TIL my USB 1.1 floppy disc drive works OK on High Sierra. I may have a job getting data off an old (1995) Mac that has a 1.44 MB FD & 2 x CD-ROM drive plus an IDE HDD.
Very likely the old machine won't boot, usually because the (horribly expensive) 4.5 v battery is flat. Some of the Macs in my collection have an adapted battery, it's the original battery's circuit board connector soldered onto a 2 x AAA & a 1 x AAA battery holder so 3 x AAA cells can provide the required power.