System 6.0.8 or System 7.0.1 disk images can be downloaded legally from Apple’s legacy FTP (for older versions) or from preservation sites. The Mini vMac emulator mounts .dsk or .image files via drag-and-drop. Start with DiskTools_Mac_6.0.8.dsk to partition a virtual hard drive.
In the 1980s and 90s, Apple stored core parts of the Macintosh Operating System (the Toolbox) on Read-Only Memory (ROM) mini vmac rom