ZFOS is a DOS-like environment created in Scratch (TurboWarp.) It uses .zip files as virtual drives to store information. ZFOS also includes a BIOS menu to load drives and another menu to boot from drives.
To boot from an archive, it must have a BOOT.htm or BOOT.sb3 file in the root directory. ZFOS will then load the HTML file as an iframe or load the .sb3 file in the TurboWarp player.