form as ciphertext.
Cipher Text
Ciphertext is encrypted text. Plaintext is what you have before encryption, and ciphertext is the encrypted result. The term cipher is sometimes used as a synonym for ciphertext, but it more properly means the method of encryption rather than the result
Ceaser cipher
A technique for encryption that shifts the alphabet by some number of characters
Random Substitution Cipher
An encryption technique that maps each letter of the alphabet to a randomly chosen other letters of the alphabet.
One Pager
A business/corporate term for one-page document that summarizes a large, topic or plan.
API
A collection of routines, protocols, and commands to help a programmer create software applications.
Library
A collection of commands/functions, typically with a shared purpose.
Decryptian
A process that reverses encryption, taking a secret message and reproducing the original plain text.
Function
A piece of code that you can easily call over and over again.
Selection
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 statement.
If-Statement
The common programming structure that implements “conditional statements”.
List
A generic term for a programming data structure that hold multiple items
Iterate
To repeat in order to achieve, or get closer to, a desired goal.
Conditionals
Statements that only run under certain conditions
Models And Simulations
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 and experiment in real life.
Event Listener
A command that can be set up to trigger a function when particular type of event occurs on a particular UI element.
Selection
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.
Global Variable
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.
Event Driven Program
A program designed to run blocks of code or functions in response to specified events (e.g. a mouse clock).
Local Variable
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.
Concatenent
To link together or join. Typically used when joining together text Strings in programming (e.g. “hello, “+name).
User Interface
The visual elements of an program through which a user controls or communications the application. Often abbreviated UI.
Data Type
All values in programming language have a “type” – such as a Number, Boolean, String – that dictates how the computer will interpret it. For example 7+5 is interpreted differently from “7” + “5”.
Variable
A placeholder for a piece of information that can change
Callback Function

 

A function specified as part of an event listener; it is written by the programmer but called by the system as the result of an event trigger.

 

Array
A data structure in JavaScript used to represent a list
Return Value
A value sent back by a function to the place in the code where the function was called from – typically asking for value (e.g. getText(id)) or the result of calculation or computation of some kind
Every Web Page Has its own URL

Examples

https://www.techterms.com

 

https://techterms.com/definition/internet

WIFI

Short for Wireless Fidelity, a way to connect to the Internet using radio waves to connect devices instead of using wires and cables.


Stands for “Wireless Fidelity” and it refers to wireless networking technology  that allows computers and other devices to communicate over a wireless signal.   

 

    Learn more here.


WiFi Hotspot
A location or spot where you can connect to a wireless network to the Internet.
Bluetooth

 

A wireless technology that enables communication between computer devices.  It is primarily used for short range connections.  Learn more here.

FiOS

 

Stands for “Fiber Optic Service” and it describes the use of fiber optic cables to transmit data via pulses of light.  Learn more here.

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