Digital Research CP/M was the dominant operating system for personal computers aimed at business users from the late 1970s through to the mid 1980s. The machines usually had only floppy disks due to the high cost of hard drives at the time.
Antique - Burroughs Adding Machine
Seiko B&W TV Watch TR02-01 (1982, Japan)
Curta calculator, a marvelous contraption by any standards.