Build a Blockchain and a Cryptocurrency from Scratch

A container is an application packaged together with the libraries and configuration it needs, run as an isolated process on a host that is already switched on, so the same package behaves the same way on a laptop, in a build pipeline and in production.

Object storage keeps every file as a self-contained object (the bytes, a unique key and some metadata) inside a flat bucket you read and write over HTTP, with no drive to mount and no directory tree underneath it.

Kubernetes is an open-source system that runs containers across a cluster of machines, keeping the number and placement of running copies matched to a declared desired state, and restarting, rescheduling and scaling them without a person intervening.

Caching keeps the result of expensive work, such as a rendered page or a database query, and serves that stored copy until it expires, making it the largest single source of speed on any busy website.

Uptime is the proportion of time a service answers requests, quoted in nines, and a service level agreement is the contract clause setting out how that proportion is counted and what the provider owes when it falls short.

Shared hosting puts your website on a machine that is simultaneously running hundreds of other people's, pooling its processor, memory and disk between all of you, which is both why it costs so little and why your speed partly depends on strangers.

Object-oriented programming is a way of organising a program as objects, each holding its own data and the operations allowed on it, with classes as the templates objects are made from, so that the code models the things it is about rather than the steps the computer takes.

Data structures are the ways a program arranges data in memory (arrays, lists, hash tables, trees, graphs) and algorithms are the step-by-step procedures that work on them; together they decide whether an operation takes a millisecond or an hour as the data grows.

Python is a general-purpose programming language that became the standard interface for driving numerical and machine-learning code written in other languages.