See https://www.youtube.com/watch?v=TpHKygZ7OHY https://www.youtube.com/watch?v=TpHKygZ7OHY CP/M 1.0 was demoed to Intel in 1974, but they didn't buy it. iCOM

See https://www.youtube.com/watch?v=TpHKygZ7OHY https://www.youtube.com/watch?v=TpHKygZ7OHY CP/M 1.0 was demoed to Intel in 1974, but they didn't buy it. iCOM FDOS was the first operating system that was available to people, and it sure didn't have environment variables. Anyway, these operating systems didn't have multiple directories. But you could use CP/M 2.x's ASSIGN command to bind a logical name to a physical name. Minicomputer operating systems had this, also IBM mainframe had JCL DD commands.