“Raspberry Pi OS[3] (formerly Raspbian) is a Debian-based Linux distribution operating system for Raspberry Pi. Since 2015 it has been officially provided by the Raspberry Pi Foundation as the primary operating system for the Raspberry Pi family of compact single-board computers.[4] The first version of Raspbian was created by Mike Thompson and Peter Green as an independent project.[5] The initial build was completed in June 2012.[6]
Previous Raspberry Pi OS versions were 32bit only and based on Debian, taking the name Raspbian. Since the more recent 64bit versions no longer use Debian, the name was changed to Raspberry Pi OS for both the 64bit and 32bit versions. As of 1 February 2021, the 64-bit version is in beta and is not suitable for general use.[7] [8]
Raspberry Pi OS is highly optimized for the Raspberry Pi line of compact single-board computers with ARM CPUs. It runs on every Raspberry Pi except the Pico microcontroller. Raspberry Pi OS uses a modified LXDE as its desktop environment with the Openbox stacking window manager, along with a unique theme. The distribution is shipped with a copy of the algebra program Wolfram Mathematica[4] and a version of Minecraft called Minecraft: Pi Edition, as well as a lightweight version of the Chromium web browser.”
(WP)