What is the Backend?
INFO 153B/253B: Backend Web Architecture
Kay Ashaolu
First, lets talk about the World Wide Web
- What is the Web?
- What happens when you go to a site like Pinterest.com?
- What happens "behind the scenes" after you click on a link?
What is the Web?
The World Wide Web, or simply web, is a way of accessing information over the medium of the internet.
What is the Internet?
The internet is a global computer network providing a variety of information and communication facilities, consisting of interconnected networks using standardized communication protocols.
The Web is built on Composable Parts
- Internet - How data gets from one network to another
- Network Stack - How data gets from one computer to another
- Servers - One (of many) destinations data goes to
- JSON/XML/Binary/HTML - One (of many) representations of data transmitted over the web
Highway vs Railway
Highway: Simple and Composable
- Any machine with wheels can use it
- Cars can drive on any highway, but also off-road
- Motorcycles and trucks can use roads as well as highways
- Uncoordinated
Railway: Complicated but Efficient
- Must have the right track gauge
- Must coordinate with other traffic
- If you upgrade one part of the system, everything else must be upgraded
- Need specially made vehicles for railway
The Internet is like a Highway
- More like an interconnected large set of highways
- It’s the longest running computer system in the world
- Protocols (UPS) are agnostic of their content (packages)
- Pieces can be upgraded incrementally
Protocols
- A protocol is a system of rules of transmitting data
- UPS has a system of trucks and vans that get packages from one place to another
- Data is delivered to a destination (browsers, mobile app, other backend services)
- Just like packages deliver to a destination (address)
- Data can be interpreted, and used as information
- Like packages can be appreciated in a number of different ways
Where does the data go?
- Browsers: powers the web front end applications that you use on your computers/mobile phones
- Mobile apps: powers the apps that are on your phone
- Internet connected devices: powers the functionality that these devices provide (e.g. Amazon Alexa)
Where does the data go?
- Web Servers: sends data to web browsers to power the UI that you view
- Application Servers: Provides a service to other servers (e.g. saving data to a database)
- Data Pipeline Clusters: Provides big data processing as a service (e.g. find out how many people hit pinterest.com this year)
What is the Backend?
A back-end developer builds and maintains the technology that powers those components which, together, enable the user-facing side of the website to even exist in the first place.
What is the Frontend?
The front end of a website is the part that users interact with. Everything that you see when you’re navigating around the Internet, from fonts and colors to dropdown menus and sliders, is a combo of HTML, CSS, and JavaScript being controlled by your computer’s browser.
We will be learning about the Backend in this class
- Focusing on Application Servers, Web Servers, Data Pipeline Clusters, and other aspects of Backend web development