[robert-brown]

Photoshop was ported to IRIX using Latitude, Quorum Software's implementation of Mac OS System 7. Apple later acquired the Quorum's code and it became part of Carbon.

[anthk]

There's System 7 for Unix 'natively', with either Executor (there's a fork under Github) or some other project: https://www.v68k.org/advanced-mac-substitute/

https://github.com/autc04/executor

https://github.com/jjuran/metamage_1/