You can use Mastodon on many retro computer systems:
Apple II - https://www.colino.net/wordpress/en/mastodon-for-apple-ii
Apple Macintosh (pre-OS X) - https://github.com/smallsco/macstodon
Commodore 64 - https://github.com/Havoc6502/MOStodon
Commodore Amiga - https://github.com/BlitterStudio/amidon
MS-DOS - https://github.com/SuperIlu/DOStodon
MVS - https://github.com/mainframed/BREXXTODON
Palm OS - https://github.com/knickish/heffalump
Windows 95 - https://github.com/meyskens/mastodon-for-workgroups