Raspberry Pi uses Linus as an operating system,

Raspberry Pi is a popular platform for hobbyists like you and me.

https://www.google.com/search?q=what+operating+system+does+raspberry+pi+use&rlz=1C1IHCB_enUS722US729&oq=which+operatibg+system+does+ra&aqs=chrome.2.69i57j0i22i30l7j0i390l2.24009j0j4&sourceid=chrome&ie=UTF-8

Linux

 

The Raspberry Pi operates in the open source ecosystem: it runs Linux (a variety of distributions), and its main supported operating system, Pi OS, is open source and runs a suite of open source software.

The other one is Arduino.

 

https://www.amazon.com/Learn-Robotics-Raspberry-Pi-Thinking/dp/1593279205/?_encoding=UTF8&pd_rd_w=mNHKS&content-id=amzn1.sym.bc5f3394-3b4c-4031-8ac0-18107ac75816&pf_rd_p=bc5f3394-3b4c-4031-8ac0-18107ac75816&pf_rd_r=W0H1CP11V2Y5R3PJGZJF&pd_rd_wg=agiJK&pd_rd_r=946e2968-57e0-48a4-8519-936c34089c3d&ref_=pd_gw_ci_mcx_mr_hp_atf_m