Episode 170 - Thoroughbred/OS

I'm back to normal episodes, and I'm running out the gate with a weird one. Thoroughbred/OS was a multi-user and multi-tasking operating system for the IBM PC. It's mian interface was... BASIC of all things! What exactly is this oddity?
winworldpc.com/product/thoroughbred-os/662 - Try Out Thoroughbred/OS yourself