Web Systems Overview and LAMP Stack Introduction

Vocabulary flashcards covering core web systems concepts, client-server architecture, and the four layers of the LAMP stack.

Client

The program requesting a web resource — almost always a browser, running on a user's own device.

Server

A program (and, informally, the machine running it) that receives requests and sends back responses.

Request-response cycle

The complete back-and-forth exchange between client and server, from the moment a request is sent to the moment a response is received.

HTTP

HyperText Transfer Protocol; the agreed-upon shared language that browsers and servers use to make requests and send responses.

Front End

Everything that runs inside the user's browser on their own device, including user interfaces, layouts, buttons, and interactive client-side code.

Back End

Everything that runs on the server out of the user's sight before a response is sent back to the browser.

LAMP

An acronym for a widely used open-source web stack consisting of Linux, Apache, MySQL, and PHP.

Linux

The open-source operating system layer of the LAMP stack that manages server hardware resources such as memory, processing power, file storage, and network connections.

Apache

The web server software in the LAMP stack that listens for incoming requests and either serves files directly or hands requests off to PHP.

MySQL

The database management system in the LAMP stack that organizes structured data into tables, giving a web system persistent memory.

PHP

A server-side scripting language in the LAMP stack that executes logic, interacts with MySQL, processes input, and constructs dynamic responses before they are sent to the client.

Server-side

Processing that happens on the server before a response is sent to the client, entirely out of the visitor's sight and reach.

Separation of concerns

A design principle in which each component of a system handles one specific responsibility so components can be maintained, replaced, or upgraded independently.