Nits: It's a Unix convention (not just Linux), and Unix traditionally ran on minicomputers (not mainframes). Mainframes had their own specialized OSes, although some could run Unix in a partition or virtual machine.
I think that "Linux ran on mainframes" was said in jest. Even though Linux runs on mainframes pretty well even now.
I think that "Linux ran on mainframes" was said in jest. Even though Linux runs on mainframes pretty well even now.